According to a report from The Existing Homes Alliance, eco refurbishment costs between £12,000 and £54,000 for a typical house, but a number of factors will affect the price you pay.
Within the SuperHomes network an investment of around £40,000 in eco refurbishment seems fairly typical. However, very divergent sums have been spent by homeowners. These range from £16,000 for eco-retrofitting a flat to £120,000 for the exemplar energy retrofit of a large 6 bedroom Victorian town house.*1
SuperHomers Robert Cohen and Russell Smith have worked out the carbon impact of various energy saving measures along with their costs. The results are shown in a report published in 2010 by The Existing Homes Alliance. The report estimates a cost of £12,000 – £54,000 for retrofitting a typical 3 bed semi. This cost reflects the work needed to cut CO2 emissions by between 70 – 80%.
Super-insulation and Mechanical Ventilation and Heat Recovery (MVHR) is a proven way to dramatically reduce energy inputs and CO2 whilst improving winter comfort. However, older houses were not built with air tightness as a priority and newer technologies like MVHR carry a price premium. This means that retrofitting a pre-war house to contemporary PassivHaus standards is likely to both challenging and expensive.
Graph: Impact of carbon reduction measures on a typical house. Click to enlarge.*2
A number of basic factors will influence the cost of your eco refurbishment:
Serious investment is needed if you want to increase your home comfort whilst greatly reducing your reliance on standard energy inputs like oil, gas and electricity (the latter usually from coal or nuclear). Most people start by significantly improving the insulation and draught proofing, then installing much more efficient heating and superior double glazing. They might then install solar thermal and PV and perhaps a heat recovery (MVHR) system if the fabric is suitably air tight.
If you are seeking an 80% CO2 reduction without reverting to wood burning you’ll probably need to install most of these measures. You may be able to control costs, however, by having several jobs done around the same time. For example, scaffolding used to put up external wall insulation could also be used to get up onto the roof to mount solar panels or fit a sun pipe.
If your property was built after 1930 it will probably have cavity walls. Insulating cavity walls is currently very much cheaper than treating solid walls so the wall type can significantly impact your costs.
A detached house will have at least 4 walls exposed to the elements – a mid terrace property may only have 2 such walls. This will impact the amount of materials and time required to insulate walls.
The larger the dimensions of your property, the greater the probable cost of refurbishment. You will be applying treatments to the various surface areas of your house to make the fabric more thermally efficient. In a larger house more materials will be required and extra rooms, conservatories and similar are liable to complicate matters.
Material, system and installation costs and subsidies can change significantly over time so it is worth taking advantage when the best deals are on offer. For example, UK government subsidies for Solar PV changed went from being 50% grants to Feed in Tariffs. These started at 43p then were quickly cut by 50%.
Modest grants are currently available for renewable heat technologies like solar thermal, biomass and heat pumps and these are now expected to be replaced by the long awaited Renewable Heat Incentive in 2013.
Cheap cavity wall insulation has been available for many years. In early 2012 energy suppliers took to offering it for free in order to meet their CERT obligations.
The Green Deal is expected to make new finance for household eco refurbishment available from early 2013. It aims to match on-going repayments to energy savings so the household can enjoy improved warmth and reduced carbon intensity at no extra cost.
A spend of around £40 – £50,000 on a 3 bedroom house has enabled a number of SuperHomers to fulfil their eco refurbishment dreams. If your refurbishment budget is considerably lower – say £12,000 – then solar technologies, MVHR and external wall insulation are likely to be off the menu. However, you will still be able to do quite a lot to make your house more energy efficient. Make sure you get the best independent advice and start with a refurbishment plan and a defined budget. Also, do spend some time surfing the SuperHomes website for inspiration – this costs nothing.
Ends | Last Updated Oct 2012
*1 Eco Refurbishment Costs depend on a project’s scale and ambition
Simon Burton invested £16,000 in the energy retrofit of his London flat.
Harriet and Chris Martin invested £46,000 in the eco-renovation of their 1932 semi.
Camden Council spent some £120,000 retrofitting a Victorian six bed semi to exemplar standard.
Free UK eco open house events in Mar/Sep