Help settle a dispute between me and DH

[DrierThanANunsNasty]

Just moved into a new house with a fancy new thermostat that can be set remotely/by phone etc. Of course, DH wanted to faff with it and has got the hot water to come on between 6am-8am and 7pm-9pm.

I personally think it’s cheaper to just boost it when we need it. We have odd hours and schedules so sometimes I’ll want to shower in the middle of the day, other times we’re out all hours and the hot water doesn’t get used that day at all (will shower at the gym or work or whatever).

AIBU to turn the timer off and just boost it when we need it? DH thinks that’ll be more expensive but I’m a penny pincher and think he’s full of crap.

YABU leaving it on a timer is better
YANBU turn the sodding timer off and just boost it when you need it

trial it for a month on one way and then on the other. Reading to the utility company - no doubt billing is online.

Winner gets a nice treat from the loser. (are we alowed to say loser here?)

My DH and I found the fancy remote settings on our boiler so complicated we've never bothered sorting them out!
Is yours a combi boiler? Ours is so we always have hot water with no need to boost. We just press the heating on and off as needed. We have very low bills so this seems to work for us.

Or leave it on constant as this is often more economical?

It’s a hot water tank, used to a combi boiler. I thought the leaving it on all the time thing was a myth?

Assuming you don't have a combi boiler which I think works differently, having the water on a timer would be better. Your hot water tank should be well insulated so if you don't use the hot water, it would stay pretty hot and would only need to go on for a short time to get it back to ideal temperature when it next came on. I seem to recall that experts say the best way to conserve energy when heating water is to keep your thermostat low - ie to prevent your boiler having to work hard to constantly get the temperature up.

So I'd agree with your DH with the proviso that I'm assuming your hot water system is similar to ours. Also, from completely cold to hot takes an hour for ours to heat up. But if it's still warm from before, we can get it to hot enough in a very short time.

Timer

I guess I’ll just have to admit defeat on this one. I won’t tell him he’s right though, of course, just let him think I’ve forgotten

I would do both to be honest (and yes another penny pincher here) so on for the am auto then as and when needed as a top up. for e.g. you don't need the hottest water for a midday shower - there shld be enough left from am but late evening might need a boost 15 min before

Go for solar on the roof that heats your hot water. Not expensive. Will heat it enough for most of the year and only require minimal topping up in the winter months.

He's right

If it can be set remotely you can turn it off if it's not needed at these times.

If you were coming home late one night or rushing out early one morning and don't need any hot water you can override it and save some money. You just need to remember then.

The water in the tank will stay warm for a long time. So if you shower mid-day, boost to replace as it will fill up with cold.

Much better to have on timer imo.

I think the difference between fine-tuning to the max and just leaving it on full-blast for 18 hours a day will probably be negligible. The hot water tank insulation is fairly effective. (If it were 100% effective there would be no difference, except to the extent that fiddling led you to accidentally have colder showers than you would otherwise have done.)

In a similar vein, I find it makes virtually no difference to my heating bill whether I have the heating on 8 hours a day or 18 hours a day. (I've no-doubt that 18 hours must be more expensive, it's just that when I look back at my annual consumption for different years, you wouldn't be able to tell the years I worked from home from those I commuted, by looking at gas consumption. I do have a well-insulated home, and I recently worked out that only a third of my gas bill is consumed by heating, which is far less than I expected.)

It is more economical to run a boiler for an hour continuously, than for twelve five-minute periods spread out over the day. This is because, each time, you will be heating up the boiler and pipework from cold, then letting it cool down again.

This is why a combi is less efficient, for hot water, than a well insulated modern cylinder.

If you are out of the house all day, not running taps, it will not be so bad.

With a cylinder, the most economical thing is to set the timer so it will start half an hour before bath/shower time, and go off half an hour afterwards. This is often twice a day. If it is modern and big enough, it will run as many baths as you want, and still be hot afterwards. It should then have enough HW to run all your washing up and handwashing for the rest of the day. The cylinder thermostat will turn off demand to the boiler as soon as the cylinder reaches its set temperature, so it will not keep using gas.

A typical modern boiler can heat a typical modern cylinder in about half an hour. Modern cylinders are well insulated and lose so little heat that even the airing cupboard will only be slightly warm.

The age, size and colour of the cylinder give important clues.

You'll probably find you don't need it on for as long, ours is on for 45 minutes 3 times a day at 6:30am, 3:30pm and 7 pm we never run out of hot water and that includes a daily toddler bath and two adult showers, plus some pot washing, everything else does go in the dishwasher though