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Isn't it less expensive and more ecofriendly to turn on the AC when you are actually there? Dumber would be smarter. Not to mention, you can be late, or early,

Isn't it less expensive and more ecofriendly to turn on the AC when you are actually there? Dumber would be smarter. Not to mention, you can be late, or early, or not arrive for the whole night.

petre 2y ago
Not always because it depends on many factors such as demand energy pricing. The house also has heat inertia, meaning it could take hours to reach a ceratin temperature, so you'd have to turn on the AC hours in advance before you arrive home.
- Scoundreller 2y ago
  Cool thing is I don’t care about the temperature of the solid mass inside of where I am, just the air really. I know when I turn on the A/C in my office, it’s not going to cool the concrete wall/floors/ceiling much in the 8h I’m there before I shut it off for the day. And that’s fine.
  - petre 2y ago
    The solid mass inside the building, the walls and floors heat the air and the AC is working harder to keep up. Also exposed glass to direct sunshine that creates a greenhouse effect.
kelnos 2y ago
Eco-friendly, possibly, buy cheaper? Maybe not. It depends on when you arrive home. If you arrive home during peak hours when your utility prices are higher, it can be cheaper to run the a/c earlier, while you're not home, to at least get the temperature down into the rough ballpark of where you want it, and then maintain that temperature into the peak hours. Even the eco-friendly bit isn't always clear, depending on your equipment. It might use less energy overall to maintain your desired temperature 24/7, even when you aren't there. Your particular equipment may run less efficiently if it has to go on full blast for an extended period of time to do a large temperature change when you first get home.
immibis 2y ago
It uses the least energy, but here we are talking about demand shifting to make use of variable electricity sources. It can be worth using more cheap solar energy in the middle of the day instead of less natural gas later on.
otherme123 2y ago
It might be, you should research how your region produces energy. For example, where I live the energy produced from 10:00 to 18:00 is almost 100% solar, eolic and nuclear (https://www.esios.ree.es/es/balance?date=04-07-2024&program=P48&agg=hour# https://www.esios.ree.es/es/balance?date=04-07-2024&program=... , orange and red bars are solar, light green are wind, dark blue are nuclear). Energy after 19:00 starts to draw gas (yellow bars) to cover the fall in solar production, peaking at 21:00. Incidentally, this also matches prices going from ~5 cents/kWh to ~20 cents/kWh (https://t.me/tarifaluz/3665 https://t.me/tarifaluz/3665). So for me it's both ecofriendy and moneyfriendly to shift as much consumption as possible to the 13:00-18:00 hours.
Qwertious 2y ago
The key point is that an insulated house acts as a heat/cold storage device, so it's like buying booze and pouring it into a (slightly leaky) bucket during happy hour, to drink later. Even if you loose a bit to the leaks, you're still saving money overall by buying the booze when it's cheap.

Isn't it less expensive and more ecofriendly to turn on the AC when you are actually there? Dumber would be smarter. Not to mention, you can be late, or early, or not arrive for the whole night.

petre 2y ago

Not always because it depends on many factors such as demand energy pricing. The house also has heat inertia, meaning it could take hours to reach a ceratin temperature, so you'd have to turn on the AC hours in advance before you arrive home.

Scoundreller 2y ago
Cool thing is I don’t care about the temperature of the solid mass inside of where I am, just the air really. I know when I turn on the A/C in my office, it’s not going to cool the concrete wall/floors/ceiling much in the 8h I’m there before I shut it off for the day. And that’s fine.
- petre 2y ago
  The solid mass inside the building, the walls and floors heat the air and the AC is working harder to keep up. Also exposed glass to direct sunshine that creates a greenhouse effect.

kelnos 2y ago

Eco-friendly, possibly, buy cheaper? Maybe not. It depends on when you arrive home. If you arrive home during peak hours when your utility prices are higher, it can be cheaper to run the a/c earlier, while you're not home, to at least get the temperature down into the rough ballpark of where you want it, and then maintain that temperature into the peak hours. Even the eco-friendly bit isn't always clear, depending on your equipment. It might use less energy overall to maintain your desired temperature 24/7, even when you aren't there. Your particular equipment may run less efficiently if it has to go on full blast for an extended period of time to do a large temperature change when you first get home.

immibis 2y ago

It uses the least energy, but here we are talking about demand shifting to make use of variable electricity sources. It can be worth using more cheap solar energy in the middle of the day instead of less natural gas later on.

otherme123 2y ago

It might be, you should research how your region produces energy. For example, where I live the energy produced from 10:00 to 18:00 is almost 100% solar, eolic and nuclear (https://www.esios.ree.es/es/balance?date=04-07-2024&program=P48&agg=hour# https://www.esios.ree.es/es/balance?date=04-07-2024&program=... , orange and red bars are solar, light green are wind, dark blue are nuclear). Energy after 19:00 starts to draw gas (yellow bars) to cover the fall in solar production, peaking at 21:00. Incidentally, this also matches prices going from ~5 cents/kWh to ~20 cents/kWh (https://t.me/tarifaluz/3665 https://t.me/tarifaluz/3665). So for me it's both ecofriendy and moneyfriendly to shift as much consumption as possible to the 13:00-18:00 hours.

Qwertious 2y ago

The key point is that an insulated house acts as a heat/cold storage device, so it's like buying booze and pouring it into a (slightly leaky) bucket during happy hour, to drink later. Even if you loose a bit to the leaks, you're still saving money overall by buying the booze when it's cheap.