Cheaply Increasing the Energy Efficiency of an Old Home
Andy takes you on a room by room tour of his house and explains the small changes he has made, which have added up to a large reduction in his fuel costs over the winter period
I was recently working out the carbon footprint of Green Cottage, and came up with a very favourable figure of less than one tonne of CO2 a year – this being associated with the grid electricity I use. I’m with Good Energy who use 100% renewable energy, but for the purposes of counting I take the figure for normal grid electricity as that’s what comes to my meter.
I was quite pleased with this – but the figure doesn’t tell the whole story. My heating in the winter is wood fuel, and in a cold winter I tend to use a LOT of it – maybe 6 tonnes or more during one of the bitterly cold winters we had a couple of years back. I don’t really feel comfortable with this – for a terraced house it seems excessive, and unsustainable.
The way to get fuel consumption down is of course by improving the thermal insulation of a house. My problem is that I live in a solid-walled Victorian end terrace, which means that it’s not possible to insulate the walls as they don’t have a cavity which can be filled in the normal way. And because I live on the end, the gable end wall is big and cold and not insulated by an adjoining house.
Are Green Deal Schemes worth the trouble?
The government is hoping to remediate homes such as mine through the new “Green Deal” scheme. Under this scheme it is intended that homeowners can get a whole-house retrofit. In my case this would mean either internal insulation on all of the walls, or external cladding. External cladding could be a problem as for a terraced house you have to persuade all of your neighbours to have it too before you can get it done, and also being on the end overhanging the pavement, the council might refuse permission as the insulation would remove some pavement space, classifying the project a ‘land grab’.
Getting internal insulation done for the whole house under the Green Deal could also be problematic – it would mean having to move out, whilst the work was in motion. Also, my kitchen and bathroom would have to be ripped out and reinstalled, and it’s not yet clear whether the “Green Deal” would pay for this. And finally, I would end up with a loan repayable through my electricity meter, at 7.5% interest.
These problems will be encountered by many in my situation. After a good think, I decided to tackle some of the main insulation problems one by one, in the hope that it would eventually increase the thermal comfort of my home and lower fuel consumption.
The first thing I did was an upgrade to the loft insulation – easy and cheap to do. I already had 270mm of glass fibre insulation installed through an energy company discount scheme, which I subsequently decided to upgrade to 420mm – apparently 500mm is the Scandinavian standard for loft insulation. I used a product from B&Q which is 55% sheep’s wool and 45% recycled plastic bottles, costing around £12 a roll, of which I used around 8.
My second job involved the bathroom, a cold room situated on the corner of the house. Though the window is double glazed, the glazing is quite old and I often feel a cold draught when I'm in the bath or shower. I decided to put an extra layer of glazing in myself, which I did with perspex sheeting and magnetic tape, sealing around the edges with a window silicone sealer. The secondary glazing has made a huge difference and cost me around £120.
To add a little extra comfort to this room, I wanted to put in an extra heat source. There is a small towel radiator which is plumbed into the wood burning stove, but it’s not really enough to keep the room warm. As it’s a bathroom it wasn’t possible to use an electric heater, and I didn’t want a big clunky gas heater in there.
In the end I opted for a bioethanol fire, at £70. The fuel comes in plastic bottles and the fire costs about £1 per hour to run. A single fill will last about 2 hours which is enough to warm the bathroom up before I have a bath or a shower. The fire produces a little bit of water vapour but nothing compared to what the bath or shower themselves produce! So an ideal solution for the bathroom. I put the fire on a spare roof slate.
The kitchen window behind the sink is of the same type as in the bathroom, and is similarly draughty. On the kitchen window I tried a cheaper solution, an idea received from @JoRichardsKent on Twitter. I bought a roll of bubble wrap intended for insulating greenhouses during the winter, and made a 6-ply pad out of it to fit onto the back of the window. I used clear sellotape to make the pad, and attached it around the window with gaffer tape.
It still lets light in, but of course is opaque with the bubble wrap, but on this particular window it doesn’t matter too much as I have a blind in front of it anyway. The bubble wrap works really well and cuts down the draught massively! The roll of bubble wrap cost about £12.
