HVAC System for New House
Hey all, new here. My web searching leads me here more often than not so I thought registering was the logical thing to do.
I’m in the process of planning a new build and have an issue with HVAC. Our average low temp here is 17F in Nebraska and the average high in July is 88F. I’m interested in saving money by skipping the furnace up front. In addition, I need the mechanicals to be quiet since they will be near a home theater. Everything has led me to wanting to run the whole house off of an inverter-driven VRF heat pump, one of the newer units that maintains heating capacity down to 5F (some as low as -5F) and saves us money in the summer. Names like Gree, Midea, Mitsubishi, Fujitsu, Toshiba, etc come to mind. We will use traditional ductwork for ventilation as there isn’t enough money to go full mini-splits and ERV and all of the complications those entail.
The trouble is twofold. 1) if I tell the builder I want to use specific units like Mr Cool or (insert brand here), they are not interested in working with me. The attitude I got made me feel that a good chunk of the house profit must be in selling the HVAC system itself! If I point them to the big name brands like Carrier or Trane which they work with, they warn me there will be big price tags to follow compared to their run-of-the-mill 13-16 SEER units + gas furnace combos. I don’t think this is right.
All of this seems to prevent the home owner from getting what they want, and it prevents greater adoption of this technology. I know it’s readily available and I know it doesn’t actually cost that much. $3-4k parts plus labor plus ductwork should do it.
What would you advise me to do? Pony up for the big brand names and pay 500% markup? Or choose the basic options and replace the A/C with a $2k heat pump later? If I do the latter, I would keep the gas furnace since it’s already there. I would just rather save the money on it up front.
The house is 2 floors which is about 2000 sq ft, and the basement will be another ~900 sq ft. That also leads into questions about whether zoning is worth it…and if so, that would complicate the plan since all the design for it needs to be done up front.
Is it typical to run into issues like this when working with a builder, and what’s the best way to get what I want? Thanks in advance.
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I'm assuming you are shopping for a spec house and this is not a custom build? If this is custom, find a new builder. If a spec build, you probably are dealing with the lowest cost subs, because that how it works, builder hires cheap, code minimum subs and he makes more money. The reality is, they will sell this house whether you buy it or not. If they won't eagerly substitute the basic HVAC package with a reasonable alternative and charge you the extra money, you should be concerned with the quality of the builder and/or HVAC sub. Maybe you can agree to hire your own HVAC sub and get what you want but that is a VERY risky move. I'm an HVAC contractor, we don't work with spec builders because cheap HVAC is usually terrible HVAC. If the builder won't let me meet with the homeowner to discuss their expectations and desires regarding HVAC, I'm not working with them.
They do custom and semi-custom. They may price what I want, as long as it goes through those who they have relationships with. That does bother me, as I feel a builder should be able to get anything needed for a house and not limit customers to certain choices/brands. Maybe I just have a naive understanding of how this business works.
In fairness to the builder they are the ones who are providing the warranty on the house and they're comfortable with whomever they have the business relationship for doing the HVAC system.
Perhaps you can work something out where you release him of any liability on the HVAC system?
Right, so one option is to pony up for a Trane XV19 or similar. I'm wondering if it's better to do that, or to have them put in a basic setup then replace the outdoor unit later?
Price it out! I’d be surprised if installing 2 is cheaper than 1, but you’ll find out.
Carrier has rebranded Midea mini splits in their line up. Both ductless and ducted.
Here is an approach that comes to mind.
I would have the budget be for a typical furnace/Ac system with ductwork. But have an allowance for the furnace and Ac condenser. Then when it comes time to design the system, insist on a ducted mini split heat pump. I bet the air handler and outdoor unit will be in budget or very close.
I'm not sure mini splits are right for this house. I would need at least 5 of them, driving up both costs and maintenance. I love the efficiency, though. You really think it would be close?
I was suggesting a ducted mini split. Something like this: https://ashp.neep.org/#!/product/36747 or this https://ashp.neep.org/#!/product/33601
I've briefly looked at ducted mini splits but I'm not well versed on why someone would choose them over other types of setups. And now that I think of it, I would likely need a few more than five. I'll do some more research on them, thanks.
