[Greenbuilding] Passive house standard for retrofits
Bob Waldrop
bob at bobwaldrop.net
Sun Oct 7 21:16:46 CDT 2012
The article below references a Passive House standard for retrofit
situations where the standard is a "maximum heating demand of 25 kWh per
meter squared. How is this determined? Do I --
- add up my winter kilowatt hours,
- subtract the base load, which gives me the heating kwh, and
- then divide by the area of the house in square meters.
http://www.passiv.de/en/03_certification/02_certification_buildings/04_enerphit/04_enerphit.htm
Begin quote:
The use of Passive House components in refurbishments of existing
buildings leads to extensive improvements with reference to thermal
comfort, economic efficiency, absence of structural damage and climate
protection. A reduction of the heating demand by 90 % was achieved in a
large number of projects. Achieving the Passive House standard in
refurbishments of existing buildings is not always a realistic goal, one
of the reasons being that basement walls remain as barely avoidable
thermal bridges even after refurbishment.
For such buildings, the Passive House Institute has developed the
“EnerPHit – Quality-Approved Energy Retrofit with Passive House
Components” Certificate. This requires either a maximum heating demand
of 25 kWh/(m²a) or alternatively the consistent use of Passive House
components in accordance with the requirements for PHI certification of
components. The heating demand calculated by the PHPP, and the quality
of thermal protection of the individual
components are indicated in the certificate. (end quote)
This paragraph --
(being quote) Today, ‘passive house’ is a clearly defined standard
across most of Europe for buildings of a very high energetic
performance. Experience has shown that a single definition of the
passive house can be used at least from 40°–60° latitude, and passive
house definition has been tested in both Scandinavia and southern
Europe. Key parameters are a specific space heat demand maximum of 15
kWh/m2 TFA, a specific primary energy demand for space heating, cooling,
domestic hot water, electricity for pumps and ventilation and household
appliances at a maximum of 120 kWh/m2 TFA, a maximum heat load of 10
W/m2 TFA, and an airtightness of n50 0.6/h maximum.(end quote)
from http://www.viking-house.ie/passive-house-retrofit.html
says "120 kilowatt hours per meter squared," for total energy use. For
our house, which is 144 square meters, if it were a passive house, we
would have to come under a total of 17,280 kilowatt hours, with no more
than 2,160 kwh attributable to heating. I am assuming this is "per year."
Are these interpretations of the standard correct?
Bob Waldrop, OKC
More information about the Greenbuilding
mailing list