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

new_owner

howee wrote: »

Lol, your cheating though as you have the benefit of the log burner (I love em btw just don't look right in a modern house).

I am happy with gas bill £56 is per mth year round so not now. House is large 'ish' 4bed detached. So plenty of heat loss walls but all insulated!

You will have taller ceiling heights though so yes your doing well very well.

Yes cheating a little

Some of them look modern.. go on treat your self, its Christmas

sheffield_lad

new_owner wrote: »

Yes cheating a little

Some of them look modern.. go on treat your self, its Christmas

I would love to lol, saying that I do a lot of driving and seeing 'spare' wood on my travels would kill me or it would the wife when she saw it stacked at the back of the shed lol. I often visit old folk in their homes and find the house only heated via electric an sparingly yet they have a vase of flowers in the chimney breast!!!

I tell them they will never look back after having a wood burner but often they think its too much messing about when getting one and having it installed is easy.

Good luck with the bills (not that you need it lol),

Cardew

MacMickster wrote: »

So you don't consider comfort or preventing damp at all relevant?

It's all about the cost and the cost alone eh?

So turn your heating off for good. Beggar the comfort. Just save money! Surely that is the ultimate logic of your argument.

There is a difference between trying to save money and being miserly. Most people want to find the cheapest way to be comfortable when they are in their home, rather than turn it into a competition for who can put up with disconfort for longer.

You have completely missed the point that some of us are trying to make in this thread.

We are trying to convince people that the notion that it is cheaper to have the heating on 24/7 is wrong and attempting to give scenarios to prove that the laws of physics hold true.

From some years experience on MSE it is absolutely certain that any series of posts trying to explain an issue will get diverted. So my P.S. was an attempt do pre-empt distractions from the issue being discussed.

Of course nobody is suggesting that dampness and comfort are not an issue - I raised the subject of damp on the first page of this thread - and of course what is more convenient and comfortable is the major issue - more important for many than costs - who said otherwise?

The whole point is that comfort and convenience come at a cost!

patman99

Don't forget that by putting a sheet of tinfoil behind the radiators you refelct heat back into the room. Also, on a daytime TV program they proved using thermal imaging that a black radiator heats up quicker than a white radiator and it also dissipates the heat better as well.

Cardew

patman99 wrote: »

Don't forget that by putting a sheet of tinfoil behind the radiators you refelct heat back into the room. Also, on a daytime TV program they proved using thermal imaging that a black radiator heats up quicker than a white radiator and it also dissipates the heat better as well.

This is from the article by EST which is the subject of this thread.

Q. Would painting my radiators black help?


a. No. It's best to keep them the standard white, although the
difference is not huge. It's more important to insulate your walls to prevent
the heat leaking out of your home altogether.

There is another thread running about reflective panels behind radiators. There have been independent tests carried out on these panels and results endorsed by the EST.

If you have non-cavity walls and all radiators against those walls you could save between £3.50p and £6 a year. If, like most of us, you have cavity insulated walls the savings are negligble - perhaps a few pence per year.

flashnazia

MacMickster wrote: »

So you don't consider comfort or preventing damp at all relevant?

It's all about the cost and the cost alone eh?

So turn your heating off for good. Beggar the comfort. Just save money! Surely that is the ultimate logic of your argument.

There is a difference between trying to save money and being miserly. Most people want to find the cheapest way to be comfortable when they are in their home, rather than turn it into a competition for who can put up with disconfort for longer.

Sigh. Yes it is that time of year again. Yawn

'Damp' and 'comfort' are red herrings. The argument in these threads (of which there are many) is whether or not keeping heating on all day is cheaper. It's not.

When the 'it's cheaper' camp start losing the argument that's when the red herrings start flying about: 'oh but it reduces damp, life's too short to be cold, etc etc'.

:rotfl:

hamletp1g

grahamc2003 wrote: »

No, a few here aren't oblivious to boiler efficiency

Boiler efficiency will increase with a lower return temperature, and that further adds to the case of it being cheaper to turn heating on only as required (i.e. heating from cold) rather than all the time (with a higher return temperature).

If the reverse were the case, then there may be some regimes where you could possibly arrange for heating on all the time toi be cheaper than on when required (i.e. the boiler efficiency more than compensating for the extra heat loss) - but it isn't, so will always act to make constant heating even more expensive (i.e. you suffer the extra heat loss and a loss due to lower boiler efficiency).

