We moved out of our house in September 2014. It was a wrench but had to be done if we were to realise our dream of a comfortable home. Now, fourteen months later, we have moved back, to a completely new environment. The house has been remodelled internally (see Our House Reborn), completely insulated (see If in Doubt, Insulate It), made airtight and given a state of the art ventilation system (see Airtightness and Ventilation) that recovers 93% of the heat from the outgoing air and uses it to heat the incoming air. We have solar panels on the roof, and pipework under our field bringing us hot water and heating via a ground source heat pump (Renewables in a Low Energy House). We have lost a bedroom (knocked two into one) and gained a conservatory. This is going to take some getting used to!
Initial impressions are: what a lot of space (the remodelled rooms are roomier!), and isn’t it warm! We shall have to keep adjusting the heating controls until it feels right as we adjust to the climate within the house. So far, the underfloor heating on the ground floor is barely on and the radiators on the first and second floors are cold, but the temperature reads 20.5degrees Celsius. Admittedly, this has been a mild October but it has been very windy at times this week and we have felt nothing of this within the house (unlike in previous years when a windy day meant a very cold house!).
The old saying goes “the proof of the pudding is in the eating”. In our case, the proof of the airtightness is in the blower door test. In an earlier post in this series, I mentioned that the blower door test performed before any work was done registered 16.9 ach (air changes per hour). In my second post, I said this:
“Although we cannot hope to achieve Passivhaus standard, and will struggle to meet EnerPhit, there is a lot that can be done to improve on 16.9ach. We have our fingers crossed for 3ach, but we shall have to wait and see”. Today, the waiting is over, the second blower door test has been performed, and the result is 2.5ach (an average of 2.2ach at 50Pascals pressure and 2.74ach on depressurisation).
The problem areas found were with the wall which was once the end wall of the original barn and is now an internal wall between the stairwell and the kitchen/living room/bedroom, and the woodburning stove. The wall was always considered to be an issue, since its solid construction forms a thermal bridge; the test showed that junction points were one degree Celsius colder than adjoining walls, so 19degrees instead of 20degrees, which in a house where the internal temperature is maintained at a comfortable constant 20degrees, this should not prove a problem, condensation-wise. The woodburning stove is another matter. It is a Chesneys Milan 4 Passive, marketed as the only stove suitable for airtight houses. However, the installation instructions, which we only saw when we eventually took delivery of the stove, admit that the stove is not airtight. There is a row of slots behind the door which is inadequately sealed, and through which we had experienced draughts when the wind was blowing hard from the south, but in addition the flue connectors, although correctly installed were also leaking at the junction with the fire. We removed the fire and sealed up the flue and retested, resulting in a 20% drop in air leakage. Recalculating the result of the blower door test based upon the blocked up flue gives us a reading of 2ach. This is a phenomenal result! Our house is over 150 years old in places, with a mixture of solid wall and cavity wall construction, and to have reduced the leakiness to only 2 air changes per hour is wonderful! Huge kudos to Green Building Company for getting this result!
I shall be blogging about our first year in our reborn home at three monthly intervals, recording what it is like living in such an environment. Look out for the next post in February 2016.