Loft conversion - should we get air con?

[user1473602935]

Sorry- this is a bit of a first-world-problems post!

We are converting our loft and can't decide if we should get air con. Our house gets pretty hot in the summer anyway and we don't have AC anywhere in the house, so would it be wise to get it up there or not necessary with today's insulation

Grateful to hear of anyone else's experience

where are you?

I should have said - london

How well would you sleep with open windows? Our house is in suburban London, and has a loft extension that's around 25 years old - the insulation in it is not great to be honest. We do have a 'portable' a/c unit that we occasionally use in my son's bedroom - we probably used it about 15 times this summer. It's wonderful to have and makes a real difference particularly as it's still so hot when he goes to bed. By the time we go to bed a couple of hours later, the temperature has generally dropped to something tolerable. But I don't think I would go so far as installing a/c as a permanent feature, unless the noise of having open windows was intolerable.

When you have the loft converted, BRs will require a high level of insulation. Ordinary lofts get hot from dun beating down on the tiles.

There is a natural convection airflow upwards in houses. If you add passive ventilation vents the hot air will rise out and escape. An open Velux looks like a good solution, except that people leave them open, and then rainstorms gush in. So you can add ventilators in the gables at each end. I'd say at least a square foot.

I actually keep the house temperature down in summer just by opening the loft hatch. My loft has well-ventilated eaves.

Be aware that water vapour is also lighter than air so will also rise into the loft, which is liable to cause condensation if you don't use bathroom extractors, or if you drape wet washing around. It rises through holes in ceilings, for example round downlighters and pipes.

"hot from SUN beating down on the tiles" (because ordinary lofts do not insulate under the tiles)

I have a loft conversion in London. This year the temperature was regularly over 25 with the windows open throughout the night. On a few occasions it was 32 and stayed that way until the early hours of the morning. I would go for it if it's affordable for you.

Thank you for your responses Everyone- very helpful

I did a loft conversion in my last house (a terrace). The room was so hot in summer it was unusable and one of the reasons we sold up in the end - it was eventually intended as my son's bedroom but there's no way he could have used it, and we couldn't have left windows open really, it wasn't worth the risk.

We did a loft conversion a couple of years ago (London) and it's the one thing I wish we'd added - especially as the people in the house at the back are out in the garden, partying, every bloody night. And they're over 100 metres away from us.