10 Questions to Ask When Hiring an HVAC Contractor for a Healthy Home

When it comes to hiring an HVAC contractor your builder is typically the one who chooses who gets the job, but should you always go with your builder’s recommendation?  What are your options?  And does it really matter which HVAC contractor they choose?

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Your HVAC system is CRUCIAL for building a healthy home!  Educating yourself about HVAC options is the wisest investment of your time that will greatly improve your chances for excellent indoor air quality, consistently comfortable temperatures, and affordable utility bills.
 
Once you understand the importance of your HVAC system, you can be involved with the selection of a contractor with the specified abilities your healthy home is requiring.  

​This selection process should start while the home is still in the design phase.  Collaboration between your home designer, builder, and HVAC system designer will assure your home can adequately accommodate mechanical rooms and chases needed for the system to be installed properly.

The earlier in the design process you select 
a skilled HVAC contractor, the better.

Photo credit: Master 1305

Not All HVAC Contractors are Equally Skilled 

There is tremendous disparity between HVAC contractors ranging from scam artists, to contractors who do things the way they’ve always been done even though the construction industry continues to shift towards higher-efficiency homes, to contractors who have gone out of their way to educate themselves about best practices for healthy HVAC system design and install.  Unfortunately, there is little continuing education available for most HVAC contractors and the industry is severely lagging behind current construction trends.

Why Won’t the HVAC Industry Do Things Right?

So, how do you find a quality HVAC contractor?
 
When researching contractors, you will come across advice from sources like Angie’s List, BBB, and from HVAC contractors themselves, and this is a GREAT place to start…but it’s only a start.  
 
Most advice offered is to help you avoid scams, because scams are still a BIG problem in the HVAC industry:

• Are they certified?
• Licensed?
• Insured?
• What is their BBB rating?
• Do they drug test?
• Can I get a written estimate?

 
Unfortunately, once you do find a legit HVAC contractor, chances are high they don’t know how to design or install an HVAC system to meet a high-performance home’s specific requirements, even though they’re certified, licensed, and insured.

Every house has different HVAC requirements!

The following are questions homeowners typically don’t know they should ask when vetting an HVAC company. 

Photo credit: Senivpetro

Questions to Ask When Vetting an HVAC Company

1. Are they the lowest bid?
When shopping around for an HVAC contractor you can pretty much assume the lowest contract bid is going to yield in the lowest performance HVAC system.  In the HVAC industry, you really do get what you pay for.  Ditch the low contract bids and inquire further into the contractors who know the value and importance of the services they provide.
 
2. What are their recommendations for designing an HVAC system that works effectively in tandem with a high-performance home?
Since the 70’s, government mandated code changes required new homes to be built high-performance to offset the impact of the oil crisis.  Because homes are designed and built to be so airtight, it is IMPERATIVE that your HVAC contractor knows how your HVAC system will provide enough clean air flow in, out, and throughout your home.

Manual J Calculations by Energy Vanguard

3. How do they calculate for HVAC heating and cooling loads?
If they measure using the square footage of your home and approximate 400 to 600 square feet per ton as a general rule of thumb, run for the hills!
 
These common miscalculations almost always lead to oversized units which are not only more expensive, they’re also a health hazard.

Why Bigger is not Better when it comes to HVAC

If they follow Manual J load calculations by taking into consideration actual ceiling heights and TOTAL volume of air space, along with your home’s insulation levels, orientation, window types, and areas of all the surfaces that gain or lose heat, then you know they’re on the right track.  Continue on to the next question.

What is Manual J?

4. Are they ALSO able to guarantee the appropriate airflow required by code?
If air isn’t flowing, it isn’t being filtered which can lead to significant negative health impacts.
 
The HVAC industry is still currently set up such that the amount of airflow supplied by the air handler is typically factory matched to the HVAC unit’s tonnage.
 
This is a BIG problem because once the HVAC unit is appropriately sized to accommodate comfortable heating and cooling with a smaller unit, air flow is also reduced. 
 
Reduced air flow leads to sick homes and sick homeowners.
 
If the contractor you’re interviewing is aware of the disparity between Manual J load calculations and airflow requirements, continue on.
 
If not, run for the hills!  This is danger zone!

5. Do they follow Manual S, Manual T, & Manual D?
These manuals have been designed as protocol for designing and installing a properly sized and fitted HVAC system required by code.  Without following the entire line of protocol, you may end up purchasing a high-efficiency HVAC unit that loses its efficiency in its delivery and potentially causes indoor air quality issues.  Not to mention your home won’t pass code, which you, the homeowner, are completely liable for.  You’d be shocked by how few HVAC contractors follow these Manuals!
 
If the contractor you’re interviewing doesn’t know about Manuals S, T, & D and can’t explain exactly how they follow protocol to design an HVAC system, or God forbid, try to convince you they’re not necessary, run for the hills ASAP!
 
If they can show you how they use the following protocols, you know they’re on the right track:

• Manual S to select equipment
• Manual T to determine location and size of supply registers, diffusers, or grills
• Manual D to design the duct system

What are Manuals S, T, & D?

Photo credit: Lennox

6. What do they recommend for ventilation?
Once homes became more airtight with the advent of high-efficiency construction, mechanical whole house ventilation became absolutely necessary.  Without mechanical ventilation, airtight homes suffer with horrible indoor air quality from lack of fresh outdoor air flow.
 
If they don’t immediately recommend mechanical whole house ventilation, run for the hills!
 
If they suggest an Energy Recovery Ventilation (ERV) system, then you know they’re on the right track.  

What’s an ERV?

7. What do they recommend for air purification?
If they suggest ozone air purifiers, run for the hills!  Ozone is dangerous and should NEVER be added to your indoor air.  When inhaled, ozone damages the lungs!  

EPA: Ozone Generators that are Sold as Air Cleaners

Photo credit: Comfort Zone Heating & Cooling

8. What air filter MERV rating do they use?
The higher the MERV rating the better the filter is at trapping smaller particles.
 
If they use anything lower than a MERV rating of 13, run for the hills!
 
If they recommend a high-MERV filter of 13 or above AND they know how to design your system for low pressure drop across the filter, continue on.
 
Note: It is CRITICAL they know how to design for low pressure drop across a high-density filter, otherwise your home will not receive the proper air flow and your system will work too hard to move the air.

What is a MERV rating?

9. Do they offer a guarantee for their services? 
If they’re not able to back up their work with a guarantee, chances are they don’t feel confident about their work.  And if they don’t feel confident, then why should you?
 
10. What are their reviews and references? 
If they struggle to come up with compelling reviews and references, you should take this as a sign that they’re not providing the quality of service you deserve.  

Photo credit: Pressfoto

Thoroughly Vet and Hire the Right HVAC Contractor from the Start 

Do not wait till your home is in its final construction drawing phase to select an HVAC contractor!  Do not turn a blind eye and leave HVAC contractor selection solely up to your builder!  And do not pinch pennies when it comes to HVAC!

HVAC is CRITICAL for a high performing healthy home!

Consider the investment in a highly skilled HVAC contractor an investment in your future…or it could cost you your health in the long run.
 
Come back on March 15th for more home design inspiration with 6 Genius Steps for Mold Prevention, Remediation, & High IAQ.
 
I intend you utilize these valuable questions to find the BEST HVAC contractor for your home from the very beginning.
 
Inspired by you,

​Jenny Pippin, CPBD, FAIBD, CGP
Pippin Home Designs

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