did some checks today, we are a family of 5, 1 at uni, 1 at sixth forth and 1 at senior school. Missus home all day and has a shower around 11am, the kids will shower when they get in from school around 3ish and i’ll have a shower around 7pm when i get in from work.
​
How do you set your hot water, i was trying to cut down on fuel, out hot water tank was set to 75degs so i’ve changed to 65degs and ive been looking at the nest settings for when we heat the tank up. ive now set it for the morning between 11-12.30 and then it comes on again for 1 hour between 17.00 and 18.00hrs for me. missus saying it needs to be on much longer as we will run out of hot water.
not sure how i work out how long it takes a water tank to reach temp, but surely a hour would be enough.
should i set it for longer and reduce over the next week until we get cold water.
7 comments
The system will work harder to heat the water from room temperature than from already quite warm.
There’s many a theory that it’s actually cheaper to leave it on 24/7 as it’s just topping up, not heating a full tank from cold.
I’d have thought you the poster family for a combi boiler.
I thought everyone had electric showers and combi boilers these days?
You could probably reduce your tank temp down at least another 10° really. Anything over 50 is considered (in Elf and safety terms) the temperature where burn injury really starts, but longer exposure to 44° can still burn.
Full thickness skin burn at 52 for 2 minutes, 30 seconds at 54. Appreciate with a HW tank you have to keep it higher as when you start to use it the tank tops up with cold water but 65 still seems massively high to me (we have a combi and temp set to 45)
Family of 4 we used to do 1.5 hours in morning and 2 hours in evening
Ours takes around 20mins to refill and reheat and it’s a pretty crap boiler tbh.
If you are going with those settings- the nest thermostat will likely turn on at somewhat random time for 2hrs for legionella protection cycle (which can be disabled). Setting the cylinder target too low could also let legionella establish, I’m no expert- these are the things I have read else where, so if there are any proper heat heads please shout here!
We set ours for 2hrs every other day, and a 1hr top up on the other day. If you set it to run about 30mins before the expected use time with a duration of an hour, it should be a good temperature.
Edit- also depends on the size of your cylinder, and boiler output power.
Mine is programmed to come on about 6am then off around midday then back on about 3pm until 10pm. Washing clothes uses a lot of hot water