blower door and energy audit

[Drewman]

We get our electric through a co-op and just had an energy audit completed. It consisted of a blower door test and then an infrared audit. I was geeking out with all the information!

The quick results were an ACH@50 with our result being 4.6 and a couple quick fixes before the report arrives within 2 weeks.

The quick fixes were

• gap found under basement cantilever beam that extends underneath our fireplace that leads directly outside...it's about an inch wide and 18-24 inches long....spans a couple rafters
• two can lights in great room
• exterior door seal shot allowing exponentially more leakage than should

My question right now is the ACH@50 calculation. How is this determined regarding the basement square footage? Is the basement included? We have main floor of 2100 sqft, upstairs of 700 sq ft and basement of 2000 sq ft. The upstairs is a loft so another 1000 sq ft is open to the downstairs and I believe is 16 foot high....

Home built in 2005 with poured basement.

 

[DickRussell]

In doing a blower door test, the instrumentation adjusts the exhaust air flow rate to maintain a standard 50 pascal pressure difference from outside to inside, and that flow (CFM) is directly observed. This increases the air leakage rate far beyond "natural," so that natural leakage( due to wind and temperature difference) is minimal relative to the induced leakage and thus give a standard measure of overall leakiness of the house. The CFM reported by the instrument is divided by some house volume (perhaps the whole house), to give a result reported as ACH50. You ought to be able to find out what the raw CFM value was. Then you can calculate whatever ACH you want, or just see what house volume was used.

 

[DBoon]

The calculated ACH50 is based on the conditioned volume of the house, which includes the basement volume.

 

[Drewman]

Thank you for the responses! I am excited for the document to arrive.

The calculated ACH50 is based on the conditioned volume of the house, which includes the basement volume.

I'll review his calculations to see if he included the basement and how he calculated our large 2nd floor dead space/loft into the home volume....I'll probably have to do my own math.