GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Using an HVAC Consultant

leon_g | Posted in General Questions on

I’m pretty much sold on the idea of using an outside consultant to design the HVAC system for our new home construction.  I’m thinking Energy Vanguard, HVAC Design Pros, or similar).

It’s a fairly expensive proposition (~$2500 for full heating & cooling design, load calculation, equipment selection, duct design, and grille & register sizing).  I’m guessing it’s money well spent compared to having a poorly designed system.

But I have a couple of questions before I lay out this kind of money:

– Will these consultants work with me collaboratively to understand my planned use for the house, to define the various conditioning zones?

– Would they try to find the best solution for installing the equipment to keep it out of sight yet accessible for service?  I’m asking because we have no attic or crawlspace, so we’ll need to run ducts in soffits, and try to mount equipment probably in closets or small spaces that we can still add to the layout.  So I’d want to make sure that they don’t just throw the equipment notionally onto a sketch, without discussing the best way to actually install the equipment.

– Probably most importantly, how likely is it that I’ll be able to find an HVAC subcontractor who’ll be willing to execute the design?  Have people had luck with that, or do the HVAC contractors resist implementing someone’s else’s design, either out of ignorance or because they don’t feel that they can’t stand behind someone else’s design?  This design service won’t do me much good (other than having the Manual J calcs) if I can’t get it executed.

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. Patrick_OSullivan | | #1

    You should ask each of those companies those first two questions, but generally speaking, I would expect them to.

    > Probably most importantly, how likely is it that I’ll be able to find an HVAC subcontractor who’ll be willing to execute the design? Have people had luck with that, or do the HVAC contractors resist implementing someone’s else’s design, either out of ignorance or because they don’t feel that they can’t stand behind someone else’s design?

    It's possible, but atypical. Minisplits are easiest because you basically can tell them "this is what I want, where" and that's it. However, a properly designed ducted system is likely to be different than what they normally throw in. I used an installer someone here recommended and they worked with me overall, though I did have to get on them about a few things. Broadly, I believe you'll have a better experience with an installer who also does a fair amount of commercial work where it is common to be installing a system someone else designed.

  2. brian_wiley | | #2

    Perhaps it’s obvious, but if you’re able to find a mechanical engineer that’s local to you, they may be able to recommend an installer in your area that they already have a relationship with. That might be worth asking as you begin to speak with them. Our mechanical engineer was able to recommend a couple different installers that they had worked with.

  3. leon_g | | #3

    Brian, Patrick, thank you for the replies. I've called many places in my area (Portland OR) and I can't find a local mechanical engineer to do the design. The ones I was able to reach only do commercial projects. When I called HVAC contractors, most of them don't do new construction. The one or two that I found who do new construction did not impress me as being even remotely as comprehensive as Energy Vanguard would be - but on the flip side, they would execute whatever design they (the contractor, not the consultant) came up with. My fear is that I can get the most beautiful system in the world designed by a consultant, and then not find anyone to execute it.

  4. Expert Member
    BILL WICHERS | | #4

    Most engineers work primarily on commercial projects. I say this as an engineer who works mostly on commercial projects :-) The reason for this is that residential projects are generally not "engineered", and the closest thing to an engineer on a typical residential project is the architect. Architects are not usually well versed in mechanical/electrical systems, so you get rule of thumb design. Residential projects are often fine with this, even though it's not ideal, since residential projects aren't usually complex enough that they have serious problems if an engineer is NOT involved. Commercial projects also pay better, and we consulting engineers do like getting paid...

    Anyway, in the residential world, "energy raters" are often the first step towards optimizing your system. Such firms will likely have engineers they work with when needed too, and since they have ongoing buisness relationships, the engineers will work on their projects.

    You generally do NOT want an HVAC contractor doing your design work. In the commercial world, this almost never happens -- there is almost always a set of engineered plans for all the trades to follow. In the residential world, HVAC contractors often bid full installation packages, and do the design too. Since the HVAC guys are worried about problems if they undersize a system, they tend to "go big" to be sure the system will be at least enough to get the job done. This tends to result in suboptimal systems that cost the owner too much in terms of purchase price, and don't keep the home as comfortable as a properly designed system would.

