Autumn - it's getting colder outside but what about inside?

As autumn progresses, we are watching the thermometer with interest to see how the house responds to the falling temperature outside.

During September (with no heating on) the thermometer fell gradually from 23 degrees C to 20.5 degrees C. And there it has remained without any fluctuation during the whole of October. I started to think there was something wrong with the thermometer so took the thermometer reading 22 degrees C in the attic and put it in the kitchen - where it continued to read 22 degrees C for some time (days / weeks).

As the house depends mainly on its occupants and our cooking / showers / use of electrical items etc. to keep it warm, we thought that going away for 6 days at the end of October would have a significant effect. But no, on opening the front door it was much as before. The second thermometer is reading 19 degrees C, and the first thermometer still says 20.5 degrees C. Either way, if the house needs no heating in October to stay at 20 degrees C give or take 1 degree, I'm happy with that!

The heat stored in the brickwork is acting like a storage heater and keeping the air temperature up at around 20 degrees C. At some point we will have to put the heating on to prevent the temperature from dropping below this - but when?

The other nice thing about coming home to this house is the air quality - we leave the ventilation system on a low setting so there is a constant trickle of fresh air coming in. When we get home after a holiday, it doesn't smell as if it has been shut up for a week. (Before the refurb, it was very noticeable on returning from holidays that the house had not been ventilated adequately while we were away.)

It's cold outside...

... but fortunately seems to be ok on the inside even when the temperature drops to -5 on the outside.

Strange but true - at 19 degrees C, the house feels warm (whereas it felt much less comfortable at the same temperature before the insulation and draught-proofing).

The plaster is still drying out and the brickwork is still warming up after a year of exposure to the elements, so the gas boiler is working harder than it will need to next year, all other things being equal.

The 3 tiny radiators are not really enough to keep every room at 19 or 20 degrees C under these circumstances, but we are happy with bedrooms dropping to 17 or 18 degrees C at the coldest point in the night. (It beats the 8-12 degrees C that was the midwinter norm in 2010 and 2011).

The other striking difference for me is the complete absence of joint pain, which was a permanent feature for at least 4 months through previous winters. I had a hunch it was down to cold and damp in the house and I'm really delighted to experience such a spectacular difference this year. (Of course, for those who haven't got an extensive collection of injured joints, it won't make much difference).

The energy bills will also have a story to tell, but I don't have enough measurements yet (and there are further efficiency improvements to make anyway before the house reaches its "as designed" state).

One thing you do have to get used to is condensation or ice on the outside of the windows (because heat loss through the triple glazing is so low that the ice can still be found on the outside of the windows for hours - until the sun melts it off). I'm not complaining - so much nicer than having the ice on the inside as was the case for days on end in winter 2010 and 2011.

Moving in!

Finally, we have moved back in! There is still a fairly long list of things yet to be done (e.g. installing a kitchen) but great progress has been made in the plumbing department since moving in 2 weeks ago.

So what's it like? Thermally, it is fantastic - warm, comfortable, the temperature is stable, no hot and cold spots, no draughts. The thermometer sits around 19-20 degrees all the time. It is a completely different house from the one we moved out of a year ago.

We have 3 tiny radiators, which are currently on to help dry out the plaster, but we've had to turn some of them down or it gets too hot. So it looks as if the heating system is about right for the house. We'll know by the end of the winter if the system is adequate in really cold weather.

Since the MVHR was switched on, air quality has also been very pleasant (much better than having a window or two open, which did not promote air flow in every room).

It is still something of a DIY zone, but we are getting there. Not quite ready to commission the MVHR system and carry out the final air tightness test...

Which gas boiler?

On the long list of decisions to make is the choice of gas boiler.

Given that hot water use will probably be higher than our heating requirements (and we are low water users to boot), we'll want a boiler that is very, very small. I'm hoping we'll be using less than 5000 kWh per year of gas in total.

A top of the price range, super-efficient boiler won't save us much, given how little gas we will use. A small and basic combi boiler at a correspondingly basic price sounds attractive right now!

Any suggestions?