Ducted mini splits evolved from designing smaller low static pressure air handlers to pair with mini split outdoor units. Some have evolved to full size air handlers. Ducted mini splits typically have better cold weather performance, a lower turndown, and are more efficient than “central” heat pumps. You could definitely heat and cool your house with one properly sized ducted mini split that would take the place of a typical furnace/ac.
I took another look and watched a presentation that gave me an idea of system design. I think if I went that route I would have one ducted mini-split for the master suite, one for the rest of the 1st floor, one for the 2nd floor, and one for the basement. So, I think I could get by with a total of 4 since each one can branch off to a few rooms to create a zone. That's a big benefit and makes them more flexible (in new construction) than on-wall units. I'll explore this option if I get to talk directly to the builder's HVAC people, though I'm afraid very few techs around here will be familiar with them.
There is also the question of whether it's best to run one outdoor unit for the house so that it runs continuously and efficiently, or multiple small units that tend to have the higher SEER and HSPF numbers. Though that is probably not cost effective.
How big is your house going to be? You've described 3 floors. The big advantage of zoning is more easily dealing with heat on the top floor or cold in the basement. Ducted minis let you do one zone for basement and first floor, and a second zone for the top floor as an example. If cost is a concern, that's a lot better than 4 zones while dealing with the primary challenge.
Roughly 1000 sq ft on 1st and 2nd, and another 900 in the basement. A cold basement and a warm 2nd floor are big reasons why zoning makes a lot of sense – and not just to equalize temperature when needed, but to let them remain unequalized during times we wish to conserve. Running the master suite at night on its own zone would be very appealing.
A few other details:
House will be OSB w/Tyvek on 2x6's, blown fiberglass to R21 in walls, R49 in attic. Apparently doing something like ZIP sheathing costs significantly more and those costs would be passed on to me, so I have little control over this.
Does your local code have an air leakage requirement, for example less than 3 ACH50
I am not sure, but how do I look it up?
If you look at the cost of a furnace+budget AC, it is pretty close to the cost of a decent cold climate heat pump. The heat pump also saves you running gas lines and combustion vents, so overall the cost should be a wash. Of course, there will always be the non standard premium.
In most markets with reasonable gas and electricity price, the cost of heating with a heat pump is less or about the same. Since you can always produce your own electricity for the heat pump but can never make you own gas, I would say for any new build go for a heat pump.
One side benefit of a cold climate heat pump is they are fully modulating units. Unlike the typical over sized single or two stage unit which will be cycling all the time, these provide a bit of cooling and heating all the time which is way more comfortable.
Never mind that you cooling bill will be way less and your heating bill a bit lower, the improvement in comfort by itself is worth the extra cost.
Along the lines of Kyle's suggestions, I think for a new build a standard furnace type air handler is a better option. Something like this:
https://ashp.neep.org/#!/product/29479
You are not in that cold of a weather, but even there a cold climate unit is a better fit. The Trane units tend to fall off a fair bit in capacity bellow 17F (ie 4ton puts out 3 ton of heat).
I may not save on the gas line since it looks like a gas water heater is the best option here. I can't make a heat pump water heater make sense in the basement (already cool room) next to a home theater (noise) and the time to ROI after paying the premium over a gas unit is about 10 years ($1000 more for the unit, and saves $100/year). I can't put the HPWH in the garage since it freezes here. The gas is both quieter and cheaper and can stay in the basement.
I agree the variable capacity units really seem like the way to go. I will make sure to emphasize cold performance when choosing one. The rest of the system is unknown at this point, be it ducted traditional with a few zones, or ducted mini-splits for the best zone control.
Another thing many don't think about is how ducts carry noise and cooking smells from one room to other areas of the house. The ducted mini-splits would be zoned off, solving that issue.
I expect to pay a little more in the winter per BTU with the heat pumps compared to natural gas, but a lot less in the summer, and as someone else mentioned, if I put them on solar I could really bring the bills down. Last I checked I can't harness gas from the sun.
If you are concerned noise but considering rooftop solar, I would put in a large Marathon tank. It will be silent. The solar will allow you to "charge up" the tank during the day and then use the water later with minimal water heating cost.
Re HPWH: Unless you're in the home theater many hours in the day, you can have it run during the 'non-theater' hours. Gas water heaters make noise too. I also wouldn't exclude putting it in the garage. Mine is in a large attached unheated garage/shop and 15F low is pretty routine, and recently we hit -10F.
If you're considering solar, verify your grid tie plan. If it isn't good the large tank as mentioned by Steve K might make sense.
