Arkansas HVACR NewsMagazine March 2020

Second, Blower Door Testing Again, by way of total transparency--I love blower door testing. You’ll never believe where and how much leakage there is in a house built before the Energy Code was adopted in Arkansas. Back in the 90s when I had my little business, we did lots of blower door tests and caulked and sealed houses. Each home was like a new experience or an affirmation of the sorry condition of most houses — big ones, little one, new ones, old ones. Today, that is not the case. Back then, people would ask, “Can you get a house too tight?” My reply was, “Haven’t seen one yet!” BUT THAT WAS BACK THEN. Today is different. A recent study demonstrated that houses are becoming REALLY too tight. Houses are frequently from 30% to 75% tighter than ASHRAE recommends. Today, no one says that houses leak like sieves unless Houses are frequently 30% to 75% tighter than ASHRAE recommends. they are talking about older stock. Today, everyone says, “Houses are too tight.” Today’s philosophy is, “Get them as tight as you can and ventilate.” Not sure I agree with taking it that far but it is none-the-

less the philosophy of well intentioned, smart people. How does this apply to our industry? Well, our code already requires mechanical ventilation for all new residential construction. It is required in the whole state but many municipalities are not enforcing it; however, enforcement seems to be on the way. So, if houses are too tight and the HVAC system has required mechanical ventilation, why the blower door. The only advantage I see is that it might allow us to reduce the volume of ventilation. For example, ASHRAE 62.2019, Table 4- 1a states that a 1,500 to 2,000 sq. ft. home with two bedrooms needs 90cfm of mechanical ventilation. If the HVAC contractor installs 90 cfm and the houses tests at a natural leakage rate of 35 cfm, then the mechanical ventilation could be cut back to 55 cfm by adjusting the damper. That is worth something. How much, I don’t know. It is 13.75% of a ton. What does it cost to operate 13.75% of a ton? Depends on the SEER and HSPF of the Heat Pump or the SEER and AFUE of the AC & Gas Furnace. Her e’s my deal, if we are required to do duct leakage tests, the Association will help train our folks to do the tests. If blower door tests are required for new construction,