Thermostat radiator valves

How Long do you Leave Your Heating on Each Day?

November 17, 2009 | Energy Efficiency

I have my central heating on first thing in the morning and in the evening to keep costs down. But my friend says it is cheaper to have it on all the time. What do you think?

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  1. I have an old house with no cavity walls or double glazing so it would cost a fortune to leave the heating on all day. If you have a modern house then it might be more cost effective to have it on all the time but with the temperature lower at certain times. I don’t think even then I would have it on all night.

  2. FIRSTLY – Always remember to allow your house to breathe!! Slightly open a window, even when your heating is on, to ensure adquate ventilation.

    As for how long to leave your heating on each day – it depends on numerous circumstances (for example:).

    1. Are you in good health?

    2. How old you are?

    3. How active you are?

    4. How long you are actually in the house?

    If your house is modern and does have insulation, it’s significantly cheaper to keep your heating on during the day and evening, ensuring your thermostat is set at a reasonable temperature (20 degrees) and your individual radiators set at number 3 when it’s nippy out! This prevents your home becoming chilled, therefore ensuring you are not forced to take drastic measures when a nasty cold spell takes hold.

    Remember, massive fluctuations in home temperature isn’t healthy and should be avoided when possible.

  3. I tried it a couple of years ago and in heating oil terms it worked out about the same for me but the trick is to have the heat on a lower level so turn the thermostat down on the boiler. However, I had to replace some copper pipes close to the hot water cylinder. The plumber though the accelerated corrosion was due to heat being on all the time. I don’t know but I have gone back to having the heat switch on and off but for longer periods than before and keeping the thermostat down low. I suspect whther its chaper or not will depend on the house you live in. Mine i s16 years old and well insulated.

  4. Assuming that your house is adequately insulated and that you have the necessary controls in place then this should be the case for central heating and hot water. As usual though this all depends upon what your house, lifestyle and heating system are like. Our experience might not be the same as yours.

    In a previous house (1930’s 3 bed semi) we had a standard gas boiler, central heating and hot water timer, programmable room thermostat, thermostatic radiator valves (TRVs) and a hotwater cylinder thermostat. In keeping the system on constantly we noticed a reduction in fuel bills and a more comfortable house.

    The theory is that it takes less fuel to keep the heat ticking over at a constant temperature rather than having to heat the house from a much lower temperature when the heating was off. Insulation is key!

    A programmable room thermostat allowed us to have a background minimum temperature of say 15 degress and a normal upper temperature of say 20 degress. In effect the CH timer was set to “Constant On 24 hours” with the programmable thermostat maintaining the required temperature. The TRVs allow individual room control.

    All of this similarly applies to the hot water i.e. set the timer to “Constant 24 hours” and the cylinder thermostat tells the boiler when to heat the water. Again it keeps the temperature ticking over at a constant rather than having to heat up twice a day from a much lower temperature.

    No doubt other people will have different experiences of this. If your house is not suitably insulated then it could be the opposite.

  5. Hi People

    I have worked out I am using an average of 150 litres per month. Is this good or bad? I have a converted barn, 2 large bedrooms etc, well insulated. My oil heats my house and water. Any tips on saving oil? Is it best to leave the thermostat set to a constant temp or have the heating come on a set times? Many thanks

    • Try 800 litres in one month!!! December might have been cold, but this is insane! Be happy with 150! I am trawling these posts to see what I can do.

      • You have a problem, your system needs checked. If you have a 3 port v/v it is

        probably passing, needs to be checked. Nozzle sizes need to be checked.

        Failing a solution on all of these… you seriously need to insulate.

        I have recently increased atic 250mm all over and have noticed a difference.

        Just to note, my cavities are also filled.

        But getting that valve check is the priority.

        And……. the result average over 12 months 66 ltrs per monthe, thats right

        800 ltrs per year, consistent over past 2 years.

    • i used 190 litres in 12 days 🙁 . i was told to switch to “on all day” but have temp set to 15.. i dont know if it was better or what but i think i’ll be going back to haveing it on in morning before we get up and couple hours at night …

    • I left mine on all night during the cold spell and averaged 200 litres a week, I have gone back to switching it off at 11.p.m and back on again at 7 a.m have used approx 1/3rd less.

  6. My heating’s not been on since March! We do have a woodburner going 24/7 at this time of year though, much nicer………… 😉

    And we do use a little bit with an Alfa on-demand stove and for the hot water, less than half a tank in that time though, say 125 litres per month.

  7. The amount of energy leaking from a building will be the same regardless of if the heating is on or not. (Or is heat loss dependent upon the temperature difference between inside and outside temperature? Must investigate this.) Logic (and ‘O’ level physics) tells me that the amount of calorific energy needed to replace that lost from the building must be same so it shouldn’t matter if this is a constant input by leaving the heating on constantly or if the heating has to raise the temperature from a lower level because it has been switched off during the day.

