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Do you even know how to calculate U?
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Cooling tips
- Thread starter MNW67
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Does insulation make your house hotter?
"Insulating homes has very little, if any, impact on the risk of overheating," said Professor Kevin Lomas from Loughborough University, who led the largest national study so far into overheating in homes.
Insulation can even help keep your home cool, because most types - certainly external wall and likely also cavity wall - will stop your home from getting as hot in the first place.
Other energy efficiency measures work both ways too: insulating pipes saves energy in winter by preventing heat from leaking - and so helping keep your home cool in summer.
The exception when it comes to insulation is if you have it on the inside of your wall, which can create a "small additional risk" of overheating by one degree Celsius or so, but only if your home isn't well ventilated anyway, explained Prof Lomas
But "other things like shading and proper ventilation have a much, much bigger effect and can reduce the internal temperature substantially", he said.
Why is my home so hot?
The main factors that let homes get too hot are "too much glazing, lack of shading, and insufficient capacity to well ventilate the home", said Julie Godefroy, head of sustainability at the Chartered Institution of Building Services Engineers (CIBSE).
Flats with "big windows at the expense of everything else" are often "designed without any consideration for what happens when the heat beats down on to these windows," said Jonny Marshall, senior economist at think tank Resolution Foundation (RF).
That pesky glazing again.
Only early (cavity) buildings that are poorly ventilated. Luckily B'regs and conscientious builders focus on both.
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I’ll take the deflection post as a No.
Do you just rely on building control to tell you what the U value is?
Do you just rely on building control to tell you what the U value is?
He clearly isn’t otherwise he wouldn’t be spending all his time on here taking about hot air
That seems pretty clear. And it chimes with what Jurassicspark said about his external insulation.
I've remembered now that about a decade ago there was a local news report on overheating in some new build flats, but they put that down to big windows with unsuitable glass.
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Insulation changes the speed of transfer. The slower the transfer the less heating/cooling is needed to maintain a given temperature based on the temperature difference.
It also means the greater the impact of any heating / cooling source desired or otherwise.
D
Deleted member 317777
That’s why new builds have a typical heat loss off 4-6kw
New builds in theory can be heated with a flow temp of 50 degrees or less. Try that in an old house!
I don’t think Boyo can comprehend heat loss, or would struggle to do the calculations
Insulation can even help keep your home cool, because most types - certainly external wall and likely also cavity wall - will stop your home from getting as hot in the first place.
Likely doing a lot of heavy lifting there.
I can totally see how external insulation will help keep cool but not cavity - once that sun gets on the brick every day and builds up and maintains the heat then that cavity insulation canni change the laws of physics captain
No. Architects specify a number. It's up to us how best to implement the products to achieve it.
Since June 2022 Part L changed significantly meaning the heat loss value through walls came down from 0.28W m²K down to 0.18W m²K
This in turn meant that using conventional glass-wool cavity batts, cavity walls would need to be upped from 100mm to 150mm. Customers are given the option of space v's cost. We can achieve the same U value using 100mm interlocking PIR boards but at something like four times the cost (product cost and installation cost).
The maths for working out the K values for the varying materials is all online. A monkey could do it. But it's rarely needed. Scenarios are all produced by block manufacturers, insulation suppliers etc.
We do rely on Building Control to (hopefully) give us notice on any future changes to B'reg's though.
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There is no slow transfer of heat leaking through the PIR or the air gap.
External wall insulation is often light coloured as well, which will reflect more of the sunlight than darker masonry.
It seems intuitive that the further away from the inside of the house the insulation is, the better it will be at stopping heat from entering
It's unequivocal.
MBK just jumps in feet first without actually reading any of his links.
Eh? It's covered in render - usually?
You mean if there was an air gap? Like in some PIR partial fill cavity wall scenarios?
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Of course there is. It’s expressed in W/m2. It’s what the friggin U value is.
