What to Discuss When Meeting with an Architect and an Energy Consultant
Hi all,
thanks for taking the time to read my post. I appreciate the thoughtfulness and insights you all have
goal: pretty good house
I live in Nashville, climate zone 4. We are due to be meeting with our architect in the next few weeks. They are finishing up general layout which is starting to look pretty good. Our leed architect had previously worked with a nashville based energy consulting company called E3 Innovate and recommended them. I am excited to hear their thoughts.
I have been thinking about how to direct the conversation but feel very much out of my depth. I have learned a great deal from the site and will be planning to talk about the issues below.
Just as a reference, this is a 5000 conditoned square foot home. 7000 square feet under roof. Custom home Building costs here start around $200/sqft and up from there. We are trying to keep the total cost under 250/sqft
my request: please add more actionable items I should discuss with the team.
1. Rainscreen system.
2. Exterior rigid foam insulation (if possible)
3. Air sealing details. Planning on zip sheathing air barrier. blower door scores goals and how to best reach them.
4. Hot water heating system. Prefer HP but family is interested in tankless. will otherwise keep everything except electric except stove.
5. Crawlspace encapsulation. Need to pay attention to air sealing details here for sure.
6. Attic. There will be ductwork there, so would like to keep it conditioned. Possibly spray foam (which will be very very expensive id imagine due to complexity of the roof). Alternatively, we could do the persist house method where we sheath the walls and roof in one continuous air barrier. Not sure about the details here.
7. Solar panel installation
8. Hvac design. E3 offers manual j, s, d. Previously, I thought I would have a third party designer like energy vanguard, but might be easier to have one energy co take the lead. Family is not interested in mini splits. They don’t like the look of them.
9. ERV/HRV design
10. Insulation: would prefer to use cellulose given its cheaper and environmentally friendly. Mineral wool is second. Spray foam in attic if needed.
11. I am desperately trying to convince fam to not have a fireplace. We have had in our home for 7 years and haven’t used it. I am trying to convince fam to forego the fireplace, build a fake decorative non functioning fireplace. If I lose that battle I will plan for non vented gas fireplace which is certain to never be used.
12. windows. Will try to get good enough triple pane windows with argon. Not the best, most expensive windows, but a good value fiberglass or alum clad window with decent U values.
13. any other low hanging fruits I should add?
That’s all I have so far. Please add more ideas. I am desperately trying to avoid being one of “those” McMansions with terrible energy and efficiency details Martin is always talking about…
thanks for your help.
Amer
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Replies
1 Why a rain screen? Do you live in a rain forest? If this detail is unfamiliar to your builder they will greatly pad the bids the cover the learning curve.
2. Exterior rigid foam insulation (if possible) I think you would be better served by picking an R value for the walls and price all the options that meet your goals.
3. Air sealing details. The question is how low do you want to go and are you willing to pay for the time to get the details right?
My opinion when you get much under 1 ACH you will need a ventilation system depending on how many sqf per person the house will have.
4. Hot water heating system. The way I see it this system put a bulls eye on your project it says to every bidder on this project money is no object add 20%. This option without any markup more than doubles the HVAC systems costs assuming you will need AC and heat.
5. Crawlspace encapsulation. I see these words as the language of slime ball salesman and best avoided. What you want is a conditioned crawlspace.
6. Attic. There will be ductwork there. In my opinion that is stupid the only reason to put ductwork in the attic is because someone is not going to pay the electric bill (IE production builder) Someone is lazy to make a workable plan that is how everyone dos it. You do understand conditioning the attic make the surface area of the thermal envelope at least 25% larger so all the HVAC equipment will be 25% larger and use 25% more fuel? A conditioned attic is only slightly better than a vented attic full of ducts. If you can’t find the courage to say no to stupid go buy a completed home and don’t build one.
11. Non vented gas fireplace = stupid! Do not do it.
12. Windows. This is a major budget item. In zone 4 my guess is triple pane windows will never save enough energy to repay their cost.
13. Keep your ceiling flat and covered in fluffy insulation.
13.Say no to any plumbing in exterior walls notably shower valves.
13.Build a computer model of your home using BEopt enter your local costs per sqf and select the best value option. This is a 20-40 hour commitment to watch the training videos and learn the software.
https://beopt.nrel.gov/home
13.Note architect’s can all too easily draw up plans you can afford to build if you give them half a chance. Then what are you going to do wad up your dreams and start over?
13.You did not talk much about money but all the stuff we love on this site adds lots costs to the bids and the banks appraiser will not see a dimes worth of value in any of it. In short if you need /want a constriction loan it will not happen without 50% of the builds cost in cash up front.
Walta
Walter,
Thank you for your response! You have a very direct way of putting things.
1. Rainscreen. What I really mean is an air gap. I really did want to make sure this was included in the plans. As Martin mentioned, this is a great way to reduce risk on any wall.
2. Exterior insulation. I like the idea of setting a goal and having the builder figure out how to get there. Let’s say I pick R30. Even if the builder uses 6 inches of MW in the stud bays, that brings me to R24. And that’s not even whole wall R30. We are getting killed by thermal bridging. So without exterior insulation, my only option would be a Mooney wall situation or Lavardera USA wall. This would be cheaper than doing a double stud wall.
3. Air sealing. Code here is 3 ACH 50. I’d like to be under that. Under 1.5 would be wonderful. How much extra cost does this actually add to the build in your opinion?
4. Hot water. Right, I think my preferred option would heat pumper water heater. My family is pushing for tankless because they hate the thought of running out of hot water.
Can you clarify why this doubles the HVAC costs?
5. Attic. I will ask the architect to bring the ducts into the conditioned space of the home. The second floor ceilings are mostly 9 feet tall. Would having ducts running through that reduce the height substantially?