    • The heat transfer from inside to outside is proportional to the heat differential, so cold weather requires more heating. Sadly, this is complicated by wind chill – more heat can be lost from a house exposed to strong winds than the same house on a still but much colder day. Similarly driving rain against a non-cavity brick wall can make it damp and greatly reduce its insulation value (think of wearing a wet cardigan…) Cavity walls were invented to solve this problem, as the inner wall remains dry so long as the inside of the house is properly ventilated. The advantage of leaving the boiler on low 24/7 is that the fabric of the house warms and acts as a heat sink, reducing wild fluctuations in internal temperature between clear days and very cold nights.

  8. An interesting read this as it was a discussion I was having only just last night, at which point I have now switched the heating on 24×7. I used to have it on for 4 hours in the morning and 8 in the evening. During this time the boiler would be firing almost constantly, Since leaving it on I didn’t hear it go once this morning during an hour long period (whilst I was in). Time will tell but I wager it’ll work out slightly better to leave it on all the time.

    Oh and just for the record, my property is about 20years old and I would say could do better, insulation wise. I have got the next two days off work to allow time to investigate,

    My last house was a modern one (bought brand new) and when I went away one winter for a week I turn the heating completely off. WHen I got back it was absolutely freezing in there and took at least 2 days of the heating being on constantly before it even remotely felt warm – I assume as the heat soaked into the brickwork and plasterboard. It is as a direct result of this experience that last night i decided to leave my heating on all the time.

    R Upton – I am very jealous! I hope to get my wood burner fitted next year.

    • I thoroughly agree. When i had my boiler on timed for twice a day it would fire up constantly and the house would just about get warm (with me sitting on the radiater trying to thaw out) when it was time to turn off again.

      I now leave it on 24/7 if the weather is bitterly cold, leaving it just ticking over on low overnight, and/or on all day otherwise on a medium heat. The boiler no more has to work and work so hard; it ticks over and tops up.

      The oil Bill stays the same and the house is never cold.

  9. Being in the energy saving field we get asked these questions on a daily basis, all be it on a much larger scale in large office blocks. Yes, it does boil down to insulation as regards how long your boiler will be on or off, but your home will leak heat regardless, and the warmer you keep your home, the more heat will escape, it’s simple physics. In the business sector, heating is always switched off when not needed and always produces savings, however there are too many factors involved to use this data for home comparisons. (Every 8 people entering an office bring in a kilowatt of heating energy for example!)

    It remains a balancing act as regards how comfortable you want (or need) to be. If I go away for any length of time, I change my heating from timed (2hrs AM, 4hrs PM) to on 24 hrs, however I set my thermostat down to 16’C (Normally 19/20’C). This keeps the house at a reasonable temperature so it doesn’t take ages to get back to a comfortable level when we get home.

    I have a 3 bed semi & the oil heats the home & hot water (we have a pumped shower drawing water from the hot water tank) and we use on average just less than 100 litres per month over a year. (I have 2 sons that love showers……)

    If you are measuring how much oil you use comparing 100% on with timed, please also be careful of the placebo effect, actually seeing good results that don’t really exist, you need to be comparing similar time periods with similar outside temperatures to be accurate.

    All in all, its personal prefence for comfort, but keeping a house warmer will always costs more.

  10. HeatingSave can run your heating for you to optimise the best times to turn on and off in the day to accurately manage your heating. It saves time and money and can adjust to extrenal temperatures or room activity as required.

  11. I have a 10 year old modern house. I have my heating on 24/7 at 20c on the main thermostat. Bedroom radiator trc’s at about 16-18c. I have tried using the timer to come on for an hour in the morning, few hours at night. But during these periods the boiler is firing constantly to heat the house up. I think if you get the temp of the house up, keep it there, don’t keep letting it cool down so much that the boiler never stops when you turn up the thermostat. I keep my boiler at max setting, I tried it on the lowest setting & it can’t get the water hot enough so fires up more frequently.

    I ocassionally have long weekends away & turn down the main thermostat to 12c to prevent damp, freezing pipes etc. It will take easily 12+ hours for the house to warm through once i turn it back up. I wonder if it would be more economical just to leave it at 20c whilst I’m away.

    Last winter (Nov-Mar) my house was empty but I left the heating on 24/7 at 12c. I reckon during this period it used 250ltrs. This winter I will be home & with using hot water for laundry, bathing etc I expect the consumption to at least double or possibly triple.

  12. This is something we were discussing last week. We would be interested to receive feedback from anyone with who could advise us about this issue.

