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How solid wall insulation cut my energy bills to a fraction of the UK average

Posted by Eric Blakeley on 27 February 2013 at 9:10 am

My  house is mid-terrace with three bedrooms and is south facing. It was built in 1920. Our solid walls were exterior insulated under a government grant scheme for the over 70s three years ago. The insulation is 50mm Phenolic foam, rendered then painted.

Electricity consumed from 9/11/2012 to 3/1/2013: 195kWh. Gas consumed during the same period: 47kWh. My energy bill has not been reduced to Passivhaus standards but is somewhere in between.The main difference is the noticeable retention of heat, especially on a sunny day because I'm south facing.

The point I'm trying to make is that we should not just be talking about the production of energy but also its conservation; they are both equally important. The Energy Saving Trust says you could save up to £490 per annum with solid wall insulation; insulation requires little or no maintenance, it's a no-brainer long-term investment.

British houses are notoriously wasteful with reference to energy use. A glance I took at house letting ads showed most had an Energy Performance Certificate (EPC) rating of C, D or E. Construction methods have changed marginally over the last 150 years: the building industry gives scant priority to energy conservation - a view reflected by the political establishment. It is not difficult - or prohibitively expensive - to construct 'zero' energy buildings. See the Guardian's recent article on Passivhaus building

The majority of houses in the UK are of solid wall construction: highly inefficient in relation to energy use. Cavity wall is marginally better. The potential for energy saving both individually and nationally is enormous but inexplicably there seems little political or industrial will to address the issue.

Solid wall insulation does not qualify for the Green Deal, but the Energy Company Obligation (ECO), which runs alongside the Green Deal, exists to help with more costly measures such as solid wall insulation. 

About the author: Eric is a retired engineer with a strong interest in making his home energy efficient. 

If you have a question about anything in the above blog, please ask it in the comments section below.

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3 comments - read them below or add one


stevegsComment left on: 2 May 2013 at 1:20 pm

My house is a fairly typical 3-bed cottage built in 1880 with solid brick walls.  It has no soffits or gable ends, so the roof would have to be extended in both dimensions to accommodate exterior insulation.  Although detached, it's only 750mm from next door.  Interior insulation is a no-no - the rooms are small enough as they are!

About 1/4 of the original exterior was incorporated into an extension in 1973.  This has a cavity, but I hardly noticed any improvement after installing insulation in that.  The attic is tiny and is now full of fibreglass insulation - likewise the gaps between the ceiling joists in the 1973 flat roof are crammed with fibreglass.  Yet, it's still cold in there.  I see similar properties on estate agents' websites whose EPC is F - mine can't be any better than E.

The saving grace is no gas - the solid fuel Rayburn burns wood or coal - the former is usually gratis if I collect it.

Thank goodness I got solar panels on the roof before this nonsense of requiring and EPC of D or better to get a decent FiT!

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fiComment left on: 27 February 2013 at 5:51 pm

I would love to have my walls insulated, but I love my brickwork - and find myself really torn about what to do!! Would it be worth just insulating the rear elevation, which is not 'original' anyway?

Any thoughts, anyone?

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MikelComment left on: 27 February 2013 at 10:41 am

It would be useful to see the energy consumption figures prior to and post the installation of the solid wall insulation. The saving against current prices can then be deduced.

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