I cant fault the supposition that maintaining a given temperature 24/7 is the most costly way of running CH, but given that in my case that amounts to an increase of 5 pc on my heating bill I dont see any reason to change.

I dont think boiler efficiency is anything to do with lower return temp or turning it on and off as required, I thought it was the ratio of power in to power out. But no matter, every CH system will have an optimum way to be run, its just a matter of finding it.

maxmiler

Cardew wrote: »

Firstly there are two types of Air Source Heat Pumps(ASHP)

You appear to have an Air to Air ASHP. The vast majority of ASHPs in UK fitted are Air to Water(Mitsubishi Ecodan etc) and can cost in excess of £10,000.

I am afraid your estimate of 2.5kW output from 360watt is simply impossible. The 'gain' from a heat pump is given by its COP(Co-efficient Of Performance). e.g. an input of 1kW giving an output of 3kW would have a COP = 3.0.

As the outside air gets colder the COP falls. To get an annual average COP of 3.0 is good, your figures suggest a COP of 6.94 which no company would dare to claim.

There are several threads on ASHPs in MSE and there are many problems with both types. Noise and units icing up are but two. I suggest anyone considering an ASHP reads these threads.

Lastly whilst a correctly operating ASHP can offer savings for oil and LPG users, all of the independent advice is don't bother if you have gas.

Couldn't agree more. My son has a 11kW Yutaki ASHP in the large church he has recently converted into a house (no gas in the village). The level of insulation is extremely high and he has a mechanical ventilation system that recovers most of the heat from the exhaust air. I have yet to fit a meter to the ASHP to accurately measure the COP, but in summer looking at the electric meter it was about 5 and this winter for the last cold month it has been about 2 (again using the incoming meter readings). We expect it to be about 1.75 or so for the next 3 months.
We reckon that the running cost will work out about the same as gas over the year, but of course that doesn't account for the installation cost. I haven't pried into his costs, but I think it was well over £8,000 to install not counting the radiators and rad circuit which we did (it is a big building).
We concluded that a ASHP was only viable if you are not on mains gas (or have a massive amount of PV on the roof).

Cardew

hamletp1g wrote: »

I cant fault the supposition that maintaining a given temperature 24/7 is the most costly way of running CH, but given that in my case that amounts to an increase of 5 pc on my heating bill I dont see any reason to change.

I dont think boiler efficiency is anything to do with lower return temp or turning it on and off as required, I thought it was the ratio of power in to power out. But no matter, every CH system will have an optimum way to be run, its just a matter of finding it.

Quantifing the penalty for 24/7 heating will vary hugely from one property to another, and also on the lifestyle of the occupants(out at work/in all day etc)

On condensing boilers the return water temperature certainly affects boiler efficiency. They need a low water temperature to remain in 'condensing mode'

The 90%+ efficiencies quoted for modern boilers are considered by some to be like car manufacturer's miles per gallon figures.

terry2

Well the original query the energy trust was replying too was probably wrong, what they should be comparing is the cost of having the heating on all the time at a constant comfortable lower temperature.

There have been lots of posts saying "heating on all the time" has to be more expensive. Well this would be true IF you kept the heating on with the same thermostat setting, but in fact you don't.

In my case (house built in the 60s with insulated walls and loft insulation and TRVs on radiators), I did lots of measurements of difference in temperatures (inside and out) compared with gas usage, for various conditions.

If I had the heating on twice a day then I needed to set the house thermostat at 20C to feel comfortable. If I left the thermostat at 20C and left the heating on all the time, then gas usage went up by 10% (BUT it took 48hrs for the house temperatures to stabilise before the usage was meaningful). However the house felt too hot at 20C 24hr. Dropping the temperature to 19C 24hr reduced the gas usage back to the original value; however the house still felt too hot. So I then tried 18C 24hr; in this state the gas usage was less than the original state (20C twice a day) and I still felt too hot. So I now run the house at 17C 24hr which still feels comfortable, and IS saving money.

So, being an experimental physicist and not a theoretician, I will continue to believe the measurements, ie it is NOT a myth: for many houses having the heating on all day with the thermostat turned down a few degrees WILL save you money, but note that after any change it will probably take the house some days to stabilise before you can check the usage.
Note that if you have an uninsulated house then this may well not be the case.