    We have recently moved to a large old farmhouse (4-bed) in an exposed area. It has 3 foot thick stone walls, but the double glazing seems to be failing, as there are drafts through a couple of windows and we have just found out there is only 2 1/2 inches of insulation in the loft. The house is rented, so there is little we can do about the windows, but we will be adding more insulation to the loft. There are also some damp spots due to failing render, which is due to be renewed next summer.

    We have been advised by our landlord to keep the central heating on 24/7 (to be honest we need to), But told us that this is likely to cost us £400+ every 2 months. Also that it would be cheaper if we kept the electric immersion heater on 24/7 for bathing & washing etc, as the shower water is drawn from the hot tank.

    • We live in an old farmhouse which is very exposed and well above the snow line on the Welsh borders.

      Although the walls are two feet thick, they are not solid, as repair work has shown. Seem to be godd stone on the outside, with rubble infill and a fairish inner skin, this tends to mean that the wind can whistle straight though where there is a gap, or is drawing the heat out, where the inner skin is sound.

      As to insulation, when we first came it was zero, as work has progressed I’ve fitted insulation between all floors, this is now starting to show results, But to the original question, I’ve found that here it pays to have the heating on 24/7, and set at 20 day / 16 night. That way the heating is just ticking over, rather that the continual running for the morning / evening. This is then also balanced by having a wood burner, which is used to top up. The water is heated by electric, for that heats directly, rather than the oil which has to send hot water from one end of the house to the other.

      Just show, when I first moved in used the large open fire, and burnt a tonne of seasoned oak in 2 weeks, and was still frozen……

  13. We have a clever room thermostat which allows four timed temperature zones to be set. This allows us to leave the boiler on but set the thermostatic to e.g. 20C from 6.00 to 8.00, 15c between 8.00 and 16.00, then back to 20c until 10.00 then 12c until 6.00 when it starts over again. The time zones can be changed for any day of the week, although the temperature would be fixed. But this can be adjust at weekends, when we are both home, to extend the 20c time zone and shorten the 15c time. When we had a new boiler about six years ago the installer wasn’t aware such a thermostat existed *sigh*. It is possible to raise or reduce the setting at any time using + and – keys but the system will then return itself to the programmed settings at the next time zone. Also it is simpe to choose the ‘night’ setting when going away to prevent the house geeting too cold. Brilliant device. Ours is made by Drayton but there are others.

  14. We have an old barn with damp issues and no wall insulation, and a few draughty windows and doors. We re insulated the roof last winter and left the heating 24/7 for the first time and found it far cheaper. We have the heating on about 23 degrees when in the house and turn it down to 20 when out or in bed. Definitelt the best thing we have done, wished we’d had the nerve to try it 15 years ago when we moved here!

  15. our heating has been turned on 24/7 for the last 13 years, it only goes off when its serviced, it supports an underfloor heating system where instant changes to the slab temperature would not work by cycling the heating on and off, as the response time of the floor slabs is slow, this is though compensated for with an external temperture compensation, so the floor slab always runs at a temperature gverned by how cold it is outside.

    While we support a large house, the boiler used to run at around 4000 ltrs oil a year, 333 a month, the biggest issue has been the rise in the cost of oil, which we compensated for last ear with solar panels, this has now reduced the oil consumption down to 2200 ltrs a year, 183 ltrs amonth, with the heating still on 24/7.

    There can be nothing better than being able to go out and come back anytime to a warm house.

    Only problem now is there is not much we can do when theoil price rises furthercurrent, insulation having already exceeded the

  16. this is interesting! Im looking to find what leave the thermostat on while im away for 2 weeks.Im in a ground floor rented flat, which has a little damp, no double glazing,but significantly warmer than my last flat due to having 2 flats above, and adjoining wall to next door neighbours!

    i used to turn on when needed, but my bro suggested to keep it on low.I turn it down to 14/15 overnight, uop to 16 in morning, and 18 when its freezing outside!bit surprised how high a lot of you have it on!dont you wear clothes inside??! i get very hot if its 20, and hate being in shops where it feels positively balmy!but then again, im outside ALOT.

  17. I personally go for leaving the boiler on more than off particulalrly mid winter, the cold down and warn up of spring and autum is slightly differrent. My 25 years experince shows you wont save money by turning it off but you get way better value for what you cant avoid spending by feeling waymore comfortable overall. I have a very large detached with 21 radiators. What the blog above seems to be missing is a bit more emphasis on controls, these days you should include outside air compensation but as a benchmark remember turning the heating down by one degree reduces fuel consumption by 10%. Then the complicated physics of heat loss comes in and depends on the house. If the heat loss is bad you need to reduce to a temperature where its stops the core from cooling too much but the heat loss is minimised but the heating will respond far better if not heating from much colder. Imagine a tea pot with a jacket on initially you can feal the warth as the insuation is inadeqaute to keep all the heat in, but an hour later it would still be warm tea as it get to a lower temerature where there is virtually no heat loss out of the jacket.

