Can I have a definitive answer to "what is the cheapest - time switch or leaving the boiler on all the time" please?

[WhizzBangCaligula]

Is there a definitive answer?

Everyone's horrified that I'm leaving my boiler on all the time (just turning it down at night and up again in the morning) but I keep reading/ hearing that that is the cheapest. Then people look horrified and I get uneasy.

Who knows?

hm...these british heating systems are just a big mystery t me...now I know using the emertion heater is not a good idea, when you have a big watertank!
Anyway, we now have a combi boiler...and we have that on timer with the heating now, and in summer off altogether, but the setting is on water, which means it springs on everytime we use water....so...what would the score be at that...(btw, we have no watertank at all in our house, all comes from the mains of the street....)

hub i'm embarrassed to ask a question because you've probably already answered it but i've tried to read this thread a number of times and all i see is 'boiler radiator thermoszzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz'. it's too boring for my mind to tolerate.

but i do have a boiler question, in that mine does not have a thermostat in the hall. and the display on the boiler (new, combi) gives readings of, like 40 and 50 and so on rather than 21 degrees.

so where is my thermostat? i remember the engineer saying something about hte radiators or something like thatzzzzzzzzzzzzzzzzzzzzzzzzzzz. but i couldn't hear him because i was asleep.

caligula, how funny that you posted this, i was going to ask the same thing. still not 100% sure what the answer is as my stupid boiler doesn't sound like everyone else's. lucky that hub is a boiler jock, isn't it?

Crumbs, this makes answering questions about Windows PCs look positively thrilling.

3anm - immersion heater is a giant kettle = expensive to run. You DO need to leave a combi boiler on to do the 'sprint into action' for hot water. You are right to turn off the central heating button for Summer. The two systems operate independently IYSWIM, so this is not a problem. If you wanted to make your system more efficient you'd need to fit a thermostat, or even better, a programmable thermostat which will let you

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You emigrate.

Failing that, turn it down for when you're out rather than off, unless you're going to the Algarve for a week.

hth

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To answer your point about 'timer thing is that no good'...

No, it's great, it's better than manual control - you've already autoamted when it comes on and off - THAT'S PROGRESS...

but I imagine sometimes (on warm days) it's on as per the timer, but you think 'I don't really feel all that cold actually, I don't need the heating on' and conversely on particularly cold days you think 'Balls, I'm cold, I need to turn the boiler up'...

A thermostat automates that temperature control.

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ooh ooh ..... definately turn it off not down!!!!!!!

We had all electric in our previous house and was on a timer. Towards the end of our time there..the pin fell out of the timer clock...(oldyworldy timer I suspect)
Our electricity bill was astronomical!!!! The heating was on continously!
We moved two years ago..and have not long finished paying for the bloomin bill from the old house!
In our new house I am really careful...only use the heating when you need it...
I can only say this for electric..no idea about gas.

My friend and I had this conversation only last week as she left her heating on too...she now has to pay off the huge bill in installments....and now is when she needs the heating on more than ever!
She was under the impression that it took more energy to keep switching it on...but it appears that is not the case.
(IME)

oh...it is only the water that is heated by electric in our new house...the house is heated by a coal fire...but even so....I'm careful to only use it when we really need it.

Electric water heating = stupid expensive. Electric house heating = v. expensive. Leaving an electric system on all day = v. expensive. BUT a gas / water / rad system is a different kettle of fish.

Of course, it DOES use less gas when it's off (it uses none at all), but most people find that the saving if they switch it off when they go out, and the discomfort experienced when coming home to a cold house, and the incremental cost doesn't add up.

hth

Ah-I have a question Hub. We have a new gas condenser boiler (not combi) for both hot water and radiators. There is a thermostat on the hot water cylinder which it says should be set to at least 60 (otherwise there is risk of things like Legionnaires Disease growing apparently-according to the instructions) Fair enough.
But there is also a thermostat on the boiler which it says should be set to "between 60 and 80 degrees".How do you decide which setting is correct, given that the room thermostat controls the temperature of the house anyway? What diiference does it make what setting you have the boiler thermostat on?

am rofl at the thought of paying attention to the men in my house. certainly visiting men of a technical bent might be an idea... but dh is clueless about all things home-studly. we have mummy's tool box in our house, and daddy's lunch box.

we have two dials, though, one that controls the temp of the water and one that controls the heat of the water going into the rads. do you think our flashing lights numbers display refers to the rad water temp?

what would be the equivalent to a 18 on a normal thermostat, do you think? it's been quite cold up here in bonnie jockland so we've been keeping it on constantly at about 35-40. am i bad/stupid/a spendthrift? thanking you, hub...

Tiggi - for those without TRVs to control the temp of their rads, this 60 - 80 kind of does that IYSWIM. Also you might not like boiling hot radiators for safety reasons. But essentially, if you have it at a higher setting the rads / house will heat quicker than if you have it at a lower setting... but you're right, it'll be the stat in the hall which dictates overall house temp. So... it'll make no difference at all to the heat of the house, only how hot the rads get. Is that clear ?

