Last April we mentioned a noteworthy project called the Passive House in the Woods. It’s a Wisconsin home with carbon-neutral ambitions designed by Tim Delhey Eian of TE Studio. It’s also the first Passive House in the state. PHitW meets the requirements of the Passive House standard, i.e. ultra-tight envelope, high efficiency heating and cooling, and minimal energy demand.
PHitW is particularly airtight. For the building scientists in the crowd, here are the numbers:
- Heating load: 3.36 kBTU/ft2 per year (less than 4.75 kBTU required);
- Source energy: 33.6 kBTU/ft2 per year (less than 38.05 kBTU required);
- Air tightness: 0.25 ACH50 (less than 0.60 required).
Located in the Town of Hudson, the three-bedroom, 1,940 square foot single-family home spans two levels and includes a walkout basement. It was constructed with an R60 slab, R95 flat roof, and an R70 facade, as well as windows and doors that help the home perform to stringent Passive House standards.
The ultra-efficient house has a heat recovery ventilator connected to a 600-foot PEX tube loop field to pre-heat and pre-cool the incoming air stream. There is no boiler or furnace, although there are in-floor heating mats with local controls which draw a nominal amount of energy.
Over time, PHitW may prove to be a net positive producer of energy due in part to a 4.7 kW photovoltaic array. Also, a 40 square-foot solar hot water collector will pre-heat water in a storage tank and provide about 85% of all hot water needs.