    I'd try the folks at Energy Vanguard and see what they say. They are easy to work with an well respected by the folks on GBA.


  5. Expert Member
    ARMANDO COBO | | #5

    Using local contractors is a crap shoot, and you need to “force” them to do the right thing, from calcs., to design, and then the install. There is a handful of contractors that will do the right thing; and to be fair, many HVAC contractors grossly oversize their system since most homes built are of horrible build quality. Some others are not educated, and some are just dishonest or lazy.
    Not long ago, I designed a house for a Mechanical Engineer, who wanted 3 units with 9 tons for 3,700 sq.ft. When I go thru working with my HVAC guy, we had 1-3ton unit. The owner has lived in that house for three years and loves it.
    Using a third party HVAC contractor is a wise move, but it’ll cost you from $0.50-0.75 per heated sq. ft., and is up to you to make sure you find the right contractor to follow your design.
    I’m using Energy Vanguard: contact Luke Bertram, [email protected], 478.954.4436

  6. mgensler | | #6

    We just went through this process. We had an architect make a recommendation of a mechanical engineer they had worked with. The engineer did the design although we did the manual J and fuel based consumption calculation which we gave to the engineer. The engineer was very open to ideas generally espoused on GBA such as return filter grilles, low friction fittings, etc. It was much more difficult to find a contractor. I think this is due to how busy they are and not because we had our own design.

    1. Expert Member
      BILL WICHERS | | #7

      All of the trades are super busy right now. Everyone is having a much more difficult time that usual scheduling projects too, because there are a lot of parts shortages too. Crazy times right now in the building world.


      1. jonny_h | | #10

        Can confirm -- I've been trying to get an insulation contractor to quote dense-pack cellulose for me, and it's taken a couple months and I don't even have a quote yet (and the most promising guy also just wanted to closed-cell spray foam). Finally just got a quote on HVAC (after another month and a half of waiting), which was both exorbitant and not what I was looking for -- to be fair, I did tell the guy I was looking for a couple specific mini-splits but was open to other options, so other options was what I got. Also, leadtimes on even getting the equipment are reportedly months. Still, $16k for a Fujitsu ductless head and an American Standard heat pump / air handler, not including any ductwork, seems a bit high -- time to go get my EPA 608 card and a few new tools ;)

        As a side note, I'm in electronics, and the chip shortages people talk about are a very real thing. I just had a manufacturer quote leadtimes of 68 weeks across the board with a straight face -- but don't worry, they're building new fabs.... that'll be online in 2025. Nobody I've talked to has ever seen anything this bad in the past.

  7. leon_g | | #8

    Armando, can you tell me how your experience with Luke from Energy Vanguard has been in regards to my first two questions above? I'm asking because I received an email from him offering the services I mentioned earlier, and I am curious how much interaction you have with him during the process. I have not yet been able to reach Luke, and they have an 8 week backlog :(.

    I also heard back from yet another local Portland designer, listed in Martin's registry, who told me they don't do new construction design. Sigh. But they did give me a name of a local installer whom they've used, and who according to them would be willing and able to install a system as designed by someone else. I'll call that company tomorrow to confirm. So there's hope - and an 8 week wait!

  8. AC200 | | #9

    What you describe is standard practice here for a custom build. Architect produces construction drawings. Structural engineer and HVAC engineer are engaged along with truss designer. Package is submitted to city for building permits. I'm hiring all them independently but my architect has a list of specialist he has worked with in the past.

  9. pandirisaivikas | | #11

    It's late but I still wanna answer the questions because it may help somebody else. Most consultants should work collaboratively with you to understand your planned use for the house and define the various conditioning zones. As for equipment installation, they should also try to find the best solution for your specific space limitations.
    Regarding finding an HVAC subcontractor to execute the design, it can be tricky, but it's not impossible. It's worth asking around and doing some research to find a contractor who is experienced in executing designs from consultants. I've had a great experience with Appliance Repair, Nashville and can recommend them. Anyways, good luck everybody!

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |