Old Black Point
Zero Energy

The clients had been in a 1930s beach cottage here for years and wanted to start over. They went to a Passive House seminar the architect was hosting, came away convinced, and we took the cottage down and rebuilt to those standards. Three bedrooms, three finished levels, 3,400 square feet.

The two hard parts were getting the numbers with minimal closed-cell foam and getting a good HERS score with that much glass in the house. It came in at HERS 39 and a blower door of 0.62 ACH50. Passive House certification calls for 0.6.

We got there with 1/2" CDX wrapped in 2.5" Zip-R, Rockwool in the cavities, SIGA Fentrim taping every window from the inside, and Intello behind the wood-clad walls. The roof got a flash coat of closed cell — it's too good an air barrier to give up there, and the flash buys you R-value at the same time. R-49.4 at the vaulted ceiling, R-43 walls, R-43.8 foundation walls, R-24 under the slab. Triple-glazed windows at U-0.150.

A Mitsubishi air-source heat pump at 10.2 HSPF and 19 SEER, a heat pump water heater, and a balanced ERV moving 118 cfm. Ducts Aerosealed and tested at 26.37 CFM25 to the outside. All electric — there's no combustion in the building.

Outside it's Alaskan yellow cedar Perfection shingles over a vented rainscreen, so the back of every shingle can dry. There's no solar on it. A gambrel doesn't give you a roof plane worth putting panels on, and the house gets to 39 without.

Inside is where the shop time went. Floor-to-ceiling shiplap, shiplap ceilings, coffers, built-ins, and a three-story open switchback stair with three-story paneling around it.

The window heads at the mansard needed pans that don't come off a shelf. We had them soldered up in lead-coated copper and flashed them in the field.

The bathroom floor says NO DIVING in black hex tile. 341 of them, set one at a time.