Heating on low all day- experiment

[User129867588]

Not sure anyone will find this useful as I know we all have different houses and boilers etc, but I trialled having my heating on all day yesterday, reduced my thermostat to 18 degrees and I spent the same on gas as previous day when the heating was on 18.5 but only on for just over an hour in morning and then for 3 hours in evening! Both days the temp on my thermostat after boiler being off all night was 14.5 degrees 🥶

House is a 2 bed semi, mid 1980’s build. Double glazing that’s over 10 years old and some getting replaced soon. House had insulation added but again that was about 15 years ago.

As seen on pictures the main expense on the gas was when heating first came on and then around tea time. I cooked on my gas hob and then all 3 of us had showers and we use a mixer shower connected to boiler for hot water. I’m with EDF on the variable rate.

I’m doing it again today and if it stays around the same I don’t see any reason for me to work in a cold house in the daytime when it costs the same (or just a tiny bit more) to heat most of the day! I can manage with 18 degrees too and still wear a jumper and extra thermals. Last years 20 degree heat is but a distant memory…….

*Have tried keeping it on all day vs short bursts on the timer

I remember reading somewhere that when you turn it off and let the house get cold, some types of houses build up condensation in the walls which draws heat out when you turn it on. Unfortunately I don't know the details or how accurate that is!

Surely it depends on outside temperature - if it’s -5 outside heating will have to run constantly.

I am doing this today as I want to see what difference it makes. The house feels very comfortable at 18 degrees. It is 6 degrees outside.

Very interested in this and am starting my own experiment now! I don't have a smart reader but can read the meter and am good at maths, so will report back in 2 days with costs! Currently have 3x 1hour bursts of heating per 24hr period and use a multistore in the lounge (lit after lunch and by the evening has spread heat around the house). Will set the thermostat tomorrow to maintain 18' in the centre of the house (apart from overnight which will be 16').
We're all cold, no-one wants to leave the living room!

My house is an 1850’s semi cottage, draughty unless I obsessively keep all the doors shut and curtains closed. My smart meter shows a max of 50p more per day with keeping the heating on at 18 all day and the house is much nicer to live in!

I’ve always done it like this, I’ve never done the blasts. My bill are higher now because I have an electric car but I’ve never had big bills.

I have found my people. I have been experimenting too and today the temp outside has finally dropped under 10°c.

Heating has been on all day as opposed to bursts. Really interested to see if this will make a big difference moneywise. Keeping a beady eye on the smart meter today.

Yep. Yesterday I kept mine on overnight at 18, then turned it up to 20 in the afternoon til midnight; total use for the day inc standing charge was £6

I just can't understand how running the boiler all day would be cheaper than turning it on for just two hours a day. Surely it's either on or off, burning gas or not burning gas? To maintain 18 degrees all day in our house it would need to be pumping out heat almost all day long in this weather!

I need to maintain 18° min in order to try stay healthy this winter; I'm just glad that keeping it on is relatively sustainable for me atm.
I don't think it's necessarily cheaper than only putting it on a couple of times but then I can't get my house consistently warm enough by doing that anyway.
It ISN'T as expensive as I anticipated though - its always worth bearing in mind that it'll use a lot more energy in the first hour or so to reach x°, and a lot less each subsequent hour it's on as it just maintains temperature.

Yes, I didn't get that either, but having done a bit of research it appears that modern boilers aren't either "on" or "off" but have varying levels of efficiency depending on what you're asking it to do. So they are actually more efficient (use less gas to produce a kw of heat energy) than when you are running them at lower temperatures pretty much continually rather than heating up the water from cold. But old-style boilers and electric heaters only run at one setting (on or off) and you don't get more efficiency from them by running continuously, so timed is better.

I haven't actually tried it out yet and I imagine it will vary depending on a bunch of factors, but I'm going to give it a try.

I don't need to do it myself as am blessed to have a smallish, warm house.
My late mum used to run our heating all day though, when we moved to a new (at the time) biggish detached house in the 60's.
The neighbours couldn't believe it as they were putting theirs on in bursts in the morning & evening & were paying more.
I know MSE & the like say it's more expensive left on, but personally I can see how it would be cheaper, with the boiler not having to really boost up & work to get the house to the required temperature. It's more just ticking over, surely, left on?

It is 0 degrees outside here at the moment according to my weather app and showing as being 10.7 degrees in my kitchen, and 62% humidity.

that’s with having the heating on for an hour this morning, it’s due to come on at 6pm for another hour or maybe 2 but that won’t be enough time to get it up over 15-16 I don’t think.

Im just really cold, like I’m totally fed up of feeling tense through my middle all the time with the shivering. It’s the same at work, freezing there too.

I have tested this and I just have mine on 19/20 all day, then boost to 22 if it's a bit chilly or drying a few bits. Checked the smart meter and it's not much different. Need it on for the dogs as it would be too cool otherwise.

It does very much depend on your house for how well it works, but mine is rated A for energy efficiency - it's so well insulated we get condensation on the OUTSIDE of the windows on cold mornings. I have my boiler on constantly, with the thermostat set to 16 degrees, so the heating only kicks in for about ten minutes at a time throughout the day. It definitely feels much more comfortable to be in (I wfh) than letting the house cool down & then blasting the heat out for an hour at 21 degrees. It's also a lot better for getting washing dry!

I don’t think I understand the OP. If thermostat is set to 18.5 deg it doesn’t matter how many hours the heating came on for, it maintained 18.5 degrees.
If this cost the same as maintaining 18 degrees (regardless of how long it’s on for), then surely it’s better to keep it at 18.5??

I have the house tick over at 19.5c from 7am -10 pm. I've a hive system that clearly shows how long the central heating is active and when. It needs to do some heavy lifting on the morning and then kicks in in short bursts throughout the day.

On days when we've put in on only when we've demanded it, it is active for just as long having to do that heavy lifting of getting up to temperature from a lower temperature more than once.

I have mine at 17 24/7 and 18 scheduled for an hour in the morning & a few hours in the afternoon (but obv it doesn’t take that long as switches off when it gets up to temp). Only £3-4 a day at the moment so works for us!

Although haven’t got down to super cold temps yet

This is really helpful thank you. We tried this earlier in the week but at 20, it was lovely but cost about £1.50 more (so too £££) I might give it another go at 19.

It depends so much on your house though. 3 floor town house here, heat set for 18 degrees on for an hour in the morning today (circa 3 degrees outside) then set to come on again at 5.30pm for 3 hours but its already turned itself off as above 18. Wasn't cold this pm with the heating off either.

Being terraced helps so much!

We're detached, but a fairly new build so reasonably well insulated, have just set Hive for 19 between 7:30am and 9pm tomorrow, will report back!

@Squirrelgate i believe it’s due to the boiler not having to heat the house up from cold and needing to run at a higher temp to get the house upto 20, if it maintains it at 18-20 degrees.

It does at my house, it doesn’t cost much more to have it on at a lower temperature all day.

Thought so, logic would say it takes much more energy to heat up a cold house vs maintaining a temperature.

Apparently the other thing you can do to make your boiler more efficient if it is a condensing boiler, is to turn the flow temperature down. Most boilers are set at 75-80C but are more efficient running at 60 or less - it can take longer to reach your thermostat temperature but it uses less gas overall to get there.