The 7 Deadly Sins Committed By HVAC Contractors
Heating and air conditioning contractors, like the rest of the human race, make mistakes. They make mistakes that hurt performance and efficiency of the HVAC systems they install and maintain. They make mistakes that hurt their customers sometimes. And they make mistakes that hurt their businesses. Let’s look at seven of the biggest mistakes today.
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 in the RESNET protocols and building analystsin 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 deal with HVAC and HVAC contractors all the time.
If you’ve read our blog, you know that I write about HVAC a lot, and many of those articles point out problems. Turns out, they’re 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 it seems that the majority does. 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 sinful contractors.
Here, then, are what I see as the 7 deadly sins committed by HVAC contractors:
1. Not understanding combustion safety
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 for the National Comfort Institute training people in combustion safety and air flow, wrote a guest postfor us a couple of years ago about this very issue.
The problem is that most HVAC contractors don’t know enough 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 ‘the box’ and ignoring air flow
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 that I do. If all HVAC contractors were pros, no one would know what a ductopus is. If HVAC contractors understood air flow, most duct systems would be larger than they are.
Mike MacFarland of, a home performance contractor in California who also does HVAC, told me at last year 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 trying to adapt the existing ductwork would lead to more trouble and expense than just starting over.
3. Ignoring the opportunities in 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 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, 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 $7000 contract or a $20,000 contract?
4. Forgetting the V 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 air tightness. 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 3 strategies for providing mechanical ventilation (positive pressure, negative pressure, and balanced)? Have you measured the air flow in your ventilation systems?</p>
5. Skipping 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. 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. 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. Failure to use 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 sin 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, and smart HVAC contractors know this stuff.
The bottom line
As 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 else underbid you. Also, if you’re committing the 7 sins 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
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Posted In: ACCA Now, Building Performance, Residential Buildings
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