Portable A/Cs

[Frnc]

I've noticed something interesting. My room warms up slightly at night and in the early morning. The electricity being used drops to about half. I'm asleep through most of that. And in the morning (I wake pretty early), it's cool outside, and I'm opening windows in other rooms.

So it cools more when you need it more - when it's hot outside, in the afternoon and early evening. When you don't need it quite so cool, it backs off, costing half as much to run.

This is not some fancy algorithm. All it is, is the warm air near the window in the afternoon/eveining, vs slightly cooler air in the night and early morning, and the sensor on the machine reading those slight differences.

[Frnc]

Data.

1100 W machine.

Set to 25°

My room about 23.2° during the afternoon. Using about 600 W.

Rising to 23.8° in the early morning. Using about 300 W.

These are approx. It has used a bit less than 300W for a few hours on day 1. Today it might use more, and creep up day by day because the house accumulates heat in a heatwave. Today is day 3 of the current heatwave.

[Yorkshire Andy]

Well I've caved in and got the huge drum fan out the attic set it in the backdoor this morning and let it run for half an hour ago shoveling the cool morning air I to the house... with the upstairs windows slightly open it's blown most the hot stale air out the house bit of forced convection works wonders when it's cool early morning / last thing at night

In the evening I'll set it by the front door and do the same once the outside temp is lower than the house

[Frnc]

Well I've caved in and got the huge drum fan out the attic set it in the backdoor this morning and let it run for half an hour ago shoveling the cool morning air I to the house... with the upstairs windows slightly open it's blown most the hot stale air out the house bit of forced convection works wonders when it's cool early morning / last thing at night

In the evening I'll set it by the front door and do the same once the outside temp is lower than the house

Not a bad idea. I've had my windows and back door open, apart from my room which has A/C. But gonna close them soon. I kept the prep room door shut, as it's warmer than the rest of the house, but had it's window open.

But your house will quickly warm back up, simply from heat stored in the walls etc. Then from sun. It's best to keep the windows shut after about 10 am when it's hotter outside than inside.

[Yorkshire Andy]

Well I've caved in and got the huge drum fan out the attic set it in the backdoor this morning and let it run for half an hour ago shoveling the cool morning air I to the house... with the upstairs windows slightly open it's blown most the hot stale air out the house bit of forced convection works wonders when it's cool early morning / last thing at night

In the evening I'll set it by the front door and do the same once the outside temp is lower than the house

Not a bad idea. I've had my windows and back door open, apart from my room which has A/C. But gonna close them soon. I kept the prep room door shut, as it's warmer than the rest of the house, but had it's window open.

But your house will quickly warm back up, simply from heat stored in the walls etc. Then from sun. It's best to keep the windows shut after about 10 am when it's hotter outside than inside.

But the house already has thermal blinds and curtains shut..

At night once the ambient outside drops below the indoor temperature the forced air through the house helps cool the internal brickwork and buildings structure to


The external walls have 6" of celotex insulation on them so the house is fairly well insulated bar the windows

[Frnc]

The external walls have 6" of celotex insulation on them

Crikey. Well that changes the equation somewhat.

[bobbylui]

I've noticed something interesting. My room warms up slightly at night and in the early morning. The electricity being used drops to about half. I'm asleep through most of that. And in the morning (I wake pretty early), it's cool outside, and I'm opening windows in other rooms.

So it cools more when you need it more - when it's hot outside, in the afternoon and early evening. When you don't need it quite so cool, it backs off, costing half as much to run.

This is not some fancy algorithm. All it is, is the warm air near the window in the afternoon/eveining, vs slightly cooler air in the night and early morning, and the sensor on the machine reading those slight differences.

I think you've hit the nail on the head regarding using the cooler morning air. Creating that cross-breeze or forced convection really makes a massive difference compared to just relying on the AC unit alone. It’s all about managing the thermal mass of the house throughout the heatwave. Clever way to keep the energy consumption down while keeping the living space habitable!

[pseudonym]

I've worked in some pretty cold/ cold and wet/wet/ hot/ hot and humid /humid Countries during my youth and one thing always helps.

Acclimatisation to your conditions. You start to introduce heat and or A/C to the picture you'll never get used to it.

Age/ medical conditions notwithstanding people's choices.

[GeraldTheBonzai]

I've worked in some pretty cold/ cold and wet/wet/ hot/ hot and humid /humid Countries during my youth and one thing always helps.

Acclimatisation to your conditions. You start to introduce heat and or A/C to the picture you'll never get used to it.

Age/ medical conditions notwithstanding people's choices.

Mrs and I were just having this conversation this afternoon, having lived in hot places. Maybe AC isn't doing anybody a favour in the long term. If this is the shape of things to come then we do need to acclimatise to it.

[korolev]

How do you acclimatise to it when you get 2 or 3 weeks a year of heatwave and the rest of the time it's raining ?