Even with all the windows and blinds closed, the temperature of the house still gets warm. Then it’s hard to expel that heat before the next day, so it gets even warmer.
A poorly insulated house would heat up quicker, and so have a higher peak indoor temperature. They will lose heat faster at night, yes, but if you ran a comparison with each house starting at the same temperature and allowing them both to equalise at the end, the average temperature of both would be the same.
The key insight is that insulation makes it slower for the outside temperature to heat the house up as well as to cool it down, so in a heatwave, insulation blunts the worst of it. Also you can actively reduce the insulative properties of a house by opening all the windows, so that it actually cools down much faster at night. This means that, in practice, the average temperature of the well-insulated house will be lower than that of the poorly one.
This kind of conversation (which occurs repeatedly whenever the weather gets hot in the UK) makes me despair, because we all need to be insulating our houses better, both to reduce our energy usage in the winter, and to protect against extreme heat.
The only way you are cooling these houses down at night is if there’s a mighty breeze and cool outdoor temperatures… or if you took the entire roof off.
Your theory might sound good, but in reality it doesnt work that way. Temperatures during this heatwave wont even drop below 20-25c at night, opening the windows doesnt magically mean that the inside drops to match outside as well. It takes hours and hours to do so, and by then the sun is back up, heating the houses up again.
Running a dehumidifier can also help lower the temperature. Water takes a much longer time to heat up/cool down than air does. If you remove the warm moisture from the air and then open the windows and let the cooler 20-25 degree air inside, it should cool the house faster.
That’s not true. I keep my shutters drawn and window shut in my room, and it’s still getting hotter and hotter.
The first couple of days my walls were still cool to the touch. They radiated cool. Now they are warm. They are actively absorbing heat faster than they can be cooled in the evening
At my place that trick works the first day, but after that it’s over. The house always heats the same under this sunshine, slowly rising to 28-30 at the end of the day with everything closed and down from like 22-24 in the morning. The only question is whether that’s better than a higher temperature with a slight breeze and fresh air. Today, it won’t be higher than 30, so I’d rather have wind. The next 4 days, it’ll be 35 or higher, so everything will get closed down during the day
Houses that trap heat also trap cool air.
People who say their well-insulated house “traps heat” are probably keeping their windows open in the hottest part of the day.
Even with all the windows and blinds closed, the temperature of the house still gets warm. Then it’s hard to expel that heat before the next day, so it gets even warmer.
A poorly insulated house would heat up quicker, and so have a higher peak indoor temperature. They will lose heat faster at night, yes, but if you ran a comparison with each house starting at the same temperature and allowing them both to equalise at the end, the average temperature of both would be the same.
The key insight is that insulation makes it slower for the outside temperature to heat the house up as well as to cool it down, so in a heatwave, insulation blunts the worst of it. Also you can actively reduce the insulative properties of a house by opening all the windows, so that it actually cools down much faster at night. This means that, in practice, the average temperature of the well-insulated house will be lower than that of the poorly one.
This kind of conversation (which occurs repeatedly whenever the weather gets hot in the UK) makes me despair, because we all need to be insulating our houses better, both to reduce our energy usage in the winter, and to protect against extreme heat.
The only way you are cooling these houses down at night is if there’s a mighty breeze and cool outdoor temperatures… or if you took the entire roof off.
Your theory might sound good, but in reality it doesnt work that way. Temperatures during this heatwave wont even drop below 20-25c at night, opening the windows doesnt magically mean that the inside drops to match outside as well. It takes hours and hours to do so, and by then the sun is back up, heating the houses up again.
Let’s take everything you said as true.
You’re still worse off if you have a poorly insulated house.
Running a dehumidifier can also help lower the temperature. Water takes a much longer time to heat up/cool down than air does. If you remove the warm moisture from the air and then open the windows and let the cooler 20-25 degree air inside, it should cool the house faster.
That’s not true. I keep my shutters drawn and window shut in my room, and it’s still getting hotter and hotter.
The first couple of days my walls were still cool to the touch. They radiated cool. Now they are warm. They are actively absorbing heat faster than they can be cooled in the evening
“The situation is bad, therefore this makes no difference”
Am I reading this right?
No, but that’s okay you’ve picked your hill
At my place that trick works the first day, but after that it’s over. The house always heats the same under this sunshine, slowly rising to 28-30 at the end of the day with everything closed and down from like 22-24 in the morning. The only question is whether that’s better than a higher temperature with a slight breeze and fresh air. Today, it won’t be higher than 30, so I’d rather have wind. The next 4 days, it’ll be 35 or higher, so everything will get closed down during the day
I’d keep things battened down so you’re starting from a lower base.
A breeze can be provided by a fan. (And it makes a huge difference - bigger than the breeze through a window)
Cold places usually have giant windows to let more sunlight in. You can definitely optimize for heating or cooling efficiency