I like the thought of bringing the ducts into the house for the additional reason of reducing cost of conditioning the attic and not expanding the thermal envelope. Another option I had read about was plenum trusses which can help me essentially create a chase for the ducts in the attic. This would be a good workaround I imagine. Any thoughts on this setup? This would bring the ducts in conditioned space without expanding the space by 25%
6. Fireplace. Agreed. Would prefer to not have one in the house. We actually planned real wood burning FP in the screened porch. However, family is asking for one, despite NEVER having used the one we have in the house currently! Anyway, I think that getting a non vented gas FP might be a good compromise in that they get a fireplace and are happy. I’ll be happy because we didn’t punch big holes in the thermal envelope and know they will hardly if ever use it.
7. Crawlspace. Got it. Will make sure to call it conditioned Crawl
8. Windows. I agree there will likely never be a good payback ROI on the triple pane windows. I’ve read Martin’s articles on how the fanciest triple panes don’t save that much extra money. So I was planning on nonfancy triple panes. We have lots of windows in the house, might be a better deal to put in double panes and more PV panels instead.
9. Will say no to plumbing in exterior walls
10. Money. I am prepared for the possibility of construction loan coming up short. We got some money under the mattress.
11. I am going to have cathedral ceilings. Question is if I use spray foam on cathedral ceilings, can the remainder of my roof still be vented and I can put fluffy stuff on the attic floor? I remember Martin pointing out that vented attics only work in simple gable roofs. This is not a simple roof.
It’s interesting building a house. All the good stuff that should be standard costs a fair amount of extra money. It’s like going to the grocery store and trying to make healthy selections. Organic eggs cost 4x regular eggs. Organic milk cost 3x as much. It’s cheaper to just eat at McDonalds daily!
Moreover, if you think to ask for the extra stuff, that automatically brings out the sharks and bullseye targets and everyone wants to take their extra pound of flesh.
In any case, thanks for the ideas! Keep them coming!
Amer
I will answer what I'm familiar with:
2- Exterior rigid foam is always possible, but can complicate certain trim details. You need to use AT LEAST the minimum amount required for your climate zone. You can use as much more than that as you want, keeping in mind that over 2" is considered "thick", and over 3" can add a lot of complexity. I would go with polyiso here, not XPS or EPS. Seal the perimeter of the polyiso to the framing with polyurethane caulk, which will help with air sealing. You MAY be able to use the taped foil face of the polyiso as your WRB in your rainscreen, but many don't like to do that. I'd wait for those here more familiar with rainscreens to comment on that before suggesting it.
4- Don't go with a tankless water heater if you're trying to be all electric. Tankless should either be natural gas or don't go with a tankless at all. Electric tankless hot water heaters represent a HUGE intermittent load and generally don't play nice with the electric grid, and they also require a BIG electric service even though they will rarely actually be using power since they only run when there is hot water demand.
5- There are lots of good articles on GBA about how to do this. I'd try to go for a full basement though, or at least a partial basement so that you'd have a place for mechanicals. This will help you keep your ductwork out of the attic, which leads us to...
6- DON'T put ductwork and mechanicals in the attic! If you don't have any mechanicals up there, you can easily insulate with blown cellulose on the attic floor, which is not only probably the cheapest way to insulate but also one of the best ways to do it. If you have mechanicals up there, then you really need to bring the attic into the building envelope, which means insulating the roof line. That's much harder to do than insulating the floor. Maintenance on mechanicals in the attic is also a lot more difficult.
7- If you have a big enough lot, the best way to install solar panels is on a frame separate from the house. This eliminates any issues with the roof. If you can't do that, You'll want to allow for some hard points to be installed in the roof to anchor the solar panels too, which means coordinating with the solar contractor so that you know where those hard points need to be located.
8- Remember that if that "energy co" is a mechanical contractor, they are well known for oversizing air conditioning systems so be careful. A third party like Energy Vanguard that specializes in OPTIMIZING systems is a better choice. A third party will also have no incentive to sell you a bigger unit than you need. I'd also be sure to zone a system in this large of a home. The simplest is to put living and sleeping spaces on separate zones, but it may make sense to do more than that depending on your floorplan and what you're trying to achive.
10- Spray foam should be thought of as a niche product. It's great for unvented cathedral ceilings, and it's great for rim joists. It's wasted in walls, and anywhere there is framing that will provide thermal bridges but could be insulated with more conventional means (read that as "reserve spray foam in regular areas to only those areas where conventional insulation would be very difficult to install properly". High density fiberglass batts are physically more similar to mineral wool, but they're cheaper and might be an option if you need to cut costs somewhere. I prefer mineral wool myself, but I've used both.
11- If they want a high-end home, they'll probably want a fireplace. You can get fireplaces with sealed combustion chambers that use outside air, and those are probably your best bet in terms of energy efficiency, but they have issues too. I keep covers on the interior vents of mine most of the time, and the gas shut off since I rarely (almost never) use it. If your client demands a conventional fireplace, try to find a damper that seals well as that's about the best you can do.
12- I'd go with fiberglass, and full-thickness 1-3/8" triple panes if you go that route. 7/8" triple panes add much of the cost with little of the benefit of the thicker triple panes. You'll probably have more options from the Canadian manufacturers for these, the major US manufacturers don't have as many options with triple pane glazing in my experience. I personally have liked working with Inline, which is near Pearson airport outside of Toronto, but there are other manufacturers up there in the frozen North that also have good reputations. Consider LoE-i89 too for maximum performance.
13- You may be able to save some copper costs by using multiple subpanels scattered around the house instead of running home runs back to the main electric panel for every circuit. The subpanels make it easier to meet volt drop requirements on distant runs, and usually allow for some load aggregation too which means less overall copper use in the design. You can save money by using aluminum feeders to those subpanels too, but if you do that I'd be sure to require compression lugs for all connections and I'd disallow the use a dieless crimp tool for those lugs. Make sure that's in your bid documents -- the dieless crimp tools are prone to causing fracturing of the barrel of compression lugs. If you don't really need to pinch your pennies, I'd stick with copper wiring throughout.