H2O - LOL @ your boxes. I think your flashing lights is just a built-in Advent calendar. Honestly - I have no idea. Maybe it's flashing because it's a clock and you haven't set the timer ? !!! What number does it flash anyway, or am I supposed to guess ?

Can you advise what the 35 - 40 refers to ? Is it a percentage ? Sounds too low for rad circulating water temp tbh (usually 50+ degrees c).

I will reserve judgement on whether you are a bad, stupid, spendthrift when I am in receipt of full info. [wink ]

Thanks Hub-that makes sense . So which is best for economy-hotter radiators which heat the house quickly or less hot ones which heat it more slowly? Or does make any difference to the overall cost?

I would go for hotter tbh. Not so hot that they burn you (or children), but I imagine a much lower setting just means the gas is burning at a lower modulation and the pump is running for longer than if the boiler can give the house a decent blast and then have a bit of time off for good behaviour IYSWIM. Maybe about 2/3 of full power might be sensible ? hth

Sounds good-thanks again

This thread is going way ove rmy head.

Hub, those control thingies on the radiators. I have them on all but one. They are numbered * - 5. However, the radiators are only warm if the setting isd turned to 5, anything else and they are stone cold. Radiator in bathroon, which doesn't have a control on it is really hot.
Boiler has settings for control of hot water, set middle, water very hot. Also thermostat in living room, set at 20. heating and hot water is set to come on between 5.30 and 8am, and 4.30 and 11pm. We can have the water heating by itself, but iof we have heating on, we have to have hot water heating as well. Why's that - it means that when i'm at home with mindees during the day, and i put the heating on for an extra hour it heats up hot water as well. I don't understand how it works

Pull up a chair, saltire...

Your plumber did good, you should have TRVs on all but one rad (so sayeth the DIY books).

Warm on 5 is good. Not warm on anything else is bad. If that is the case it sounds like it might actually be an air block as the rad isn't heating up unless the TRV is more or less full open. When it's on 3 it should still get warm, just not as warm IYSWIM. I think you might need to bleed your rads.

The forced 'link' between hot water availability and heating on is somewhat daft, but some systems are designed like that. This is because to do it properly needs two pumps (one for each circuit) and possibly some clever (expensive) valves etc. and it is cheaper to cripple the boiler functionality somewhat.

hth

Oh, BTW EVERYBODY: I just spoke to my dad who is a far bigger boiler geek than me and he says he thinks you can keep the temperature of the water in the rad circuit (ie what Tiggiwinkle) was asking about low (I suggested 2/3 ish) and still be fine as apparently the minimum modulated output temperature is still really quite high IYSWIM. Further, he found that if it is too high the system hysteresis (tendency to go from house too cold > boiler on > house too hot > boiler off etc.) is worse than if it's at a lower level whereby the house feels more comfortable IYSWIM. I understand his point but am not 100% sure I agree. (Also his house has a bl00dy big old boiler and it's probably better running that at a lower setting all of the time than having it cycle on and off more often at a higher setting IYSWIM).

Sorry this is not the most thrilling thread in the universe.

I can't believe that there are 96 messages on a thread with boliers as its topic. ALthough I have to say that was drawn in to reading it through.

I think it should be called Boilernet.

Am determined to get this to 100 posts.

I can't believe it either. It sounds like most people's systems have the control sophistication of a Victorian Segway.

OK this is message number 99. And I've come up with a genuine question. Hub, if my boiler is turned right down and I am cold sitting in my office but when walking around the house it is reasonably warm, is it cheaper to turn the boiler up or turn on the electric convector heater which gets far too hot after 20 minutes so I have to turn it off again?

It might be cheaper to buy slippers or put on extra socks (if it's just your feet, I have the same ).

The rad in your office... is it bled, does it have a TRV ? (and if so is it on max) and if you don't have one you might want to consider checking the lockshield valve thingy at both ends is open to the max (when 'balancing a system' the heating engineer will throttle each rad 'just so' so the heatloss across each rad is consistent IYSWIM. It could be the office isn't quite perfectly balanced... (is it the furthest point from the boiler btw ?)

I think if you need your convector for just 20 minutes, and that sorts the room out so it's lovely, and you're happy there all day, that would be cheaper... but typically gas is far more cost-effective, and I'd consider trying to figure out why the office is not warm enough. You might need to move from a single to a double or triple rad (same physical size but more heat output as they are comprised of multiple panels on the inside IYSWIM).

OH-OH,

I have read all this (otherwise I have to do my filing, which is V V V V boring).

Just realised that when I got rid of our economy 7 electric 2 months ago, I forgot to switch off the timer that switches on the water overnight. So for 2 months our immersion heater has been heating the water.

I guess it would have been cheaper to turn it off completely, and just leave the hot water on the gas boiler permanently?

So my attempt to reduce my electric bills (cos we use masses of daytime electric), has come to nought.

b*gger