[michael]

I recently submitted plans to the local (Northern California) planning department for the construction of a new 2 bedroom house. They came back from the plan checker with some necessary corrections, but the one that has me stumped details requirements for whole house ventilation. I'll describe below my understanding of this, but I wonder if anyone on this board can help me make sense of it. The state energy agency (energy.ca.gov) requires that a house of 1200 SF such as ours have a continuously running 40 cfm exhaust fan or in-blowing fan so that whole house air changes happen regularly. The regs state specifically that opening windows is not a sufficient plan, but that a mechanical system must be in place to continuously exchange the air in the house. It can be done with intermittent fans such as a combination of kitchen and bath exhaust fans, but the formula, in the end, requires either such large fans in those locations or that they be on for such a long period of time that a single, moderately sized fan seems like a better choice. The federal government documents on this subject admit that nearly all forms of whole house ventilation result in higher heating and cooling costs. I understand the concern that some folks have regarding trapped, stale or toxic air inside new, energy efficient, tightly sealed dwellings, but I don't understand the sense of insulating a house, reducing infiltration to a minimum, and then pumping the heated or cooled air to the outside all day long. Logic tells me that in some places, the in coming outdoor air will be just as polluted as the air in the house. All that aside, it still seems like an affront to all the folks who are trying to build safe, energy efficient houses, to be paying instead to pump their heated or cooled air out of the house daily, continually. Can someone help me see some sense in this plan?

Michael Moreland
Mendocino, CA