I’ve heard some people say that it is cheaper to heat your house at a constant temperature controlled by the thermostat than use the timer to heat when you need it and let the house get cold in between.

I’m not entirely convinced, what are your thoughts?

No answer but I think it depends on how long you leave it, thermal mass of the house, outside temp etc.
We turn our heating off during the day and overnight and let the temp inside drift down. Overnight it’ll go down 2-3 deg C and take 30min or so to get back up. (1970’s deteched house, oil fired central heating + log burner).

I think from what i’ve read of other similar posts on here that it costs slightly more but you have a nice cosy house at the end of it.

I tried it for a couple of days a couple of weeks ago when we had the last bout of really cold weather and i only noticed a slight increase in temperature but not a great amount so put it back to timed useage. and i have a couple of questions that i’d like answering – should you keep it on over night as well? and does it take longer than a couple of days to feel a greater increase?

I have the thermostat at 20 deg for what it counts in a 60s detached house with gas central heating. Living room drops from about 17-18oC in evening to 11-12oC when we get up in the morning and hope from work.

Mine’s on constant at 19 degrees, now that the house is usually occupied all day, used to be timed but I figured that the boiler was on for about 2 hours getting up to the desired temperature for each cyle. Seems to fire up about 10 minutes every hour when on constant. It’s probably a little more expensive but nothing that makes cry TBH.

In theory no, it’s an urban myth.

There have been other threads recently about this, one of them had a link to a study that showed it’s definitely not cheaper to have it on all the time. It might be more pleasant but that’s a different thing.

I have a large 170 year old house with single glazed windows and solid walls (no cavities, so no cavity insulation). I set the thermostat to 18C for getting up time and for the evenings and 13C the rest of the time. It’s nice & cosy and I don’t think it costs significantly more than if I let it get cold in between times. Certainly much more comfortable.

I would like to see that study, just done a search on here but couldn’t find thread, am googling..

That being said, I don’t think it needs much study, a bit of basic thermodynamics tells you this is a fallacy..

edit: semi official refutation..

Certainly much more comfortable.

This is a different issue, the OP asked was it cheaper to keep it on all day than only when you need, the answer is certainly no. It seems you need to keep it on all day so the OP’s question is moot really. You are answering the question “is it nicer to keep it on all day?” the answer is certainly yes!!!!

It was dicussed on Radio 2 drive time show thing one evening last week.. or was it the week before, anyhow I didnt hear it, but they tend to get professors etc anyswering the questions…

I know that if we leave our heating on at say constant 19, the boiler doesnt fire up that often and the radiators only ever need to get luke warm.

If the house gets cold it can take 4-5hours to bring it back up to the same temperature and the boiler will work constantly.

We tried this last year:

1. Friends live in a converted two-up-two down in a terrace and kept turning their heat on and off
2. We live in a 3 bed bungalow and kept the thermostat at a constant 21 degs c when not in

At the end of last winter we had spent an extra £30 on heating

My advice is keep it warm and constant – our friends where coming home from work and asking the boiler (pleading with it) to lift the temperature from 12 degs to 21 degs + so were basically getting the place warm by bed time!

I seriously think in this weather anything else is false economy

FunkyDunc – Member
It was dicussed on Radio 2 drive time show thing one evening last week.. or was it the week before, anyhow I didnt hear it, but they tend to get professors etc anyswering the questions…

Yeah, it was, and it came back as inconclusive… 😕

we had a new combi fitted in march and the guy who put it in said it is better for the system in the long run to keep it constant and let the thermostat do the work rather than have it off when your not in then it has to fight like hell to get up to temp.

i checked with our provider who we have gas and elecetric combined with and it has gone up about £20 a month, we can afford this and rather have a wamr house to come home to and when having a pee at 4am.

each to their own i guess.

I love STW.

This

each to their own i guess.

is fabricated disagreement, not a single poster has said it is cheaper to leave it on all day, everyone appears to accept that its more expensive, but we all agree that it is nicer.