Fitting Internal Wall Insulation in the Bedroom
The most expensive and ambitious measure I’ve taken is the insertion of internal wall insulation on the gable end wall in my bedroom.
I made a wooden frame on the wall to hold panels of ‘ecotherm’ insulation – a PIR rigid insulation board of the type commonly used in building modern relatively well-insulated homes. I used 75mm thick panels.
A professional installer would have removed the radiator from the wall, re-plumbed and re-attached it once the wall had been insulated. However, being an amateur, I made a box around it and lined it with reflective foam in order to push all the heat into the room rather than heating the wall behind it.
Once I had attached the insulation to the wall, I screwed plasterboard over the top and added a layer of plaster, which I then painted. I used buckets of ready-mixed plaster as I’m an amateur. The finish was a bit rough but after I sanded it and painted it white, it now looks quite attrative and ‘cottagy’. The wall insulation, plus the extra insulation in the loft, has made my bedroom toasty warm, a huge difference. Insulating this wall cost me about £500 in materials.
Using leftover materials for the spare bedroom
With my excess insulation panels and bubble, I completely filled my spare room window. it’s hardly ever used and it’s the only room in the house where the window is still single glazed. It’s a little dark in there now but it does have has an internal light. The benefit however is that the room no longer sucks out the precious warmth from the rest of the house.
These various measures, put together, have made a huge difference to the energy efficiency of Green Cottage. I’m hoping to carry out some more improvements in the future, with perhaps some more internal wall insulation, thermally lined curtains and other measures. Most importantly this shows that tackling a range of small insulation jobs can be affordable, while increasing the overall comfort and energy efficiency of an old home.
To find out more about Andy's house and community projects, visit www.ourgreencottage.wordpress.com
I work for LATCH - a small housing charity in Leeds. Most of our houses are Victorian terraces with solid walls, difficult both to keep warm and to insulate. We have worked with architects and engineers to develop a system and guidance manual for improving the thermal performance of our properties based on Passivhaus principles and using standard building materials.
We are currently refurbishing a house as a Green Deal showhome, with monitoring by the Institute of Sustainability to pilot this approach.
If you would to know more about how to fit solid wall and underfloor insulation you can download a copy of the Guidance Manual from http://latch.org.uk/what-we-do/superinsulation.html
This is a great success story and I applaud Andy Hunt for taking on the thermal improvement work he's done.
The housing stock in Britain is about the oldest in Europe and was built when standards were poor and energy was cheap.
Pretty much every home in the UK suffers from poor if not non-existent insulation.
The good news is that every home can be made warm and comfortable.
I'm the principal author of the Guidance Manual mentioned in the post by Mags from LATCH.
I also run a Social Enterprise company which super-insulates houses in and around Leeds - creating local jobs for local people in the process.
I gave a talk last year to the Leeds Permaculture group and you can see the PowerPoint here:
Mentioned in the Guidance Manual, and in my talk, are some important issues about Internal Wall Insulation.
Most important is the creation of an airtight vapour barrier on the warm side of the insulation. This stops water vapour getting behind the insulation and condensing.
As for the thickness of the PIR insulation I recommend a minimum of 100mm. This will give you a U Value of better than 0.25 - very toasty.
We don't use a wooden frame and instead attach the insulation directly to the wall - with glue and nylon plugs. Wood is not really that good an insulator so there will be cold points on a wall with a frame.
I can't really agree with leaving the wall behind a radiator uninsulated.
Its not that hard to move the radiator and not that expensive even if you get a plumber to do it.
This kind of super-insulation is only likely to be done once in the life of the house so better to do it right the first time.
The boxing round the rad in the picture looks like it will restrict the convected air flow as well.
Definitely a great idea to pack your loft with mineral wool - at least 400mm - and don't forget to insulate the hatch and make it airtight.
For windows do consider secondary double glazed units. These are less expensive than you might think and could even be taken down again in summer.
Good luck with your projects.
Stay well - stay warm.