Arkansas HVACR NewsMagazine November 2024

HVACR NewsMagazine November 2024 Tech News

Again, the readings are based upon necessary air flow mandated by the load calculation . This fact leads us to another point. If the duct is not sealed at the grill, is it truly duct leakage, envelope leakage, or both? A duct blower test indicates this type of leak as duct leakage on older homes, but is it? When duct is tested during construction rough-in, the boots or buckets are sealed off. What happens when drywall is applied, and grilles are fitted. This also shines a light on why duct leakage is still prevalent on homes built after 2006 where third-party duct testing was mandated. If I employ a third-party tester that tells me my duct jobs stink, how long will that third party stay in business? The last tool (should be the first) was the blower door. This tool tells us the actual leakage of the home . The actual leakage of the home. If you wonder why I repeated the phrase, think about the load you guessed at. Without accurate information the load is wrong, the air flow requirements for individual rooms will be wrong, everything will be wrong. When a blower door is utilized, you have an advocate for everything you do. You have a benchmark where you begin your work, and that same benchmark enables you to measure end results. Imagine measuring improvements! Imagine understanding the homeowner really has need of new windows or doors. Perhaps the home had severe problems the day it was built. We have witnessed homes with double the load than a rule of thumb might indicate due to misaligned insulation and air barriers. Imagine what you get, is what everyone else missed.

Our conversation here leads to a singular fact. If you don’t employ blower door calculations in your load calc, you are guessing, and 60% of the time, with all your experience, you will guess wrong. If you don’t utilize a blower door in day-to-day operations, you will leave customers unhappy, opportunity missed, and money on the table. As an example, we were called to investigate a home originally built in the 1950’s, updated a couple of times then updated again and sold in 2018. The home had nice curb appeal and appeared to be in good shape. The customer complained the new heating and cooling system installed when updated could not keep up. Upon listening to the homeowner, we began some preliminary research. After about half an hour the issue was clear. The home was built on pier and beam with concrete walls forming a rough basement area of about 200 square feet. There were a couple of accent walls on the main level that were finished as painted wood.

Amazingly there was no drywall and no insulation on any of those walls. The door to the basement was an aluminum storm door from twenty years ago or more. The remodel contractor did not

Photo as an example- not the home investigated

catch the issue, the city inspector did not catch the issue and most importantly for our industry the salesman for the job did not catch the issue. Of course, everyone was working off plans and everyone assumed