(Goes away to bury head in sand)

Define marginally more expensive as a function of comfort?

(goes away to bury head in concrete) 🙄

With added insulation ours has been keeping the house warm left at 15 degrees.

I suspected it wouldn’t be cheaper. But sounds like the extra cost is quite small so I will carry on with the comfort option.

We tried this last year:

1. Friends live in a converted two-up-two down in a terrace and kept turning their heat on and off
2. We live in a 3 bed bungalow and kept the thermostat at a constant 21 degs c when not in

At the end of last winter we had spent an extra £30 on heating

Ever heard of apples and oranges? Your end result is still correct but really they’re not even close to being comparable 🙂

The heat loss from the walls of the house is proportional to the temperature difference across the extremities. The time taken to heat the house up (and for it to cool) is proportional to (among other things) the size of the rads, the physical mass of the building and contents etc.
On any two identical houses. te house with constant heating will waste more energy. However the house that cycles in heat will need to be timed correctly in order to prevent the warm-up, cool-down processes being noticable to the occupier.
Points to note – most modern boilers can be running for an hour at a time, but not burning fuel by the ton – they throttle back just to keep the rads at full temp. So you might note your boiler is on for 3 hours to warm the house up but a large portion of that time it’ll just be ticking over.
Condensing boilers work most efficiently with their CH return temp <55c, if your rads are too small or your output temp too high the boiler won’t condense and so works less efficiently (I believe old boilers worked more efficiently at higher temps, which can confuse). Rads are also more effective with higher temps (again, heating ability from them depends on temp difference – hotter rads = faster heating of room to a great degree).

The A-level physics says it is not cheaper to leave your heating on all the time. Heat lost to the outside is proportional to the difference in temperature between the inside and outside. So the longer your house is kept warm, the more heat will be lost. To be honest I am not sure I can think of a reason why this would not be the case.

depends how much you’re in the house 🙄

People heat their their houses to 21 deg.C in winter? Seriously? Cripes! FWIW a jumper may be a useful investment, or failing that an industrial sized crate of MTFU!

our house has averaged about -1 indoors the past 2 weeks. do i win a prize?

(we visit friends houses to warm up)

We tried this last year:
1. Friends live in a converted two-up-two down in a terrace and kept turning their heat on and off
2. We live in a 3 bed bungalow and kept the thermostat at a constant 21 degs c when not in
At the end of last winter we had spent an extra £30 on heating
My advice is keep it warm and constant – our friends where coming home from work and asking the boiler (pleading with it) to lift the temperature from 12 degs to 21 degs + so were basically getting the place warm by bed time!
I seriously think in this weather anything else is false economy

That just depends on waaaaay toany other factors to be comparable. Our boiler takes our 3 bed semi from “off all day” temperature to 19 degrees in well under an hour. But it’s a brand new and very efficient one, with a big new radiator in the biggest room…..

poppa – Member
People heat their their houses to 21 deg.C in winter? Seriously? Cripes! FWIW a jumper may be a useful investment, or failing that an industrial sized crate of MTFU!

You’re content in allowing small children to freeze?

PeterPoddy – Member
We tried this last year:
1. Friends live in a converted two-up-two down in a terrace and kept turning their heat on and off
2. We live in a 3 bed bungalow and kept the thermostat at a constant 21 degs c when not in
At the end of last winter we had spent an extra £30 on heating
My advice is keep it warm and constant – our friends where coming home from work and asking the boiler (pleading with it) to lift the temperature from 12 degs to 21 degs + so were basically getting the place warm by bed time!
I seriously think in this weather anything else is false economy
That just depends on waaaaay toany other factors to be comparable

Yes

People heat their their houses to 21 deg.C in winter? Seriously? Cripes!

Many people, especially the elderly, heat their home to 23+ all day as they’re in the house all day and feel the cold more than you or I.
I personally don’t have it over about 19c, but I do own a jumper.

We run ours 24 hours a day. I suspect it’s not cheaper, but in these temperatures if we turn it off overnight the dog gets into bed with us.

