January 2011
Now that we’ve lived in our 1950’s 3 bed detached house for one year, much thought has gone into deciding what changes we’d like to make.
The “eco” wish-list includes:
• A generous porch on the front to minimise heat loss when entering/leaving the house.
• A utility room by the back door to create the same draught-lobby effect there.
• Super-insulate the loft conversion, the solid walls (externally) and the ground floor.
• Replace the single glazed windows with high quality timber framed windows (hopefully achieving a whole window u value <1, preferably 0.75)
• Ensure air tightness of 3m3/m2 at 50 pa pressure, or less than 1m3/m2 if possible
• Install a mechanical ventilation system with heat recovery (MVHR)
• Replace the ailing gas boiler with suitable means of space and water heating
• Installing low-flow devices to reduce water use
• Possibly add PV panels on the south-facing roof
In other words, we will apply to our house some of the principles which form the basis of the Passivhaus approach to building ultra-low energy homes.
(For further information, go to this summary about the house)
The Passive House standard is for new buildings, but there is another standard which is specifically for existing buildings. This is the EnerPHit standard for Passive House retrofit. Houses built to this standard will use about 80-85% less heat and power than the average home.
This is the standard that we are aiming towards – although we don’t know yet just how close we might be able to get. To see a relatively recent description of this standard (a draft document), go to http://www.passiv.de/01_dph/Bestand/EnerPHit/EnerPHit_Criteria_Residential_EN.pdf
The really difficult question is “How far does it make sense to go, and what is within our budget?
