A cheap and effective form of house insulation?

chimney sweepSally Philips, the inventor of the Chimney Sheep (www.chimneysweep.co.uk), sent me the following email over the weekend. I think that Sally's story clearly illustrates the challenges that energy efficiency entrepreneurs face. Although her product offers savings that match other improvements, such as better loft insulation, entrepreneurs like her face difficult obstacles in getting their product accepted by regulatory bodies. Products that improve air tightness are vital additions to the armoury of energy efficiency inventions but never get the attention that they deserve. (Her letter is reprinted with her permission). ***

Hi Chris,

I was interested to read the Guardian article recently ('The energy efficiency 'savings' that are just hot air') that referred to your blog.

I have developed a draught excluder for chimneys made of felted sheep wool. We lose about 4% of our household heat up redundant chimney flues. About two thirds of the UK housing stock was constructed pre-1970’s before central heating was installed as standard, meaning millions of UK homes have open chimneys, many of them with several. Plugging the gap with a Chimney Sheep saves about £64 per year, according to recent research conducted by the University of Liverpool:


I don’t know why the issue of heat loss up chimneys is completely ignored by the industry, by DECC, by EST…nobody takes it seriously but it is a problem that affects a significant number of homes and is so readily resolved.

I actually won a Green Economy Award in a category that was sponsored by DECC but nothing has happened as a consequence.

BRE estimate that 40 cubic metres of air is drawn up an open chimney flue per hour. I asked them to look at my product as the first step to getting it approved by OFGEM to be used as an ECO product. They calculated its performance in SAP, then told me that SAP assumes a closed flue is still 50% open to allow for ventilation. This isn’t a building regulations requirement so I don’t know how they can still use that calculation but they have and are now charging £5K for a report that shows that the product is half efficient!

HMRC said they would be happy to add my product to the list of insulation / draught exclusion products that are eligible for 5% VAT rate but I would have to get the law changed first. I met my MP who wrote a few letters to people who haven’t written back.

To be a member of the National Insulation Association I need a test that costs £15K.

To be listed among the products that are eligible to be used for ECO measures I need a different test that costs £15K. To be endorsed by EST I need another test that costs £5K

I’m not getting in touch just to have a moan, but I thought you might be interested to know just how hard it is to get the issue of chimney insulation noticed or taken seriously, when such a tremendous lot of heat is wasted up chimneys and it is so easy to prevent.

Yours sincerely

Sally Phillips

Chimney Sheep Ltd

19K Solway Industrial Estate



CA15 8NF


Web: www.chimneysheep.co.uk

Phone: 01900 825019

Facebook www.facebook.com/chimneysheep