House design questions
Ndirish147
| Posted in General Questions on
Hi, my name is Kurt. I am from central Indiana, zone 5. I have been reading articles on this forum for the past 2 years and driving my wife crazy with all the info on here. First and foremost we have learned that there are no builders in our area that build green homes. The first thing I would like to ask is: what are your thoughts on me heating and cooling this design with 2 or 3 minisplit systems? The house will be built with 2×6 construction, taped OSB, with blown in cellulose and I hope 4″ of EPS on the exterior.
Thank you for any input.
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Replies
Kurt - Not enough information.
First question is how you plan to use the 5 bedrooms? Minisplits help with zoning if you plan on using some rooms seasonally. It also helps with the hot air rising in an open plan.
Second question is what is the roof/ceiling insulation. It makes little sense to take the walls to R-40 without proportionately increasing the roof insulation. It wasn't clear from the plans what level of insulation the roof would have. Window and floor/basement insulation should also increase proportionately.
This leads to the third question. I'm not a fan of minisplits in a primarily heating zone relying on grid power given the current economics of fossil fuels. The wood stove helps assuage those concerns but substitutes manpower for convenience. They work great for supplementary heating for additions and seasonal rooms.
Other questions that might be a part of your decision-making process include sensitivity to sound, temperature variations, availability of fuel sources both short & long term, allocation of space for equipment, make-up air system.
Kurt,
I think your floor plan is well suited to using mini-splits - perhaps a combination of ductless and ducted for the rooms which may be more frequently used with the doors closed. The scissor-trusses alleviate the usual problems associated with cathedral roofs. Unless someone comes up with some obstacle I've missed it is certainly looks worth pursuing.
Just out of curiosity (as I can't blow-up the plans), what's that device next to the wall in the dining room?
When you talk to contractor do not say “green home” they will roll their eyes and walk away. If you say “high performance home” you will get a much more receptive audience.
In general story and a half style home turn out to be energy pigs as it is very difficult to stop the air from getting out from under the second floor and into the knee wall attic. I say move bedrooms 2 and 3 upstairs and so you keep the same number of square feet and design a full 2 story home.
I feel the same way about cathedral ceiling, they are bests avoided in high performance homes.
From a dollars per square foot point of view 4 inches of foam can be an expensive wall to build.
Wood fireplaces do not generally work well in high performance homes we work very hard to seal every little gap in the house so the fireplace will not draw well and the house fills with smoke so you must open a window to get to too work.
Of course all of these feathers can be done well but it become expensive and time consuming to do them well and it is all too easy to cut corners when the budget gets tight.
Walta
Hi Kurt,
Sounds like you have been doing your homework. But if you haven't seen these articles, you might find them helpful when contemplating the minisplit vs. other heating options for a small, efficient home.
https://www.greenbuildingadvisor.com/article/rules-of-thumb-for-ductless-minisplits
https://www.greenbuildingadvisor.com/article/just-two-minisplits-heat-and-cool-the-whole-house
https://www.greenbuildingadvisor.com/article/heating-options-for-a-small-home
Hi thank you for all the info and questions as I definitely did not give enough info.
My plan is to do r40 wall and r60 roof if i can get it done within my price range. We will build slab on grade because the water table at our farm is pretty high. We do not have access to natural gas so everything will be electric and hopefully net zero at some point. There will be a wood stove inside as of now but that could change if i need it to.
It is pretty amazing how many builders and designer still say a house has to breathe. Every time i hear it i laugh inside because i have read some much on here about how that isnt true. Alot of builders in my area seem to like trusses so that is why we have them here. I plan on having a 20" or so energy heal on them.
Thank you for the minisplit links. I have read most of them and that is one reason I posted my question. The house is not quite as small as the ones listed and not as compact either. I do understand that the vaulted ceiling is not as efficient but that is one thing I know that we do not want to change about the house.
In the end my goal is to be net zero but i would like to get there in the most cost effective way possible.
