FIRST PASSIVHAUS IN UK?
I have been lead to believe, and I think Mr Brinkley will confirm, that there are no house in the UK built to the German Passivhaus standard. I think Mr Brinkley was considering building one but I don’t know if he has done it. In any event, I have just come across what I believe to be the first.
It is actually 2 flats, a 1-bedroom and 2-bedroom, built in the inner city of Cardiff, by an Italian lady. The lady is in fact an architect, educated in Munich, so it is perhaps less surprising that she adopted the Passivhaus standard.
The property is a very contemporary looking house, built in the quiet cul-de-sacs of the Roath area of Cardiff. It has a slightly surreal feel being surrounded as it is by Victorian terraces. The 2 properties next door are also modern-looking but in a more traditional way, which helps to soften the impact of the house.
For those that don’t know the Passivhaus standard was established by the Passivhaus Istitut in Darmstadt, Germany is 1996. Since then around 6,000 houses have been built and certified to the standard, across Europe and the USA. What Passivhaus means, in broad terms, is that the building is insulated to a level that allows the sun and other passive heat gains to produce enough energy to heat the home. Passive gain is the heat from daily activity, given off by people, cooking, the shower, making toast, boiling the kettle. Pretty much everything we do produces heat which can be captured and circulated from warmer rooms (bathroom and kitchen) to cooler rooms (lounge and bedroom) by a heat recovery and ventilation system. Passive solar heat always plays a big role in this design of house and, as is typical, this house has a south-facing wall that is entirely glazed. These are triple-glazed sliding doors that give good access to the garden in summer but allow heat to be captured in winter. They have a U-value of less than 1 compared to 1.8 for the best double-glazed windows.
On the day I visited, the outside air temperature was 50C. The temperature inside was a very comfy 190C. This is a little lower than the typical central heated house, indeed my office is at this moment 210C, but feels cooler than the Cardiff house. This is attributed to the walls of the Cardiff house being lined in plywood. The lady who built it said “wood gives off less coolth than stone”. And I believe her. Mine is a stone cottage and the walls are cool to the touch. Her walls felt warm.
This house has a has a number of remarkable features.
1. It has no heating. No boiler, no fireplace, no stove, no fan heater, nothing. And it is warm.
2. It is a timber-frame house built entirely by local labour. It is not a pre-fab manufactured by hyper-efficient German engineers. She used ordinary Welsh builders with no special skills and no special knowledge. In fact these guys were learning on the job, which did lead to a bit of budget and schedule over-run.
3. The house came in at around £1,200 per m². Which may be a bit high for the standard of finish achieved, but is within bounds and would show a profit if she sold it.
4. The house has lots of solar energy on the roof, both thermal which generates around 70% of her hot water, and PV which generates about 50% of her electrical demand (and these are included in the £1,200 per m²)
5. The whole house, every last detail, is recyclable. Further, most of it is reusable, i.e. it has been built in such a way as to be immediately removable, without damage, to be re-used in another house.
6. She has installed rainwater harvesting to reduce her water consumption from the mains to less than half the normal.
A house that needs no heating needs a lot of insulation. This house has 380mm in the walls, 200mm under the floor and 430mm in the roof. This insulation is all hemp, which has low embodied energy and ever sequesters CO2. This compares to the normal UK standard of 90mm in the walls, 75mm under the floor and 270mm in the roof. In also needs a very high level of air-tightness to prevent heat losses from air movement, and that is where the contractors encountered most of their problems. They were just not used to building to these levels of precision and had to re-do a fair bit of the work.
The point of all this is that it can be done. What this lady has proved is that a self-builder can build a highly efficient house, with trivial running costs (she estimates her annual energy bill at less than £200) without recourse to specialist materials or suppliers. Under the Code for Sustainable Homes the house would easily reach level 4 and maybe level 5.
What she has shown is that all the bleating from the house building industry that zero carbon is unachievable is nonsense. If the process that this lady has pioneered were taken up by the big companies it could be lifted to level 6 and zero carbon emissions without too much trouble. And bring in affordable, sustainable and profitable houses. Is it not time that the house building industry stopped whinging and got on with building the houses we need?