Providing for electric car charges might be something your client would be interested in. If they don't want that now, it's probably worth prewiring for one for the future. It's much easier and cheaper to add that now than to do a retrofit later.
If they will want a backup generator, plan your gas and electric service entrances so that the generator needs a minimum of both piping and wiring for connection to those services. This will keep costs down and will also minimize the use of materials. If you use CSST for the gas lines, WATCH YOUR CONTRACTORS -- a lot of people install it incorrectly with far to tight of bends which is dangerous. Most areas require the CSST tubing to be bonded to the building electrical ground too. I personally would stick with black iron pipe as much as possible as it's safer in the long term. I spec "gimme the green stuff" (silly name, good product) pipe dope for all gas fittings, I do not allow the use of pipe tape. This again is for safety.
Be careful with your laundry area(s) and venting. The same goes for bathroom exhaust fans. You want rigid duct only, no flex, and you want runs as straight as possible. Be sure the exhaust vents are in areas that will allow the humid air to get sucked into soffit vents or anywhere else it could get into the attic.
Hopefully that will give you something to get started. I'm sure you'll get some other good suggestions here.
Bill
Bill,
Thanks for taking the time to post your response. I really appreciate it.
I wanted to mention I am the owner of the house in question. I am not a building person of any kind. My experience here is pretty much nil, so I appreciate all the advice.
1. Exterior insulation. I agree with trying to use 2 inches of polyiso here. (I think code minimum is R-5 for exterior insulation here). Good point about caulking the polyiso perimeter. That’s a great tip! I will be sure to add an air gap in front of polyiso for water shedding.
Of course this will all be moot if i can’t find a contractor to agree to do exterior rigid foam
2. Tankless. I had read indeed tankless can take huge draws and need extra electrical work to set up. I would love to scrap the tankless and put in heat pump water heater. Given their concern about not having water for showers or waiting too long for shower hot water, I saw that I can install a point of use 10 gallon hot water tank. This would be a good compromise
3. I have been thinking about a basement to house the mechanical equipment. Would a partial basement be substantially more expensive than crawlspace? I had just assumed a basement adds complexity, cost, time. Crawls would be cheaper. But perhaps with all the conditioning costs of the crawlspace, they may become equivalent.
4. After reading Walters comments above, I will definitely talk to the architect to see what we can do about keeping the ductwork in the conditioned envelope. The problem I see is because of the cathedral ceilings, the remainder of the attic may not be able to be vented because of the complex roof.
7. Solar framing separate from the roof is a great idea. The lot is about an acre in size but unfortunately has lots of mature trees we are unwilling to cut down. I would imagine we’d need about 30 panels. I had really hoped Tesla solar roofs would be available in Nashville soon but it doesn’t look like it’s gonna work out
8. Interesting point about energy consulting company. I had hoped to use energy vanguard, but I was tempted to use E3 innovate because they could help with other things like the building envelope, energy modeling, etc. but I can’t tell from their
Website if they do mechanical work and have an interest in selling me a larger system. Will look into this a little closer
9. Windows. Great point about the window specs. I had not looked at inline windows. I had checked out alpen, Marvin, Loewen websites. Will opt for something thicker panes distance as you mentioned.
Unfortunately with the pandemic I can’t walk into showrooms and look at the windows firsthand which stinks because I know u factors and SHGC and LoE have their place, but windows can be a very subjective thing.
10. I will have to look up information about the sub panel setup. I understood too little of that comment
Will definitely plan for electric car charging. Already drive a hybrid. Next car will be plug in hybrid or full electric depending on how much this house costs!
11. I really do not want a backup generator. But given Nashville’s propensity for tornadoes, bad storms, and apparently bombings, this may be an idea we would consider. Rather than buying an 8k generator, I would be more Inclined to buy solar batteries that get used all the time rather than generator that gets used once a year.
12. Good point about bathroom Vents. I am trying to convince wife about the benefits of heat pump dryers which appear to be non vented
Bill, thanks very much again for your help. I appreciate your thoughts.
Amer
Couple points to consider/reconsider...
You mention a complicated roof line...why not uncomplicate that now in the design phase? Complex roofs cost more, leak more, and are sooooo trendy that they'll look dated soon. Keep it simple, keep it clean, keep it timeless and save some money.
Mini splits don't have to be wall mounted. You can use ceiling cassettes that are far less obtrusive. This also has the potential to solve your ducts in the attic issue as you won't need the ducts.
As budget realities start to intrude on green wishlist you may want to check out https://www.prettygoodhouse.org
Andy,
Thank you for posting. I will definitely try to have the roofline simplified as much as possible. The persistent problem is gonna be the cathedral ceilings. We can see what the architect has to say about simplifying the roof.
I’ll look at those ceiling cassettes and see how they are received. Are those typically ducted? Or non ducted? Do I lose a lot of efficiency with ceiling cassettes as opposed to wall mounts?
For item 3, journal of light construction, April 2018 had an article on air sealing using Huber Zip. Specify an ach of at least 1.
For item 4, look at an air to water heat pump that can do your domestic hot water, heating, cooling and dehumidification, have your architect look at warmboard. Hire an independent HVAC designer who know space pak, chiltrix, Artic heat pumps, etc. my carpenters installed the warmboard and the plumber connected the pex tubing.
Hire energy vanguard for the manual j and the entire HVAC design, good ventilation is important. You want an independent review.
Read building science corporation ba1005 report they pretty much address the insulation questions.
For fireplaces, look at an electric fireplace as an option.
William,
Thank your posting your thoughts. I appreciate it.
I’ll find that article. I like the idea of using zip, but I like your idea of having a specific goal of 1 ach even better
I think I must have used the wrong terminolgu above. We are not planning on using “hydronic” heating like warmboard. When I mentioned water heating above I meant regular domestic water heating with electric resistance or heat pump
Water heater. Because of the confusion, I’m wondering if I need to go back and read a few more article on water heaters. I don’t want to confuse my architect
Fireplace. Interesting. I had not even thought of an electric fireplace. Will see how they are received.
