Two questions about cost/benefit for insulation and ventilation in a mild climate
I’m in the early stages of designing a house and would love to get some unbiased input on a couple of sticking points between me and the builder.
1. We live in zone 4A, so we generally have mild winters and warm summers. After spending some time on this site, I was ready to advocate for the whole insulation package – closed cell spray foam and a rigid wrap to minimize thermal bridging. The builder I’m talking with is trying to talk me out of this, saying that for the expense is not really justified in a climate like this. He’s suggesting 2x6s with an inch or so of closed-cell foam and then filling the remaining spaces with blown-in fiberglass with adhesive, and a super light weight house wrap. He’s not generally opposed to a heavier insulation approach, but just doesn’t think it’s worth the added expense in this part of the country.
2. Either way, I’ll end up with a pretty tight house. I’ve read a lot on this site about different approaches to ventilation. While there are a lot of high-tech devices around, again I wonder about the relationship of where I am to what I need. We have windows open most of the year, which I assume would provide pretty good ventilation along with typical kitchen and bath exhaust fans. The builder is also suggesting a couple of cheaper alternatives to an ERV or HRV system, namely some recently introduced high-volume exhaust fans that run most of the time. While I like the low-tech approach, it seems to me that having exhaust-only fans (which essentially depend on air being pulled in through leaks when the windows aren’t open) kind of defeats the purpose of having a tight house. On the other hand, does my situation really justify spending thousands of dollars on an HRV or ERV system?
I’m not necessary looking for a yes or no answer, but if anyone can help provide a way to think through this it would be very much appreciated. Thanks a lot.
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