Blower Door Test & Air Tightness

Amongst the sea of sustainable architecture issues to discuss, an important testing procedure has not been mentioned enough in the reading I've encountered.  The Blower Door Test helps energy auditors determine a home's air tightness.  The reasons to understand building tightness include thermal comfort, moisture control, air quality control and of course to identify energy waste due to air leakage.

How they work from the U.S. Department of Energy Efficiency and Renewable 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. The auditors may use a smoke pencil to detect air leaks. These tests determine the air infiltration rate of a building.

I also recently read an article that asks if homes too air tight.  From this article:

Probably the most widely published symptom of a tight underventilated house is condensation and moisture build-up. Condensation on windows, mold growth on cold surfaces and dust mite infestations in carpets are becoming more frequent in new houses as airtightening reduces natural ventilation rates and indoor humidity levels increase.

So it seems there is important reason for both an air tight home and a home that has adequate natural ventilation.  To keep occupants comfortable, obviously, we need mechanical ventilation and a tight home that does not waste energy through air leakage.  On the flip side, to avoid the behemoth of a problem that is mold and mildew, we need some natural ventilation.  The article concludes with some suggestions for successful strategies:

Mechanical ventilation for your houses does not have to be complex or expensive. Something as simple as a quiet 75 CFM bathroom fan running continuously will be adequate in some houses.

Most experts agree that continuously operating, low-level ventilation that requires little occupant attention is best. Studies indicate that homeowners often turn off or permanently disable mechanical ventilation for a variety of reasons, but especially due to noise. If you choose the right system and have it properly installed, noise simply shouldn't be a problem. The bottom line is that if homeowners can't hear the ventilation system running, it has the best chance of being used.

Any mechanical engineers out there that can offer direction or innovative solutions on this topic?

Comments

[Aspen Vacation Home]

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