I’ll check out the article. Thanks for the reference. Thanks for your time.
Amer
Lots of good comments already. For your sake, I hope that the cost of quality construction around Nashville is lower than New Jersey.
$/sq. ft. is an incredibly reductive metric and hard to use as a guide, but I cannot imagine getting anything close to quality construction and materials for $200/sq. ft. anywhere. Labor costs vary widely across the country, but material costs do not. You're contemplating a lot of expensive details and will have to make some very hard decisions.
I'd personally consider a smaller house, but that's just me.
Patrick,
I hope so! I don’t know what things cost in NJ, but in Nashville, our lot 1 acre lot cost a little over 500k. And while it’s gorgeous, it’s in a crummy school district! So I just handed myself a bill for private school tuition as well.
We are in quite a bubble in Nashville. The housing market is hot. People are buying 1 acre lots in the city for 5-800k. Developers are then splitting the lots and putting tall and skinny homes as fast as they can put em together.
I would anticipate that which ever builder I go with is not gonna be happy with the headaches I cause for him. It’s much easier and profitable to build a million dollar spec home with average details!
Yeah, the decisions regarding cost will not be easy. Atleast we don’t have tiles imported from Tuscany or stone work from Mediterranean or something ridiculous.
Agree about the smaller house. But we have extended families that like to visit and stay for a bit. My current house at 3000 sqft feels small when they are here.
Amer,
I personally believe it's difficult to take 'just any design' (especially a 'MacMansion') and then try to make it a high performance home. The high performance elements really need to be integrated into the design.
The appearance (elevations), roof line, window design, number of corners, framing elements, ductwork, utility room location, orientation, overhangs, shading etc. must all be thought out with high-performance/ proper building science in mind at the beginning. I think this is best achieved with an architect and builder that have experience designing high performance homes. Special praise should be reserved for these people as striking the balance between Function, Durability, Efficiency and Beauty is not easy.
Also, consider reading the book 'Get Your House Right'. If this book were required reading for all architects then Macmansions would go the way of the Passenger Pigeon.
Rick,
I appreciate your thoughts. It would be ideal to make decisions in this manner where the design goals reflected the end goal of a high efficiency home.
Unfortunately, there were lots of things we wanted that have energy penalties. Large house, two story great room, bonus room over garage, cathedral ceilings in main, guest, and kids bedroom.
The best we can hope to do is mitigate the damage from our design. As Walter mentioned, I didn’t have the “courage” to say no to some of the stupid things I wanted!
I will be trying to incorporate the large overhangs in the rear south facing sections of the house. We have tried hard to reduce the number of corners and make as much of a rectangle as possible. Again, compromises were made.
I wish I had a little more time. I’ll check out that book get your house right on Amazon.
Thanks for your help!
Amer
Kudos for wanting to do better than the average where you are. To be clear, though the Pretty Good House movement is largely an open-source concept, people sometimes think it just means doing a little better than typical with insulation and air-sealing. A Pretty Good House also needs to be reasonably small, simple, built with low-carbon materials as much as possible, and other things that a 7,000 sq.ft. house with a lot of windows and a complicated roofline simply can't be. It sounds like you are aiming for reasonably high energy performance, and considering indoor air quality. Those are good goals.
1. Rainscreen system.
>In most climates, with most assemblies, the most under-rated building science development in the last 20 years. It does require understanding concepts that most builders and home designers still aren't familiar with, so tread carefully. There are lots of details on this site and at Fine Homebuilding.
2. Exterior rigid foam insulation (if possible)
>Often the lowest-cost way to improve energy performance. Some risk of moisture accumulation if not designed and built properly. XPS foam is a potent greenhouse gas and should be avoided. Choose recycled foam if possible because all foam insulation comes with larger carbon footprints than alternative approaches.
3. Air sealing details. Planning on zip sheathing air barrier. blower door scores goals and how to best reach them.
>Travis Brungardt, Kansas City-area builder and co-host of The BS + Beer Show, likes to say, "caulking and caring, taping and trying." It's not rocket surgery--just find the leaks and plug them while they are still accessible. To find the leaks you need to use a blower door. Zip sheathing system works well as an air control layer--just pay attention to transitions to other materials.
4. Hot water heating system. Prefer HP but family is interested in tankless. will otherwise keep everything except electric except stove.
>Tankless water heaters are usually energy hogs compared to tank-style units. The exception is when the home is only occupied occasionally. With a house that large, and a climate that mild, I would not consider anything other than a heat pump water heater. (Pretty Good Houses don't burn fossil fuels on site unless there is no reasonable option.)
5. Crawlspace encapsulation. Need to pay attention to air sealing details here for sure.
>Good approach. I find it easiest to insulate the interior with Thermax polyiso, which can remain exposed in most cases.
6. Attic. There will be ductwork there, so would like to keep it conditioned. Possibly spray foam (which will be very very expensive id imagine due to complexity of the roof). Alternatively, we could do the persist house method where we sheath the walls and roof in one continuous air barrier. Not sure about the details here.
>Not just expensive to spray foam, but huge, unnecessary carbon emissions too. Consider using plenum trusses for your ductwork and loose-blown insulation above that.
7. Solar panel installation
>Good to plan for. Does TN have good net metering rules?
8. Hvac design. E3 offers manual j, s, d. Previously, I thought I would have a third party designer like energy vanguard, but might be easier to have one energy co take the lead. Family is not interested in mini splits. They don’t like the look of them.
>I prefer third party engineering unless the HVAC company is known for high performance systems.
9. ERV/HRV design
>Important, the "V" in HVAC. Have the same engineer design all systems. Just make sure they don't try to get you to combine them in the same ductwork.
