The ideal low energy house?

What we've set out to do at ECF is to build a house which will use 70% less energy than one built to current building regulations. Its timber frame construction detailing hasn't wavered too far from the 'norm' to present any major problems for a timber frame kit manufacturer, decent building contractor or building control, and the costs of going this 'extra mile' haven't been excessive to the extent that they will be paid back within a decade in terms of reduced energy costs.

In essence, we have built to a standard which is accessable now by most contractors and self builders which is around 5-6 yrs before its time if the UK Government is to fully implement its Code for Sustainable Homes (CSH) strategy, on which this building should come in at around 3-4 on a scale of 1-6. There is clearly some distance to go from this to 'zero carbon', so what represents the 'optimum' for 'Level 6 living', the magical zero carbon level required by 2016 for all new homes?

Well, the same principles apply, namely...

• building orientation to maximise solar gain in winter, spring and autumn whilst avoiding overheating in summer


• high levels of insulation around the entire building envelope


• high levels of airtightness coupled with heat recovery ventilation


• highly insulated and well sealed doors and windows

...but for CSH level 6 the wall insulation would need to be increased to >300mm (from our 200mm), roof insulation to >450mm (from our 350mm) and windows to be triple glazed krypton filled units with insulated frames and glazing spacers (vs. our argon filled double glazed units). This would result in a building which could feasibly rely on the heat given off by its occupants and collected though its windows to keep it at a comfortable temperature without having to introduce a heating system. Construction might rely on internal masonry/concrete walls to store heat and keep a steady internal temperature, with the insulation fixed to the outside of this.

On the face of it quite simple, but a seriously long way from what the UK housebuilding industry is used to. Roll on 2016.....there is a lot of catching up to do and mindsets to be re-programmed.

Still raining in Scotland

Where to begin? Like many 'phone conversations and chats if you speak to someone often enough you catch up on lots of news but if you haven't spoken to them for a while you can't think of a thing that you've done. As we've been in our friend's house for a week and have now moved to a holiday house nearby we're not on the internet so blogging has been sporadic in the past 10 days. Activity at the farm has been considerable so we'll let photos explain where we're at.
One of the past day's issues is the internal wallhead height in the upper rooms. As the house is 1.5 storeys the trick is to achieve a well-balanced room which is usable without looking like a triangle and providing lots of awkward corners. The architect has proposed 1.55m wall head in the master bedroom but we personally have huge difficulties 'wasting' all that floorspace behind the joinery/plasterboard. The elevation shown looks west; here we've agreed with the joiner not to put any internal joinery on that side, other than boxing out the flue which can be seen, but to reduce the wallhead on the east elevation to 1.35m. This still entails the 'loss' of floorspace but provides proper walls for placing a bedhead against. The second photo shows the framework in place for that. On one of the landings we're creating an eaves storage cupboard. We're hoping to achieve optimal usable floor space and create a desirable room.

The second photo looks east and shows the framework now at 1.35m, this will be plasterboarded imminently.

Downstairs and the hallway looks a little less finished.

Tomorrow the heating guys return to start work on the heat pump installation in the utility room. Jim, the electrician is connecting the last elements of the heat recovery ventilation system upstairs and will then move downstairs. The wood burning stove arrives tomorrow and the final long lost window arrives. The slates were finished last week and look grand.

Photos

One happy hen, good to see the sunshine again. Although freezing at night time. One house with vapour membrane complete. Imagine the condensation and damp here without a ventilation system in place. No draughts though.
One gorgeous view from our bedroom window.
One selection of electrical tagliatelle feeding into the utility room.One snapshot of infrastructure to the master bedroom en-suite. Heat recovery ventilation, hot and cold water feeds and returns, underfloor heating and soil pipe.

Good weather = Good Progress

Afterwhat has seemed a long spell of dreich weather, the sun finally came out today and the slaters made significant progress on the roof, now about 75% slated. Inside the joiners completed the poythen vapour membrane work on the 1st floor such that we now have a near airtight house.

As I have mentioned before airtightness is an essential element in low energy housing; it allows the insulation to work properly, prevents draughts and ensures that ventilation can be properly controlled. The old adage 'insulate tight - ventilate right' has to be the watchword for the eco-selfbuilder, and if planned and implemented properly, will go a long way to achieving significant savings in energy even before considering renewable energy systems and high efficiency boilers.