The Contura wood burning stove in place in the main sitting room. We sourced this through EcoLiving who also supplied the ground source heat pump. The photo below is of the less attractive connection through the main bedroom to the chimney but this will be boxed in when the fitting is complete. This will still be a few days as the lower section of the external chimney and roof flashing need to be replaced because they have been damaged on site and a good seal with the internal pipes can't be achieved.

The slate tiles in the hallway will receive another coat of seal this weekend.

Just a short while left in our temporary home - we moved in here in mid June 07 and we're moving out next week. Its been pretty hard work at times and I can still feel the cold of the week before Christmas but being on site while the house has been built has been fun and essential.

Passive house weekend...

After our airtightness test was done last Friday I switched off the heating, having 'cooked' the house for a couple of days to aid the thermal imaging tests. On Friday evening it was 20.5 deg. in the ground floor and 19 deg in our unheated 1st floor bedroom.
After a chilly and breezy Friday night, both these readings had dropped by just 1 deg overnight and still no heating. During the day the readings dropped a further 1 deg (tilers in - patio door fully open!) then raised a little towards the late aftenoon/evening as the sun peeped out.
Saturday night was again cold (as snow moved into northern Britain) but temperatures only dropped a couple of degrees in the house overnight, only to rise again during today to as much as 23 deg. in the ground floor and 20 deg. in our bedroom due to solar gain, despite the continuing biting cold wind outside (and leaky patio doors!).
In essence the house was behaving passively, with perhaps the circulation pump (set to continuous within the heat pump unit) helping to spread the heat from solar heated rooms to the rest of the house, an effect which will be helped further by the MVHR unit when switched on.

Airtightness testing - the man with the fan..!

Early last week we took up an offer to have the house tested for airtightness by the Leeds Met. Uni's Centre for the Built Environment. Unlike in England, such test are not (yet) a requirement of building reg's in Scotland, but given that we are aiming to achieve the AECB's Silver standard I was keen to ensure we were at the very least close to our design target!So how do we measure airtightness? Until Friday, this was a mystery - then it all fell into place; method as follows:1. Close all trickle vents, windows and doors, fill all drain/water traps.2. Open main door of house and fit blower fan sealed within frame.3. Switch on fan and measure air flow rate into house (in m.cu. per hr) when air pressure in house is a steady 50 Pascals higher than outside.4. Record this flow rate and divide by surface area of house. Hey presto, this give the air permeability figure in m3 per m2 per hr - or m/hr.The results? Pretty good for a first test appeared to be the concensus. Under the current building reg's in England, the number has to be less than 10; ours was 4.8. Put another way, if we add up all the gaps in our building we have a hole the size of a dinner plate between us and fully airtight.However, the AECB's Silver target level is 3.0 for a house using a Mechanical Extract Ventilation system, or 1.5 for MVHR (our option); in other words we need to try and reduce our dinner plate to a saucer!So where do we look? Thermal imaging and smoke tests under pressure showed airflow through the service void, all of which are connected to the 1st floor joist void and loft space. This leads me to suspect we have some leakage at the soil vent pipe penetrations and possibly the airtightness membrane joints within the loft. Another significant 'problem' is clearly the seals around the large sliding patio doors, of which we have three sets, and which were actually letting water in last week during a driving rain storm. Our tester reckoned that sorting the doors alone could bring our figure down a futher 1 to 2 m/hr, getting us much closer to our target. Other issues included leaks between plasterboard and window frames.As a postscript to this, today I noticed a 1.5 inch waste pipe in the kitchen open to the elements with a gale blowing out of it into the house which we had omitted to seal; so that's an egg cup off our dinner plate!

Today the tilers are here enjoying the peace of the weekend to get on with their work without a dozen other folks hoofing their way over the floor. Its looking good. We can't quite work out when we'll be in..so close but not certain. One of the most inspiring things is the view from the windows. We've had beautiful weather this morning and threatening clouds this afternoon; majestic skies all day.