People heat their their houses to 21 deg.C in winter? Seriously? Cripes! FWIW a jumper may be a useful investment, or failing that an industrial sized crate of MTFU!

a Level 6 house ought to be able to achieve between 20 and 30kWh/m2 pa in heating requirement. That’s around a fifth of a normal house so in theory in the right house you could maintain a higher temperature for a lot less cost than the bulk of the UK housing stock.

My Victorian Terrace, with a modern exterior wall on the back (cavity etc) won’t drop below 16C during the day (with CH off) unless it’s seriously cold outside eg well below freezing. Thermostat is set at 19 when I’m home.

In this cold we have had our heating on all the time (we usually don’t) because lil Grips is still wriggling around a lot and ends up out of her blankets each night. We put her in fleecy pyjamas as much as we can but she still wakes up cold if we don’t have the heating on.

Oh, and my calculations for heating the barn came out at about 14kW to maintain a 20degree differential.

In the coldest spells of late and an internal target temp of about 18-19degrees, we’ve been burning wood pellets at about the rate of 120-150kWh per day*. SO not too bad really.

* thats the equivalent of about 15 litres of oil a day I think. About £6.

poppa – Member
People heat their their houses to 21 deg.C in winter? Seriously? Cripes! FWIW a jumper may be a useful investment, or failing that an industrial sized crate of MTFU!

You’re content in allowing small children to freeze?

Come on! Do you heat it to 21 degrees in summer too?

You’re content in allowing small children to freeze?

Ooooooohhhhhhh dramatic but IME they feel the cold a lot less than adults. they learn to winge and moan from their parents.
My kids often run around semi dressed in an unheated house and despite being cold to my touch insist they are ok and warm
Dont make your children as soft as you eh 😉
HTH

You’re content in allowing small children to freeze?

Not sure I understand this bit. Unless you can’t buy warm clothes for kids any more.

Oh well, I guess I must come from a line of cold lovers then. Dropping the thermostat down to 17 or so and wearing warmer clothes is better for your wallet and the environment though.

Surely it depends on exactly how long you leave it off. IF you have it on for 4 hours a day and off for 20 then it will be better cheaper than leaving it on for 24. ALternatively if you have it on for 20 and off for 4 It would probably make very little difference having it on continuously.

Is this going to turn into a plane on conveyor belt type thread…

We have bought a thermostatic oil filled radiator for a 8 month olds bedroom. He appears not to like it below 18 degrees at night so we reckoned it would be cheaper to heat his box room, rather than the whole house?

FD – we did that in the old house where it was impractical to heat the whole house (single skin drafty sash windows victorian cottage).

In winter we would set the thermostat on the boiler to 15degs and just run a gas stove in one day room and the electric radiator in the little’uns.

Now we have a fully insulated almost airtight new house we can be more flippant with the thermostat 🙂

We have bought a thermostatic oil filled radiator for a 8 month olds bedroom. He appears not to like it below 18 degrees at night so we reckoned it would be cheaper to heat his box room, rather than the whole house?

Possibly, but it depends on the heater. I’m sure someone here knows how efficient that sort of heater is.

its 100% efficient because it’s electric. The losses of fuel conversion into energy are at the power plant.

Its is however much more expensive. Elec costs about 12-15p kWh. Gas about 3pkWh. Assume say 85% efficiency of a gas boiler and your heat costs 3.5p kWh.

EDIT, sorry poppa, I assume you mean maybe total cost.

Maybe the whole house needs 15kW/h to keep warm and the kids room just say 1/8th of that,, or 2kW/h to keep warm.

So either 15kW x 3.5p/kWh = 52.5p per hour to heat the house versus 2kW x 15p = 30p per hour to heat juniors room.

Yup, if you have special requirements I’d go with an elec heater in the one room. However that could work out financially unwise if you’re not careful – the elec heater + the cost of elec (2-3x the cost of gas per kwh) would mean the benefit could become marginal in a small well insulated house.

🙂