Eco House Build

Ribin

Whilst posting on the Pension forum I have been asked for details of our recent house build.
I spent several years looking at building a zero carbon house development. The banks proved to be very uncooperative so the development never took place but I learnt a significant amount about what energy saving systems worked i.e. saved money as well as the true cost of building.
Frustrated by the development not proceeding I decided to build our own house. Built close to Passive House standards, we built a 200sqm detached house at just over £1000 per sqm and with land costs the total build came to circa £325k. Last month, the house was valued at £500k. Build time around 10 months. Not only have we added value but now have a house with running costs 20% of a standard property.
If you want to know more please ask.

Myser

Would be useful if you could post some of your energy saving measures you have installed.

Ken68

Yes please Ribin, would be interesting to have all the details.
Which way does it face, how many rooms, do you have PV/Solar water heating.etc

Ribin

OK will do.

First thing I learnt was that there is a whole industry out there grown up on the back of what I call 'Greenwash'. By this I mean, selling you energy saving kit you do not need. The majority do not need expensive heat pumps, solar PV, solar thermal etc if you can get mains services i.e gas, electric.

From this I developed the 'Fab Roi' principle. This is based on a Fabric First build i.e. put all your efforts into building a super insulated airtight house, taking care not to over engineer it otherwise costs will spiral. Then every bit of 'kit' I considered for the house had to give a Return On Investment based on the following:- 1-5 years, almost certainly goes in, 6-10 years and it is carefully considered, over 10 years then it was thrown out. My reasoning on this is that technology is moving at a pace that within 5 years most of what is today considered efficient is likely to be surpassed - a good example is fuel cell central heating boilers, too expensive at the moment but Crest Nicholson are piloting houses with them, so in 5 years????

I also said that our house was close to Passive House Standards. There are three main reasons I did not go the 'whole hog'. There is a significant cost in achieving the last 5-10% of the passive house standard but can cost 30% plus of the total build cost - so therefore did not pass my ROI test. The second reason is that not everyone has a house that sits on a nice sunny south facing plot. The third is design, I am passionate about getting houses to look good and fit in with their surroundings. Passive Houses tend to look modern unless you again spend a fortune.

So that's my basic theories out of the way. So what did I build?
Timber frame house using rockwool/HD EPS in the walls and roof with an insulated beam and block floor. So the house is like a big thermos flask wrapped in insulation. U values for walls/roof/ floor approx 0.12 Great attention paid to airtightness. The goal was 0.6 but we always knew this would be impossible as we have 3g sash because we chose design over performance - it is a New England style house - but we managed to get airtightness down to 1. Installed a MVHR system - brilliant by the way, the house is so fresh - and for heating a simple gas condensing boiler feeding U/F heating to groundfloor. The house is SW facing and we do have significant solar gain. Things we did consider, solar thermal, heat sink under the house, water recycling but none came close to passing the ROI test.

I'll shut up now but happy to pass on info/knowledge

Furts

I have recently demolished, rebuilt and extended my home giving some thought to air tightness, solar gain, solar mass, generating pv electricity, coming off the surface water sewers. I did nothing analytical or advanced - just simple things.

With careful buying, and a tremendous commitment from both myself and OH the build costs came in at under £500 per square metre.

The running costs for a 200 metre square home for water, drainage, telephone, broadband, TV, electric, gas, council tax come in at £2500 per year.

Ribin

Furts wrote: »

I have recently demolished, rebuilt and extended my home giving some thought to air tightness, solar gain, solar mass, generating pv electricity, coming off the surface water sewers. I did nothing analytical or advanced - just simple things.

With careful buying, and a tremendous commitment from both myself and OH the build costs came in at under £500 per square metre.

The running costs for a 200 metre square home for water, drainage, telephone, broadband, TV, electric, gas, council tax come in at £2500 per year.

There is no doubt that if you do the majority of the work then you can seriously reduce the £ per sqm cost. How long did it take you?
Also with running costs at £2.5k inc council tax is amazing. Our council tax is £2,500! Mind you I guess yours is based on the previous property, so substantially lower. If that is the case make sure you budget for a hike as after the next election I can see the government going for a revaluation across the country

Hintza

Ribin wrote: »

Mind you I guess yours is based on the previous property, so substantially lower.

Our house was revalued straight away after demolition (16 months in caravan at band A) then the assessor was out pretty damn fast on completion and bumped us up to Band E. We were band C in the original cottage which in my view was an over valuation.

Is banding similar in England?

anotherbaldrick

Hintza wrote: »

Our house was revalued straight away after demolition (16 months in caravan at band A) then the assessor was out pretty damn fast on completion and bumped us up to Band E. We were band C in the original cottage which in my view was an over valuation.

Is banding similar in England?

The only thing that seems to influence your banding around here is the number of bedrooms. If your property is a load of dilapidated jerry built clapboard or a modern Eco Build you all end up in the same band.

PS> Our house is new timber framed high insulation airtight with heat exchange mechanical ventilation. I would recommend solar thermal, our Eco meter tells us we have used no gas at all (domestic HW) since the end of Spring.
Our first years total all up fuel bill in March - March was just under £1K

System

how did you go about this?
did you actually design it yourself (i.e. without an architect/designer on board)
did you have a contractor or did you build most of it yourself with specialist contractors on site when needed?

the per m2 figure is good for something that high spec - I'm looking at similar design ideas but my services are going to add a fair bit to the cost (no mains water/gas/sewers etc!)

anotherbaldrick

Another good thing of course, is when we get a really hot day, the air temp on the patio today is 50 deg C, inside is at 25 deg.

Furts

Ribin wrote: »

There is no doubt that if you do the majority of the work then you can seriously reduce the £ per sqm cost. How long did it take you?
Also with running costs at £2.5k inc council tax is amazing. Our council tax is £2,500! Mind you I guess yours is based on the previous property, so substantially lower. If that is the case make sure you budget for a hike as after the next election I can see the government going for a revaluation across the country

The whole process took far too long!

A realistic time from sketches and thoughts, through to close-ish to completion was two years. During this time there were business, work and family commitments. It was always a juggling act. Certainly a social life by-passed us!