[Closed] Heating the house... urban myth?

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: [url= http://www.energychoices.co.uk/energy-efficient-heating-ask-our-expert.html ]semi official refutation..[/url]

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.

(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?

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.

🙂

Dont make your children as soft as you eh

Lil Grips doesn't seem to care much about temperature generally, she is a hot little thing. Mrs Grips worries much more than I do about putting jackets etc on her (although not overly). It's more in the interests of getting a full night's kip than being soft on her. If her room is cold then she can wake up whining with seriously icy little hands and possibly feet.

"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."

The heat loss is proportional to the temp differential so the longer you have the house warmer, the more energy lost. Continual heating = continual loss at max temp differential ie maximises losses.

I fitted a timed thermostat so ours is on all the time, just timed to different temps throughout the day. For us, I cant say it costs more than off-on, but our house is a 60's ex-council semi with concrete walls (no wall insulation). If the house retained more heat the off-on would probably be cheaper as it would lose less heat & would heat-up quicker. If our heating goes off the place goes very cold & takes hours to heat back up.

I'm astonished how hot people think they must have their house. Especially reading these comments on the home of MTFU! And blaming it on cosseting the kids! What a laugh - how the hell do you think mankind got to this point? 20 degrees indoors all year round is an product of this current generation only. Go back 30 years and most people were unaware that such extravagance and softness was even possible.

My parents still live in the house I was born in (indeed the house my dad was born in). There is no heating at all apart from a Rayburn and log burner downstairs. No double glazing, no loft insulation. Plenty of ice indoors. I survived it, as did my brother and sister - as did dad and his five siblings.

My gas boiler is set for 19 degrees but is now on for most of the day. last year I had it set to come on and heat the house from 5.30 until 10.30 weekdays and then most of the day on weekends. this year I have had the heating on low from 6.30 to 10 and the house is toasty and I have the same kW/h usage I had last year. My Dad has done the same with oil and he thinks he's made a saving.

I don't want my house boiling but I don't want it too cold. I like chilling in the house wearign shorts and a tshirt but I'm equally happy in my chav pants and a fleecey hoody.

Physics says no, everything else is just cosyness.
Do you find it uses less petrol to leave the car engine running overnight too?

on a slightly related note, do radiators 'degrade' over time? Our living room rad is short (sits under the window sill) but fairly wide (6' or so) and 'double thickness', but the room is noticably cooler than others, even with the valves open full. Would replacing like for like improve things (my knowledge of these things suggests no) or do I need to find a way of upping the BTUs?

I'm astonished how hot people think they must have their house.

I don't think they think they "must", more "I can have it at 21, so I will".

Physics says no, everything else is just cosyness.
Do you find it uses less petrol to leave the car engine running overnight too?

Nicely put. Though I should have left my car running the other night, after a sustained -20 all night it wouldn't start 🙂

Go back 30 years and most people were unaware that such extravagance and softness was even possible.

And, according to my folks, it was pretty f'in miserable most winters! My Nan had to get up at 5am before everyone else to light the fire. Do you do that?

What a fascinating modern era we live in

Let's all turn the clock back to 1920 and FREEEZZZZEEE!
😛

There is some middle ground! Somewhere in between freezing and swanning about in your pants in the depths of winter. The world is a mad place when we are so soft that we can't tolerate being indoors with a jumper on.

And then people moan because fuel is expensive.

And. Some of the same people are all full of "mtfu" advice on other subjects!

Jeez. Some middle ground is all.

Middle ground on STW.........? 😆

Do you find it uses less petrol to leave the car engine running overnight too?

you don't really have to heat the thermal envelope of a car to keep you warm though do you. If I did keep it on all night then my road might thaw out a little quicker

my heating is on and im still cold....lol i live in a victorian terrace where the ceilings are pretty high and rooms are big.. warm in summer and freeeezing in winter... gud job the whippet keeps me toastie warm snuggled next to me at nite ! 😉

We have been pondering turning off the house heating during the day, and using the leccy radiator in the GF's home-office only.

The difference in volume between her office and the whole house is ~1/10th, while the cost uplift per unit of using the leccy rad is x5. So that suggests a 50% cost saving over the day-time period.