Kurt,
If you insulate your scissor-trusses with R60, I can't see how it is any less efficient then the same level of insulation in a standard gable-truss. There is a small energy penalty for the additional surface area of the bottom of the trusses, but nothing worth changing the design to address.
Malcolm, I forgot to answer you. the device next to the dinning are is supposed to be a heating unit. To be honest I think I am also going to struggle with even finding an hvac installer that has even used minisplits to heat and cool a whole house. at least not in this area. one thought i had was to use one head and its own pump to heat the great room area and then a second zoned system to heat the bedrooms downs stairs and upstairs.
After meeting with the builder i think we will go with we decided to do rafters instead of trusses and will still shoot for between r50 and r60 in the ceilings. If i am only able to do r50 ceilings r30 walls and picture fram insulation under the slab how hard is it going to be to hit net zero? My pv panels will not be mounted on my house.
I encourage you to think outside net zero. Net zero doesn't accurately mean much about environmental impact or cost effectiveness. So why make it a goal?
It has been awhile but i am back with another question. My builder is having trouble finding anyone in my area that is comfortable with using a mini split system in my house. Do i go with a conventional heat pump or just insist on the mini split? I am still a few months from building but trying to get these last details straight is keeping me up at night.
Kurt,
You may want to read this article: "Ducted Air-Source Heat Pumps from American Manufacturers."
Have you even run a Manual-J on the place as-designed yet?
That's the very FIRST step before looking at the heating & cooling solutions. Without it you'll be stuck with the rules-of-thumb contractors too uncomfortable with designing tiny (in their minds) equipment.
Without the load numbers nobody is going to be comfortable with anything that isn't ridiculously oversized. With an engineer specifying and certifying the room by room load numbers (or even the equipment) it takes a lot of risk away from the HVAC contractors, making them more amenable to working with smaller systems they may be less familiar with. Some contractors are still going to balk or push back hard with all kinds of rationale or thumping, but you don't need to use them.
Even with a "...conventional heat pump..." it's important to get it sized right, and most contractors are going to drive you crazy with oversizing if you don't tell THEM up front what it needs, and how much oversizing you'll tolerate on any proposals.
As usual, a lot of responses on equipment and systems and nothing on the functionality of the plan itself (well, to be fair just about everyone on this site is a building scientist, not a designer).
First off, your great room really is great. I mean, it's huge (more than enough space for 3 distinct seating areas) and yet your dining area is small and rather tucked away into a corner. I think you'd have a much nicer dining experience if you moved the dining table into the left quarter of the great room and then put a set of club chairs in front of the fireplace and a seating area in the right third of the room. More than enough room.
Your kitchen is also very small, with not very much counter prep surface. I would slide the kitchen wall (with the kitchen stove and fridge) south and west and also move the sink area and cabinetry south and west (into the great room area a bit more). Moving the kitchen here will allow the room to have an exterior window.
I think your floor plan is okay, other than somewhat excessive overall square footage. I think a really large home is sort of contrary to the Green Building ethos.
The scissor trusses are ok but you should add a raised heel. You're going to R50 or R60 on the ceilings but you're going to have R20 or less at the edges where it pinches off.
Even with just r30 walls, r40 floors r60 top I think you will find you need less heating/cooling than you think. You should visit a similar home in the area and get their feedback.
Trusses are quicker and more economical, the builders like rafters because it means more labor hours for them.
Yes a building needs to breath, maybe just not the way your builders are thinking. Do you have an HRV that will integrate with the mini splits?
Kurt, you said: "My builder is having trouble finding anyone in my area that is comfortable with using a mini split system in my house. Do i go with a conventional heat pump or just insist on the mini split?"
First of all, stick with the minisplits! They're awesome. Mine is having no trouble keeping our place toasty warm as the polar vortex blows over. And it's virtually silent. I have no backup--airtightness and pretty good insulation will keep the place habitable through any power outages.
