Most economic way to use CH.

[Big Tone]

Not specific to CH, per se, more of a science project or study perhaps. But I’ve found there’s more trolling on GD, sadly, so I hope this isn’t inappropriate here.

I’m not sure if this has been covered before, (I can’t see it anywhere or quite sure what search words to use), but now winter is here it’s about whether to turn the CH off during the day when you’re out or leave it on very low.

The argument falls into two camps: -

1) Yes, of course, you turn it off otherwise you are wasting heat all day in a room, or rooms, when no one is there.
2) No, of course not, otherwise you are having to heat up a room, or rooms, from stone cold, (literally bricks and all).

I’ve heard both sides from many people now who each believe they are right. The latest was from a guy at work who believes in #2). His reasoning, as explained to me, is “if you are in a car going somewhere you wouldn’t get the best MPG by accelerating, (heating up), and backing off, (cooling down), all the way. You would, however, from travelling at a more steady pace".

I’m not convinced that’s comparing like-with-like, but I’ve heard similar analogies. I figure someone, somewhere, must surely have done a definitive and conclusive study on this, and I figure if this isn’t the right or best place to find out I don’t know where is. Also, does it depend on whether your house is well insulated or not I wonder?

As I speak, (out all day), mine is set to 18.5c. I’ll turn it up to 21c when I get back home and then down again when I go to bed.

Thanks in advance and I hope this is helpful for not just for me but the many othes who are also faced with money difficulties and ever-rising energy bills...

 

[kbdiy]

I have experimented with this very same conundrum over the years and agree there are arguments for both options. However I have found that it is marginally more expensive (in terms of consumption and therefore hard cash) to run the heating all the time whilst varying the temperature setting to suit whether occupied or not.

Not a very scientific study I will admit and my house is well insulated - cavity 50mm and loft in excess of 400mm - but 1930's construction so plusses and minuses I guess. But at the end of the day CH is all about comfort - which we all have different perceptions of.

 

[paulc2]

I'd say the physics tells you that heat is lost to the environment via roof, walls and ground, and that the larger the temperature difference between the two, the larger the heat loss. Therefore when not needed, turn it off. Also, use the smallest room in the house practicable (or the least of >1 room) and turn it off in the other rooms. Depends how desparate you are to save money/heating bills, don't get too miserable trying not to use it etc.

 

[Big Tone]

Actually, I didn't think too deeply about it at the time but my friend's driving analogy falls down at the first post. It would be more like getting out of the car and it going along by itself with no one in it!

 

[ALEC1]

the point about a car looses validity because they are stopped so often..

efficient energy usage is related to occupancy rates of buildings..

boilers with compensation controls work more efficiently the lower the flow temperature...but you can only really acheive that with heating on for a good chunk of the day..

 

[Big Tone]

the point about a car looses validity because they are stopped so often..

Although I didn't mention it, he was thinking motorways. "Going to Manchester". That said, you're still right about being stopped so often these days (M6 north).

efficient energy usage is related to occupancy rates of buildings..

This is where it gets, (more), complicated. For instance, each human body gives off heat @ ~200 watts IIRC....?

boilers with compensation controls work more efficiently the lower the flow temperature...but you can only really acheive that with heating on for a good chunk of the day..

This sounds like you're for keeping it on low throughout the day Alec?

Also, not being a CH boffin, I didn't know until recently that condenser type combies are much more efficient. Is this another factor in the 'what's best to do' equation...?

 

[bazdaman]

As there are many factors to consider occupancy rates, comfort level insulation, system and controls etc, i always tell my customer to use it for a week turning off and on then a week keeping the house at a steady temp on constant and check usage at meter.

 

[Armo74]

I think apart from good system design and controls the key is to try and keep the heat in the house for as long as possible

 

[Big Tone]

As there are many factors to consider occupancy rates, comfort level insulation, system and controls etc, i always tell my customer to use it for a week turning off and on then a week keeping the house at a steady temp on constant and check usage at meter.

And their findings and/or feedback was....?

Oh, you're such a tease!

I think apart from good system design and controls the key is to try and keep the heat in the house for as long as possible

You're cut from the same cloth as Big Baz!

Come on, don't be mean to me. It's a serious question and this is a 'Forum' on which to put this old nugget to bed once and for all.

If it's too vague or unanswerable that's okay. Sometimes "nobody knows" is valid. (I watch QI)

 

[bazdaman]

Thats the whole point every property is different so the results will vary, so measure your usage and see whats best for you!

 

[Armo74]

I think it is quite a valid reply,
Poor system controls, whole house insulation and poor design= boiler having to be on more than it needs to leading to it being less efficient and inevitably higher fuel consumption and more costly bills.

 

[Big Tone]

Fair criticism Arno & respect mate.

Thats the whole point every property is different so the results will vary, so measure your usage and see whats best for you!

But most people have busy lives and need something to 'hang their coat on'. (Fair?)

My car is miss-firing? "Become a car mechanic"
I've got a rash. "Diagnose yourself and go to Boots"
I passed a weird looking stool today. "I hope you haven't brought it with you?"

Kidding aside, is there really nothing more substantial which could help someone, (lots of people I strongly suspect), than being all things in a world all too ready to rip us all off

What would non-savvy gran do when she's thinking "heat or eat" and I go in and say to her........? (Not an unreal situation for me BTW).

 

[bazdaman]

Shall i use my heating on timed or constant for efficiency? "Become a heating engineer and work out the heat loss calcs!"

 

[Big Tone]

With respect, and I say again, if the definitive answer is we dont know or there are so many variables "it depends" then fair enough.

So no general 'rules of thumb' or tests even in this area? I'm surprised, very surprised actually, given the magnitude of this very basic need.

 

[ALEC1]

well as a clue germany boilers have to use an outdoor sensor to help match heat load with heat loss...

not perfect but good.

around that has developed a whole technology to keep flow temperatures down and comfort levels up..

it doesn't involve turning the boiler on and off (cycling) it just aims to keep the boiler running in condensing mode as much as possible...