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Building Science

The 7 Biggest Opportunities for HVAC Contractors

Forget about being the low bidder — it’s time to focus on combustion safety, ducting, ventilation, load calculations, home performance issues, and house-as-a-system thinking

Image 1 of 4
A sharp bend in flex duct reduces air flow dramatically. The HVAC company that installed this duct missed the opportunity to get the air flow right.
Image Credit: Energy Vanguard
A sharp bend in flex duct reduces air flow dramatically. The HVAC company that installed this duct missed the opportunity to get the air flow right.
Image Credit: Energy Vanguard
Release the Kraken! The ductopus is a monster that shouldn't be part of any HVAC system.
Image Credit: Energy Vanguard
Doing the math is essential to a good HVAC install. Relying on rules of thumb or incorrect techniques like Manual E, shown here, often results in poor performance.
Image Credit: Energy Vanguard
When you're trying to heat and cool a home with building enclosure problems like this huge hole in the attic, you're missing the opportunity to serve your customer better. HVAC isn't separate from the building enclosure, so including home performance is a big opportunity for HVAC companies.
Image Credit: Energy Vanguard

Heating and air conditioning contractors have a lot of opportunities to make homes better and to be profitable. The surprising thing is just how few HVAC companies take advantage of all the opportunities that are available to them.

Although my company, Energy Vanguard, is not an HVAC contractor, we have a lot to do with heating and air conditioning systems. We train home energy raters (a.k.a. HERS raters) in the RESNET protocols and building analysts in the BPI protocols. We also do quality assurance for HERS raters, which requires us to enforce guidelines for programs like Energy Star New Homes. We may not be licensed to install and maintain equipment, but we know a thing or two about HVAC because we deal with it all the time.

If you’ve been reading my articles for a while, you know that I write about HVAC a lot, and many of those articles point out problems. It turns out that these problems are very easy to find because so many HVAC contractors leave big messes in their customers’ homes. Not all HVAC contractors work this way, of course, but I’d wager that the majority do. The good ones have successful businesses not only because they do good work for their customers, but they make more money by coming in and cleaning up the messes left by the sloppy contractors.

Here, then, are what I see as the top seven opportunities for HVAC contractors:

1. Looking for combustion safety problems

If an HVAC contractor responds to a call about carbon monoxide, they’ll usually go straight to the furnace and look for cracks in the heat exchanger. When they find that it’s OK, they often assume it must have just been a false alarm, so they change the batteries in the CO alarm. David Richardson, a former HVAC contractor who now works fulltime for the National Comfort Institute training people in combustion safety and air flow, wrote a guest post for us here a couple of years ago about this very issue.

The problem is that most HVAC contractors don’t know much about backdrafting of combustion appliances. Nor do they test for it. If you’re an HVAC contractor and not testing for flue gases and worst-case depressurization on these calls, you’re leaving a potentially dangerous situation. You never want to find out the next day that the people in the house you just visited are in the hospital with CO poisoning.

2. Focusing on air flow, not just “the box”

This is the problem that I’ve probably written more articles about than any other. If the vast majority of HVAC contractors did professional quality work, I wouldn’t be able to go into house after house after house and find the kind of duct problem you see at the top of this page. If all HVAC contractors were pros, no one would know what a ductopus is (see Image #2, below). If HVAC contractors understood air flow, most duct systems would be larger than they are.

Mike MacFarland of Energy Docs, a home performance contractor in California, told me last year at Building Science Summer Camp that he pretty much never does a system changeout without also doing a duct changeout. Why? Because he knows that the existing ductwork, even if it’s relatively new, probably wasn’t sized right, is too leaky, and would lead to more trouble and expense than just starting over. Not all customers will have the budget for that, but make sure they know about the cost of keeping the crappy system they have now.

3. Expanding services to include home performance

In the residential market, HVAC contractors go into people’s homes every single day. They go into attics, crawl spaces, and basements, where they can see the quality of the insulation and air sealing in the home’s building enclosure. Even if the HVAC contractor doesn’t do the insulation and air-sealing work, it’s a great complementary service to advise the homeowners on the other work their home could use to improve its overall performance.

It seems a bit paradoxical that so many HVAC company names include the word “comfort” yet they don’t really address all the issues that affect comfort. Once you truly understand that naked people need building science, you know that mechanical systems aren’t the answer to all comfort problems.

And if you walk out of a house without looking at all of the home performance issues, you’re leaving money on the table, as the saying goes. Would you rather walk out with a $7,000 contract or a $20,000 contract?

4. Putting the V back in HVAC

Ah, yes, ventilation. The insulting way to state this is that any HVAC contractor who doesn’t address the V in HVAC is just a HAC (read: hack). New homes are tighter than ever because of energy codes that require higher levels of air-sealing and in some cases, blower door tests to verify the airtightness. Tight homes need mechanical ventilation. All homes need spot ventilation in kitchens and bathrooms.

Are you really including the V in HVAC? Do you know what ASHRAE 62.2 is? Do you understand the three strategies for providing mechanical ventilation (positive pressure, negative pressure, and balanced)? Have you measured the air flow in your ventilation systems?

5. Doing the math

My friend John Barba, a trainer for hydronics manufacturer Taco, suggested this title, and I love it. HVAC contractors like rules of thumb. (See Image #3, below.) They also rely on what they think worked in the past. “Son, this is the way we’ve always done it around here, and we’ve been in business longer than you’ve been alive.”

