Energy myth-busting: Is it cheaper to have heating on all day?

victor2

Mister_G wrote: »

Are you sure? - they appear to have MSE's blessing

jk0 wrote: »

Oh, well that's all right then. Let them spam away.

With a link to their own website in the first line of their post too.
Summer does appear to be over though, so it's tradition for this thread to rise from the ashes once more...

Richie-from-the-Boro

Given that farIR is all the same I too found out surprising that with the amount of Fischer Future Heat ASA adjuctions that went against them it's a risky marketing reference to domestic IR.

Theres no 13a supply to ceilings so their correct statement that panels are best mounted on ceilings, would lead to an expensive rewire requirements is a risky marketing reference to domestic IR.

1+6

Rockersandrew

Good article. Just a couple of observations.
Before work/school we turn the heat on about half an hour before we wake up. Then it turns off about 15 minutes after. There is then enough heat in the house until we all leave plus the combination of breakfast and people keep it warm till we leave.
Again, when we come home, we turn the heating on about 15 mins before the first arrive home, then it goes off at about 7:30pm. There is still plenty of heat from cooking, people etc to last for the day.
Weekends and days off are similar though if the temperature does drop, we would turn the heating on till about noon. After that it can revert back to a typical afternoon/evening pattern.


Plus, in the UK with our damp climate, I cannot sing the praises of dehumidifiers enough. These have transformed our Victorian house so it is much more comfortable, and great for drying clothes. Personally I think every UK home and flat should have one as it also acts as a heat exchanger so the costs are offset by the heat it produces.

JerryBald

CPC recently circulated an email advert with the title "Get More with Energy Efficient Heating!" which was advertising electric heaters.

Pumping heat from under the ground is energy efficient. Recovering waste heat from other systems is energy efficient.
Power stations disposing of a great deal of ‘surplus’ heat in cooling towers - not to mention all the extra energy expended in mining, delivering and also pulverising raw materials for any coal-fired ones – is not.
Sure, electric heating doesn’t involve a hot gas-boiler flue warming up the outside air at the user’s premises. Instead, there’s a huge heat loss at the power station, usually warming up the air or the sea.
This is not a Tungsten-vs-Halogen debate either; this is about making heat. How you convert the electricity doesn’t make much difference. Very little energy is wasted in unwanted light, so all the energy consumed is converted to heat. So it's efficient at the user premises but not at the power-station, as suggested by the higher cost of electricity.

Discuss

zeupater

JerryBald wrote: »

CPC recently circulated an email advert with the title "Get More with Energy Efficient Heating!" which was advertising electric heaters.

Pumping heat from under the ground is energy efficient. Recovering waste heat from other systems is energy efficient.
Power stations disposing of a great deal of ‘surplus’ heat in cooling towers - not to mention all the extra energy expended in mining, delivering and also pulverising raw materials for any coal-fired ones – is not.
Sure, electric heating doesn’t involve a hot gas-boiler flue warming up the outside air at the user’s premises. Instead, there’s a huge heat loss at the power station, usually warming up the air or the sea.
This is not a Tungsten-vs-Halogen debate either; this is about making heat. How you convert the electricity doesn’t make much difference. Very little energy is wasted in unwanted light, so all the energy consumed is converted to heat. So it's efficient at the user premises but not at the power-station, as suggested by the higher cost of electricity.

Discuss

Hi

That's really far more suited to opening your own discussion thread than hijacking this long-running one, but the efficiency of resistance heating has already been the subject of many past exchanges, as has the climactic impact of one form of heating vs another! ... anyway, welcome to the forum ...

HTH
Z

jon_acers

notanewuser wrote: »

My FIL worked for British Gas as a heating engineer for 42 years and swears blind that it should just be left switched on with a thermostat at the temperature you want. He's a (very) tight northerner so I'd be surprised if this weren't the most cost effective option.

Sadly he didn't look at the British Gas website which says under other ways to save: 'Use your central heating timer (not the thermostat) to turn heating on and off.'

orrery

jon_acers wrote: »

Sadly he didn't look at the British Gas website which says under other ways to save: 'Use your central heating timer (not the thermostat) to turn heating on and off.'

Ironic that, seeing as that is how most timers do it now - by just setting a different temperature at different times.

malc_b

Cardew wrote: »

However well meaning, IMO this thread is in danger of spreading the wrong message to the majority of readers seeking advice on keeping energy costs as low as possible.

Whenever this statement is made we get posts advancing scenarios where it doesn't apply to a particular set of circumstances in a particular property.

All of these cases appear to be based on assumptions that savings in keeping a boiler in condensing mode are so great that they outweigh any other consideration. Yet they can't quantify those savings or indeed know exactly when a boiler is in condensing mode.

I have a new boiler with all the gizmos, including weather compensation, yet nowhere in the instructions, and talking to the design engineers at the factory, does it recommend keeping the heating on 24/7.

The basis for the advocates of heating constantly appears to be the assumption that heating a cold house means the boiler will not be in 'condensing mode'. Not true as far as I am concerned! A boiler modulates its output.

Sorry, but none of this factual. Of course it is possible to calculate this. Likewise it is possible to tell when a boiler is in condensing mode. The boiler modulating enables it to go into condensing mode IF the conditions are right. And the right conditions are NOT asking the boiler to put out max power.


The most efficient way to use a condensing boiler is to keep it in condensing mode. That means a cool return 55C is the commonly accepted figure. Just google "return water temperature for condensing boiler". This means cooler water coming out of the boiler (i.e. boiler is modulating to a lower power). Less heat into the house. Less efficient radiators.