As for HVAC contractors, I'm guessing the same anti-minisplit region I'm in here in NW Ohio extends over to you. But it could be that in fact your BUILDER is the one who's uncomfortable with pushing the envelope, and isn't trying very hard to find someone. Find a creative HVAC person youself--look on the Fujitsu and Mitsubishi websites for their authorized dealers. (Not saying that those listed will all be helpful, but the chances are better than the general list of local contractors.) Just keep calling around. And get that Manual J done (and you MUST do this, don't hire anyone who will supply HVAC equipment without it.)
Note that the mini-ducted version, which might serve your upstairs bedrooms, is the most time-consuming to install, and otherwise pro-minisplit installers might sour on all the extra work and price it sky high.
Hello, I made a copy of your first floor plan which allowed me to zoom in and study the layout a lot better. The main problem with the floor plan as it stands right now is that there is no “sense of arrival”. When a visitor arrives at the house and walks up onto the front covered porch they are greeted by two doors. One leads into a mudroom, the other opens right into the corner of the great room. Unless the visitor has been to the house before they don’t know which door to use.
Family members will probably use the mudroom door, but if a visitor chooses that one the first thing they will probably see are piles of shoes, coats hanging on hooks, perhaps a pile of newspapers waiting to be recycled, etc. That’s not a very good first impression to make, especially for such a nice house. Also, once the visitor chooses the mudroom entrance they then have to walk through the interior mudroom door, down a hallway, into the kitchen and around the corner before finally coming into the great room. The entire journey is a bit of a maze. On the other hand, if the visitor chooses the other exterior door, they are immediately in the great room. There’s no place there to sit down and take off wet shoes, no place to hang their coat, etc. For a visitor either door creates an awkward entrance to the home.
What I suggest is moving the staircase about 2 feet into the great room and about 2 feet towards the kitchen. This will give you enough space for a proper front entrance hall and also leaves you enough room for a separate mudroom (I would suggest closing it off from the front hall with a pocket door and also using 2 foot deep storage cabinets along the north and east mudroom walls to hide clutter - you could also add a seating bench on the north wall of the mudroom). The entry hall itself has room for a table next to the front door and there are also built-in bookcases (or display cases) which face towards the front door.
The kitchen stove and fridge wall has been shifted west (and lengthened) and brought south by about 2 feet. The sink island has also been moved west and moved south by about 2 feet (and lengthened). The kitchen can now gain an exterior window and a lot more counter prep area. The table on the other side of the sink island has been narrowed and turned into a raised breakfast bar with stools. A small desk and upper cabinet has been recessed under the stairs.
The back hall has been widened a bit and the laundry/pantry room has been lengthened with space for a standard washer/dryer in a recess. A run of cabinets and a sink area can go on the wall opposite the washer/dryer.
Each bathroom has been widened from a standard 5 feet to 6 feet (widening the bathrooms also makes the master bedroom 2 feet wider as well). The bed and nightstands should go against the west wall. The closets in the two smaller bedrooms are wider and a couple of interior door locations were moved. I would also suggest adding a window to the master bath.
One thing that should be considered when designing a home are interior sight lines, not only within rooms but also between rooms. People prefer to walk towards either light or a view so any place you can put a window at the end of a sight line is great. Some examples would be to locate a window directly opposite the door leading into that room or at the end of a long hallway.
Hopefully you’ll like some of my suggestions. I would suggest that the next step should be testing the layout by drawing in the furniture and making sure that the circulation paths work for you (both in the rooms and between rooms). For your plan I tried to align interior walls and sight lines so that framing will be simplified, and even though I moved the staircase over a bit it’s fortunate that the upstairs layout isn’t really affected by that at all.
Let me know if you have any questions.
PS. You may think that narrowing the great room by 2 feet would be a bad idea, but the room is so large you’ll never notice it. I would consider, however, lengthening the house to 52 feet and sticking the extra two feet into the widths of the laundry/pantry and back hallway (and one foot each into the widths of the mudroom and the bedroom). Widening the back hall allows for additional pantry storage. See Option 2.
