That's good! And I'm feeling the pressure! One correction, however, is that in Dec-Feb, the average low is 40 while the average high is 52, so the daily average temperature difference might be more like 45-70 instead of 30-70. When it does reach 30 at night, it's much warmer by mid-day. So, your figures could be modified a bit to around 25k BTU/d. That would require our heater to burn $1.50 in diesel to make up the lost heat. If that were the case, on average, for a third of the year, we can expect to pay something less than $200 for the benefit of fresh air. When I have a heat pump installed that cost should be rather less, say $70-80 per year. I wonder how that compares to the 5 or 10 year amortized cost of an HRV plus operating costs. Honestly, I really like the idea of HRVs, certainly far more than blowing lots of dearly heated air out the side of the house, but I just want to check out the trade off. I like your persuasive arguments. mm
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