do I need solar control glass?

[Tom]

We will be putting in a long run of sliding doors in a south/south-east elevation - total length 10m x 2.4m high. How important is solar control glass? I was about to pull the trigger on a quote and noticed this wasn't included and am now in two minds whether to pay for the extra. The room where these are is quite large - 18mx9m with a vaulted ceiling up to approx 5m. What factors are important here? We plan to have sliding shutters on the outside of these doors (like timber-clad barn doors) to help with the solar gain. Looks like visible light is reduced by 30% too which isn't great. If the consensus is equivocal I'd probably go without, but given the amount of glazing I'm having second thoughts. Any views?

Thanks all

[SteamyTea]

You can get a solar film retrofitted if there is a problem.

 

[Tom]

Aha, good point ?

[IanR]

1 hour ago, Tom said:

We will be putting in a long run of sliding doors in a south/south-east elevation - total length 10m x 2.4m high. How important is solar control glass? I was about to pull the trigger on a quote and noticed this wasn't included and am now in two minds whether to pay for the extra. The room where these are is quite large - 18mx9m with a vaulted ceiling up to approx 5m. What factors are important here? We plan to have sliding shutters on the outside of these doors (like timber-clad barn doors) to help with the solar gain. Looks like visible light is reduced by 30% too which isn't great. If the consensus is equivocal I'd probably go without, but given the amount of glazing I'm having second thoughts. Any views?

Thanks all

 

I believe you' need more than Solar Control glass, and relying on manual shutters won't work when you are away from the house or insolation levels are changeable, unless you just leave them shut, which detracts from having all that glazing. Or, are you powering the shutters and automating their use?

 

Have you considered automated, external Venetians?

 

My experience comes from a similar setup to yours, where I have 33m² of glazing on a South-West facade into an open plan area of a similar size to you, that is also double volume with vaulted ceilings. If I don't deploy the external blinds, then with as little as 3 hours of sunshine in Spring or Autumn the internal temp will be above 25°C and normally heading towards 28°C. In the Summer this would be over 30°C.

Due to my window sizing and the wish for single span blinds, I've "only" covered 22m² of the glazed area, so I have 5m x 2.2m area uncovered by external blinds. This is OK in Spring and Autumn, it warms the area without over-heating, but in Summer I have to deploy active cooling through the ASHP. I'm considering adding a film to this window to reduce the cooling need.

[Tom]

That's useful to hear your experiences, thanks Ian.

It does sound like it could be an issue, but I suppose I'm erring on the side of without, as I'd prefer not to look through tinted glass and rely on removable things eg shutters or the venetians you suggest, to use as and when needed. I guess the external film is removable? So could put this on for a few months then remove for the rest of the year?

[JohnMo]

We have a huge overhang above our lounge windows, great in the summer, but we do get solar gain after lunch now, we had the windows open to get some cold (8 deg) air in the house last night as it was 24 degs inside.

[Claire B]

On 10/11/2021 at 12:01, IanR said:

Have you considered automated, external Venetians?

Do you have external shutters? I too have double height ceilings and a lots of glass. I don't have a problem with overheating really in the summer as I have Velux windows in the ceiling so the heat goes up and out through those. 

I do have an issue with it being cold here in the winter months though and have been thinking about external shutters for a while as they would also provide another level of security. I'd want them automated though somehow so I don't have to go and physically close them when it's cold outside. 

[IanR]

I do have automated, external, Ventian blinds from Hunter Douglas. I'm well insulated, so my issues are over-heating rather than cold.

 

Hunter Douglas can supply all the kit for them to be automated, ie. wind and rain sensors and controller, although I haven't used their automation as that would have made them stand alone and I wanted them integrated into the rest of the house automation, so for me Loxone looks after them.

 

These aren't going to help with security though, nor for keeping the heat in.