Best of luck with your build!
Having to come into the main entrance in order to get to the mudroom somewhat defeats the purpose of the mudroom. It's not really a mudroom anymore, rather a utility storage / shoe rack room.
Scott
I totally agree with you on the mudroom, it's quite improved keeping the mudroom accessible but not a mandatory entry corridor.
But the 6' between the wall counters (sink) and the stove island make for long walking distances in the kitchen work triangle. This kitchen is more suited to three cooks than one.
Another big unused space is the 6' (7'?) wide hallways. The bathrooms are still small with only 30" vanities due to the hallways being unnecessarily wide. A minimum hall is 36", so 48" would be just fine. More room for bigger baths and maybe enough room to even make the master bdrm closet a walk in.
And the water heater in the closet could go to the laundry room now that it's been enlarged, freeing up even more room. Service techs (and DIYers) don't like water heaters in the closet, it makes them twice as hard to work on.
I would like to say thank you for all the replies it really is amazing the time all of you take to put in to other peoples projects.
Dana
I know that I need a manual j calculation but I am going to run into the same issue I had when I purchased the furnace I currently have. HVAC contractors around here just dont do them. I will have to try to widen my search in order to find someone willing to work with me.
Chris
We are going back to scissor trusses with an energy heal. Right now the slab will only have insulation on the inside of the stem wall. We will have an hrv but I dont have the specs for that just yet.
Andy
You hit the nail on the head with your comment about contractors as well as the hvac guys...they seem very anti minisplit. My builder told me today that the reason that the hvac company doesnt like them is because the house has too much open volume and that it is on a slab so there is no good way to run the condensate lines. Like Dana said I am just going to have to search someone out myself.
Scott
Thank you very much for taking the time to look over our design so closely! The mud room front door area and kitchen have really been a struggle for us. I will go over these with my wife but i really like the way you moved things around it make the floor plan so much better. I really appreciate you taking the time to do this.
Scott,
Excellent job there, really opens up the place and reduces the corner bead budget by at least 70%!
One change I would suggest is to find a way to get a more direct access from the kitchen to the pantry.
Kurt,
There is nothing wrong with open rooms and mini splits. I have a single head for a 13
x45' room with 14' ceiling but I use it for cooling only. I have tried it for heat as an experiment but I find the ends of the room furthest from the unit are a bit chilly. I ran my condensate drains to the riser for the washing machine. Nothing magical there.
For your layout, the best would be two ducted mini splits. One on the top floor to heat/cool the rooms there as well as a larger feed to the upper part of the open area (this will handle most of your cooling load). The 2nd one on the main floor for the bedrooms as well as two runs to the ends of the great room (this would do most of your heating). One way to get around the silly costs of ducted mini quotes is to split the job, get somebody to design the duct-work and have your GC install it, then have the HVAC guy come in and just quote installing the splits (not a guarantee but better chance).
Trevor: Mudrooms are rather tricky. Every house should have one but it doesn't necessarily have to be the first thing you see when you enter the house. They should, however, be as close to the main door as possible so that coats, umbrellas and wet shoes can be stored before proceeding into the house.
The other problem with mudroom entries is that the family members tend to use only that entrance and their big, beautiful front entry hall becomes wasted space. In this case everyone gets to enjoy the entrance hall. Visitors can go right into the great room, people with wet shoes can turn into the mudroom. You can then head right into the kitchen or head down the hall to the bathroom.
As to the pantry access from the kitchen, if you didn't want so much countertop on the fridge/stove wall you could shorten both lengths of cabinets and shift the stove and fridge over to the right. That would give you enough room to add a pocket door from the kitchen into the laundry/pantry. However, with all the storage in the kitchen now the pantry can be used primarily for all the "extras" that you want nearby but don't need on a day to day basis so direct access from the kitchen shouldn't be needed.