10. Insulation: would prefer to use cellulose given its cheaper and environmentally friendly. Mineral wool is second. Spray foam in attic if needed.
>Spray foam is only necessary above grade when proper planning doesn't take place.
11. I am desperately trying to convince fam to not have a fireplace. We have had in our home for 7 years and haven’t used it. I am trying to convince fam to forego the fireplace, build a fake decorative non functioning fireplace. If I lose that battle I will plan for non vented gas fireplace which is certain to never be used.
>Under no circumstances should you (or anyone) install an unvented gas fireplace. Watch our recent BS + Beer Show about combustion appliances.
12. windows. Will try to get good enough triple pane windows with argon. Not the best, most expensive windows, but a good value fiberglass or alum clad window with decent U values.
>I wouldn't think about double pane vs triple pane, but look for a low U-factor. I use a simple energy model to determine what U-factor and SHGC makes sense for each project. A couple of hours with BEOpt (a free download from the DOE) allows you to make an informed decision, not a guess.
13. any other low hanging fruits I should add?
>Energy modeling helps with not just window selection but fine-tuning all of the homes' systems, including the enclosure. If you don't want to teach yourself, pay someone to help you. You're planning to spend well over a million dollars on this house, which will be around for decades or more--invest in getting it right.
Michael,
Thanks for posting your thoughts! That’s a lot to digest.
1. Rainscreen system. Agreed. Once I saw this detail, my thought was of course we should have this! All builders should be doing this. This is not controversial and should not be earning me higher bids reflexively.
2. Insulation. With the caveat that I can find someone to do exterior insulation, I would love to use recycled insulation. I think Dana Dorsett had previously put up a link to a company called insulation depot that I could try to use.
3. Air sealing. Indeed, we will hopefully be using zip sheathing. I am open to using plywood and taping seams, but then we have to separately install the air barrier. If zip is easier to fool proof I would rather use that. I am also planning on using blower door scores to do air sealing. We will see how that plays out.
4. Crawlspace. Do you prefer to condition the crawlspace by thermax on the inside? I am not sure of the details, but if we can do exterior insulation, wouldn’t it be preferable to use exterior polyiso? That way rim joists are covered etc. or do I have that wrong? Alternatively if I can’t get exterior rigid foam done, I will have the contractor do polyiso in the crawlspace. Good ideas.
5. hPWH. Will try to convince fam about this and use multiple smaller 10 gallon point of use tanks so we don’t have long wait times, don’t run out of hot water, pay recirculating system penalties. Since we are planning to do solar anyway, I’d really prefer this system over a gas setup
6. Plenum trusses. Will investigate and discuss. I love this idea. We originally designed a second floor hvac room with plenum trusses in mind so we could have duct work traveling in conditioned spaces. So this is definitely on the table. Plenum trusses have size limitations correct? If I’m thinking about vented attic and doing fluffy insulation, I need raised heel trusses also. Can I add both of these trusses?
7. Hvac. I agree, I’m not sold on E3 doing the hvac work, but I like the idea of keeping everything in one place with one company. I may still reach out to energy vanguard and have them do the hvac duct work design etc
ERV. Roger that. Will make sure they don’t try to piggy back the ducts.
8. Solar. No, TN is terrible for solar. No net metering. But, we are not looking at this as strictly ROI. We can afford to splurge here and since it’s good for the environment, saving on coal and nuclear power, that’s a bonus. I know it doesn’t make sense for us financially. Especially once we add a battery.
9. Spray foam. Will try to avoid. Am trying to head it off now that I have decided not to seal the entire attic off. Hopefully plenum trusses plan works out.
10. Fireplace. Preaching to the choir.
11. Windows: I’ll take a look at beoopt. I’ve sort of been avoiding that because I’m bad with computers. Will try to learn. It’s amusing because I work in science based tech heavy industry.
12. Will check on energy modeling.
Thanks for taking the time to write these pointers down, Michael. I really appreciate it.
Best,
Amer
You're welcome! In your climate, Zip should be an excellent choice for sheathing. I get nervous about it here in Maine (zone 6) when there is not enough exterior insulation to protect against moisture accumulation, but with a bit of exterior foam you shouldn't have that problem.
I prefer to insulate the interior of basements and crawlspaces because concrete is a great exterior material, the embodied carbon in interior foam vs. exterior foam or mineral wool is minor, and it's easier to get a continuous thermal control layer when insulating the interior, where we need to insulate below slabs as well. Exterior insulation requires parging or another material over the insulation, and you will likely have a thermal bridge at the footing. I often inset my rim joist and cover it with rigid insulation, or spray foam the interior with HFO-blown foam.
Michael,
Sorry to bend your ear again. I have been thinking about backup plans if builder won’t do exterior rigid foam. How would you feel about zip R6?
I imagine concern for sheathing getting cold, even in mild climate zone 4, would make the assembly riskier?
Thanks for your thoughts on interior foam in the crawlspace.
Amer
Amer, Zip R6 is a good product and should work well in your climate zone. There is some risk of moisture accumulation but if you use a rain screen and make sure the tape is rolled (verify yourself--this important detail is often skipped) it should be airtight. Little moisture should get through from the interior, and a rain screen gap alllows any moisture that comes in from the exterior to dry quickly.
"Hot Water Heating System" . Not sure if you mean the domestic hot water source or hydronic heat for the house. If the latter, your question re: doubling the HVAC costs. Example 3000 sq ft reno project in zone 5 Eastern MA. 40K for ducted cold climate heat pumps ( 3 air handlers plus outside units). 20K-ish to add boiler/hydro coils. Add another 20K if you want in-floor radiant, baseboards, etc.
No way I would put an unvented gas fireplace in my house.
Also consider induction for the cooktop.
Wooba,
Indeed I meant the former. Thanks for pointing that out. I remember reading some articles mentioning hydronic wasn’t economically feasible. Particularly in climate zone 4. So it hasn’t been on our radar.