I guess I ruled out the HPWH because since the best place for it seems to be the garage, it won't achieve its rated efficiency during the cold months. Since it will take 10 years to pay for itself, it's a hard sell.
In most cases gas meter fee wipes out any savings of running a gas water heater. Standard electric resistance would probably cost about the same once you add that on.
HPWH will definitely be cheaper. If you look at the cost delta between a gas water heater+gas line+vent add in the cost of the CO sensors in the house, you are very close the the cost of a HPWH. I'm not sure where you are getting the ROI from, but it should be well under 10 years.
Even if you don't run the unit in heat pump mode for part of the year, it is still saving you money the rest of the time plus giving you free cooling in the summer time.
Most HPWH have programmable schedules, if you are worried about sound, set it to only run during times you are not in the basement.
+1 to what Akos said. The payoff period is closer to 1 year since you can eliminate the gas line. That saved me about $1200 up front if my memory is correct, + a monthly fee. The very particular cook in my house says that induction cooktop is way superior to a gas stove.
Well, a couple of things.
1. HPWH costs ~$1000 more and saves ~$100/year in energy vs gas.
2. We can't cut the gas bill. The other half insists on a gas range. The glass tops scratch up and look terrible in a short amount of time.
I doubt the 10 year payback, but plenty of good decisions have been made accepting a 10+ year payback. BUT, consider one less combustion source in your home. Also, if you have a ducted mini, and you are considerate of where the minisplit and hpwh are located, you could easily pipe the hpwh output into the return plenum. The hpwh takes heat out of the air, and the mini puts heat back into it before the air gets to any room in the zone.
Cost to operate:
Gas tank water heater: ~$200/yr
HP tank water heater: ~$100/yr
Cost to purchase:
Gas tank water heater: ~$600
HP tank water heater: ~$1600
"We can't cut the gas bill. The other half insists on a gas range. The glass tops scratch up and look terrible in a short amount of time."
You need to tell your wife she's wrong :) You do need to be careful with the lower priced induction cooktops, but a gas range is a PITA to keep clean.
You might want to share this report with your wife: https://ucla.app.box.com/s/xyzt8jc1ixnetiv0269qe704wu0ihif7.
The gas industry has spent decades propagandizing the superior cooking qualities of gas. They are the 21st century's cigarette industry if you're looking for an analogy.
FWIW. I've had induction in three homes. A good quality cooktop is superior to gas in every way (and won't poison you while turned on).
Thanks for the link.
I'll wager that she would go for induction if it could be maintained and kept looking nice. The appeal of gas is mostly the iron grates that are impervious to scratching, unlike glass.
Just as an FYI, variable refrigerant flow (VRF) is intended for commercial and multi-family residential projects. When configured with heat recovery, a system can heat and cool simultaneously, which is pretty cool (so to speak).
Is it not the VRF that enables variable capacity? If so, it isn't just for commercial applications :).
I think you are referring to the inverter, which allows the outdoor compressor motor to modulate to a lower speed. You definitely want an inverter-driven unit for comfort and efficiency.
The insulation package sound like the normal code minimum production build. From a dollars and cents point of view since most people sell before year 7 code min is the low-cost option for them.
The upgrading the equipment and insulation will only payoff if you are in the house in year 15 or if energy prices double from here but that seems much more likely than 2 years ago.
Please tell me they will not be putting the equipment or ductwork in the attic. A very common and stupid practices.
Walta
It is most common for homes here to have their HVAC systems in the basement or, if there is no basement, on the 1st floor. This house has its own mechanical room with sump pump in the basement.
The best system is the one that is professionally designed, properly installed and appropriately commissioned. The skill set to make that a reality is dwindling every day. You can do as much Google research as you want. But at the end of the day, there's likely no one in your market who can design, install and maintain the technology you think is best. The worst thing that can happen is the builder becomes complicit with the HVAC contractor's incompetence and earnestly tries to give you what you want. Then you will experience a substantially miserable situation. I've seen it hundreds of times and testified as a witness in numerous cases. It's an epidemic problem that's getting worse. To reduce the risk, you must stick with something simple and familiar. Even that will be an uphill battle with proper design.
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Well, I will ask for what I want and will ask lots of questions of the people who will do the work. If I get a sense that there's no experience with this stuff, I won't have them do it. Thanks for the warning to keep it simple.
