Ecodan owners - how do you handle your hot water?

ADringer

Hi all,
Recently got my Ecodan (250L) installed and trying to work out what's best for our house. I think I've got the heating sorted but not sure what to do with the hot water.

The initial settings are for a tank temperature of 50C with a drop of 10C before reheating. I feel this heats too often between when I actually need it (morning shower, evening bath) and so is a waste of energy to reheat when I don't need it.

I spoke to someone else and what they have is set it to 52C to heat overnight and that should more or less last the whole day. I've tried this and the temp drops quite a bit throughout and don't think that it will actually last the whole day.

I'm waiting to switch over to Octopus Agile and so have also got to think about when to reheat. Obviously would be cheapest to reheat at night but then I wouldn't want to top it up for an evening bath as this will be very expensive in comparison.

So Ecodan owners - how do you schedule/configure your hot water?

Thanks!

matelodave

not got an Ecodan but I've got a Daikin heatpump which heats the 200l hot water tank and I just have it on for two hours a day before we get up and before the heating starts - that gives us more than enough hot water for all our needs until the next day. Average daily consumption to heat the tank is around 2kwh

We only heat it to 45 degrees with a weekly boost to 60 once a week for legionella sterilisation. 

As we heat the place for nearly all day and not so much overnight I cant see that Agile or any other sort of off-peak supply would suit. We therefore go for the cheapest single rate tariff we can get. Personally I think I'd try to work out what the daily consumption profile is like especially if you are needing to heat the place during Agile's peak times. Which is sort of what I suggested in your previous thread regarding tariffs.

Make sure that you don't end up with the boost heater kicking in which it will at flow temperatures over between 50-55degrees.

ADringer

Thanks for the info.
Is yours still using 2kwh to heat it in this cold weather? Mine used 3.8kwh last night to heat it to 52c from cold.

Mine definitely wouldn't last that long, the temperature drops too quick over the day to maintain it. It dropped about 15c in 4 hours yesterday. The tank is in the garage which is unheated, do you think that's causing it to lose the heat?

Ideally I would like to heat it once like you and for it to last, but at the moment it definitely won't last the day.

matelodave

Yep, it used about 1.8kwh last night but when it's everso cold it can peak up to nearly 2,5. In the summer it's only uses around 1.5kwh day. Our tank is in the utility room inside the house and the ute, is quite warm as one of the underfloor heating manifolds and hydrobox (ours is a split heatpump rather than a monobloc) are all in there as well.

As we only heat the tank to 45 degrees it will use less energy than heating it to 52. We both have showers but we don't spend ages in there (I can manage a full shower & hair wash etc in less than 2 minutes). We have a dishwasher so there's hardly anything that gets washed up - I try to persuade my wife not to keep running off nigh on a gallon of cold just to wash off a yoghurt pot in hot water, same with hand rinsing but she still does it. Bear in mind that what you run off to get the hot coming through leaves the same amount of hot sitting in the pipework to get stone cold so it's pretty easy to waste a fair amount of hot water without trying. The hot water heats between 0430 and 0630 (until it's up to temp) and the various rooms then start calling for extra heat around 0700 (they all set back to 17 or 18 degrees overnight).

Our shower has an eco shower head which limits the flow to 6lpm and all the taps have flow reducers to avoid flush vast quantities of water down the sink (again my wife seems incapable of adjusting tap flows, they are either off or full on). It may take a minute or so longer to fill a sink but it does help reduce the waste of both hot and cold water.

Our hot water temp is down to around 39 degrees by nightfall which is warm enough to ablute before going to bed and at a pinch we can both get another shower.but the second one ends up running quite cool. On Saturday lunchtime (1200 to 1400) the hot water tank boosts to 60 for sterilisation (although it doesn't actually get to 60 because I've shut off the boost heater) but it gets up to 55 and maintains it there. Because of that, the hot water reheat on Sunday mornings is is done very quickly if at all)

If you are running out of hot water then try timing it it for your morning ablutions and then again later for another hour or so for the evening. There's no real advantage in keeping the tank red hot for 24hours a day - the hotter it is, the more ist costs to heat and the more heat it loses to the surroundings. Make sure that all pipework that gets hot or warm is well insulated to avoid conduction heat from the tank (even our pipework is insulated in the ute to reduce heat loss from the hot pipes and condensation on the cold)

Just found this which is quite interesting and gives you a view of the energy pricing of Agile & Go tariffs and it just confirms for my daily energy consumption profile that I'm better off on my fixed 12.25p/kwh and 13p/day standing charge https://www.energy-stats.uk/ as you can see from above there's not a lot of point to shifting my hotwater production to the low period when I'm only using a couple of kwh a day but possibly paying 20-30p/kwh when the heating is running between 1600 and 1900