Anticipating solar gain / overheating in a new extension

[SteamyTea]

10 hours ago, saveasteading said:

The good thing about a glass roof in the UK is that the sun doesn't get very high, so we get lots of daylight and not too much direct sun

There is also a difference in OAT depending on how near the coast you are.

It is a very rare event if the temperature drops to 0⁰C down here, and even rarer it goes above 24⁰C. That is for the warmest region in the UK.

Go to Central England, below freezing, is not unusual, above 26⁰C happens fairly often I am told.

So allowing for natural ventilation will depend on the likelihood of high OAT, sun angles, time if year and duration of the above events happening.

Bloody horrible down here at the moment.

[ProDave]

1 minute ago, SteamyTea said:

10 hours ago, saveasteading said:

 

There is also a difference in OAT depending on how near the coast you are.

Yes in Oxfordshire cold frosty nights were common when the wind was not blowing, and again in still conditions in summer it just got hotter and hotter.  It was the summer heatwaves that I hated the most.

[SteamyTea]

10 minutes ago, ProDave said:

It was the summer heatwaves that I hated the most

Not for me, meant school was out and I did not have to kill time in Witney.

[Iceverge]

19 hours ago, saveasteading said:

The good thing about a glass roof in the UK is that the sun doesn't get very high, so we get lots of daylight and not too much direct sun.

 

I once put huge amounts into a school classroom with the clients blessing (and their accepting the risk) because it was an art studio.

Did it ever get too hot? Yes, for a few days per annum. Teachers hung assemblages resembling clouds to stop direct rays.

It wasn't as hot as we feared. They had windows. "The best art practicing  space I have ever known".

 

Vaguely relevant...again lots of windows and skylights in a big lounge for a nursing home. The building inspector claimed it failed regs on overheating.

We pointed out the french doors, that aircon was bad environentally  and hinted we would box the skylights in until signed off.

Then the client killed the subject by saying to the bco " if ever my residents get too hot, I will take one of their blankets off".

 

My point is that there are calculations and hunches, but individual preferences vary.

You can always add greenhouse shading or louvres ( or a sheet of ply) to a skylight, perhaps even only in extreme summers.

And when it is that hot, you can usually open doors and windows.

 

 

 

 

 

Unlike a house the school was unlightly to be unoccupied during the hottest months of the year and nobody has to sleep there.

 

Did you ever take any post install temperature readings? 

 

Similarly with the nursing home, high temperatures can be dangerous for the elderly. I've had the displeasures of staying in an attic room with a pair of veluxs. The internal blinds blocked all the light but simply turned into radiators themselve being inside the glazing. There's only so many layers of clothes you can take off. 

 

Adding dramatic amounts of shading post construction is a failure of design in my book. 

 

[saveasteading]

5 hours ago, Iceverge said:

unlikely to be unoccupied during the hottest months of the year and nobody has to sleep

Absolutely right. In fact the guidelines for school sports halls forbids cooling, on the basis of summer closure. Can be very hot for summer schools.

 

5 hours ago, Iceverge said:

Adding dramatic amounts of shading post construction is a failure of design in my book. 

No shading was added, and the client is still very happy, 10 years on.

It was all appropriate.

The client was being facetious and practical.

Of course if temeperatures were ever too high, then the patients would have been in the old miserable lounges for a while, instead of the bright cheerful one. In reality it hasnt been necessary.

 

My point was about balancing the building regs rules and formulae  against reasonable judgement, and client requiremnts. A known and expert client is essential.