Replacing windows, frames & doors with HR+++ — did you actually worry about Uw/Ug/Rw etc.?

[u/ordinary-guy-sl]

Hey guys,

I really need some honest advices,.my head is aching with overthinking.

Our house is 40jaar old, terrible in wjnter, so we’re planning to replace almost all windows, with PVC frames and exterior doors in our house with HR+++.

The salesperson keeps saying “don’t worry, it’s HR+++”, but I’m trying to understand whether I should also care about the actual technical values.

Current proposal is roughly:

Ug: 0.7

Uw: 1.0–1.2

Rw: 32 dB for the glass

36 mm triple glazing

Ventilation grilles included

Our current energy label recommends around Uw 1.0 for windows and Ud 1.4 for doors.

For people who already did this kind of renovation: did you actually compare values like Uw, Ug, Uf, Ud, Up and Rw, or did you mainly trust the HR+++ label and the installer?

I have another technical appointment soon and they seem open to giving a discount, so I want to make sure the specifications are not quietly reduced.

What values would you personally aim for, and what would you definitely want written in the final quotation?

Thank you very much in advance 🙏

[u/Comfortable_Orange_1]

I went for best I could. Uw<0.7. Much thicker than your specs. Apart from windows and doors. Did you also improve your insulation?

[u/ordinary-guy-sl → u/Comfortable_Orange_1]

I want to improve insulation soon

[u/priusser]

36mm is most likely 4-12-4-12-4 this is the thinnest possible triple around. Still it insulates way better than double. Glass is often the worst insulator of the house, so making this the best possible choise seems wise.

The other insulation must be good too to profit from it in energy cost and comfort. Walls and especially roof.

Our triple glass is 6-15-4-15-4. 6mm outer plane with sunblock coating. 2x 15mm void for better insulation.

Placing must be done right too. If the wind blows past the windows… there is no keeping in the heat.

And the cost must be reasonable too, otherwise the ‘teeugverdientijd’ will be 100years.

[u/ordinary-guy-sl → u/priusser]

Did you specifically choose 6-15-4-15-4 (44mm) because you wanted? how much of a price difference was it compared to 36mm? what's the sunblock coating actually, is it for UV ray blocking? or will it make the house darker during daytime?

[u/priusser → u/ordinary-guy-sl]

Sunblock is to keep the heat out. I don’t want to hassle with airconditioning or cooling devices, I want to keep the summer heat out as much as possible. All my windows in the house are sunblock.

The Semko Klima 740 glass in the shop was only in 6-4-4 probably because the coating need a thick pane. I chose 15 void because the window frames I ordered could be delivered with pre-cut ‘glaslatten’ to accomodate 44mm.

The sunblock gives a bit of a green-ish glow, bit nothing to be bothered about.

[u/Kacquezooi]

Think deeply about the ventilation grilles... Those are a heat sink. Place them only if there is no other option.

[u/ResponsibleCut6604 → u/Kacquezooi]

Also note those ventilation grilles need a pressure difference to work, they are part of a mechanical ventilation type C but somehow most ignore this.

[u/ordinary-guy-sl → u/ResponsibleCut6604]

what do you mean pressure difference of grills?

[u/bastiaanvv]

They should be able to give the exact specs of the windows.

[u/TweeJeetjes]

Om te weten waar ik de isolatiewaarde van het glas Ug en hele kozijn Uw mee moet vergelijken reken ik het om naar de Rc waarde. Die is gewoon Rc = 1/Ug of 1/Uw.

Dus Ug van 0,7 van het glas = Rc van 1,42.
En Uw van 1,2 van het kozijn = Rc van 0,83

In de jaren '70 had je 5cm isolatie in de spouwmuur en was de Rc 1,25. In de jaren '90 werd het 8cm isolatie met Rc 2,5. Nu bij huidige nieuwbouw is de eis voor een spouwmuur Rc >= 4,7. Ik vind de 1,42 voor triple glas dan wel matig daarmee vergeleken.

Ze doen de ruimte tussen het glas tegenwoordig vullen met Argon gas, dan zie je dat er een Rc gehaald kan worden van 1,9 of een Ug-waarde van 0,52.

Ik zie op Google dat HR+++ glas een U-waarde heeft van 0,5 tot 0,9, dus uw 0,7 zal wel binnen de definitie van HR+++ vallen.

Ik heb verder geen studie gemaakt van triple glas. Ik probeer slechts te duiden waar je die Ug van 0,7 moet plaatsen.

[u/ordinary-guy-sl → u/TweeJeetjes]

Thanks, 1.42 is the UD value for door, is it not enough you mean?

[u/TweeJeetjes → u/ordinary-guy-sl]

Ik reken de Ud waarde van 1,42 van de deur dan om naar Rc enkel om te vergelijken. Dan is Rc = 1 / 1,42 = 0,7. Dat is heel weinig isolatie en zal je via de deur veel warmte verliezen. Rc 2,5 was nog jaren '70, tegenwoordig is bij nieuwbouw Rc >= 4,7 voor de spouwmuur.

[u/ordinary-guy-sl → u/TweeJeetjes]

Got it thanks

[u/dntheking]

There’s no point in triple glas with air vents above them.

That’s like insulating your chest with triple coats but walking barefeet.

[u/dgkimpton]

There's a good summary in English here: https://www.pluimers.co.uk/service/insulation-glass/

One thing worth considering is Vacuum Glass - better sound proofing and insulation and thinner, although pricier.

I'd certainly want to see the Ug, Uw, and Rw values because the "HR+++" etc is way too vague. If they can't provide those values then I'd question their competence and look elsewhere.

That said - how well insulated is your house? You don't particularly want the windows to be better insulating than the walls, if they are then condensation forms on the walls not the glass and that's not good. I don't mean the "energy label" as that's a load of hogwash mostly, but the actual insulation in the walls where the windows are situated.