Yes, the induction cooktop is something we can definitely think about.
Thanks for taking the time to post your comments. I appreciate it
Amer
Amer,
I hoping this is a multi-generational home. Otherwise, a big sigh on the square footage and carbon footprint. With that rant out of the way, let me second going with a HPWH. With such a massive home, you probably want to install multiple smaller tanks located near the primary points of use. I'd also consider putting the solar array on the back burner if Tennessee's rules are anything like ours in Georgia. If you want solar without the upfront costs, it might make more sense to go with community solar.
On the $200 a square foot target, I think that is wishful thinking in today's market (even in the south). A bit more than $300 a square foot not counting land costs is more realistic (and probably seems like a bargain to people in the northeast and west coast).
Do not count on cost savings during your build. Instead, count on unexpected expenses that drive up the overall budget.
Steve,
Thanks for your thoughts.
It’s not a true multigenerational home. Yet. But given our parents health, it may happen. We have already built them a guest room and bathroom on the opposite side of the house. Zero entry shower wheelchair accessible doorways etc.
Agreed on heat pump water heater. I had read an gba article about smaller point of use tanks and was very interested. I figure we will waste a bunch of water without it waiting for warm water. Great thought.
Indeed. Tennessee has no solar net metering policies. We used to but I suppose special interests killed it off. I think we remain excited about solar. Specially since it seems like the 26% tax credit will remain in effect for Atleast 2021
Yes, 200 is on the low end of the ballpark estimates I’ve heard. 300 for all square footage including non conditioned area, brings our 7000 under roof sq footage to 2.1 million. Yikes. We were planning on maxing out at 1.75. I guess hard decisions will have have to be made.
I appreciate your help!
Amer
Amer,
Had another thought. You might want to compare the cost of a conditioned crawl space and a full basement. With a finished basement, it’s likely you could shrink the home’s overall footprint and lower your costs. Your lot is a factor of course. A walkout basement is more pleasant (to me) than one that has to be fully below grade.
Steve,
Thanks for your thoughts. The lot is actually super flat. The walkout would be hard to implement.
I would actually prefer to build on a slab but my family is worried about future changes and remodeling and really would prefer a crawlspace. I think a partial basement would be a good compromise, allow the mechanicals as some have suggested. Is executing a partial basement and larger crawl space combo difficult to execute? Seems like it would be more details and work for crew to get right.
One thing we both really want is to be out in the yard after only a few steps down. A crawlspace seemed like a good way to do that. We both really disliked having to take 10 steps from the garage to first floor. Or 5-8 steps into the backyard.
I really appreciate your time and thoughts!
Amer
Hi Amer,
I understand wanting to stay close to the ground. On the remodeling concern, those sort of apprehensions have plagued our past projects as well. But you have to ask yourself. How realistic is it this concern? It's much more likely that you will want or need to move before there's any real need for a remodel.
I suspect that your build is going to be very expensive. If you want to dial that back a bit, I would consider doing a slab with a partial basement (assuming site conditions support this plan). While I don't like bunkers in the ground, they do provide less costly space for utilities, storage, and so on. Moreover, Nashville is subject to tornadoes and severe thunderstorms. When the sirens go off, it's nice to have somewhere safe to wait for the all-clear.
You got great advise above, so my comments are about THE TEAM and PROCESS. Here is how I start ALL my projects...
1. Make sure your Architect and Builder are experienced, and if not, hire someone that is, so it can guide the project along.
2. Make sure the subs are on board to do things differently, willing to learn new ways, and not the typical "I've done it like this for that last 30 years". If a sub is not willing to learn, and to follow new direction, get a new sub that will.
3. Suzanne Massie thought Ronal Reagan a Russian proverb "Doveryai, no proveryai"... Trust but verify. Hire an experienced HERS Rater to verify the work done at different steps.
4. Start your first team meeting as soon as you can, so you know who to count on, what materials, systems and processes to follow... and stick to your guns, unless anyone else is willing to pay your mortgage.
5. Having regular meetings with key participants on the regular basis, keeps the project running smoothly.
All these steps above are used in most successful businesses and corporations, so why not in your project, while you pay for the largest investment of your life time. Generally speaking!
Armando,
Thanks for taking the time to post your thoughts! I appreciate it. I wish the market wasn’t so hot, because it sure doesn’t feel like I’m in charge. The builders and subs have so much work, it’s easier to not deal with a headache like me....
I really like the idea of having an experienced HERS rate come and check the work. Will that person do a blower door test as well?
Two of the builders we are consider hold weekly meetings with the clients. We are particularly attracted to that idea, as it shows a more service oriented builder. Also great to head off mistakes before they become huge.
I did not know Susan Massie taught that phrase so commonly attributed to Reagan. How interesting!
Thanks for all your thoughts, Armando. I really appreciate it. Great ideas on team work.
Best,
Amer
All excellent advice and I'm not going to add to the details either. From a top-level, I would add (or clarify):
1. Your design team needs to include the energy/HVAC designers from the start. Making these decisions at the front end means that the required spaces are incorporated into the design. If not, the HVAC designers end up having to shoehorn in the equipment and ducts and this is why they always end up in the attic - there's simply nowhere else to put them. Spend the time upfront to incorporate them into the design. Ideas like plenum trusses, dropped soffits and mechanical rooms are your friends.
2. It looks like the folks at E3 are a pretty comprehensive source for everything from the building envelope to HVAC design and installation. They could be your primary performance partner. I don't love the fact that they are also HVAC installers, but the attitude they show on their website is pretty good overall and I like that they are also energy auditors and building performance contractors. The fact that they even know what Manual J, S, D, etc. are and include them as a feature on their website is a big plus.