  18. We are also living in a rented farmhouse with oil heating radiators, water and an Aga for cooking. We have just got through 500 litres in 3 weeks. We leave the heating on all day but off from about 11.30pm till 7.30am. Our thermostat is also set at 20. It is a very big house with 5 bedrooms – double glazed (old) but no cavity walls and an attic so no roof insulation. We have only been in a year so are still trying to work out the best way to be economical. I look after my 91 year old mother who is frail and has dementia so need the house warm. Any ideas?

    • Depending on length of tenancy definitely look further at roof insulation options – with an over 70 dependant could well be free depending on where you are – contact Energy Savings Trust.

  19. Thermostatic valves are the answer turn them down in the rooms you do not use or rooms requiring a lower temperature and leave the heating on 24/7 this will keep the latent heat within the walls and will not subject furniture or musical instruments to sudden changes of temperature or humidity which will cause damage.You can turn the boiler thermostat down slightly to prevent the open circuit radiator pushing out maximum heat making (usually the bathroom)to hot.Do not turn the boiler thermostat down to low as this will cause condensation inside the boiler flue ways and eventually corrode the boiler.Turn the boiler thermostat back up when you require a bath and back down when you have finished, you will still have tepid hot water for dishes etc.

  20. i thought we were using a lot, used 700 litres in 7 weeks, also live in an old 16c house but it is doubleg glazed and the loft is insulated, no room thermostat only radiator ones but dont have the boiler on high. I thought it was the boiler that was faulty, could just be the weather thats been very cold. Has anyone compared LPG usage to oil, have LPG cooker and was considering changing the boiler to LPG but have had differing views on how much it will save us if anything.

    • I had an lpg rayburnj for 10 years and when it leaked replaced it with oil, you use less oil I have 2 off 2000 litre fills of oil per year but with the lPG I used to have 3 2000 litres fills per year. I thnk it comes down to the density of the fuel and LPG is also dearer per litre.

  21. I have used about 350 litres since the beginning of dec (way more than usual) keeping a poorly insulated 4 bed detached farm house warm enough, 24/7 boiler on, keeping the house at 16 degrees, and topping up the solar hot water. I think that’s plenty warm enough, I am amazed how much people here spend, like Saira says, don’t people wear winter clothes??

  22. I have used 8-900 litres since September 2008 which was when we last had the tank filled. We have no gas where we live and had a woodburner installed in September 2008. Our boiler is a combi approx 15 years old. We only have the heating and hot water on for approx 3 hours in the evening so the house is warm when we get in. We don’t bother with heating or hot water in the morning as the heat bank in the boiler retains enough water for the morning and the house stays warm from the wood burner overnight. I’m lucky as I don’t pay for wood and the chimney breast warms our bedroom. I am amazed at how much oil people use. I would recommend a wood burner to anyone and no you don’t need a chimney as long as you have an outside wall to attach a flue.

  23. Heating is on continuous, electronic thermostat set at 18C, well insulated and leak free 60’s detached, recently replaced all the glass with a rated units, more comfort and no glass condensation resulted. When we first moved here 14 years ago we used 75-100 litres a week. Today we are using 30 a week and we still use the woodburner in winter but find it heats more of the house than it did Only been running the continuous setting for two years but saw a immediate reduction using this method, probably down from 60 to 45 ish litres a week.

  24. I live with my wife in a 16 month old, timber framed 3 bed house, about a 100 sq.m, with a Warmflow combi boiler. Keeping a regular check on our oil suggests we are using much less than I expected to keep the whole house heated – we’ve used somewhere in the region of 400 litres since last September when it was filled to the brim. We have a 1,500 litre tank and both the sonic sensor and the ‘dip stick’ show clearly there is still ¾ left in the tank.

    We keep the heating on 24/7, set to 15 degrees when we’re out or in bed, and 18 degrees when we’re in. The house is in an exposed location, but when all the snow was on the ground just the sun shining on the front of the house made the house amply warm during daylight hours and even into the early evening after sunset.

    Even in the really cold spell in January (my outside thermometer went off the scale – below minus 10 degrees – several times) the heating only clicked on for a few hours per day. With the current weather the boiler only appears to come on for a couple of hours maximum in the evening and then clicks itself off till the next evening.

    This compares to the last property we lived in which was a barn conversion of about half the size and we used 1,500 litres/year just to keep the temperature nearly comfortable. Mostly it was cold and the place suffered from damp.

