Water/Heating - Twice or All Day?

tomstickland

There was a long thread on the "on all time versus timed" last week.
Timed will be more efficient.
The fallacy is due to the claim "on all the time" means that the house doesn't have to be heated up from cold. The thing is though that the process of keeping the house warm (so it doesn't have to be heated up from cold) means that energy has been put into it to counter the continuous losses to the outside world.

Rate of heat loss is proportional to the temperarture difference between the house and the outside world. On all day means more heat loss than if it's timed.

As for water on all the time - I was advised by a plumber years ago that it is best to have it on all the time. Of couse the tank has to be well lagged. I seem to recall dong a check on gas usage and it definitely worked out more economical to have it on all the time.

Well, I've got an electric heater and don't have it on all of the time. Even if it's very well lagged it will still be losing heat. Would you leave it on whilst you went on holiday for 2 weeks? No, you'd realise that you were throwing heat away. Same principle applies to smaller time periods.

jennifernil

We have heating on, in winter, 6.30 to 9.00 and 5.00 to 10.00. Not had it on yet as winter has not arrived!
Hot water we have on all the time so it is there when we need it.

tomstickland

I run my heater overnight only and the water is still very hot the next evening.