3. You mentioned a goal of a "pretty good house" and Andy posted the link to prettygoodhouse.org. Go there and study. As mentioned above, it is a philosophy as much as a set of specifications. If you buy into the philosophy, make sure that your architect also goes there and understands and embraces your goals. If you intend to build a truly high-performance house, every design decision is measured against these overall goals. If that's not really your thing, that's OK. You are welcome to borrow some of the goals and forgo others. As others have hinted above, it will be very difficult to build a 7000sf house within the PGH framework.
4. If the reason for the very large house is primarily extended family visits, have you considered an "Auxiliary Dwelling Unit?" and are they allowed in Nashville? An ADU is better known as a guest house. A separate building on the same site, used for guests. It gives them their own space while still being nearby. And in many places, they can be rented when you don't have your own family visiting. I would think that Nashville rentals would be pretty healthy. While the overall building envelope for two houses will be larger than putting all of that space under one roof, you may find enough other savings to even things out. Maybe keep the ADU relatively small, and let the relatives fight it out among themselves. After all, they're not paying the bills, right? Just a thought. If not a full separate ADU, you might look into zoning off the guest "wing" so that it can be mostly shut down when not occupied.
Peter,
Thanks for taking the time to go E3 innovate website and checking (vetting) them out. I heard about them from a builder, but also found them listed on GBA website which was encouraging. Hopefully someone had a good experience and pointed them out to Martin
Indeed, I was also made wary by the fact they install hvac equipment and insulation. This tingled my spidey sense. But I’ve heard about from both builder and architect, so clearly they are helpful. In fact, I found a mention of them on energy vanguard website where Allison baile checked out one of their homes and approved. This was high praise!
ADU. What an interesting idea. In reality, the parents bedroom and bathroom doesn’t add much more than 350 square. Its one of the rooms with a cathedral ceiling, so no rooms above it. Also, my parents would take it as personal affront if I built an ADU for them!
I will definitely check out PGH website and see what knowledge I can incorporate from there.
Thanks for your ideas. I appreciate it!
Amer
I am still afraid you may end of design a home that will cost way more than you expect to build please be careful. It sounds to me like your window package may cost 40% of your proposed budget.
Yes the teenager’s bedroom real must have a cathedral ceiling. Again you are needlessly making the thermal envelope larger how much awake time do most people spend in a bedroom. Read this forum for a week or two you will find 3 or 4 people ask how to fix their leaky, rotting and or cold cathedral ceiling. Let’s see your R60 cathedral ceiling design can you fit 10 pounds of Styrofoam in a 5 pound bag? My guess is a flat ceiling covered in R 60 fluffy stuff for 1/3 the cost. Say no to stupid.
Walta
Walter,
I think part of the issue is we are still in design phase. We haven’t decided on a builder yet, so we don’t know how and to what degree our choices are affecting the budget.
I’ve been thinking more and more about cathedral ceilings. I agree there’s no way to mitigate that it will cost more than flat ceiling. However, after spending some time on PGH website, I learned about raised heel scissor trusses. This would allow us to make a more standard vented attic with blown cellulose as long as we keep the pitch low enough.
I have no ideas what windows cost. We will try to be as standard as possible, no custom items. The big window splurge is something along the lines of a Marvin lift and slide door. We may pare back the triple pane stuff once we start gettin sticker shock.
I’m sorry, did you mean 40% tota budget or window budget? What are you thinking is a good window budget for a 5000 sq ft home? How do I think about it?
Thanks for your help, Walter. I really appreciate it!
Non-vented fireplaces are just a bad idea. Someone might use it. But you can integrate a vented gas fireplace into a wall used for a large screen TV, and at least not "waste" space on it.
Consider zoning. Over generations the house may have less or more people. If your area allows, consider if some areas are best configured as rentable in-law units. And make sure it's not all heated, if the castle has empty rooms.
I actually looked at some electrical fireplaces on Amazon today. They really aren’t too bad...think it might work out...
Interesting thought about zoning. In Nashville, land is becoming harder to come by. And many developers are buying an acre lot or a half acre lot and subdividing and building two spec homes on it.
I think adding another dwelling on the lot is feasible, but we wouldn’t do it.
I think you will find windows are shockingly expensive and take a big bite out of every constriction budget. It is a wild guess but everything on your list has been supers sized so far and I suspect the plan will call for lots of windows and likely large ones if they are imported tilt turn triple pane that take up 20% of your wall area of 5000 sqf house will cost enough to make almost anyone cry.
Building a house is a very stressful undertaking that has killed many marriages. Every little thing is a choice and if can’t agree things get ugly fast. The sheer number of choices that needs to be made day after day is unrelenting.
If you and your Architect let your let yours selves run wild it is very easy to dream beyond one’s ability to pay. Once you have poured your heart, soul and thousands of dollars into a set of plans that you have fallen in love with only to find it will cost way more you wanted to spend you are left with poor options. Tear up your dream plan and throwing away the thousands it costs to draw them and start over or double the budget. I am not trying to be mean just save you from a broken heart.
Our old house had a wood burning fireplace that would see one fire a year maybe. The new house has a vented gas fireplace that we use often.
Walta
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Walter,
I have been looking up and counting the windows in our house and there are probably about 60 windows in the house. And there are windows on the ground floor that are 6,7, 8 feet tall. Even if I assume the windows are 4 x 6 (24 sq ft x 60 windows) we are getting around 1500 square feet. Assuming $50 per square ft, we are looking at 75k. Is 50 dollars per square foot too low a number to be thinking for triple panes? Or should I be in the $75/sqft category for good triple panes? I am just ballparking trying to get a feel for this. If we use 75 per square foot, I’m looking at about 110k just for windows. That is eye watering! Perhaps double pane with low U factor might work better with some extra PV panels after all.