Well, guess what. Heating and cooling systems aren’t the same as they were 50 years ago. Nor are homes. Rules of thumb don’t work because every house is different. If you want to size a system properly, you’ve got to come up with some way of getting at the rate of heat loss and heat gain in the home you’re working on. Manual J is probably the best way for new homes, and timing the existing system’s runtime during design conditions is the best for existing homes (if you have that option).

HVAC systems are complex technology. If you’re relying on rules of thumb or doing things the way you’ve always done them, then you’re not serving your customers well.

6. Not trying to be the low bidder

The race to the bottom results in everyone being a loser. The ones who don’t get the contract lose. The one who gets the contract can’t do the work properly because they have to scrimp on labor and materials. And the homeowner loses because, as the saying goes, you get what you pay for.

When contractors try to get low-bid work, they have to keep all their costs as low as possible. They hire poorly trained techs and then don’t do enough—or anything—to get them trained properly and keep them updated. They use equipment that won’t last. They do the least work they possibly can on the distribution system. (See #2 above.)

This is no way to run a business. Because there are so many companies willing to do this, though, there will always be room for smart contractors to come in and do things right.

7. Using house-as-a-system thinking

First, you’ve got to get to HVAC-as-a-system thinking by getting past the sins described in numbers 1, 2, and 4 above. Once you include combustion safety and distribution and ventilation in your scope, you’re ready to go beyond and look at the whole house. This leads to the opportunities in mistake number 3 above, of course, but it’s bigger than that. When you understand the house-as-a-system concept, you become a problem solver. You know how to listen to homeowners and help fix things so their daughter’s cough goes away or the mildew in the bathroom stops growing or that one room they can’t stand to be in becomes part of their living space again. This is Building Science 101, and smart HVAC contractors know this stuff.

The bottom line

If you’re an HVAC contractor, which path will you choose? One path leads to problems. You constantly have to find new customers because it’s hard for the ones you have to feel any loyalty to you if your work isn’t remarkable. And if your customers are always looking for the low bid, you may get them one time, but the next time you follow up with them, you find that someone underbid you. Also, if you’re making the 7 mistakes above, you may find your work featured in the Energy Vanguard Blog…as an example of what NOT to do.

The other path leads to greater profitability, happier and more loyal customers, more referrals, and peace of mind. The choice is yours, HVAC contractors.

Allison Bailes of Decatur, Georgia, is a speaker, writer, energy consultant, RESNET-certified trainer, and the author of the Energy Vanguard Blog. You can follow him on Twitter at @EnergyVanguard.


  1. LucyF | | #1

    HVAC advice when building a house

    Could you give a layperson advice on how to pick out someone who can help you evaluate the ventilation, heating and cooling needs of a home? I don't have much confidence the HVAC contractors in my area (Upstate SC) knowing much about this stuff.

    Thank you. Lucy

  2. watercop | | #2

    Quality HVAC
    First a quick bit of advice to Lucy, then on to some aspects of the main blog post...

    Lucy - find a well respected local energy rater or auditor and then ask him / her what HVAC contractor(s) perform well in situations where the home is under consideration as a system.

    As to the 7 deadly sins (or opportunities...same difference) described by Allison:

    1) We in Florida don't often deal with combustion appliance zones, but I often throw a flag on the potentially disastrous combination of gargantuan range hoods, tight homes, lack of operable kitchen windows, and fireplaces.

    2) Most homes have oversized systems connected to undersized, hopelessly unbalanced ductwork. I no longer ask IF there are uncomfortable rooms; instead I ask WHICH rooms are too hot or cold. At minimum we perform a room by room Man J load calc and then enlarge and balance ductwork to deliver required CFM to each and every room.

    Deeper projects include attic spray foam, dropping load by 1/3 or more, which then allows a single carefully ducted higher efficiency system to take the place of two or even three older, poorly installed systems. We QC the foam using blower door and theatrical fog.

    3) Home performance - while our core competence is high performance HVAC, our energy audits routinely uncover and report opportunities with far faster payback than HVAC investments - lighting, pool pumping, refrigeration, laundry, and others.

    4) Ventilation - pretty much every HVAC project that gets a load calculation also gets a blower door test. It takes just 15 minutes and allows us to replace a tightness guesstimate with a real leakage value. The blower door test at least partly informs ventilation concerns. At minimum, we insist that ranges be ventilated outside and bathrooms get quiet fans with timers independent of light switches.

    5) We apply Manual J to all changeout projects, not just new construction. Our goal is to furnish the smallest possible system consistent with comfort.

    6) We are rarely the low bidder, nor do we desire to so be.

    7) We always consider the house as a system, quod erat demonstrandum.

  3. GBA Editor
    Allison A. Bailes III, PhD | | #3

    Response to Lucy Foxworth
    In addition to Curt's advice, you can check out his article I wrote a while back:

    5 Questions to Ask When Replacing Your Air Conditioner

  4. facemyerac | | #4

    Asking Questions
    Great tip on focusing on airflow. Following this will tell everything about what to improve upon. Another great tip is asking questions to the customer on how they think they air conditioning system is performing. Listening to them will help pinpoint possible areas where the air flow may not be as good and lead to more opportunities.


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