Can a Passivhaus building also win over architecture fans? Are good design principals and Passivhaus principals mutually exclusive? We certainly hope not. But as we are in the throws of designing our home, we are discovering that it ain’t easy being green.
Mark and I finally arrived at a design we loved. We went over to the lot, staked it out, and were generally feeling pretty fantastic about what we had come up with. *Pat on back* That is, until Mark started the energy modelling. The numbers weren’t looking as good as we had hoped. If we increase the thickness of our walls (from 18” to 24”), put in top-of-the-line triple-glazed windows, and added a sources of heat (radiant floors/ducting), we’d still be borderline for Passivhaus.
If we had a large lot, with great exposure and few neighbours – building a Passivhaus that met our architectural/design snobbery requirements would be no promlemo. Our lot, however, poses several large challenges in terms of Passivhaus design:
- It’s narrow. The narrow shape of our lot wills a narrow house plan. Plus we need to push the house as far over to the North side of the lot as possible, to allow for better exposure on the South-facing windows – further increasing the need for a narrow house plan. However, for best energy performance, a more square shape is preferable. How do we create more of a square plan while maximizing solar gain on those South windows?
- Limiting distance. Limiting distance in the building code restricts the number of windows we are allowed to have on a side facade facing neighbours. Our South facade just so happens to be along the side of the house, facing the orange neighbours. So depending on the area of our south facade, we’re only allowed a small fraction of it to be windowed. We’re looking at 10–12% window coverage. This is pretty piddly compared to the area of window we would like to have.
Never to back down from a challenge, we are readdressing the design to see what changes we might be able to make. Hopefully just tweaks, and not a major overhaul. We may feel slightly deflated by this set back, but are still determined to make friends out of these two…without breaking the bank…