So, where do people find people with the qualifications for current HVAC tech?
If I knew, I would share it. It seems the brightest and best don’t do new homes. It doesn't take long for the ones who can count $$ to figure it out.
My wife works for an HVAC contractor who’s been extremely successful for some 40 years. They have exceptionally talented people. But they won’t touch a new home. The profit is just not there.
These folks can choose to spend their talent pool on changing out systems, that usually takes one to two days for $3k-$5k gross profit. Or they can choose to do a new home that could take 2 to 3 weeks, over 8 months to a year. Even if the gross profit is 2x, it doesn’t take a math genus to figure it out.
The ones that do new construction profitably seem to have it down to a franchise-like operation. That’s why when you suggest cooking fries with an air fryer, they run the other way. No need to mess up the plan, even if your ideas are head and shoulders better.Just my observation.
I’m learning to retire . But I can tell you if it weren't for HVAC incompetence, my meager income would have suffered a drastic hit over the last 20 years or so. And the inventory of those failures is growing everyday.
Exactly right. We are a 55 year old HVAC company and we stopped installing systems for spec builders 20+ years ago, not worth the risk, trouble and low profit. If I could offer some advice to buying quality HVAC, seek out the HVAC contractors in your area that have the best reputation and reviews, chat with them to see who fits your vision the best, and then pay them what they want. You have a good chance of being happy in the end. Any high quality HVAC company (or any business for that matter) that is truly pricing to provide the best design, service and install and make a reasonable profit that justifies the risk will likely be 25-50% higher, maybe more, than "Chuck in a truck" that is just making a day's pay. If your shopping for lowest price because you think its just about what the equipment costs online, you will get screwed. The big cost is not the equipment, its the design and installation expertise (and support after the install) that is where the cost is. Speaking of equipment, we stick with 3 main equipment manufacturers, 1 for "traditional" systems, 1 for "ductless" and 1 for hydronics. We can design/install a great system 99.9% of the time by sticking with those 3 lines (and some minor others for IAQ, pumps, etc). We do this because we know the equipment inside and out (install & service), we get great support and I have leverage when I need a favor. If you request something outside that box, I'm probably not going to sell it to you for those reasons.
At the end of the day, its our reputation and we install what we can support, what poses the least risk and not necessarily the system that offers a .5 higher SEER on 1 model for example. Usually equipment from a major brand is the least of your concerns, choose best support over best features or top efficiency always, in my opinion.
FWIW, I just built a 1,900 sq/ft house, installed 100% of the HVAC myself, bought all at wholesale cost, and I'm shocked at what I spent! Great HVAC is not cheap!
Sounds like this is a production home. Not a bad thing if it is, just is what it is. Here a few of my thoughts having working in the industry and around these types of homes.
They will have subcontractors priced for specific units and systems and deviating from this set menu of options can be quite expensive for you as the purchaser. The subs are most likely extremely busy, don't have the parts pre-purchased and most likely just don't want to deal with it. Additionally, if you go with a system off menu, the tech installing it may not be familiar with that systems install best practices or how it is supposed to function properly. So additional cost is not surprising but also does not guarantee that it will still be installed correctly. Thus, take pictures.
If you do decided to go with a more efficient, HVAC system (which I think you should) the worse case is if they really don't want to do it or if they are charging way to much is ask the project manager if they would be willing to take it out of their scope of work. If they say they would be then go and solicit a bid for the system yourself. If you get a proposal that you like then, and only then, signup the guy that you found and go back to the PM and have them write up the change order for removing it from their scope of work and giving you the credit for their base spec'd system that was in the original contract.
Now the remainder of my rambling thoughts on this:
First is if you are, or once you are, under contract on the home politely communicate with the builder that you will be onsite often and will take lots of pictures often. Be courteous to them and notify them before you show up so the superintendent can walk with you (safety issue). This is one of the biggest investments most people make and you want it documented and want to understand how your home is being built and to see progress, but be extremely patient with them with the schedule.
I would first make sure that they are meeting code requirements. Best way to find out is to ask the builder what code this house was permitted under for IRC and IECC. Then go to the building department who issued the permit and confirm this is correct (trust but verify).
Now if it was more recent I believe that your state adopted 2018 IECC which would be less than 3ACH. However, I imagine it was permitted under a previous code as no mention of an ERV has come up since IECC states that we must mechanically ventilate if tighter than 3ACH.
