Disconcerting draught from new uPVC windows

[2BorNot2Q]

I had new windows installed some months back by alleged professionals. With the recent dip in temperature here, I see the problem is much worse than initially thought. It's not even winter yet and I feel very nippy air blowing at me as I type this, not far from my window. It does seem to line up with breezy moments outside. The heat has been off for hours, so I think I'm not creating much convection. And after a couple of very cold nights, I found condensation on most windows the next morning. I never ever had that before!

Surely this is not normal. My old non-PVC windows were far better for comfort. The air feels cold right near the edges of the glass, also on large fixed panes. Rubber seals look OK when I try the paper test.

I'm not at all impressed with the fitters after my dealings with them, so I seek more qualified opinions here. What could it be? I already found and patched tiny gaps in the silicone in a few rooms.

 

[foxhole]

What is the condensation on the inside or the outside?

 

[Harry Bloomfield]

It does seem to line up with breezy moments outside. The heat has been off for hours, so I think I'm not creating much convection. And after a couple of very cold nights, I found condensation on most windows the next morning. I never ever had that before!

Joss sticks will help you locate sources of drafts. Is the condensation on the inside or outside? This present humid weather, causes a lot of condensation on the outside.

 

[^woody^]

You can get draughts from high performance windows due to the way the heating is arranged in the room, drawing air down the frame. But firstly check the perimeter of the frame and the casement gaskets for draughts.

If you get cold edges of the glass, even condensation there, that is a sign of poor spacer bars in the unit, or non-thermally broken frame sections.

 

[2BorNot2Q]

Thanks for your replies. Condensation is on the inner glazing where I can easily wipe it. A (generally thin) section across the entire bottom. One large window sometimes goes much higher.

But firstly check the perimeter of the frame and the casement gaskets for draughts.

I did patch some tiny silicone gaps indoors. The air right next to the rubber does feel cold, but the paper test didn't reveal any gaps if that's what you mean. The heat is off and I still feel these air currents.

If you get cold edges of the glass, even condensation there, that is a sign of poor spacer bars in the unit, or non-thermally broken frame sections.

From what I've learned about the manufacturer, I wouldn't be surprised if both are true. The spacers are aluminium.

I like the Joss idea. Outdoors I've only been able to check the ground floor. There are some small gaps in the silicone around the frames. Hmm, would that be a gamechanger for me?

 

[Harry Bloomfield]

I like the Joss idea. Outdoors I've only been able to check the ground floor. There are some small gaps in the silicone around the frames. Hmm, would that be a gamechanger for me?

If there are gaps, then you should be calling the installers back to rectify their work..

 

[Notch7]

The spacers are aluminium

Are you sure?
are they definitely aluminium and not silver plastic?
I thought warm edge spacer bars were necessary to reach the u values for building regs compliance.

What is the specification of the glass on your order?
these days it is generally: low emissivity coating / warm edge spacer / argon gas fill.

Sometimes old windows have poor draught sealing and that actually helps reduce condensation.

 

[Notch7]

Are you heating the house less this winter than previously?

maybe the condensation is due to a lower ambient temperature rather than a fault of the new windows.

the latest double glazing is good, but it can’t perform miracles

 

[2BorNot2Q]

Prices are nuts but I have not changed my heating habits just yet. I still warm up the place daily. I assume the old windows weren't poor since they didn't make me want to run away.

If there are gaps, then you should be calling the installers back to rectify their work..

Point taken, though I hesitate to engage this lot again.

This is the spec for my room:

Std Reinforcing Windows
35MM GOLD HANDLE
10 Inch Friction
Std Window Espag 400
4mm KS, 20mm Gold Aluminium, 4mm Clear
4mm KS, 20mm Gold Aluminium, 4mm Clear *

 

[diy_fun_uk]

Have you checked around the entire installation including any internal plastic/wooden trims? Sometimes if there are gaps between trim and wall, that can be a source of air getting in.

 

[2BorNot2Q]

I've plugged all the gaps I found inside. That leaves the outside, but I don't see why it feels like Mr. Freeze is blasting me every now and then.

Here's a photo from the manufacturer's website. There's no guarantee it matches my product, but what does everyone think of the design?

 

[Notch7]

Prices are nuts but I have not changed my heating habits just yet. I still warm up the place daily. I assume the old windows weren't poor since they didn't make me want to run away.


Point taken, though I hesitate to engage this lot again.

This is the spec for my room:

the Camden group say:

A rated performance as standard.

90% argon gas fill
warm edge spacer

the test results for their 70mm casement windows is 1.3 u value, glass u value is 1.219 and g value = 0.71
air leakage = negligable

https://www.camdengroup.co.uk/media/1352/u20250-1-bfrc-report-70mm-13-a-rated.pdf

 

[DiyNutJob]

Get a covid style thermometer. It will help you with a better assessment. The cold you feel could well be psychological given your negative views about the installers. Negative, as in sub-zero.

For comparison, on my 75% glassed kitchen-garden door:

Timber frame: 16.2C
Brass door hardware: 18.4C
Plaster wall, side of door: 16.5C
Door hinge: 14.6C
Center of glass: 14.6C
Outside air: 7.4C
Internal air: 16.7
Internal fully wooded door to exit kitchen: 17.1C
30 year old double glazed window glass: 14.1C
Central wood frame for window: 15.5C

The kitchen is currently heated by the waste heat of the fridge and a 500W oil radiator. The side of my thigh over the radiator is 29C. I am pretty toasty while I type because of the air convection.

 

[2BorNot2Q]

They make grand claims, they do. Their reviews are not so nice. Can a spacer really be a warm edge spacer if it's alu?

 

[DiyNutJob]

I never looked inside the modern windows and have no knowledge of the internal components. But, I can give you more data for comparison.

Good quality modern 10 year old aluminum window in an unheated flat:

Outside air: 8.1C
Inside air: 15.5C
Alum frame: 14.7C
Center of glass 15.4C
Plasterboard sides of window recess: 15C
Wooden sill: 15C

The alum and nearby glass area do condense a little water at times, but not today.