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Is it normal to calculate how much money you spent running the AC today?

In case you're wondering, the AC unit in our bedroom costs $0.16/hour. The living room costs $0.50/hour.

My wife is trying to make me stop. She says it's annoying.

66 comments
  • It's sensible to calculate this sort of cost, regardless of being normal or not. However be careful when and how you share this info with your family - because depending on the context, you'll be basically saying "I put $0.16 over your hourly well-being". (In special, pissing kids with this is a bad idea. They might even leave the AC turned on needlessly, just to spite you.)

    • Thanks, this is the answer I was looking for. I'm trying to save money because we don't have a lot. My wife is on board with saving, but she hasn't done the math to see where most of our money is going.

      I might need to back off a bit. I like to save, but this might be a bit much.

      • In your situation I'd probably compile a list of general expenses of the household per month (or week), then for the higher expenses project a few costs contributing with those expenses. It should be more convincing when you show "we're likely spending around $15 per week just on A/C" than "we're spending $0.50 per hour".

        And context is key - don't bring this up just because she turned the A/C on, instead bring this up when talking about the overall finances of the household. And it might be useful to ask her for a few other corners that could/should be cut, as she'll likely notice different ones than you do, based on her subjective values.

      • I also like to obsesively monitor power use of various things in my house just because I like knowing stats. I used to work with inverter setups so I put power monitors on all of my circuits right at the panel just for the hell of it.

        Asuming you have central air and not just a window AC or something then turning your AC on and off frequently is not the best way to save money. When you first turn the AC on it needs to work really hard and run continously to lower the temperature in your home and remove a whole bunch of humidity from the air. That process is very energy intensive. If you just leave the AC on then it only needs to actually run ocasionally to maintain a cool temp. Unless you are planning on shutting off your AC for days at a time then the actual cost savings are fairly minimal.

        I used to have roomates who would constantly turn off the AC and open the windows whenever the AC "didn't need to be on". The AC would remain off for several hours until things started getting swelteringly hot in the middle of the day then they eventually closed everything back up and turned on the AC. Now that they (thankfully) moved out I just leave my AC running all the time. The power usage from the AC has actually dropped since I started doing that. I'm even way more agressive with the temp setting on the AC now than I was then. My house is rarely above 70F indoors and I'm still using slightly less electricity than when it was being shut off regularly.

    • I like this take as you take into account the human element, but might even take it a step further in that this kind of knowledge could actually be good for more people to know this cost. Especially if cost is an issue, could help families work together in easy ways for a common goal. Maybe it's not worth it to say anything during a heat wave to save a few bucks, but on a cooler week maybe open some windows to save some cash sans suffering.

      Extreme example: as a dad I feel a cultural obligation to get upset when random lights are left on when no ones in the room (not really, but does beg the question of why) - when you actually do the math on led lights it ends up something insignificant, like a cent. Not an issue that really deserves any attention.

      • If I got this right, that isn't even an extreme example, it sounds for me like you're trying to drill your children into attentiveness - like, "pay attention to what you do, what you don't, and the impact of your actions".

        And even in the case of working towards common goals, to cut corners, I think that the parents can and should tell the children what's going on. Children can be surprisingly reasonable once you're reasonable with them, and that avoids the whole "oh no, mum/dad will scold me if I leave the lights on".

        For a more extreme example: afternoon in a rather sunless city, child with poor sight is studying with the lamps turned on, shithead turns off the lights and wastes 15min of the child's studying time by screeching on how the kid is wasting its money. This is the sort of thing that should be avoided at all costs IMO, as it's outright immoral - we humans should be have money for more comfortable lives, not cause the others' discomfort to hoard money.

  • Not a bad thing. It's nice to know where your money is going to know if there's places you could easily save.

    Installed an Iotawatt a couple years ago to track power usage of the whole house and individual circuits.

    The AC in my living room has used 3.35kwh so far today, and the main plugs circuit that has my server and a portable AC unit on it has used 5.56kwh.

    • This is awesome! Did you install the censors in the breaker box?

      • Yup: there's a current transformer on each circuit leaving the breaker panel (up to 14 different circuits), one on each of the main feed lines, and then a small plug-in voltage transformer to measure voltage, phase angle, and frequency.

        It takes all that data, polling each sensor a few dozen times a second, calculates power usage, stores, and presents it all with the above graphs in a simple little web interface. It can also export that data to more powerful graphing/data analysis solutions, but I've been pretty happy with what's onboard.

        You can see the live data too:

        (2 phases of a 3 phase apartment supply. Outputs are math output of multiple inputs. Ex: Main_A+Main_C=Total_Power)

        The setup inside the breaker panel is something you should hire an electrician for if you aren't extremely confident and knowledgeable about what you're looking at. There is a lot of potential to injure yourself or burn your house down, even with all the breakers off.

  • IDK, that doesn't sound healthy.

    Life is made up of infinite details. Looking too closely at any of them shouldn't be done without a reason, that way lies madness

    Looking at details makes sense when the data is actionable. If you think "my electric bill is too high" or "I'm worried about my power consumption", then try living with it a bit hotter/colder. That's a decision to make on more like a monthly basis, maybe every couple weeks - day to day it's one of a ton of variables. It's not useful information outside a spreadsheet

    Making that decision on a daily basis sounds like obsession. If you just think it's interesting, you should probably keep it to yourself (and similar minded people)... If your wife doesn't want to hear it, you should listen to her

    Tell me once, fine, maybe it's a bit interesting. Do it every day for a week, and my brain starts trying to keep a running estimate. I would get very angry, very quickly, because it would make my life slightly worse moving forward for no benefit

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