    It’s all about insulation guys, but with double glazing make sure you are getting enough ventilation to keep the air fresh!

  25. with the high price for oil at the moment I am trying to delay filling up with oil. We have a 1900 litre tank and on the gauge in the house there are two lines left. I think when full there is about 8 lines but I am not sure. our new double skinned tank is a round shape looking at it and I am trying to work out – have we got a tiny bit of oil left at bottom of circle or is the tank flat at t he bottom and could it have quite a bit left? anyone got any thoughts ?

    • Just moved into old largeish farmhouse – 1000 litres lasted 5 weeks. Gulp. Last time we had a delivery the guy told me that the wireless gauges are notoriously inaccurate. He told me that they are always doing emergency deliveries to people who have run out and say “but the gauge said I still had some left” He told me you are better off using a stick!

      • well the bad news this morning is the gauge is down to one stroke which officially means empty. I can still see oil in the clear tube coming out from the tank but maybe I will try poking a stick in ! I think I will have to order a small amount today although it pains me to pay the price on offer at the moment . We have used a huge amount of oil over this cold spell to keep large barn reasonably comfortable. We didn’t even turn heating fully on until November and use woodburners 24/7 to keep chill off core of the house. I can’t help wondering if it would be cheaper to buy the kids fan heaters for their bedrooms just to take chill off in the morning and at bedtime rather than have heating on am and pm.

        • last week i made the mistake of running out of oil, the ball in the gauge hed stuck so i still thought i had some oil left, but clearly didnt as the boiler broke down.placed an emergency oil delivery(as it was snowing and had 2 babies needed to keep warm),delivered oil same day thankfully but boiler still wouldnt start so had to call someone out, turned out to be very very expensive to fix. so my advice to everyone out there, dont leave it too late to order your oil.i wont make that mistake again.

  26. Our rural 4-bedroom bungalow has double glazing, insulated cavity walls, 250mm loft insulation, sealed against drafts, etc. We leave the heating on 24 hrs but use a programmable thermostat set for lower temperatures at night (set for 14C night and 20 or 21C daytime). It never seems to need to come on at night and only runs when the house drops below the set temperature. Generally we use about 1600 litres of oil per year, depending on how cold it gets outdoors.

    We use a Worcester Danemoor 18/25 boiler 4 years old and running at 93.4% efficiency at last service (October).

    We can’t think of any additional way of improving insulation and get a reasonable pay-back period.

  27. hi moved into an old farmhouse on dec 1st last year and up to date have had 1700 litres in our tank.had loads of problems due to landlords incompetence up until jan 25th when it is meant to have been sorted out.we seem to be using about 16 litres a day.we are at our wits end house is 2 bedroomed fairly large and yes it is old.evryone tells us 500 litres should last about 3 months.short of robbing a a bank to cover costs what else can we is a grandee 50 boiler and the combi part has been un combied.

  28. i have a 2500litre plastic oil tank. had 2000litres delivered last week but gauge only shows half full. since having it delivered ive marked the gauge and its dropping by 10mm per day, is this about right or do you think ive got a leak. have it on 19degrees 8hours per day.

    dont want to call anyone out yet and pay high call out fees to check for any leaks(cant see any) just in case it is normal for it to drop that much?

    • Claire

      We use a similar amount of oil daily, if not more. When our metal tank began to leak we knew by the smell, but with a bonded plastic tank I don’t suppose it would be that obvious. I dont know much about the plastic tanks, but is there a way of looking into the outer shell through a hatch or something?

    • Claire

      It’s difficult to say if 10mm per day is good or bad without knowing the size, exposure and insulation of your house…….I assumed I had a leak initially with my tank but I’m just getting used to oil heating.

      One test for a leak would be to mark the level as the heating goes off and check it again some time later before it comes back on – if the level has dropped then you could reasonably assume you have a leak.

  29. For the last four years our central heating has been on all winter simply working from the roomstat. Set at 20deg evenings and down to 15 deg at bedtime through to the next evening. I have a large 5 bed house reasonably well insulated and a 14 year old boiler due for upgrade if the £400 grants come through for Scotland. Since August we have only used 1200 litres in this cold winter and expect the usual amount of 2200 litres for the full 12 months. It is far more economical to leave the heating on throughout the winter if you have reasonable insulation and a lot more comfortable.This also includes hot water throughout the year

  30. We moved into a 1988, oil heated, 4 bed, detatched house last year. Since then I have improved the loft insulation to about 200mm but I have no double glazing, no cavity wall insulation, no wood burner and the house is heated pretty much all day as we have two young kids. We do have well insulated hot water tank and TRV’s in every room that are used effectively to only heat the rooms we are using.

