Month: October 2009

low energy lighting

18w dimmable fluorescent downlighters (6), 20W HID spotlights (4) and recessed downlights (4), 4 tungsten halogen task lights (4) and compact fluorescents everywhere else.

The house had to be re-wired on acquisition in 2005, so the opportunity was taken to light the house with the most efficient lighting available at the time, but not just utilitarian to show that low energy could mean good design too. LED’s were not available at the time, so spotlighting had to be done with High Intensity Discharge (HID) lamps. Downlighting is done mainly with dimmable, recessed compact fluorescent (PL) downlighters. There are 4 dimmable, separately controlled tungsten halogen tasklights – quite inefficient in comparison now, but only on when needed, and rarely on full brightness. The PL downlighters are a great success providing a warm, attractive, diffuse light. Their dimmability means they can be used according to mood or required function at the time. The HID’s are not so good, they take a while to warm up and once turned off cannot be relit until they have cooled down. Despite assurances from the iGuzzini salesman that these models were not too bad, the warm up time means you cannot turn on the light and walk straight into a room and the relighting period is still about 10 minutes so these lights tend to get left on too much – slightly undermining their energy saving potential. That said they are more efficient that fluorescent and spotlighting can provide much more attractive lighting. The first strip LED’s are about to be installed.

Existing Windows

New windows triple glazed in locally made FSC hardwood frames with double seals. All existing windows refurbished with coated double glazed units or secondary glazing to original stained glass.

The windows were almost all original single glazed timber windows except the attic windows which were later replacements already beyond repair. They are sliding sash on the back, opening casement on the front.

IMG_3101 smlWe’ve upgraded the existing windows instead of replacing them using a local carpenter, Reddiseals sash window parts and FSC certified hardwood (Guariuba) to build replacements where the existing had decayed too far. All the windows were fitted with double glazed units low E coated but not argon filled, initial windows had a tiny 6mm cavity as we perfected the way of doing it, this then increased to 9mm or 12mm where space allowed. Original stained glass has been secondary glazed on the inside to avoid condensation, mostly with single glazing but double where space has allowed. All the windows are now fully draft sealed – the sash windows have new parting and staff beads pre-fitted with draft seals. Neoprene O-profiles were routed into the casements, new and existing.

Some of the stained glass needed repairing, which was done by David Sidgwick in Stockport who did a great job.


Waxed FSC hardwood and Venetian plaster wetroom accommodating reclaimed bath.

The floor in the existing bathroom was mostly rotten so had to be stripped down, floor boards binned and half the joists replaced. The opportunity was taken to set the new floor to fall towards the centre of the room into a new floor drain.  The outside wall was internally insulated with 40mm of high density glass fibre then overclad with cementitious particle board (Viroc) as it is moisture resistant and stable (although it turns out not quite stable enough to avoid hairline cracks in the plaster). This was then coated in a sheet of thin polyester webbing soaked in liquid neoprene in all the areas likely to get a soaking. Due to the amount of movement in the floor the usual tile solution was not advisable so the floor and most of the 2 long walls were covered in 18mm tongue and groove FSC certified Cumaru from the Ecological Timber Company.

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The internal face of the outside wall was covered in Venetian plaster from The Polished Plaster Company, the raw materials from Keighley, applied by our plasterer. The floor and polished plaster are waxed regularly and so far there have been no problems. The bath and taps are the originals. The bath was reglazed, taps just serviced and cleaned. The new taps are low flow spray taps.

Carbon Neutral Heating

40kW gasifying log burner and 10 sq.m of solar thermal collectors both feeding into heat stores providing space heating and hot water.

The boiler the house came with was so arthritic no engineer would touch it. Manchester is a smoke control zone. The only kit with the DEFRA exemption was either too big or eye wateringly expensive or both, and its fuel – pellets was mostly shipped in from abroad, slightly denting the low carbon credentials. Sundance Renewables – a co-op in south Wales introduced us to the Atmos gasifying log burner. It burns logs, sucking the flames into a chamber beneath the logs which ensures a very hot clean burn with minimal ash. We got hold of the test data and it is well below the threshold for exemption so after 18 months we talked the smoke control officer into letting us install one – although with the caveat that he has the right to insist on its removal if he gets complaints. It does emit smoke, but only really an issue for the first half an hour then it calms down and the whole process of a burn is finished within 2 hours anyway, all the heat is dumped into 2 water tanks – thermal accumulators. IMG_5493 sml They both have solar and hot water heat exchange coils in them. Cold water is pre-warmed in the lower larger tank first, then taken up to full temperature in the upper one. In summer the solar panels feed into the top tank first then when up to top temperature feed into the bottom. In winter they feed into the cooler lower tank. The top tank made by Consolar also has syphons in it that help make sure the store stratifies so that even when the heating draws hot water from the middle of the tank the top where the hot water is drawn through remains hot.IMG_4455 sml

We had alot of help with designing and fitting the system from Richard Drover and also from Greenshop Solar, who sold us the control system. solar panels

Solar Panels

We have put as many panels up as we could fit neatly to minimise the amount of wood we’ll have to burn. There are 80 tubes in 4 arrays running the full length of the ridge with a thin access walkway running beneath them that both masks them from the street below a little and allows safe access.  These are the cheapest well reviewed ones we could find from Navitron on the basis that with so much water into which to put the heat we do not need expensive methods of dealing with overheating. We have an added overheat protection of an old radiator from the top of the house plumbed behind the stored wood in the cellar so that spare heat can be used to dry wood further – needless to say in a Mancunian summer there was only 1 day when it looked like it might divert from the 2 tanks to this.

