Energy Efficient Design in Action, Part III

RESULTS ARE IN!

Remember the Downtown Carriage House that we explored as a test case in Energy Efficiency and Practice Pt. II? Well, thanks to our friends at Think Little Inc., we received confirmation via blower door test that the building envelope came in significantly below the current (and stringent) metric for passive house design:

the numbers

Test result (cubic feet per minute at 50 Pascal test pressure): 96 cfm50

Conditioned volume: 6575 ft3

Building envelope: 2660 ft2

Air changes per hour (at 50 Pascal test pressure): 0.88 ACH50

Envelope Leakage Ratio (ELR = cubic feet per minute of air leakage per square foot of building envelope): 0.036 CFM/SFBE

wait, what’s a blower door test?

This test is a tool used by home energy auditors to determine the airtightness of a building, which directly affects the efficiency of heating and cooling as well as the prevention of condensation within the wall assembly. As explained by the U.S. Department of Energy:

“A blower door is a powerful fan that mounts into the frame of an exterior door. The fan pulls air out of the house, lowering the air pressure inside. The higher outside air pressure then flows in through all unsealed cracks and openings.”

As the outside air filters into the vacuum created by the fan, the calibrated blower door system provides data that allow the auditor to accurately quantify the amount of air leakage, and therefore the overall airtightness of the building envelope.

what do these results tell us?

That the structure is very airtight, and therefore will prove to be extremely efficient in regards to heating and cooling. Special thanks to Dwell Construction for helping us make this happen!