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Eliminating the draughts that push up your heating bills

Posted by Cathy Debenham on 12 November 2010 at 4:58 pm

Leaks and draughts are a guaranteed way of increasing your heating bills. You might as well throw your money on the woodburner! But, the good news is that it's relatively easy to block the worst ones up, and now, with a new gadget it's very easy to find where the worst ones are.

I don't usually review products, but when Black & Decker offered me the opportunity to try the new thermal leak detector, I leapt at it. It's really easy to use, and you can choose the level of sensitivity you want to measure.

First you take a reference reading. I did this on internal walls. Then you set the difference you're looking for. This could be 0.5, 3 or 5.5 degrees C. I plumped for 3C. If the difference in temperature between the reference reading and what you're pointing the leak detector at is less than 3C, the light stays green. If it's more than 3C colder, the light goes blue. More than 3C hotter, and it turns red. Couldn't be simpler.

What I liked most about it, is that it showed me what are the priorities for action. I hadn't realised how leaky the back door is, and I had thought that a couple of holes in the floor boards in the living room were worse in terms of heat loss than they actually are (though they're still worth tackling!). I was interested to find differences in temperature of the same outside wall, just by moving the detector a foot or so along. Does this mean the cavity wall isn't evenly packed in?

There were nice surprises too. The metal venetian blinds that I thought assumed would be hopeless insulators are doing a good job of keeping the heat in. It will be even better if I clear the window cill of clutter, so we can close them properly each night. I confirmed that curtains are good news for heat retention. 

All in all it was satisfying to find that our house is not too bad in terms of draughts. I had much more fun at my parents house, which is much older, with cold air from single glazed windows leaking into the room above the curtains and some howling draughts under doors.

The Black & Decker thermal leak detector is available for £49.99 from B&Q. I think it's definitely worth having. It makes it really easy to see which are the priority areas to highlight and help keep your bills down.


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

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6 comments - read them below or add one

Cathy Debenham

Cathy DebenhamComment left on: 11 January 2011 at 9:03 am


I've just checked the instruction manual on different materials. It says: "Shiny or polished surfaces can give inaccurate readings. To compensate for this, cover the surface with masking tape or flat coloured paint. When the tape or paint reaches the same temperature as the target underneath, measure the temperature of the item."

As my blinds are painted with a matt paint I think they are giving a real reading. Just feeling them with my hand, they are significantly warmer than the window.

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Cathy Debenham

Cathy DebenhamComment left on: 14 December 2010 at 5:33 pm

The press office says that B&Q does stock them, but I too have failed to find any evidence of that. They also say that Argos has them, but I couldn't find them on their website. However, I did find it listed on Amazon's website.

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Angela McGarry

Angela McGarryComment left on: 13 December 2010 at 9:15 pm

Discussed your review & video with my electrician. Local B&Q had no knowledge of it. Contacted B&Q main website - had reply back they they did not stock. Left message on Black & Decker site - no reply. Who will stock it, please?  Electrician said trade models cost about £150.

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iadamComment left on: 24 November 2010 at 4:12 pm

Hi Cathy, im sorry im not qualified to explain properly but remember reading in the manual which came with mine about surface properties affecting the reading. i did a quick search on wikipedia about emissivity, and black bodies and and very quickly got completely confused.  

maybe B&D mention something in the manual? but very shiney surfaces are going to cause some confusion with the meter. 

this is the sort of thing i mean

 you might also find that the meter is measuring in a cone shape so the further you are from the object the more area and more general a reading you will get - thats kind of useful really.

the bottom line is, don't trust the meter entirely! 

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Cathy Debenham

Cathy DebenhamComment left on: 23 November 2010 at 11:27 am

Thank you for pointing this out. How does that work? And how do I identify what's a real reading and what isn't? I guess I don't understand how infra red works!

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iadamComment left on: 19 November 2010 at 9:17 pm

hi i have a  similar gadget - no fancy colour changes though! you need to bear in mind the emissivity (i think!) of different materials. in effect that metal blind may well have been as cold as the window but the difference in material can effect the apparent temperature as far as an infra red device is concerned.

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