Will a skylight in a south facing house make it overheat?

8 years ago

We have a south facing garden and are building an extension and intend to install large sliding doors and full width skylights (one at each end of the extension to bring light deep into the house).

Would love to hear from people with similar set ups – does it overheat?

Do the things you can do to mitigate the heat (fancy glass, vents in the doors etc) actually work?

We're imagining that we might just have to open the windows a little more in the summer, which is fine, but maybe we're underestimating the impact.

Any thoughts on heat reducing options welcome! What works for you?

Many thanks.

Featured Answer

PRO

Ecoflap

7 years ago

We have a couple of skylights and find the different vent options very useful. On lovely days we open them up completely or we can set them to trickle ventilation if we don't want a draught (of course we don't, draughtproofing is what we're all about!) or just shut them completely.

Comments (10)

PRO
Sunsquare Ltd
7 years ago
Have you considered opening skylights as an alternative option? Then you've got the best of both worlds.

Plus you could invest in a remote control panel to open and close (and thus regulate the temperature) automatically when necessary?
mrjohnnyd thanked Sunsquare Ltd
Sarah W
7 years ago
Just looking into the same thing myself at the moment. Did your research show up anything in the end?
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mrjohnnyd
Original Author
7 years ago
Sarah, what you see above represents pretty much all of my research! I found a few things online but they were mainly from countries with much hotter weather for longer stretches of the year. I spoke to a couple of households with a similar design. One was N facing so not entirely applicable but they did love the light coming in. The S facing design said that yes, it does get warm, but you just open the doors a little. So pretty straightforward really. Certainly nothing to indicate it was a big problem in the UK (people abroad, say in Australia, experienced a bit more difficulty). Hope that helps a bit.
PRO
Sterlingbuild
7 years ago
Hello mrjohnnyd & Sarah W,

You're right to think about overheating. It's a huge consideration for home extensions as skylights in a pitch roof for example, add up 40% more light than vertical windows - so yes, they will generate more heat too.

There are a few things you can think about to mitigate solar gain in the hotter months:

* Internal/external blinds to prevent solar gain. This is the most pocket friendly option
* Opt for a glazing that will reflect UV rays
* Choose skylights that will open and close, of course. There are slide open and hinged options, and roof lanterns that have opening panes.

It's a good job you'll have vertical windows. As you mentioned you can throw them and your upstairs windows open once summer arrives to create a chimney effect.

If you would you like any more advice - honest, no hard sale - call our team on 01304 219922. They know their stuff!

Plus they might be able to help you with the prices as we have a free delivery option and price match guarantee to ensure you get the best price.

www.sterlingbuild.co.uk/flat-rooflights

Feel free to message me if you have any questions!

^Emma
mrjohnnyd thanked Sterlingbuild
PRO
N7 Design Studio Ltd.
7 years ago
Hi, I've worked on a few sunroom extensions which have large expanses of glass from doors, window and rooflights. Each glazed element has a u-value which is the insulation property of the glass. The lower the u-value the less the glass will transmit heat both from inside and outside. A standard velux rooflight has a u-value of 1.4W/m2K but these can go as low as 1.1W/m2K and even less. The likes of Velux also provide electronically openable rooflights which is ideal for letting out the hot air that rises.

I hope you find this useful.
Sarah W
7 years ago
Very helpful comments thank you everyone!
User
3 years ago
What did you end up going with in the end?
Laura Shepherd
3 years ago
Hi, we are also concerned with the over heating aspect of roof lanterns. The uk summers seem to always have a couple of very hot periods and I can imagine south facing rooms with a lot of glazing could become unbearable. How effective are the options like blinds in them?
mrjohnnyd
Original Author
3 years ago
Apologies, I missed a few comments. In the end, I used a company called Skyglaze. They were good. The glass has some UV protection. I can't seem to find the spec - if I can I'll come back on here, but it's been 3 years now, so forgive me.

We had a skylight (approx 150cm by 150cm) and folding patio doors (about 3m wide). There's no excessive heat from the Skylight (although it opens, which helps). The patio doors obviously open too. When they're closed, there is a period of about 3 weeks a year where the wooden floor just inside the house becomes too hot to stand on. It's a patch about 2m square, I'd say. We put a rug or towel on it which solves the problem.

This is partly to do with expense, partly how fiddly we thought that blinds might get. In the end we decided that 2-3 weeks of excessive heat on a small patch of floor was a reasonable price to pay for the insulation and warmth you get when there's a bit of sun on a cold day.

tl;dr Yes it does get too hot for a part of the year, but it wasn't as much of a big deal as I worried it might be.

Sorry for lack of detail. I hope that helps.

Will a skylight in a south facing house make it overheat?

Ecoflap

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