On average each hour the system will use 1kWh to maintain a comfortable temperature. Every 10 hours the system will use 5kWh to bring the temperature from 15C to 20C and over the course of 10 hours the temperature will drop back down to 15C. On average each hour the system will use 0. Someone finally explains this in great detail.

Absolute nonsense, spouted by an idiot who thinks they are a genius! I think some people are confusing efficiency with cost.

In my own newbuild home, I find that the boiler works to replace heat infrequently because heat loss is low. Insulation is high. However if I go out for a week and I always turn down the stat when I do this the temperature can drop down as low as 12C before I return — it takes a lot of energy to bring this back up to 20C when I do return.

There are also other factors while the house is occupied. Using cooking appliances particularly can work to increase the ambient temperature of an area, reducing the demand on the boiler from the thermostat. Perhaps I should add that my thermostats are set to 16 constantly, unless I feel particularly cold when I boost it higher, but I find my gas bills are low.

I find the boiler can spend a good few hours bringing the temperature up from 12 to 16, but only comes on 6 or so times a day for less than an hour in total to maintain the temperature. I think scientifically it takes more energy to increase a temperature than it does to maintain a temperature….

Something to do with the specific heat capacity of a given substance. I certainly agree that an older house or a less well insulated one would lose heat at a rate higher than my own, and therefore running the heating constantly may prove costly.

Older type well insulated Homes have solid internal walls, these act as massive thermal stores, in long cold external temperatures keeping the temp buffer stable, therefor continuous heating of a slightly lower than required and boost when the home is occupied Stove is most efficient, stops lots of cycling of central heating systems. The idea that using heat now can save on heat later literally goes against the first law of thermodynamics.

The simplest way to explain this is by using a leaky bucket as a metaphor for your house. You can keep it topped up full; you can keep it topped up to a lower level reducing the rate of loss ; or you can let it empty completely stopping the loss entirely. If you allow it to empty completely before filling it back up when needed, this simply cannot use more water than keeping it topped up to a low level the entire time. The amount of insulation is exactly the same as the size of the leak. A smaller leak will lose less water over time but the principle remains the same as a larger leak.

Been there, done it. We had LPG when first married. Our bungalow was over insulated if there can be such a thing — we built the property ourselves and put rock wool under the voided floor, hanging the insulation in netting between the floor joists, but still keeping a void, super insulated the loft and used insulated blocks for the inner walls. For a week we put the heating on constant, but at a low temperature and boosted it for an hour when we came home. The following week, in very similar weather conditions, we put the heating on timed — 2 hours am and pm.

We took meter readings at the beginning and end of each week and found that leaving it on a low setting constantly was more economical. A building in the heating season losses heat at a rate that depends on the difference between inside and outside temperature. Remember your first day in science? Heat goes to cold? If you heat a house to above the outside temperature you lose heat.

It is called heat loss for a reason. That is energy. You have to replace it if you want to maintain the temperature. Next, when does your boiler operate most efficiently? When it has the coldest return temperature i. This is because the boiler then gives back the latent heat component of the flue gas heat and hence you see plumes of condensation coming out your flue. If you have an old house, put the thermostat on a reduced temperature to protect the fabric against condensation while you are away especially if unoccupied for a long time.

Would you keep a kettle boiling all day because you think it will be cheaper than heating it up everytime you want a cuppa? Would you leave your car running overnight so it was nice and toasty for the drive to work in the morning because it is better to keep it hot than warm it up each day?

You know you are wrong to all those who continue the myth and to those realising this misguided direction do not follow, stop them with the above simple and accurate statement.

I just read there were a lot more comments on this as I was about to post. There are obviously still too many people that think they are educated in this state but have no idea of fundamentals. I appreciate that electricity is more expensive, but we are considering buying a retirement home part of a converted stable block well insulated, but with only electric Underfloor heating.

No figures available for annual running costs. Thanks for posting about the Energy Efficient Boilers that help to maintain the thermal effect. Its really helpful. What do you think in that situatiod? Regards, Mike OR. Do you mean to say that in this example, there is no energy saving when the house is only heated when needed?

WC constantly adjusts the boiler flow temperature to the outdoor temperature and, if set correctly, can exactly match the heat loss of the building in all temperatures. Catch-up requires a boiler to exceed the building heat loss. Therefore, you can either a run WC; or b run set-back. Plus, as the temperature is constant, most people are able to set it around 1C lower than intermittent heating, as the fabric of the building and furniture are also already warm.

