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.
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.
Dehumidifyers produce a lot of heat though
I didnt realize that. I used one and the room it was in still cooled down considerably.
Glad it worked for you. If you wanna know more as with all things heating there is a Technology Connections video about this.