Hence if you get up in a morning and then slam the heating on and up to max the boiler will NOT be condensing. Or if you come home and do that. The heating needs to be set to remain in condensing mode and then the time clock set to give enough time for the house to warm up. Modern clever controls do this, adjusting the start time depending on weather. Your clever controller will just ask you to set a temperature and time. It will decide when to turn the heating on.



What most people don't understand is that because of the thermal mass of a house there is very little difference between 24/24 or 16/24 or 4+6/24, etc.. The mass of the house averages its temperature over a day (different if you go away for a week of course). The energy saving timed to 24hr is 5-10%. That is comparable to the difference between condensing and non condensing. That's why some people say they find 24hr running cheaper. If fact there should be a better option between the two but you would need good controls to find that and I imagine only the extremes have been tested.


Most people have problems with the idea that the house energy need is so constant but if the house is still warmer than outside it is still leaking heat to outside. Where is that heat coming from? It is from the house structure and eventually you have to pay that heat back.

richardc1983

malc_b wrote: »

Sorry, but none of this factual. Of course it is possible to calculate this. Likewise it is possible to tell when a boiler is in condensing mode. The boiler modulating enables it to go into condensing mode IF the conditions are right. And the right conditions are NOT asking the boiler to put out max power.

The most efficient way to use a condensing boiler is to keep it in condensing mode. That means a cool return 55C is the commonly accepted figure. Just google "return water temperature for condensing boiler". This means cooler water coming out of the boiler (i.e. boiler is modulating to a lower power). Less heat into the house. Less efficient radiators.

Hence if you get up in a morning and then slam the heating on and up to max the boiler will NOT be condensing. Or if you come home and do that. The heating needs to be set to remain in condensing mode and then the time clock set to give enough time for the house to warm up. Modern clever controls do this, adjusting the start time depending on weather. Your clever controller will just ask you to set a temperature and time. It will decide when to turn the heating on.

What most people don't understand is that because of the thermal mass of a house there is very little difference between 24/24 or 16/24 or 4+6/24, etc.. The mass of the house averages its temperature over a day (different if you go away for a week of course). The energy saving timed to 24hr is 5-10%. That is comparable to the difference between condensing and non condensing. That's why some people say they find 24hr running cheaper. If fact there should be a better option between the two but you would need good controls to find that and I imagine only the extremes have been tested.

Most people have problems with the idea that the house energy need is so constant but if the house is still warmer than outside it is still leaking heat to outside. Where is that heat coming from? It is from the house structure and eventually you have to pay that heat back.

Some good points raised and I used to keep my older condensing boiler running 24/7 but with a lower flow temp of max say 40c set on the boiler dials, this was with a click on/off dial set at 19c for setback. The house would always stay warm even on colder days I maybe had to put it up half a degree to keep the rads on an evening as the thermostat would still cycle.

With my new Ideal Vogue opentherm boiler and Honeywell lyric controller it varies the flow temp based on the conditions, now for us we usually have it on at 21/22c in the evenings or when getting up and then set back to 18c. I have set a maximum flow rate on the boiler of 60c so that it can never request a higher flow temp than this meaning the boiler should be in condensing mode most of the time, the boiler says its in "Super Efficiency" mode 98% of its time.

I think what your saying is to leave it at 21/22c all the time or your choice of comfort temp all the time.

Now if we use the first method and have a night set back the house never drops below 18c, the boiler cannot modulate low enough to supply a low enough flow temp to keep the rads on so the burner will cycle a few times in the night. When I come home from work the boiler will have been on its optimised start by the controller so will be running at 60c flow and the return is usually 55c or below. As the evening goes on by 9pm the flow temp is running at between 45 & 50c and the thermostat says its at 21/22c. If I was to keep it at 21/22c I note that at this time of year the flow temp will probably keep at 45/50c to keep the house warm.

What I do note is that in the past when I kept the heating running at 19C 24/7 and then only increasing to 20c in the evenings, because the house had not got as cold we didn't have to have the comfort temp in the evenings set as high as the thermal mass of the house was already at a reasonable temperature.

The lower the comfort temp the lower the opentherm controller will keep the flow temp at as there is less heat needed to put into the house. I think 18c set back for us makes the house feel cold in the night, whereas 19c seems to be reasonable and if you wake up in the night it doesnt feel too cold. The house seems to recover quicker too when it is turned back up to the comfort temp. In fact 22c is usually too warm and we find its comfortable at 21c.

Alcorn60

Good Afternoon



All I can say is ! we have a dual zone system fitted with 9 cast iron radiators ,and 1 bathroom radiator and a small bathroom radiator in the downstairs toilet running on a Ideal Logic 30 Combi.



If on timed setting , i.e x 2 times a day 2 hrs in the morning and 2.5 hrs in the evening according to the smart metre it uses around £4.90 to £5.45 a day during cold weather period & includes average gas fire use, and hot water etc. Gas cost 0.450 kw on fixed tariff until 2021 best we could get at the moment .


If on daily program i.e (permanently On ) running under thermostat from 730am until 730pm smart metre initially shows it uses a lot of gas first thing to bring heating up to temperature but then boiler really reduces gas consumption & settles down once system hot and then just ticks over keeping it hot. around £4.80 to £5.00 a day max for heating, constantly 12 hrs. (again gas fire on low on an evening & shower water etc included.)

So my conclusion is very similar costings for a 12 hr warm house until bedtime .Vs twice a day timed with a cold spell between . As y wife and I are retired will take the warm all day .


Please note not technically minded, just tried and tested personal results. Merry Xmas all.



OH !!!!A good tip for radiating heat around large rooms from cast iron radiators, is to put x 2 USB CPU cooling fans at the back top of the radiator one either side ,plugged into a USB charger on a timer plug turns on when radiator up to temperature . they gently circulate the air around the room nicely with no noise. Completely hidden,pennies to buy,very cheap to run. Hope this helps