I should probably rename the website, because we're not actually building a full-fledged Passive House. But first, this update:
After waiting ages for our permits, we got our well drilled last week! It's 485 feet deep, which is roughly what we were expecting, and the flow rate is a respectable 8.5 GPM. The good news is that no hydrofracking was required (i.e. fracturing the rock in order to get more water out of it), which would have cost an extra $2,500. So that'll cover the cost our blowout engineering meeting a few weeks ago -- whee!
Anyway, we decided at the engineering meeting that we're not going to pursue Passive House certification. We haven't ditched any of our goals for energy-efficiency — we're simply not trying to shoehorn ourselves into a standard the house wasn't really designed for. Passive Houses are already extremely hard to build in North America, and we have the added challenges of a semi-wooded southern exposure and an architect who doesn't specialize in this kind of thing.
The good news is we're still building a really efficient house. It's going to be very tightly sealed, and we're taking extreme care to minimize thermal bridging. We're limiting the overall glazing, ordering fancy-pants windows from Germany (ka-ching!), using heaps of insulation, installing heat pumps and solar hot water, etc. Marc estimates that our heating and cooling load will be less than the plug load in a normal house.
So even though this won't be a Passive House™, it'll still adhere to the Passive House principles and be a major leap forward from standard construction.
Ordinary houses breathe through leaky joints and poor seals, losing heat and wasting energy. But our house won't leak, so we'll use a heat recovery ventilator (HRV) to admit fresh air and expel stale air, transferring heat from one stream to the other.