Why HVAC Contractors Should Be Leading The Way

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We are an HVAC and plumbing company here in Southwest Oklahoma. We are still learning about home performance and how it affects the whole house and the HVAC system. We currently have some utility rebates available for home performance work to include high efficiency equipment, duct sealing, air sealing, windows, and insulation. The utility company also has some rebates for low income housing and rental houses. This has created companies that do not do HVAC, but just do home performance.

These home performance companies will come in and hook up a blower door and have two to three men in the attic and a couple in the house looking for air leakage and then they insulate. They do not touch the equipment or do any duct work modifications (they are not licensed to do those items). They do a really good job doing this and usually complete the job in one day or less. They do not charge the customer any money and just collect the rebate money from the utility company. My point today is, some of these sealing jobs could be destroying the HVAC system and equipment.

My example of how this could happen is a house we did this last week. Here in Southwest Oklahoma we have furnaces or air handlers in closets up on a platform with the duct work up in the attic. This particular house had high air leakage and high duct leakage. It also had high statics on the return. We had 53% duct leakage operating. The supply air was only supplying 78% of the required air flow to the inside of house and return coming from the inside of house was 41%.

After removing the unit we could see why the return static was high and the return air coming from inside the house was low. The original installer was trying to use walls behind the unit as a return. The return duct work in the attic looked fair but until we removed the furnace, coil and plenum you could not have seen the disaster they had behind this unit. That explained why 53 % of the return air was coming from the attic and garage and also explained the high return static, which was slowing down the supply air to inside of house.

This is why if one of the home performance companies would have happened to have sealed up this house like they do, it would have created worse statics on the return and less supply air. The third party testing company would have tested the house and the duct work for pressure and it would have passed like normal, but would have choked down the return more, which creates all kinds of problems.

This particular customer wanted a high efficiency unit, because his utility bills were very high. He was also never comfortable in his house (he actually didn’t realize that until we made his system work like it was supposed to). We installed a lower efficiency unit, which still met the utility requirements, repaired his duct work, did some air sealing, and put in new insulation. We now have proper balanced air flow throughout the house with only a 4% duct leakage and we reduced the air leakage of the house by 60%. This customer made a trip to our office to tell us he has never felt this comfortable ever in his house.

I feel it is very important for the HVAC to be in charge of the home performance for reasons like above and there are other reasons as well. In our area most of the air leakage of the house comes from the duct system.

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Posted In: Building Performance, Residential Buildings