07-14-2008, 03:24 AM
I often take short trips of a few days. If I turn off the water heater for 1 day the water is not really noticeably colder when I get back. Two days and the effect is noticeable. Three days and the water is too cool for a shower, and so on. One way of looking at it is that energy wise it is like using a whole tank of water every three days for the privilege of keeping the water hot. Keep in mind I have a very small water heater. A large water heater would stay warmer much longer.
As in the post above, the pitfall is when you turn the heater back on it will kick on full power. After midnight and if you have turned off everything else in your house, this may not make much difference, but during the evening peak, that is like wearing a kick-me sign demand-charge wise.
I don't know about HELCO, but HECO on Oahu will hook your water heater up to some kind of device that allows them to shut it off whenever they need to to shed load. You get a better rate on your bill for your sacrifice. They only do that if you have a large enough water heater though. The point is the instantaneous demand is the big deal.
As in the post above, the pitfall is when you turn the heater back on it will kick on full power. After midnight and if you have turned off everything else in your house, this may not make much difference, but during the evening peak, that is like wearing a kick-me sign demand-charge wise.
I don't know about HELCO, but HECO on Oahu will hook your water heater up to some kind of device that allows them to shut it off whenever they need to to shed load. You get a better rate on your bill for your sacrifice. They only do that if you have a large enough water heater though. The point is the instantaneous demand is the big deal.