Energy Remodel
Hey there,
I have a 3/1 sfh built in 84 that I want to do some energy improvements to next spring. Based on the articles I’m reading on here I’m trying to put together a timeline and figure out all the contractors I need to involve and how to make the decisions for each part of the project so that they don’t conflict. Just looking for feedback on what I am thinking about and how to find the right people.
I am the Wasatch front in Utah, so dry zone 5. While I’m looking for efficiency especially during heat waves I am also concerned about the declining air quality due to the increasingly exposed lakebed, so an HRV system with filtration or something similar is at the top of my list if it works for the structure.
I would like to take the house all electric if possible, from a gas water heater, furnace, and fireplace with electric central air. I understand this is somewhat dependent upon how tightly the building can be sealed and insulated. I want to change the size of the kitchen and add a bathroom, which I think need to happen before any sealing or designing an HRV system since I understand these are the rooms from which stale air is typically evacuated.
Plan:
-Complete bathroom addition and moving walls etc
-Energy audit and envelope sealing/radiant barrier in the attic and similar
My main concern based on my very limited knowledge is sealing up the envelope and adding mechanical ventilation might cause air quality problems with the remaining gas water heater or furnace during this process or in the event that all electric is not a viable option. Any thoughts on this being an actual issue or not? Anyone installing any sort of ventilation will be able to model and account for this right? This is the portion people I’ve talked to seem the least familiar with, at least on a remodel rather than new build.
I have looked at some contractors who do either the mini split install or the audit and insulation, but I feel like I need someone experienced with all of these systems to help me design and coordinate the whole process so there aren’t unexpected conflicts or shortfalls in performance that leave the home in a bad spot. I’ve talked to a few architects who said they didn’t have the most extensive experience with this combination of projects, so I’m thinking I should be finding a mechanical engineer who specializes in sfh systems or something similar since the HRV seems to be the portion I’m not finding people with much experience with? I’m not sure where to look or how to search more specifically than I have been.
Any feedback, suggestions, or referrals would be much appreciated.
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Replies
Try this if you have existing fuel usage: https://www.greenbuildingadvisor.com/article/replacing-a-furnace-or-boiler.
You might not need to reduce load at all to switch to a heat pump, but the data will help you with that. That puts the air sealing and insulation in the comfort/savings bucket in my opinion. If you have an existing ducted system, adding a centrally ducted heat instead of ductless heads makes a lot of sense - they’re cheaper to replace, provide better distribution, better filtration, and can match loads better. Do you have existing AC?
A lot of this work is dependent on other parts to some degree, but the electrification portion less so. You could change out the water heater and fire place tomorrow if you wanted.
That is a great resource, thank you! I do have existing central air. I have been thinking of the ductless largely because I have allergies and have always done better in buildings done with mini splits vs ducts, but also just because of the zone climate control. Differences in performance or cost for a central heat pump might be enough to persuade me otherwise though. Thank you for suggesting it, I'll be sure to compare.
Interesting! Often it’s the other way around - the ductless heads can grow mold and they’re more challenging to clean and they have awful filter options. Central should be significantly cheaper and the highest end central units will be as efficient (or close to ductless). Beware multi-splits, which are one outdoor unit tied to several indoor units, especially if they try to install a ductless head in every bedroom. That pretty much guarantees poor performance.
Thinking about it, it wouldn't surprise me if all of my experiences with these systems were pretty new and maybe hadn't gotten to those problems yet.
Having a head in each room seems to be the main selling point half the time when I hear about them. Is it just the amount of volume in multiple rooms to the single outdoor unit that kills performance?
Usually the opposite actually - the outdoor unit inevitably is much too large for the indoor units so they cycle on and off inefficiently and over heat/over cool the rooms because even when some rooms are off, refrigerant is flowing through them. The smallest ductless head is usually 6,000 btu, which is too large for most bedrooms.
In general your plan seems pretty straightforward. Regarding air sealing, the best time to do it is probably during construction, when everything is all opened up. If you're able to do your project as one big project where you do everything, rather than a bunch of little ones, that's probably better, although I understand that there are frequently practical reasons that prevent that!
"I’m trying to put together a timeline and figure out all the contractors I need to involve and how to make the decisions for each part of the project so that they don’t conflict."
If you're able to do the whole project at once, this sort of coordination is exactly what a general contractors job is. You can save some money (as long as you don't screw anything up!) by doing this coordination yourself, but you can save a lot of heartache by hiring a GC to manage all the subcontractors for you.
I agree with Paul that it is worth exploring the option of reusing your existing ducts and swapping your furnace to a heat pump. There's a whole lot of "it depends" in terms of figuring out the right approach however, so talking through the details of your project with an HVAC designer might be a good way to figure out what makes the most sense.
Hiring a mechanical engineer with experience with single-family homes to design the system is probably wise, unless you can find a very reputable mechanical contractor who specializes in high-performance homes, ERVs, heat pumps, etc. It is common for residential mechanical contractors to design systems based on rules of thumb that are not going to give optimal results in a project like yours. Having a mechanical engineer to do the design can solve that problem. Regarding hiring a mechanical engineer, Allison Bailes is a frequent contributor on GBA and you could always reach out to them! https://www.energyvanguard.com/
In terms of looking for an architect (or a design-build contractor, also a very appropriate choice for this type of project), have you looked for ones who advertise that specialize in green building? "Kitchen and bath renovation + air sealing + improved ventilation + switching to all-electric" shouldn't be a particularly exotic project for anyone in the green building world. If you do hire an architect or a designer, discussing with them whether they should hire the mechanical engineer as a consultant or whether you should hire them directly would be a reasonable conversation (similar issues with coordination and scheduling in terms of hiring a GC vs being your own GC).
If you're struggling with finding green builders, one place to start would be looking at this directory of passive house designers and builders in your area: https://www.phius.org/find-professional?_page=1&keywords=&_limit=10&area=110
Not because you want a passive house, but because I would expect anyone who's gone through the PHIUS certification process would be very comfortable with your project's goals, and PHIUS publishes the handy dandy list of certifications! There may be other local green building certifications and directories that could be useful to you, but I don't know what they are in Utah.
Lastly, one airsealing option you might do a little research about is Aerobarrier: https://aeroseal.com/aerobarrier/ and while the marketing is perhaps a little over the top selling it as a miracle cure for everything, it could be a good fit for a renovation like yours. It's also not the only approach, just an option!
Great points, thank you. I have looked for architects or design-build contractors but most of them seem to be focused on projects more high end residential or institutional. I have spoken to the one I mentioned in my post, but maybe I just need to reach out to more and see what they say. She was willing to work on the project though for figuring out the more traditional remodel elements, so maybe the move is to find a green building GC who has done refits.
PHIUS seems so obvious now that you've brought it up haha. I had looked at BPI and RESNET but this has already given me a few great leads, thank you. I will check out Energy vanguard and also aeroseal. I've seen several contractors talk about using it.