Gas boiler - fill hot water tank every two days?

chubsta

Like most, I am trying to eke every bit of value out of my energy usage!
For a couple of months I have been trialling the following - I have a gas boiler connected to a hot water tank. For various reasons I don't use an awful lot of hot water - there is a shower each day and washing up probably every two. I reduced the temp of the hot water too.
During the hot summer it was fine to have a hot shower one day, and a not so hot shower (but still doable) the next - on days when I didn't put the hot water on I of course didn't use any gas - result!
Now it is colder I find that the shower the 2nd day is a little uncomfortable, particularly at 5.30am as I don't have the heating on at all yet, and probably won't until the weather gets really cold.
So, now to the rambling bit - if I fill the tank up every 2nd day then it is starting off with less hot water in it than if I did it each day, so doing this won't save me 50% of the energy usage. As I have turned the temperature down I may be able to get away with every other day if I turn it up so the water is hotter to start off with but of course that will need more energy to do, but still may be better than running it every day.
So, what is likely to use less energy...
top the tank up with hot water each day at 'acceptable' temperature
top the tank up every two days at 'higher' temperature

I know there are variables such as length of shower, size of tank, lagging etc, but this is just a general question as I have a bit of time before I go to work and am deciding whether to treat myself to a hot shower as I had one yesterday!

Astria

The hotter the tank is the faster it will lose heat. I'd personally have it at a lower temperature and heat it up each day, the second day it shouldn't take as long if it's still warm. Turn the hot water down to 50c and turn it upto 60c about month a month to stop any bacteria forming if you don't use the entire tank, although the chance of you catching something is very slim if you disinfect the shower head on a regular occasion like you should for any type of shower.

chubsta

Astria said:

The hotter the tank is the faster it will lose heat. I'd personally have it at a lower temperature and heat it up each day, the second day it shouldn't take as long if it's still warm. Turn the hot water down to 50c and turn it upto 60c about month a month to stop any bacteria forming if you don't use the entire tank, although the chance of you catching something is very slim.

thanks very much for the quick reply - that is what I will try, I am sure I will be able to get away with 50 every two days in summer but just not for the next few months.

Alnat1

We heat ours for 40 minutes a day and it's good for 2 showers and a bit over. It was originally set at 90 minutes a day and I gradually reduced it by 10 minutes every few days. When I got a tepid shower, I knew I'd gone 10 minutes too far!

macman

For 6 months of the year, or for any time when you have the CH on, it doesn't really matter, as all the heat lost from the tank will serve to heat the house anyway.

Alnat1

macman said:

For 6 months of the year, or for any time when you have the CH on, it doesn't really matter, as all the heat lost from the tank will serve to heat the house anyway.

It might be heating bits of the house that don't need heating though. 

Lorian

Make sure all the pipes leading to the tank are insulated and the tank itself is. My tank, older style. Has its foam coating plus two of the red jackets and some extra insulation at the top. It slows the heat loss quite a bit.

chubsta

Lorian said:

Make sure all the pipes leading to the tank are insulated and the tank itself is. My tank, older style. Has its foam coating plus two of the red jackets and some extra insulation at the top. It slows the heat loss quite a bit.

think I will have a look at lagging all the pipes, very good idea.