Heating and hot water on at the same time

[con1_uk]

Hi, been tracking my usage of gas and experimenting with how long to have the hot water on etc, one thing I noticed was the usage didn’t go up that much when I had the heating on at the same time as the hot water, is this right? Is my theory correct?

I have an Ideal standard fx with a hot water tank upstairs.

 

[Deleted member 267285]

Do you get similar figures separately though?

 

[con1_uk]

Hi, sorry, not sure what you mean?

 

[Deleted member 267285]

I thought you’d worked out how much gas was being used? Say you use 3 cubic meters for hot water and 2 cubic meters for heating individually, do you use 5 cubic meters for both?

 

[con1_uk]

Ahh I get you sorry, so far I have had the hot water on on its own then on with the heating (different day) and both wasn’t much more than just the heating.

 

[flameport]

There won't be much difference, because gas usage for hot water is tiny compared to heating a building.

 

[jeff the gasman]

If you trust a smart meter then DON’T.
Take meter readings instead. Then study pure mathematics to doctorate level and work it out yourself.
Smart meters are not smart! They always favour the supplier.
Imo.

 

[oilhead]

Run your hot water on its own for an hour, then compare it with running heating on its own for an hour. Then compare with running both for an hour. You need to ensure you have the same state of hot water and heating before the start of each test.

 

[Talay]

Run your hot water on its own for an hour, then compare it with running heating on its own for an hour. Then compare with running both for an hour. You need to ensure you have the same state of hot water and heating before the start of each test.

Absolutely and as that will be almost impossible to achieve naturally, the only way to establish a baseline will be to do so artificially, by raising the temperature to a certain level and then maintaining it there or advancing it further.

You may be starting with 18c, 15c, 9c as ambient room temperature but you would need to bring them all up to say 20c and then push it to 25c for an hour.

Same with the water. The only way to know how much hot water you have and what temperature it is is to run it to cold and then heat to Xc but you might relinquish this to the inward water temperature and then accept some minor variances.