Wall Insulation

Gable wall – external ly insulated – Udireco rendered 170mm recycled woodfibre. Front and back walls – internally insulated (bought but not yet fitted) 27mm Spacetherm glued to Fermacel board. Outrigger – tbc.

This took ages to work out, trying to marry up recyclability with embodied energy and while avoiding pervasive toxins, environmental degradation and derivatives of fossil fuels. Originally we were going to use Foamglas externally on the gable and internally on the front and back but the price was very high for what it is, and while the product is recycled, it is from a very high grade feedstock. Also this would have meant the whole house became entirely vapour sealed which splits commentators as to how bad this is.


Once deciding on breathability as key there are very few choices – mineral wool or wood fibre with either lime or diffusion open polymer render. They are pretty closely matched on embodied energy and toxicity. The tip to the balance was from sequestered carbon, the benign properties of wood fibre over glass, and UDI’s sustainability efforts through the entire product – glues, etc combined with the service from them and their UK agents Back to Earth. This produced a U-value of 0.2W/m/K


Breathable internal insulation is not advised here in the UK, internal insulation can cause issue anyway as the internal surface of the brickwork under the insulation will most likely be below dewpoint for much of the year so any water vapour there will turn into water so the strategies deployed are usually to prevent it getting there in the first place or ventilating the space between the lining and the masonry.

Add to this the fact that we want to keep the original plasterwork details – nothing spectacular, but part of the character of the place and our choices are very limited. The plaster is quite deep so we’ve got about 40mm to play with. The desire to avoid fossil fuels and foams becomes a prohibition internally as most of these materials would add considerably to the toxic load in a fire. Spacetherm uses aerogel impregnated into a mat, glued to a board it has the highest insulating properties after vacuum insulating panels – 0.13 W/m2/K and while high in embodied energy very little is used it is non toxic and enabels the walls to reach a U-value of 0.38 without thickening the wall. Its key disadvantage is cost, but it can be fixed directly to the wall with no framing or glueing so the cost of the material should be offset by the ease of installation. The boards have a built in vapour barrier and the mat itself is hygrophobic so with so little space in which vapour can gather the problem of interstitial condensation should be minimised.

The price of the Spacetherm is so high that where there are no plaster details left and window reveals can be adapted there is still room for another solution. As this is a pilot the intention is to try out a breathing internal wall insulation. There are 2 wood fibre solutions out there.

Roof Insulation

Recycled slates on TLX Gold vapour permeable multifoil sarking overall, over either formaldehyde free glasswool to 350mm, high density glass-fibre batts on Spacetherm or Thermafleece sheep’s wool between built up rafters, underdrawn with plasterboard

There are 3 configurations to the the roof insulation once past the covering:

The remaining floorspace above the attic rooms, in which we have simply topped up the glasswool, down the middle we have used some unwanted rigid insulation to create a crawlway now the insulation is so deep, to get to the solar plumbing. U-value 0.1 W/m2/K

The main slope of the roof has had the rafters built up to accommodate 200mm Thermafleece and is then underdrawn with 10mm plasterboard and skim with no vapour barrier, so fully vapour permeable. U-value 0.143 W/m2/K

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The area under the half gable and dormers where space is at a premium has 100mm Hi-Cav 32 rigid glass wool batts, at the time of installation formaldehyde free was not available but to get the highest insulation value for the smallest thickness this is undrawn with 27mm of Spacetherm on Fermacel board which is vapour impermeable. U-value 0.148 W/m2/K

New Windows

Triple, argon filled,coated glazing units in FSC hardwood double sealed timber frames and a feature frameless oriel window of double, argon filled, coated glazing units.

IMG_2631 smlThe triple glazing units came from Floatglass in Wythenshawe.  The timber came in the same shipment as the bathroom timber and was made up by local joiners.

IMG_2985 smlThe special doubles for the oriel came from Cheadle Glass after Hansen glass tripled the price from their first and second estimates once it came to ordering. They were then sent to Structural Glazing in Telford for gluing.


97% recycled plastic gutters.

Swish have just brought these out, they use recycled plastic for most of the piece but with a think skin of new plastic on top.  So far only the actual gutter and pipe are made this way the rest of the fittings are still new plastic. But overlall this seemed a most resource efficient solution over alternatives like zinc, cast iron or aluminium.


New flooring, eaves and verge boards – FSC certified, UK grown Douglas fir.

This took a while to source, but in the end found from a company called Inwood that grows it to make their laminated timber structural beams with grown on a Sussex plantation.

a zero carbon Victorian semi?

Chorlton001We moved out of Hulme after 20 years as we had outgrown our flat, price restricted us to a pretty run down house backing on to the pizza shop. It had been separately let rooms before we returned it to a family house. The order of the works below is the order we had to do it in to minimise the health hazards.

We have occasional days when you can have a look at the work we’ve done and talk to us about how to do it to your own home – the next one is on March 16th, books here: Superhome website

Paints & Finishes

All the paints and finishes use no fossil fuel products. VOC’s were avoided.

We have tried  a suite of natural paints to make sure that we minimise the toxicity of the internal environment and maximise where necessary the vapour permeability. Floors are finished with Polyx oil in low traffic areas, but we have found it is just not robust enough for heavy traffic so used Danish Oil in high traffic areas and just made sure we ventilated well for a bit.

Still to come

Fully recycled/recyclable kitchen

The kitchen will use unglued/backed stainless steel for the worktop, the doors will be from recycled school worktops


Once the debate over feed in tariffs has settled down we’ll look at seeing how much further we get the house to full neutrality – there’s not enough roof space left to get all the way but we’ll see.