# Saving money by turning off your water heater **URL:** \ **Category:** Factual Questions\ **Created:** [December 18, 2004, 12:47am UTC](https://boards.straightdope.com/t/saving-money-by-turning-off-your-water-heater/280451 "2004-12-18T00:47:55Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [December 19, 2004, 5:52pm UTC](https://boards.straightdope.com/t/saving-money-by-turning-off-your-water-heater/280451/21 "2004-12-19T17:52:37Z")
> [@SanibelMan](#): > > I’m going out of town for about 10 days later this month. Can I turn off the water heater before I leave to save on energy costs? Will horrible things grow in the tank? Should I turn it off and flush it out first? I routinely turn off my HWH when I’m away from home, and I’ve never had a problem with this, even when away for much longer than 10 days. I suppose YMMV, but I don’t see how much that’s horrible can get very far in 10 days, or withstand the sudden return of heat when you arrive back from your trip. ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [December 20, 2004, 12:13am UTC](https://boards.straightdope.com/t/saving-money-by-turning-off-your-water-heater/280451/22 "2004-12-20T00:13:14Z")
If this question is pretty much beaten to death, I’d like to ask a similar one: We live in the midwest…plenty cold. (especially today). Our forced air heater is on a thermostat so that it goes off at 9 when we leave, back on at 4. My question is this: When it goes on at 4, and the house has gotten very very cold (we set the day time temp at 64), it seems to run forever to get up to 72 again, cycles frequently, and seems to be running an awful lot. If we just set the thing to, say, 70, it would run more during the day, but not that much, and wouldn’t spend forever getting back up to 72. Would we save money? Can you say for sure? Does it depend on our own house? what’s the deal? xo C ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [December 20, 2004, 3:05am UTC](https://boards.straightdope.com/t/saving-money-by-turning-off-your-water-heater/280451/23 "2004-12-20T03:05:35Z")
> [@](#): > > The maximum expected saving using a timer to turn off the water heater 18 hours per day would be about $22.09 per year for two people using about 40 gallons of water per day… However, for a family of four using about 80 gallons of water per day, the saving is much less, or about $12.27 per year… The analysis was based on electric rate of 7.5 cents per kilowatt hour. So payback period grows to over 6 years. > [@](#): > > I’d like to ask a similar one: We live in the midwest…plenty cold. (especially today). Our forced air heater is on a thermostat so that it goes off at 9 when we leave, back on at 4. My understanding is as a estimate, you can’t count the cool-down time, nor the warm up time, just the savings at the lower temp once you reach steady state. ---
**Author:** ![JimOfAllTrades](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@JimOfAllTrades](https://boards.straightdope.com/u/JimOfAllTrades)\ **Post date:** [December 20, 2004, 3:34am UTC](https://boards.straightdope.com/t/saving-money-by-turning-off-your-water-heater/280451/24 "2004-12-20T03:34:05Z")
> [@CC](#): > > If this question is pretty much beaten to death, I’d like to ask a similar one: We live in the midwest…plenty cold. (especially today). Our forced air heater is on a thermostat so that it goes off at 9 when we leave, back on at 4. My question is this: When it goes on at 4, and the house has gotten very very cold (we set the day time temp at 64), it seems to run forever to get up to 72 again, cycles frequently, and seems to be running an awful lot. If we just set the thing to, say, 70, it would run more during the day, but not that much, and wouldn’t spend forever getting back up to 72. Would we save money? Can you say for sure? Does it depend on our own house? what’s the deal? xo C The answer here is the same as for the water heater: It will always cost less to turn the heat down for a few hours than to keep it set higher. It may seem like the furnace will run more to bring the house back up to temp than it runs when simply maintaining the temperature, but it’s not true. If you left the temperature set at 72 (or 70) for those seven hours, and tracked the total time the furnace ran, you would find that it ran more than it does to bring the heat up from 64. This will always be the case, assuming the heat loss from your home is reasonably consistent (that is, you don’t have a window or door open while you’re trying to reheat the house that isn’t open during the time when the house is unoccupied). ---
**Author:** ![beltbuckle](https://avatars.discourse-cdn.com/v4/letter/b/3da27b/32.png) [@beltbuckle](https://boards.straightdope.com/u/beltbuckle)\ **Post date:** [December 20, 2004, 8:19pm UTC](https://boards.straightdope.com/t/saving-money-by-turning-off-your-water-heater/280451/25 "2004-12-20T20:19:49Z")
I just wanted to nitpick and remind people that it is not a HOT Water Heater. It is just a water heater. It just heats water. If the water was already hot it would not need heating. Thank you for this brief interruption. [Previous page](https://boards.straightdope.com/t/saving-money-by-turning-off-your-water-heater/280451.md?page=1)