    For me, there are two ways of looking at this issue……..

    First – Experience:

    I have been tracking approximate daily oil use for the past 6 weeks and I can say (from my experience) that the amount of oil used is directly related to two factors.

    1. The length of time the heating is on.

    2. The outside temperature (and therefore the difference between in and out).

    I expect that the number of rooms we are heating also affects it but this pattern is fairly consistent and I don’t have sufficient, accruate data to compare.

    So if you want to save money, turn your heating off when you don’t need it.

    Second – Simple Science/Common Sense:

    For this I’m assuming the following;

    1. Every home “leaks” heat when it’s colder outside. The bigger the difference the faster the leak.

    2. Whether your boiler is working as efficienctly as possible is largely immaterial. It’s either burning oil or it’s not.

    3. You only need a “warm” house at certain times of the day/night.

    Whether or not you should leave the heating on is determined by the speed your house cools down and how long it is between warm periods. You could roughly establish the former by heating a room by say +5deg and then timing how quickly it cools back to original temp for a given outside difference.

    Example1: If your “leaking” takes 3 hours and you only need “warm” 6-8am in the morning and then 6-11pm in the evening. You are “wasting” heat put in between 8am and 3pm as this will have “leaked” before you get any benefit.

    Example2: If your leaking takes 4 hours and you pop out for an hour then you may as well leave your heating on as maintaining the temp will use about the same amount of energy as re-heating on your return.

    Example3: Overnight. I fail to see how it can be more efficient to leave heating on overnight. Assuming that even the best insulated homes will leak quicker than 8 hours and most people want a cool bedroom when sleeping then you will simply be heating rooms you are not using and all the early night heat will have leaked before you get up. Add to that the fact that it’s colder at night (so faster leaking) it just can’t be a good idea and the waste would outweigh any potential boiler “efficiency” benefits of running 24/7.

  31. I moved into a 3 bed 1970 built semi 18 months ago and naturally just set up the timer for 3hrs in morning and 5 hrs evening (stat at 19 or 20). Filled up 1000 litre tank on 6th Nov first year and had used 900ltrs by end of march. By chance filled up almosty exactly same time (8th Nov) last year and only after reading these posts and speaking to others took the gamble and change heating habits to on 24/7 (20 degrees day & 17.5 degrees while in bed). House has no cavity wall and orginal wooden double glazing that is leaky, still not got round to upgrading loft insulation so still vey poor approx 3cm left). Now end march and tank still has almost a quarter left in it after the so called coldest winter in 30yrs. House feels much more confortable and seemed to have used considerably less oil leaving it permenatly on 24hrs a day. Still cant work out all the physics behind it but the boiler spends much less time firing instead of almost constantly firing when it was on the timed periods. I’d say 24/7 give it a try, it seems to be working for me!

  32. For non-cavity walls look into SEMPATAP wall insulation – it’s like a thick wallpaper that’s applied to the interior of the outer walls, and can be painted or papered. We live in an elderly Swedish imported all-timber house and I reckon I’ve only survived the last two winters because of Sempatap. My floors are soon to be Sempafloor-ed.

  33. Leave heating on all the time? I’m impressed with these accounts, maybe I’ll try. I read the other day that we are very sensitive to the the temperatures of surfaces around us, so if walls, floors etc get cold we want more heat input, while if they are warm we want less. So if the heating is on 24/7 we will likely be happy with a lower temperature, which will save a lot of fuel. That might partly explain why it is fuel efficient. Insulation wins again.

    Since I read that, I have noticed that it seems to be true – if the house is warm I feel happy with an air temp of about 18 degC while if the room is cold I want more like 20 degC plus.

  34. I am in the process of renovation work on my house of 26 yrs.I have fitted a thermal store instead of my old water tank,fitting a wood burner with back boiler. The oil consumption is down by 50%. My next move is solar panels to bring the oil down to hopefully 0% during the summer and help out during the winter.Oil prices WILL continue to rise so we need to come away from oil only heating systems in the future.

    I believe that air to water heat pumps will be the replacement to oil boilers and can be powered by photovoltaic panels.The government to offering a deal to make these panels a interesting investment starting from April 10.

    If I decide to go down this path, if I can afford the set up costs, it would mean a negligible heating bill. Next question is can we afford not to investigate this technology. How much was your oil bill last year ?

  35. It is unfortunate that nearly all of these posts are from people without any understanding of thermodynamics but the two or three that do are right in saying it saves money to turn it off part or most of the day. The rest are just unreliable anecdotes to justify having the heat on for comfort. The weather varies so much that week to week variations in oil use (how do they measure that accurately without a flow meter?) will not answer this question.

