We actually slept downstairs in the guest bedroom last night, which is north facing, and the coolest room in the house. Just checked the master bedroom temperature tis morning and it's already 27.5C. Carpeted, reasonably well insulated and stiflingly warm.

We haven't been too bad.

Our house is white rendered which may be helpful.

The main rooms we use are all dual aspect (bedroom, kitchen dinner, living room) so we can get some through draft.

There is one relatively cool room which use to contain the pantry in the days before domestic fridges even existed. This is fine, although cold in winter with very little solar gain. This is now a study. 

We have kept our thermal blinds and curtains closed permanently on the back sunny side of the house, easier when rooms are dual aspect. 

The bathroom is completely tiled which seems to help.

Like you upstairs is definitely hotter than downstairs,although our utility room is the worse. 

We have a lot of insulation - 150mm EWI, and a very heavyweight house - brick & solid concrete floor, so it takes days and days to change the temperature indoors.  Our thermometer says it's 42C just now outside here in Cambridge, and 23C inside downstairs.  It's actually quite windy here, but feels like standing in front of a fan heater outside.  All our south facing windows have closed curtains with a white blackout lining added, and all our windows are closed.  We have MVHR, which is trying to keep the air fresh without bringing in any heat, and recently we've been opening windows at night, closing them at first light.  

External blinds, or awnings, I'm sure would work well.  Got to keep the sun out!

Hi Mars,

You should maybe consider installing an A2A ASHP. At the moment our A2A is keeping the indoor temperature at a comfortable 24C and is being powered solely from our solar PV.

Posted by: @editor

While the UK is still a ‘cold’ country when compared to global hotspots, this mini heatwave has been very uncomfortable because our insulation attempts. I imagine we’re not alone.

To negate the heat, we’ve closed all blinds and curtains to reduce solar gain, but the house is still remaining very warm. Opening windows hasn’t helped, and fans just move around hot air.

What’s your experience been like, and how have you kept your house cool(er)?

Don't know; we're in Greece keeping cool 😆 🤣. It was a chilly 31C today, although it's warming up a bit later this week.

Doesn't insulation work for heat as well, i.e. it keeps the heat out as well as keeping it in?

Posted by: @editor

What’s your experience been like, and how have you kept your house cool(er)?

Yes our upstairs rooms were pretty warm too. On Monday afternoon I was in the loft with a solar installation engineer; it was pretty unpleasant up there, so once the installation is complete (in a few months?) I'm considering DIY installing foil insulation on the rafters to keep the heat from the roof from getting into the loft space. An alternative/supplement would be some kind of in-roof-vent. Does anyone have experience of these products?

With impeccable timing an air-con engineer inspected the house on Tuesday afternoon. As the house currently has 1cm microbore central heating (which will cost over £5000 including 20% VAT to replace) I am considering going down the air-con route for heating/cooling. With a large solar array and batteries in planning (14*455W panels, 2x 280Ah 48V batteries), the system should have no impact on the grid, and the maximum of 14kW of heat dumped to the atmosphere is small with respect to, say, the cooling effect of growing trees in gardens or painting buildings white.

We can be grateful that overnight air temperature drops significantly; it does mean disturbed sleep from managing airflow/street noise, but the free air conditioning is really powerful and refreshing!

If you have a loft hatch it can be useful to leave it open during extreme hot weather.  It will act as a ‘chimney’ moving hot air upwards whilst pulling fresher air into and through the house via open windows.

@morgan years ago in my old house I bought a large fan and cut down a bit of wood which fit in the loft hatch. I made a hole for the fan and popped it in the loft hatch with the fan pushing into the loft. Worked a treat as it sucked the air out of the house and drew cooler air in. Super cheap way to increase airflow in the evenings.

Posted by: @kev-m

Doesn't insulation work for heat as well, i.e. it keeps the heat out as well as keeping it in?