Is intermittent heating more efficient than continuous when running WC? Sorry this artical is wrong. It is always more energy efficient to use the heating when it is required.

So time clock with a room thermostate is best in every case. I can show the maths! I have also see the test data. To run a system all the tume will be more efficent on the system but will still cost you more! To run a system all the time will be more efficent on the system but will still cost you more! Unless maybe its only off for an hour a day. Insulation is key though so a lot of this artical is good.

Check out bri website for accurate info. Definitely worth it on external walls as they tend to leech heat, but also generally a good idea for party walls too! They easily pay for themselves over their lifetime. We have a constant boiler and at this present time the boiler needs firing up manually at least twice a day if the boiler is turned off.

Will it be ok if we turn the radiators off and thermostat down and still enable the boiler to come on in order that we have hot water. Will this still waste money? I wanted to find out about heating my water. This article only talks about central heating. I think that since the rate of cooling of a house is greater when hot more heat is lost if the heating remains on rather than turning it off. We have a elm LeBlanc gas boiler that Heats radiators and water.

The boiler is 17 years old and is no problem. Will it need to be replaced for safety. I had an old Leblanc boiler in a lettings house many moons ago and it was replaced with a Potterton Profile and more recently with a condensing boiler which they all are now and can recommend the Baxi Potterton which has a long guarantee and easy to fit and service etc Plumbers also recommend Ideal Vogue I enjoy one in my home and rather dearer the Worcester Bosch Greenstar and Vaillant Ecotech or Viessman boilers.

One will have to set the thermostat to high the max they want the room heated to. Set too low and the house feels cold, Thermostat could be a life saver if the house is too hot like the bedroom. My house has no thermostat inside and one morning woke up with my tongue sticking to the roof of my mouth, it all do the radiator was on full black during the summer, my bedroom door was closed, I live alone.

Think I am lucky I lived!!!! You could cover this on your page too feel free to share my story. It will be more cost-effective to heat the home as and when you need it, as any heat you generate will be lost fairly quickly through the walls, so if you try and maintain that warmer temperature all the time, your boiler is going to have worked incredibly hard. Interesting approach but you are not taking into account the moisture content of air in the property. Warm air holds a lot of moisture, and when the heating goes off, it condenses.

In an old solid walled property, it is ESSENTIAL that the fabric temperature does not drop below dew point or you will experience damp problemsx — interstitial condensation in walls for eg, and mould. You NEED to keep walls above dew point — which for an average home in winter is going to be 10 degrees or more. You can set your thermostat to its minimum temperature before you go to bed in the evening.

You can set the on and off times for every day of the week. So, you can set it to switch off at, say, 11 p. The timer will override the thermostat, so even if the temperature drops below the setting you have it on, the heating will not switch on. The timer and the thermostat should not affect the preheating process or a combi-boiler, however.

This is completely normal, and is there to ensure you have hot water when you turn it on. One final thing to consider is the presence of an immersion heater in your system or heat-only cylinder. Why would you do that? It is cheaper and more energy-efficient to switch your boiler on, only when you need the hot water. Bear in mind that your results may differ slightly. The better insulated your tank, the lower the cost will be to keep your water warm for longer. And the amount you save or spend will depend on how much you pay per unit.

Take a look at your latest energy bill to see how much you pay for gas. You can, but it will cost you more. Once your water reaches a certain temperature, the water heater will turn off.

It will turn back on again when the water cools. It will do this all through the day. Notify me of follow-up comments by email. Notify me of new posts by email. This site uses Akismet to reduce spam. Learn how your comment data is processed. Great experiment and thank you! I've wondered this fora couple years. I have moved to a new property that does not have a combi-boiler and have to turn on hot water as and when I need it. For more read our wall insulation guide.

Even if you don't opt for insulation, there are still small changes you can make around the home to improve energy efficiency. Draught proofing is the most basic, and consists of filling any gaps around the edge of doors and windows, but also extends to chimneys and letterboxes for example.

The best thing about draught proofing is that it's incredibly cheap to install and you can do it yourself. Expanding foam for example can be picked up in almost any DIY store and can quickly seal gaps around windows. The other obvious source of heat loss is your windows, but again the solution is easy.

While double-glazing will save a lot of energy in the long run, it's also expensive to install. However, you can also minimise heat loss by closing curtains when the temperature drops and opening them when the sun's out.

Likewise, insulating covers inside curtains can help reflect even more heat. If you're looking for other ways to save on your energy costs, be sure to run an energy comparison. It only takes a few minutes and you could save hundreds off your energy bills — without touching that thermostat.