    The laws of thermodynamics show that the amount of heat loss (and hence amount of oil burnt and cost incurred) depends on the difference between indoor and out door temperatures at any time if insulation and draft proofing remain the same. The only other factor will sometimes be windspeed. This is true whether you have good insulation or bad but obviously in the former case you will burn less oil in any particular circumstance.

    Say the temperature outside is 10C and you want to maintain 20C in downstairs rooms most of the time. You set the stat to 10. When the inside temp is 20 you will lose heat at a certain rate. If you turn the heating off for a few hours such as when you are at work or snug in your bed at night, the temp will after a while be 15 C and your heat loss will halve. When the heating comes on it will initially just have to warm the air in the house up to 20C which does not take very long (even in our poorly insulated leaky house it’s about 30 minutes) after which you will need to use enough to sustain that double rate of heat loss.

    If you are at home all day and don’t want to bundle up (I am wearing a sweater on 31 May!) then you may want the heating on occasionally and you can use the 1 hour button. Why on earth would you need the heating on when you are in bed unless it is raging cold outdoors? Set the stat to go off an hour or two before you go to bed and on again 30-60 minutes before you get up.

    You don’t actually need an excuse if you want to have the heat on all day if you can afford it but please don’t pretend it will save you money compared to being sensible – it’ll cost you and the planet more.

  36. Reply to:

    Simon Green May 31st, 2010 10:56 am

    Hi Simon

    Finally, another sensible post (see my Post 2/3/2010) using science and not emotion!!

    You make an interesting point regarding the accurate measurement of oil use. Throughout the winter I was taking daily cm readings from the sight on the tank and (whilst there were some strange readings) I was able to determin approx oil use relative to heating time and weather and saw that science prevailed.

    However, that was when I only had <500litres in the tank. Now I'm back up to 2000ltrs again the fluctuation of a few degrees in outside temp can cause the oil to expand/contract by up to +/- 1.5cms (i know because the heating is off) making any readings at this time of year (with minimal usage) impossible.

  37. I have a question! We have a boiler that services our house (Old, very large house with 40 radiators) The system that we have in place to turn the radiators on is a pump that we manually plug in or out that pumps hot water directly from a large hot water tank through the radiators and back again. I am wondering if it would be more efficient to leave the pump plugged in full time. When you unplug the pump and the radiators go cold you then have a huge volume of cold water that returns to the hot water tank once you re-plug the pump in a few hours later.This seems like a large strain on the system and maybe it would be better to keep the hot water circulating all the time…Any thoughts?!?

  38. We live in a 3 bed 1930s semi, original windows and we get a problem with the draught. We have our heating on first thing in the morning and in the evenings til about 7.30, then once the kids are in bed we get the real fire going and that keeps us toastie for the rest of the night.

    Can’t beat a real fire burning quality seasoned hardwood logs!

  39. My house is over 100 years old and due to the age I lose a lot of heat through the walls and flooring. Last year I got my roof insulated for the winter and I didn’t notice that I wasn’t losing a lot of heating. My husband and I work 9 – 5 and both are home around 6 – 6:30. I don’t have the heating on all of the time as it is a waste and it can be very expensive as I do end up having to pay for heat that escapes. I set my boiler to come on at 5 so when we wake up at 6 the house will be warm and the hot water for the shower will be warm up quicker. The heating goes off 8:30 when we leave and comes back on at 4:30 so when we are home it will be warm. I did hear that it can be cheaper to have your heating on all day then on and off as it can waste power and money with the system having to turn on and off at set times.

  40. I’ve recently moved into a large, stone built, farm house, constructed around 1910. The loft seems to be very well insulated, all windows double glazed and draft free etc I have just calculated that I am using an alarming 400litres of oil every 2 weeks! I find this very worrying and a lttle hard to believe, is it possible for a worcester heatslave combi to burn oil at this alarming rate? I’ve had a close look around the tank which is a modern bunded plastic version and no signs of leakage.

    On moving into the property approximately 2 months ago I had the boiler fully checked/serviced. I’m actually hoping that I do have a small leak on the tank as burning 800ltrs per month is rapidly becoming a major financial drain.

    • We have a Worcester with a heat-bank in a modern 5 bed house, admittedly we have a few leaks however we are burning 1000L a month in Dec type weather. It comes with the territory Four/Five years ago – when we rebuilt – Oil was less than 25p a litre. We burn 6000L a year so annual cost of £1500 not too bad. current price of 69p £4130 per year – bang goes the summer holiday, the new clothes, and even the food shopping has seen a credible impact. Thermostats are down thermal undies on and the local trees are quaking in their roots.