Thanks

except buzz that doesnt take into account the additional energy you need to sink in to the fabric of the cold house at the end of the day to get it up to comfort temperature again for the evening.

To heat your home economically and still have it warm take a look at Weather compensators. We've had one fitted with our new fully modulating boiler. Dare I say it, awesome bit of kit. There is an outside temp sensor that measure outside air temp and constantly adjust the flow temp of your heating to maintain a constant temp in the house. It learns how quickly your house warms & cools so it knows when to gently start heating again. On a scale of 0-5 in boiler power (5 is the highest) ours rarely gets above 2. On a standard boiler/room stat setup you more or less modulate between 0-1 (1 being full pelt)

Its cut our gas usage in half from our old boiler.

It is conclusive that if you leave your heating on permanently rather than timed that you will pay more.

It's not so much about the heat being created as the heat loss. All heat is absorbed through the fabric of the building over a period of time, so when your heating is on, you are losing it through the walls/windows/ceiling. The longer it is on the more you lose!

"except buzz that doesnt take into account the additional energy you need to sink in to the fabric of the cold house at the end of the day to get it up to comfort temperature again for the evening."

I understand: insulation plays a big part to whether cycling is efficient. The warmed walls slowly radiate their heat both internally and externally as they cool. Even with the heating system off for a further 8 hours during the day, the inside of the house will only drop to ~ +10 degrees, as it does overnight. And the internal air is very quickly brought up to comfort temperature, while the walls are being slowly re-heated.

At the end of the day, I'm avoiding pointlessly heating 10/10ths of the house for a 1/3rd of the day, and another 9/10th's of the house for a further 1/3rd of the day.

But more importantly, the GF just said "No". So much for the laws of physics!

To heat your home economically and still have it warm take a look at Weather compensators. We've had one fitted with our new fully modulating boiler. Dare I say it, awesome bit of kit. There is an outside temp sensor that measure outside air temp and constantly adjust the flow temp of your heating to maintain a constant temp in the house. It learns how quickly your house warms & cools so it knows when to gently start heating again. On a scale of 0-5 in boiler power (5 is the highest) ours rarely gets above 2. On a standard boiler/room stat setup you more or less modulate between 0-1 (1 being full pelt)

Its cut our gas usage in half from our old boiler.

Sounds interesting - any particular product? How easy is this to fit?

glenp - Member
I'm astonished how hot people think they must have their house. Especially reading these comments on the home of MTFU! And blaming it on cosseting the kids! What a laugh - how the hell do you think mankind got to this point? 20 degrees indoors all year round is an product of this current generation only. Go back 30 years and most people were unaware that such extravagance and softness was even possible.

My parents still live in the house I was born in (indeed the house my dad was born in). There is no heating at all apart from a Rayburn and log burner downstairs. No double glazing, no loft insulation. Plenty of ice indoors. I survived it, as did my brother and sister - as did dad and his five siblings.

Mong - my thermostat is usually above 20 deg in Winter. This is because it gets the house to a lovely warm temperature where I feel comfortable and I want to have it at that temp. I don't, however moan about fuel bills.

I used to live in a house that had ice on the inside of the windows in Winter and it was effin 'orrible.

Just for the record, I work outside in minus whatever it has been just lately, so no, I won't be MTFUpping any time soon.

As for heating.our combi gets the house up to temp in about 30 mins, so on that basis the timer is set prior to us getting up and getting home from work.

I think it depends on your boiler. Most of the big manufacturers offer an add on kit for their own products.

We've gone for a remeha broag boiler, this has the WC built in, you just need to add the external temp sensor which costs £15.

It was 2 wires for the temp sensor and 2 wires for the starship enterprise style controller.

Molgrips:
Can really recommend the Grobag sleeping bags (other brands are available just make sure they have zips all the way round the bottom and are long enough). They snapper over the shoulder and don't have arms. Baby Kip has a 2.5tog one and when it's nippy (as at the mo) she's in a short sleeve vest, babygrow, fleecy babygrow and grobag. sounds like alot but her hands stay warmish and her legs/feet are also warm. Also means she can't kick it off...genius.