Heating water - combi with unvented tank

Standingtall

Hi all

We have just moved into a house that heats the water with a combi / condensing boiler feeding into an unvented cylinder. It also heats the radiators but I am ok on operating them, my question is on the water heating. How often should we have the tank water being heated by the boiler please? We have a fully programmable timer. Should we just set it to come on for an hour on a morning and a couple of hours on a night? Certainly the latter is what we are doing at the moment. There are only three of us so we do not use mega amounts of water. Maybe a quick shower each and a bath a couple of times a week.

Alternatively, is it better to have it heating up more constantly and maintaining the temp in the tank by not giving the cold intake chance to mix (is this technically possible even as I am quite ignorant on the plumbing front)

I hope you understand my questions - any advice appreciated.

Regards
ST

matelodave

If you've got a hot water tank then it's not a combi although it might be a condensing boiler. A combi heats water as you use it and therefore you don't need a hot water tank.

Keeping the tank hot all the time is a waste of energy so ideally you want to set the timer to just heat sufficient for your needs. If you shower in the mornings and don't use much hot water in the evenings then try heating it for an hour before you get up and not heating in the evening.

If you are a night time shower/bath person then heat it for an hour before you want to have your bath/shower and see if there's still enough hot water left over for your morning ablutions.

It's a case of trial & error to optimise the amount of heating you require to ensure that it's hot when you want it and that you've got enough for your needs. A tankful of hot water will lose about 1.5-2kwh of heat a day (about 6-8p worth of gas = £25-£30 a year) so you can save money by letting it cool down when you don't need it.