    • 800 ltrs per month, not that outrageous considering the really cold weather we’ve had lately. My place is reasonably large, reasonably well insulated although solid wall construction and we were using around 20-25 litres per day in the coldest spell in December. We don’t have a combi though and it’s a pretty inefficient old boiler. If you really want to know if you’ve got a leak, turn the boiler off for a day or so and see if the level still drops…

      • i had 1000ltrs delivered 12/01/11 when we ran out of oil over the coldest days at xmas , had to wait as the depot had run out themselves at that point.( left some in so it didnt suck up sludge in older iron tank ) after new load i hadnt checked for a few weeks the level , when i did it was 3/4 full then it got milder put it back to twice a day only and at 18-20 on dial sometimes less when log fire going or during day none at all. then i found this tues. 7/02 1 day short of 4 weeks- since last delivery ( costing £635.25 ) i had COMPLETELY RUN OUT AGAIN ! i phoned a boiler servicer, noting new filter fitted by prev. owners 2009 he said on 7 rads- old or new- AND the use of a log burner- there was NO WAY i can have used up that ammount – he said if i had a leak ( tube to boiler thru garage ,not under concrete ) i would know about it as would be swimming in it. He recons its been stolen. Look on the web police blogs – it is happening everywhere . keep tabs on what your using- i’m not filling up again until i have a padlock on lid etc. luckily i have electric as an option. theres no way electric is going to cost me £160 week like this last load has done !!!???? i’m sitting here with a coat on- not intending to fill up at least until March the theiving bar stuards can go freeze . i was born in a council house with a coal fire and crittall windows – i’ll survive ! hot water bottles are my only needs around here from now on until spring , to save some of our money back…

  41. We have a small 3 deb end of terrace brick house with double glazed windows. We used 500 litres in just over two months, we only have the heating on for 2 hours in the morning, mainly to heat the water and then for a few hours in the evening. I think this is going very quickly, the radiators are old and constantly need bleeding, do you think there is a major problem with the system or is it normal to use this much??

  42. last year i was only putting the heating on when the house went cold and this used up a lot of oil,

    i was told it takes more oil to heat the house from cold,

    so i was advised to leave the heating on continues and the thermostat between 15 & 20 in the day and 10 at night that way it uses less oil to heat the house as its not working on a very cold house,

    i only started this in jan last year and i also only had a small amount of oil left but this worked as it got me through,

  43. I recently started working for Scottish power and there seems to be a lot of confusion when it comes to heating costs. It is not wise to have your heating on all the time regardless of the temp. Really what you want to do is have it on as little as possible and at the lowest heat that you are comfortable with. Turning your temp down just 1 degree does make a difference, not a huge one but a difference in the long run. Try using draft excluders and have doors and windows closed to keep the heat in. Call your energy supplier and make sure your on the cheapest option available and they can even give you an energy efficiency no which will give lots of advice on how to reduce your costs. Hope this helps!

  44. Detached 2 bed well insulated bungalow. 15 year old boiler thermo rad valves on 7 rads. We are working class pensioners, not rich but comfortable. Home all day most days. In recent hard winters if living room temp 18 c or < we put heating on for 1 hour first thing.( If temp above that we don't) Then 1 hr boost again lunch time unless temp above 19 c. Main heating on from 15:30 to 19:30. (Temp gets up to about 22 c) Bedtime after 22:30, room temp still comfortable.We use oil all summer for hot water & we prefer baths to showers. We use approx 1200 litres P.A.

  45. I have been pondering the question on whether to leave the heating on all day or once in the morning and once in the evening.

    I have always taken my meter readings regularly, so have a very good record of Gas usage throughout the year. I have been doing a trial for the past month taking readings every day.

    My house is 4 bedrooms, cavity wall insulated and 12″ insulation in the loft. So what are the results, Taking into account that the last month has been warmer than November in the last 2 years, I have found that the usage has reduced by about 25%, even on the few near Zero days that we have had it only uses 8 units, I would have expected 10+ units going on past readings of similar days when the house was not heated from 11 am to 6 pm. We also have thermostatic controls on every radiator, set to the temperature required in each room. The boiler thermostat is in the hall, set to 21 Deg. The radiator thermostat in the hall is set to number 3, whatever that means in degrees.

    I will continue this trial throughout the winter to see if it really makes a difference in the long term.

  46. Anyone who doesn’t receive emails from MSE might find some answers to this discussion here.

  47. I have a combi boiler, which I keep switched on constantly during the winter, with water on the eco setting. There is separate general thermostat for central heating, which I rarely turn up higher than 10 when I am in or 5 when I am out.

    This seems fairly effective from a cost point of view, combined with double glazing and insulation, and prevents the temperature of the house from dropping too low at night, when it is colder outside. If I am cold, I can always have a quick burst of 15 and/or put on extra clothes.

    Should I try a different plan?

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