It does, but once it's in, it's pretty difficult to get out when it's roasting outside  😀 😓 

Posted by: @derek-m

Hi Mars,

You should maybe consider installing an A2A ASHP. At the moment our A2A is keeping the indoor temperature at a comfortable 24C and is being powered solely from our solar PV.

This is something I'm definitely going to look into – the only issue is it'll be difficult to integrate an A2A unit from an aesthetics perspective into our property. But I'll see if I can figure it out. 

On a related note, I have seen a few articles about portable A2A ASHPs that can heat and cool. They look very interesting because you can wheel them around the house so you have the flexibility of chilling or heating different rooms at different times.

@editor those are useful but very very inefficient as you are housing the compressor element in the house. Split is way better and more efficient.

You have solar, get AC, it's a no brainer and you can use for a burst of heat in the winter.

Posted by: @batalto

@editor those are useful but very very inefficient as you are housing the compressor element in the house. Split is way better and more efficient.

You have solar, get AC, it's a no brainer and you can use for a burst of heat in the winter.

Completely agree:

Last Monday and Tuesday, house was 20.7 and 22.5 degrees with 'dry' non humid air. Upstairs 12,000BTU unit ran for 8 hours and a Portable 12,000BTU with pipe pushed through the Cat-Flap in Kitchen for 6 hours. Cats slept on bed all day so not upset at their door being sealed. Most of the time running the AC all days, leaves house dry and cool, only Tuesday did we need to run it again for an hour at 10pm.

Power Cost - completely FREE.

If nothing else, buy a Portable and cut a board the size of a window to pop pipe through. As per, my other posts, a Mini Split has many advantages of 120 days for supplemental Heating - 30 days cooling!!

Multi-Mini Splits are not ridiculous in pricing, £900 for 2 room and £1400 for 3 from one outside unit.

@diverted-energy 

I know they are your panels and therefore it's your free to you electricity but I feel just a little uneasy at running AC in UK homes.  Theoretically the energy you are not exporting while your AC is running may be generated by gas or other ffs, although I know that's a bit of a spurious argument.  And what you are doing is far better than importing the energy.  However I definitely wouldn't be happy about any funded scheme for PV using the power generated to run AC.  Or a swimming pool or hot tub. It's the same way I feel about how large, high performance EVs are subsidised so heavily. 

I'm currently in Athens and it's a normal cloudless 37C outside.  Night time temps are about 28C.  The flat I'm in is currently about 27.5C with no AC.  It's warm but still pleasant.  The 6 month old baby with us is perfectly fine too. The people we're staying with don't use the AC much, mainly if there are visitors. Having said that the houses here are built to withstand heat; white walls, shutters, awnings and tiled floors. 

Just a thought ...

I must admit I'm also not entirely convinced about aircon in the UK as the norm.

Firstly, aircon needs power wherever it comes from, so if you're powering it from your own solar PV then it still isn't free; it's costing you what would have been paid if you'd exported those kWh to the grid. Moreover, any solar PV power you don't export as green energy is power others on the grid will consume at the prevailing CO2/kWh mix (in other words, you may not be adding to the problem, but you're reducing the amount you're part of making the problem better).

Secondly, and illustrated rather well by @kev-m above, is that for most of us prolonged exposure to higher temperatures just means our bodies will adapt. If aircon is installed, it just means you don't give your body a chance to adapt, meaning you either delay the issue or decide to live in an air-conditioned bubble only ever moving from air-conditioned house via air-conditioned car to air-conditioned office or air-conditioned shops/restaurants etc.

I'm certainly not going to suggest that aircon shouldn't be used, but I will say that for me and my family it's not the right choice. I would certainly and happily agree with aircon as an important and useful tool for anyone with a medical condition that is affected by the higher temperatures, but for anyone not in that bracket I'd urge a closer look at aircon's trade-offs before deciding whether or not to go down that route.

I hasten to underline here that I'm not suggesting aircon is a lazy fix or inappropriate. Everyone's situation is different, so all I'd like is that people make considered decisions rather than the admittedly tempting knee-jerk reactions that the current high temperatures can easily encourage.