I agree about decision fatigue. Luckily, my wife has a pretty solid imagination and is also pretty decisive. She already has a pretty good idea of what she’s looking for. I’m not super concerned about the interior aesthetics, she will do a great job with that. I’m more interested in the building science aspect and building a durable efficient house. She’s leaving that part to me. So we each kind of have separate interests that we enjoy and want to contribute
I’ll dream big with the architect. Worst case scenario, I can’t do some of the things above because they are prohibitive in cost or ROI. But overall, the knowledge I’ve gained from this site will help me in making better choices. At the very least we will be better than the average 1.5 million dollar spec home in our area.
So please, keep the ideas coming!
Amer
Amer, you can get very good windows for $50/sf or less, depending on what is important to you. Just like any square foot pricing, it's not accurate, but helps show a ballpark idea. European-style triple glazed windows can have amazing performance but have vinyl frames, which bring the cost down, or aluminum-clad wood that drives the cost up. I would start by learning the differences between different window types--not just number of panes, but how they operate. Once you understand that, look at U-factors and cost. Don't worry about the number of panes.
Michael,
Thanks for confirming good windows can be had for $50/sqft. That’s a helpful metric.
I’ll try to check out a few more articles on GBA about windows.
The one that really sticks with me is Martin’s article which asserts that the best, most expensive windows, are only somewhat better than good windows. Martin’s takeaway was better to get good windows and more PV which I agree with.
I had just assumed goals for windows: triple panes, argon filled, some sort of LoE, make as many picture/inoperable windows as possible. In terms of materials and price: vinyl < fiberglass < wood < wood clad thermally broken aluminum
I had actually not realized that a double pane window may rival, equal, or better triple panes in term of u factors. That could be a considerable cost saving. I appreciate you pointing my that out.
I think one of the tough things about windows, it’s a challenge to get a handle on their costs because every house is so different. And not to mention companies thrive on this information opacity and asymmetry. An unwary consumer is what they are hoping for.
One more question: when you get a bid from Marvin, Andersen, or whoever, are those prices negotiable? Hey I’ll go with your company if you can knock off 12 percent? Like buying a car? Or not?
Thanks again for sharing your thoughts. I appreciate it
Amer
My definition of a Pretty Good House Is one that you can afford and one that won’t kill you. (Use materials that stand the test of Time). Are you planning on doing any foundation work, framing. Electrical, plumbing, mechanical, air sealing, painting or finish carpentry? Labour costs are accumulative. Have you decided what you are going to hire out and what you are going to do yourself?
William,
While I can dream and learn things on this website, I don’t have real world experience in ANY of the things you mentioned above. So no, definitely will not be doing anything myself.
Interesting, I was telling my wife the other day about a Matt risinger video where he went and flashed any overdriven nails on the bottom 3 feet of his zip panels. Anyway I told her this was something I could do. Something small, easy to handle, idiot proof, and probably not super critical. She laughed for a surprisingly long time....
I was showing my retired builder father in law the plans to a house I was about to start building. "Looks like a first house." Huh? He explained that when someone builds their first house they throw in every single thing they've ever wanted or even seen and it winds up way too expensive. They realize they don't need all that stuff and their next house is super cheap and easy to build. Too cheap. They then have to build a third house where they actually wind up with the stuff they really use and just the right finishes.
Now that’s pretty funny! I’ll try to get it right for the next one!
Amer
That is very sage advice. Sometimes just going through the design process can yield that wisdom for a much smaller amount of time and money spent.
Before we landed on the form of our in process addition/renovation, we went through construction drawings and pricing of a bigger project. That ultimately helped us realize it was more than we needed for very little gain.
I'm not an ascetic and I could never live in a tiny house, but I do shake my head at so much of the overbuilt and blown to the zoning setback houses I see in my area.
I'd rather have a smaller house detailed and finished well than a large house with mediocre details all over it.
"I'd rather have a smaller house detailed and finished well than a large house with mediocre details all over it."
100%, however we are sadly in the minority with this opinion.
Throwing away stuff is the first item of any design effort. Clothes get donated if they have not been worn in 3 years. Once that is done, measure how much closet space you need. Tools and toys get donated or thrown away. Then identify how much storage you need. Make a list of the rooms you really use, on a regular basis. Where are you going to read, use a computer, watch TV, entertain, etc. that helps identify the rooms. Next look at the acoustics, do you need quiet space, or do people have different sleep schedules. There is a reason why TVs are placed in the basement.
Check out the single family home guide here https://redwoodenergy.net/research/ - lots of well-informed advice that is applicable to your project.
Andy and Patrick,
Thanks for weighing in. I appreciate it.
When you say detailed and finished well, could you elaborate and clarify? What details are referring to specifically? In your opinion, what details are making it mediocre?
We are definitely trying to build a home with good rather than mediocre details. We appreciate the insights you all have provided.
Start here: https://www.amazon.com/Get-Your-House-Right-Architectural/dp/1402791038/
It's a good book detailing in simple terms why some house details "look right" and others don't.
After reading that book start an apprenticeship with an experienced restoration carpenter and after ten years of that...ok, just kidding about that part but there is an endless amount to learn about how homes are built and then an endless amount to learn about how they are built well.
LOL. Please feel free to condense knowledge you’ve acquired over a lifetime of hard work into a series short forum posts. :)
There is an awful lot of good advice here, and if you want to try your hand at residential design it can be a lot of fun.
But if you wish to avoid getting down in the weeds with technical details, there is another way to approach the problem. Just tell your architect and your energy consultant that you want to get certified as a Zero Energy Ready Home. A successful ZERH certification will give you a "pretty good house" with a HERS score of 50. It includes an energy model and some good IAQ specs.
Studies suggest that the ZERH upgrade adds 3% to 9% to the cost. No heroics required. But of course you will need to design and build with ZERH in mind - it is not an afterthought.
In my own house, built in 2019, we started with a pretty good house of my own design. I decided to go for ZERH certification after we had started building, and we made the changes without too much trouble, but I really wish we had done the energy model before we finalized the design.
One last comment: We used a direct-vent gas fireplace in our ZERH house. We love it!