We recently completed a new house that generally meets the criteria for Passive House but is not certified. Can we call it a Passive House?
all photos by built photo
As more people gain awareness of Passive House, many projects claim to be similar to Passive House, using Passive House principals, almost Passive House, etc. In Germany, Austria, and other European countries where PH is prevalent, it turns out that a majority of Passive House buildings are actually not certified (but have been modeled during design and blower door tested during construction).
modeling results from PHPP
Conceptually, Passive House buildings must be superinsulated with high performance doors and windows, thermal bridge free, airtight, and mechanically ventilated with heat recovery,. Technically, a Passive House must be modeled using special software (either PHPP or WUFI Passive) and meet criteria for Annual Heat Demand, Annual Cooling Demand (or heating or cooling load), Annual Primary Energy Demand (i.e. source energy), and Airtightness. Certification generally involves a third-party review of the energy modeling, blower door testing to determine airtightness, and commissioning of the ventilation system.
Here’s some data on the 18th Ave Residence (as calculated per PHPP):
Treated Floor Area 2100 ft²
Annual Heat Demand 5.34 kBTU/ft²a
Heating Load 2.92 BTU/ h ft²
Primary Energy 29.5 kBTU/ ft² a
Site Energy 11.1 kBTU/ ft² a
Airtightness .48 ach50
main wall assembly
5/8″ gypboard
5 1/2″ wood studs w/ dens-pack cellulose
1/2″ plywood taped as air barrier
2″ rockwool exterior insulation
cedar rainscreen
R-value = 27
south wall assembly above windows
5/8″ gypboard
5 1/2″ wood studs w/ dens-pack cellulose
1/2″ plywood taped as air barrier
9 ½” TJI w/ dens-pack cellulose
½” plywood
cedar rainscreen
R value = 48
basement wall assembly
veneer plaster
12″ Faswall blocks
1 1/2″ rockwool inserts
exterior cementitious skimcoat and waterproofing
R value = 21
floor assembly
4″ slab on grade
10 mil vapor barrier
4″ EPS type II insulation
R value = 18
main roof assembly
5/8” gypboard
1x4 wood furring
16” trusses w/ dens-pack cellulose
5/8” plywood taped as air barrier
4” min polyisocyanurate
½” protection board
TPO membrane roofing
R value = 78
windows and doors
Euroclime Larch Windows and Doors w/ triple glazing
SHGC = .50
U value = 0.15 btu/hr ft² F
ventilation
Zehnder CA-350
heating / cooling
Mitsubishi Ductless Mini-Split (2 heads)
electric convection heaters for backup
water heating
GE hybrid electric heat pump
exterior shading
moveable wood screens
So what do you think? Is it a Passive House?