7 ms·

If you have same schedule every week, don't go on vacation, your kids don't have breaks, don't have seasons, then 'set and forget' dumb thermostat will work for

• userbinator 4d ago
  You shouldn't need to change the temperature regardless of those things. My house remains at 68-72F basically all the time. Thermal cycling accelerates aging of materials.
  • spicypixel 4d ago
    Sounds expensive at the equivalent rate of 38 cents a kilowatt hour that I pay during the day.
    • userbinator 4d ago
      Power is cheaper than things failing earlier than they could have due to thermal cycling.
      • rcxdude 4d ago
        Do you have any citation for thermal cycling through the range of an AC inside a house affecting the failure rate of any household goods? Based on my experience this does not seem likely to be the case: thermal effects tend to be exponential or high powers of temperature, and most thermal cycling that people worry about is on the order of 100C or more. 10/20C of variation seems unlikely to be relevant. (There is a case where if your house is well insulated enough, then it can be worth avoiding cycling your AC during the day, because it is both less efficient and will wear more while pulling the temperature down and this can be worse than just leaving it running in a sufficiently insulated house. It still is probably worth turning it off if you're away for a week, though)
        • dgacmu 3d ago
          But with most houses, the AC will cycle on and off throughout the day anyway - raising the temp while you're gone will often result in less cycling. Especially if you also increase the hysteresis range while out. So you get a triple efficiency win, from better AC efficiency, less AC motor wear, and less heat loss to the outside.
        • ssl-3 3d ago
          > because it is both less efficient and will wear more while pulling the temperature down That's just not true. Aircon is a heat pump. It pumps heat more efficiently when more heat is available to be pumped. Warmer indoor air increases evaporator temperature. A higher evaporator temperature means that the system operates with less temperature lift. This means that the system does less work (per BTU pumped) to cool a house that is hot inside, than one that is already conditioned inside. Equipment longevity also tends to be increased with less-frequent, longer runtimes than with more-frequent, shorter runtimes. There's less temperature cycling, fewer in-rush current events, and the lubricating oil in a running compressor is actively circulated to the parts that need lubricated. Reducing the number of compressor start-ups is a good thing; these machines like to run. So even if same number of BTUs enter the home and need pumped out whether the aircon is running or not, then: Letting things warm up inside when there's nobody home to care about that constitutes an improvement in a broad number of ways. Reality is even better: On a hot day, a house that is hot inside takes in fewer BTUs than one that is cool inside, due to the reduced temperature delta between indoors and out. When we have fewer BTUs coming in, then we have fewer BTUs that we must ultimately pay to pump back out.
  • dzhiurgis 4d ago
    How about sleep? Ideal temperature is 18C.
    • fhdkweig 3d ago
      That is 64F. Not everyone considers that an ideal temperature.
  • duckmysick 4d ago
    Isn't the thermal cycling greater outdoor than indoor because of the differences in the outdoor temperature between day and night? So most ordinary materials indoors should be fine with a delta of even 10 Kelvins/10 Celsius/18 F. All of the material thermal failures I can think of come from localized and more extreme sources: electronics, lightbulbs, washing/drying clothes, washing dishes in a dishwasher. Water below freezing point too, but that's because the temperature fell below a threshold. None of these are from heating or cooling rooms directly with HVAC.
• deleted 3d ago
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