Squashed loft insulation 50 percent less effective

March 18, 2013

Research from the National Physical Laboratory (NPL) has shown that by squashing down loft insulation, for example under storage boxes, homeowners almost halve its performance.

According to the Energy Saving Trust, a quarter of a home's heat (and hence the heating bill) is lost through an un-insulated roof. Loft insulation is a relatively cheap and easy way to save on but needs to be installed correctly to achieve its full benefits.

Loftzone are a UK company supported by the Carbon Trust that manufacture a raised loft floor designed to protect loft insulation while allowing homeowners access to their loft. The company approached NPL to carry out research into the thermal resistance of loft insulation when it is compressed, and an NPL Fund project was set up for this work.

The research tested loft insulation at the recommended installed thickness of 270 mm and then compared it to insulation that was compressed to a thickness of 100 mm. The results showed that the loft insulation performs to manufacturer's specifications when installed correctly but that its thermal resistance was reduced from 6.11 m2.K/W to 3.09 m2.K/W when compressed.

NPL's Ray Williams, who worked on the project, said: "There are rigorous requirements for manufacturers of insulation to quote performance values based on accredited measurements, but further measurements have shown that achieving this in practise requires correct installation."

A survey sponsored by the Carbon Trust has previously shown that 82% of households use their loft for storage, compressing insulation either by boarding the loft or simply putting belongings on top of it. There appears to have been a communications breakdown with only 26% of people asked in the survey saying that they knew compressing insulation made it less effective. This implies that many homeowners may be reducing the effectiveness of their insulation, as well as any associated energy and , without realising it.

Dave Raval, chief executive of LoftZone, said: "We all know that people use their lofts for storage. But compressing insulation halves its performance and what's worrying is that so few realise this. If you live in a house, and are worried by your fuel bills, don't use your loft for storage unless you have protected the insulation first."

Explore further: Simple tips can help keep your home warm this winter

Related Stories

If you can't measure the heat...

July 29, 2008

Accurate measurement of thermal performance is crucial if new government legislation aimed at producing dramatic reductions in CO2 emissions is to be successful. The UK's National Physical Laboratory (NPL) is offering construction ...

1930s home goes green

August 5, 2009

A 1930s house built in 2008 is about to undergo the first of three energy efficiency upgrades which will ultimately convert an energy inefficient house into a zero carbon home designed to meet the Government's 2016 CO2 targets ...

Roof and attic design proves efficient in summer and winter

October 19, 2012

(Phys.org)—A new kind of roof-and-attic system field-tested at the Department of Energy's Oak Ridge National Laboratory keeps homes cool in summer and prevents heat loss in winter, a multi-seasonal efficiency uncommon in ...

Disappearing homing pigeon mystery solved

January 30, 2013

Homing pigeons are usually remarkably efficient navigators, however, on rare occasions, things go drastically wrong. So, when Jon Hagstrum of the US Geological Survey read in his local newspaper about two races when pigeons ...

Recommended for you

The ethics of robot love

November 25, 2015

There was to have been a conference in Malaysia last week called Love and Sex with Robots but it was cancelled. Malaysian police branded it "illegal" and "ridiculous". "There is nothing scientific about sex with robots," ...

Nevada researchers trying to turn roadside weed into biofuel

November 26, 2015

Three decades ago, a University of Nevada researcher who obtained one of the first U.S. Energy Department grants to study the potential to turn plants into biofuels became convinced that a roadside weed—curly top gumweed—was ...


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Mar 18, 2013
I just topped up my insulation to 20" deep. I'd like to see if it's the height of insulation or the compaction that causes the loss.

IE does 10" of fluffed insulation do better or worse than 20" of insulation compacted to 10".

Obviously 20" would be better than 10". That's all they're saying here.
1 / 5 (2) Mar 19, 2013
The "results" of a UK funded project could be stolen as http://issuu.com/...ublePage

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.