Once you know what code it was permitted under than you can read through that code online on ICCs website for free to know what they are supposed to be doing.
Make sure that they are hitting the required air sealing requirements and require that they provide you with a blower door test result. Also, once you decide on a mechanical system require that they provide to you a ACCA Manual J and Manual S for review and your records. If you can squeeze those out of them you may also want to ask for a Manual D & T, probably wont get them, but worth a shot. If anything it will nonverbally communicate to them that you are aware of the codes and the calcs and the Super may spend an extra 10 minutes making sure that things are installed correctly for his own CYA. Again, be respectful but don't let them roll over you. Make sure they are following the codes and they are nailing the primary control layers (In order: Bulk water, air barrier, vapor barrier, thermal barrier).
Please don't take this as bad mouthing or bashing of this type of construction. Just voicing my thoughts on past experiences and observations. These homes serve a large purpose in the market and most builders are doing their best with the resources they have. Just be aware and be involved.
Thank you, this is very helpful advice.
This is considered a semi-custom home. Meaning, I'm selecting a pre-existing plan, but can change some things.
I think you have a good angle on this. I've proposed, per another poster, an allowance system for the HVAC system so that we can work with their sub/supplier. Failing that, I will try your approach.
I'm convinced of the zoned approach with ducted mini-splits but am afraid I won't be able to make it happen since some modifications to the plan need to be made to tuck the units away in walls, closets, etc. They likely have ductwork pre-factored into the design so I'll have to see what is possible and what is not. Otherwise, just getting the heat pump in place and running the standard ducted air handler with a couple of old-school zones may be the option to keep it simple. I won't get the full benefit but it's better than nothing.
Who would have thought getting a new home built with modern tech would be so difficult? I thought new construction was your chance to go with new stuff!
"Who would have thought getting a new home built with modern tech would be so difficult? I thought new construction was your chance to go with new stuff!"
It really depends on the type of new construction. On a production build it can be very difficult to make changes outside of finishes. Some builders even have HVAC companies pay builders to install rental HVAC systems that purchasers are obligated to take! Even full custom where the builder owns the land can be a bit challenging.
My current build is fully custom where I bought the land, choose and hire directly architect, surveyor, structural engineer, HVAC engineer, GC builder and subs. I can do anything I want within building codes and zoning by-laws. Even then, my wish list is tempered by budget and practical advice from my consultants.
It sound like it's being built to something fairly old like 07 IECC since the OP mentioned 2x6 R21 walls and no external insulation.
I have purchased a new house before like that from a production builder. They will price any changes not based on market value but on how much buyers want them and whether they want to do them. There are upgrades that everyone buys because the base is so basic it doesn't suit the house. They make good margin on those. There are some that they will price at huge mark-ups just to dissuade you from taking them. And if you do, they have enough money for the trouble. Sounds like HVAC is the latter, they want you to stick with the standard (almost all buyers do so they don't want to manage any changes in HVAC. The sub may even install the standard on auto-pilot and not look at a change order and then the builder refuses to change it. I've seen that happen)
There are many change decisions in a new build. You just have to decide how important the HVAC is given the restrictions the builder is imposing and try to upgrade it within reason, pay the huge premium for what you want, or change it later. This was back in 2000, but in my case I let them install their standard minimum code 80% furnace and low seer AC and changed it out at 10yrs for a 98% modulating furnace with a high seer heat pump, well before the useful life of the old system. The performance difference was huge and if I had to do it over again, I would probably change it at 5-8 yrs whenever there was an government energy incentive.
“I'll wager that she would go for induction if it could be maintained and kept looking nice. The appeal of gas is mostly the iron grates that are impervious to scratching, unlike glass.”
My induction glass looks like new after almost 5 years of daily usage.
They may look like the old fashion hot glass cooktops but they are a very different animal. Get one you will not be sorry.
Walta
My advice would be to shop around and find a builder who is willing to work with you and your specific needs. Don't settle for a system that you're not happy with just because it's easier or cheaper. As for financing your new build, you may want to consider speaking with a mortgage broker in Shrewsbury https://birminghammoneyman.com/mortgage-broker-shrewsbury/ . They can help guide you through the process and find the best mortgage option for your situation. Good luck with your new build!