Cold room, is it the windows?

Just had an interesting conversation with a customer who has 2 rooms which are always cold and thinks it is the windows causing that... they are double glazed aluminium. She says the aluminium frame feels cold. And I agreed it would feel cold but the Uw Value is what counts as this is the true measure of heat transference. Many things are cold to touch, try sitting on a porcelain toilet in a heated home with the seat up ... So I asked "when you have the heating on normal, and you close the door to the room, does the room get warmer, or colder". She said warmer, and that means that the room itself is not losing as much heat as the rest of the house, so the problem is not in the room. Many people seem to think that adding insulation like double glazing to your home will make your home warmer, but it can only maintain a level of heat when you heat your home. The complaint was especially about overnight so I asked about overnight heating and this was turned off at night. I suggested that the heating remains on at night but at a low temperature of 15 degrees to maintain circulation.

That should be an end to it... but watch this space.

If the aluminium frames are not thermally broken, then a lot of heat and cold is conducted through the frame.
Are they thermally broken?

At the end of the day, it is the Uw that the window achieves which decides what the energy performance is, it is not the style, not the configuration, not the colour and not whether it is thermally broken or not. The Uw is a measure of heat loss( gain) in Watts per square metre per degree Celsius, the lower the U value, the better the window performs.

You may want to check with a qualified building scientist on that. Of course the frames contribute to heat loss.

No I don't need to check with anyone... the measure is all that matters. I never said that the frames don't contribute to heat loss, every part of a window contributes to heat loss, but a well designed non-broken aluminium window will beat an ordinary thermally broken aluminium window every time.

Got it. So you are saying that a well built product beats a poorly built product. OK.
That’s means that a well designed and well built thermally broken window out performs a thermally unbroken window of the same quality.
If there is any scientific evidence to dispute this conclusion then I would love to see it.

Let's keep in mind that majority of heat loss still comes from the glass and not the frame.

When we developed the EcoTech window, we developed at the same time its identical twin with a thermally broken frame fully expecting this to yield a significant improvement in performance over its non-broken twin. But no, there was zero improvement.

I employed Dr Peter Lyons who established WERS and is the industry expert on window performance, he advised me to widen the thermal break material (polyamide) to create a greater gap, well that had no affect.

In the end I came to the conclusion that the system was optimised in aluminium as it was an it could not be improved because the heat loss was in balance be it convection, radiation (between the profiles) or conduction.

LPJ drop in and see....

Happy to. Are your windows passive house certified? We are in Council now and will be going out for quotes soon.

I think that the only passive house certified windows in Australia are done by these guys... imported from Europe... likely $3,000/m2 +

Internorm hybrid PVC/aluminium windows are certified for Australia and are also Passivhaus certified, with Uw values below 0.6 (when measured by European standards).

They have distributor in Perth, PM me for the details. $1250-1600 per sqm.

They're not on the website

I also found it strange as Internorm are mentioning multiple times that most of they profiles and glass are Passivhaus Certified. But, in the end of the day, I think what is really important to the end customer is the actual performance numbers rather listing on the PHI Web site (which is not free, as far as I understand).

I agree. I assume they are listed elsewhere in the world.

these guys say they are PH certified

https://blueskywindows.com.au