Better to keep heating on constant ambient temperature or flick on when needed?

[behappy1736]

Does anyone know if it's more cost effective flicking the heating on when you need it or keeping it at say 19 degrees so the temperature is consistent and it comes in only when it drops below that temp?
So this morning it was pretty chilly and thermostat read 16 so I flicked the heating on and it took at least 30 minutes to reach 19 degrees.
I just can't work out what is better.
Any help much appreciated thanks

@roses2 im running my experiment today, let heating click to away when at work it fell to 13 from 16.5 this morning when I left at 8 and returned to 13 at 2. I will see if I can find a place on my smart monitor where it compares the KWh over the days

Ok so yesterday heating ran for 7 and 1/4 hours again, my dishwasher is connected to
the hot water inlet as can’t be connected to cold due to a reason I can’t remember, it was run on eco setting and heats it’s own hot water as far As I know so would hopefully only pull so much, here are my comparisons but need account for some hot water

Thanks for posting this. Am I reading it right - leaving the heating on all day (off at night) only cost £1 more than switching it on for a little bit morning and night (off in the afternoon and night)?

Ours I cheaper left on all day.

I can get it down to £10.50 if I have it at 18 and flow rate set at 60 but it’s a bit chilly for us.

Turning off for 12 hrs and reheating costs us £14 a day as we need to increase the flow rate to 70 to get it actually up to temp.

Keeping a constant temp of 19 at night/ 20 in the day I have decided is the sweet spot costing us £12.50 with flow rate at 65

@AlaskaThunderfuckHiiiiiiiii why the big diff in electricity 8 to 14. What did you do diff

and answering @behappy1736 I honestly don’t know

heating up cold radiators takes longer where is on constant but move thermostat to click on then radiators heat up quickly

last month we did an hour am and 2/3 tops pm

this month as much colder - been - 4/5 I’ve had on more but clicking on at 16

ive got used to a colder house - last year ag 3p I had heating on all day and evening and bill was £78

now at 10p and on much less and bill was £188 🙀🙀🙀

Incorrect. With a little basic physics knowledge it’s very easy to see that it will always be cheaper to run the heating only when needed - allow me to explain.

The amount heat transferred to outside (which is where all of the input heat eventually goes) is directly proportional to the difference in indoor vs outdoor temperature - the bigger the differential, the more heat is transferred (physics 101).

Having the heating set to 19 all the time creates a bigger differential - thus more heat transfer equating to more overall heat needing to be input in the first place.

It doesn’t matter if it’s a well-insulated bungalow or a 12th century church - the above applies.

@roses2 it cost more to run it a couple of times a day than it did to have it on a lower heat all day but as I say the dishwasher was also on.
@Blondeshavemorefun the 14 is because it was Sunday and we were in all day, the 8 was Monday we were all at work/school

@AlaskaThunderfuckHiiiiiiiii ah interesting how different weekend to work /school day

I don't think people believe science anymore.

The laws of physics says it has to cost more to keep your heating on longer at the same temperature than to switch it on or off

It’s cheaper to flick on / off. I have it on 6-9am and 7-9pm. Works well.

Ps for money saving do think about your hot water tank. I keep the hot water turned off unless I’m going to need if for a bath and then I just turn on for 30 mins before I want the water. First month of doing this my bills actually went down despite the energy unit price increase.

Incorrect. With a little basic physics knowledge it’s very easy to see that it will always be cheaper to run the heating only when needed - allow me to explain.

The amount heat transferred to outside (which is where all of the input heat eventually goes) is directly proportional to the difference in indoor vs outdoor temperature - the bigger the differential, the more heat is transferred (physics 101).

Having the heating set to 19 all the time creates a bigger differential - thus more heat transfer equating to more overall heat needing to be input in the first place

But I always understood the comparison to be it was better to have your heating set at a lower temperature for longer than having short bursts to get it up to a higher temp. So e.g. heating the house from 7am to 9pm at a constant 19C can use less power and feel more comfortable than heating the house to 25C from 7am to 9am then 6pm to 9pm which is good to know if you WFH.

There are several factors that impact how much energy you use , it's not just time the heating is on. The temperature you set the thermostat to, the flow rate, the type, size and location of your house, the amount of insulation you have, how many rooms you heat, whether you draw your curtains at dusk etc etc all affect the amount of energy you use.

Are you talking about an immeraion heater?

Madness to have that in all the time

heating the house from 7am to 9pm at a constant 19C can use less power and feel more comfortable than heating the house to 25C from 7am to 9am then 6pm to 9pm

If that's what you're doing no wonder your bills are high! Those are both very high temperatures to set the thermostat at.

Depends on your house and the type of heating. With a gas boiler blasting out heat, you only have it on when you need. We have a heat pump and you do all that via the thermostat. it turns the heat on as needed to maintain the set temperature. If I wanted to use less electricity, I would put my thermostat lower. But yes, if your house is poorly insulated, then whatever type of heat you have, your system will always be working against the heat loss.

I keep my home at 19.5c and my annual gas consumption is almost spot on average at 12,000kwh. And it's actually much lower than the average for a four bed detached, which is 15000kwh. It's comfortable and affordable for me and only marginally more costly than firing it up in stints and letting the temperature fall again.

The benefit of keeping it at a steady temperature through the day is that you can turn the flow right down with a modern combi boiler and the system works more effectively. If you let is fall to uncomfortable levels and then you are whacking the heating on for relief, having the flow down so low would be like a bad joke as it takes its sweet time slowly building the warmth in the house.

If that's what you're doing no wonder your bills are high! Those are both very high temperatures to set the thermostat at.

These are example temperatures. However 19C really isn't high, at work the office is kept at a constant 22C which feels comfortable. Constant temperatures do feel more comfortable than fluctuating temperatures so for those of us who can afford it and who WFH it does make more sense to have a well insulated house with a constant slightly lower temperature set than blasting out the heat twice a day and then feeling it gradually drop. If you are out of the house at work or whatever it makes sense to only have it on when you are in the house.

I think it can vary, my thermostat is in the hall next to the kitchen, in the kitchen the oven is behind where the thermostat is so if I've got the oven on I would need the thermostat higher or the rest of the house gets too cold. I generally have mine at 19 or 20 but my DH is mid 70s and disabled so not really moving about so we can't let it get too cold. He'd have it at 21 ideally but we are being careful at the moment so trying to manage with it lower.