AIBU to want to make sure everyone knows this information to help save on their gas bill?

[PuzzledObserver]

Maybe too late for this winter, but it will stand you in good stead for next.

Most modern boilers don’t reach the efficiency promised because the flow temperature is set too high. I turned ours down in December, the house is still warm, and we cut our gas usage noticeably. Maybe 10%. You may need to experiment to find the optimum setting for your house, but significant savings are possible.

www.theheatinghub.co.uk/articles/turn-down-the-boiler-flow-temperature

Ooh I didn't know that! Nice one, OP.

Superstar!

We did this just before Christmas and we have saved about 5% on what our gas bill would probably have been otherwise without noticing much difference. (Suggested by our energy supplier, Octopus, and they have tracker our usage as part of the winter saving campaign they ran.)

That might explain why our gas usage has been less this winter - we do have the 'optimum' mark at around 2/3rd of the dial (I always wondered what it meant) but unless it's very cold outside, I have taken to turning the dial to around the 1/2 point. I now understand - thanks to that article - that effectively I have reduced the flow temperature which has reduced gas consumption. We haven't really noticed any difference in the temperature of the house, so it's all good!

Ah, after reading a similar article on here I think I’d turned mine too low. Put it back to where the “e” is - which I think means efficiency.

Thanks!

Thanks for this. We had a new boiler last year and it was sitting at 65, I've reduced it to 55. Will see what happens.

Thanks OP!

Ours has been on about 50c for years....and hot water lower....never run it at full temp....

Makes a huge difference. Many people have their boilers too hot so there is no condensation.

For real efficiency you can fit a temperature compensation kit to some which allows the boiler to run at the lowest possible flow temperature whist maintaining thermostat temp.

On ours I have a thermometer on the return pipe and aim for a return of 40-45. (Condensing stops at 55)

@Wherearemymarbles so how do you use this….. adjust the flow temp until the return temp is at the ideal level, I assume? Do you need to tweak it if it gets very cold outside?

I feel like there was a thread about this recently and you need to be careful. Under 60 degrees and you put yourself at risk of legionella’s

@blueberryporridge

We did this just before Christmas and we have saved about 5% on what our gas bill would probably have been otherwise without noticing much difference. (Suggested by our energy supplier, Octopus, and they have tracker our usage as part of the winter saving campaign they ran.)

I heard about this via Octopus too.

I think our target was set too low (first winter in new house) - 1 week in to the challenge we were apparently 10% over target and after 2 weeks it was 20%!! I then reduced the flow temp, and our usage started to fall. By the end we were 6% over, but that’s a lot better than 20%, and I imagine that would have risen further if we hadn’t taken action.

A combi drops about 20 degrees from out flow temp to return temp (of ideally 50-55 degrees for full condensing efficiency.

So 65-70 flow temp and 55 for hot water (which also saves water if on a meter because you aren’t adding much, if any extra cold to cool it down. If your hot water is too hot to stick your hand in without adding cold then it’s too bloody hot!
It’s also amazing how many people think that whacking the heating up to over 22 degrees makes it warm up faster 🙄 (looking at you DD).
Setting the boiler too low is bad because it then ‘cycles’ more frequently, using more power and causing more wear and tear.

@SixteenTwelve

I feel like there was a thread about this recently and you need to be careful. Under 60 degrees and you put yourself at risk of legionella’s

If you're drinking your central heating water, you've definitely got bigger problems than legionellas.

@SixteenTwelve

I feel like there was a thread about this recently and you need to be careful. Under 60 degrees and you put yourself at risk of legionella’s

Only if you have a hot water tank - in that case, you turn it up to 60 for an hour or so once a fortnight and can then turn it down again.

With a combi boiler there is no risk of Legionella because the water is only heated when needed, there is no warm standing water to incubate legionella.

Changing the central heating flow temperature poses no risk because that water is sealed within the system, you’re not going to be exposed to it.

@SixteenTwelve

I feel like there was a thread about this recently and you need to be careful. Under 60 degrees and you put yourself at risk of legionella’s

Not on the central heating you won't, it's in a closed system.

We've got a compensated curve on our flow temperature so if it's warm outside, the flow temperature is low and if it's cold, it's hotter.

Basically yes. A modern system is designed to lose around 20 deg so a flow of 65 gives a return of 45.

But if the boiler is new but system old you can have problems as old boilers were designed to run with a flow of 80 and return 10 deg lower (to avoid condensation) As a result radiators were smaller so in a new boiler they cant dissipate enough heat to allow for condensation

When its very cold or i need hot water in a hurry i crank it up

@SixteenTwelve

I feel like there was a thread about this recently and you need to be careful. Under 60 degrees and you put yourself at risk of legionella’s

There was and I got quite excited about being able to save some money and then couldn't work out how to do it on my boiler

For a modern combi with a digital control panel, you can find youtube videos showing how to find your flow return temp, usually within the ‘set up’ or test settings.
DH is training to be a gas engineer 😉

Im a bit confused. I read an octupus article that said set the flow to 55 but another one says it should be 65?

We have a combi meter and I'm not getting the flow

We've turned out water temp down though (I get that!)

read righ to the end...if you have an older house (like mine) then the central heating pipework might be microbore and then this won't work.

@BorgQueen you seem to know something about this.

A combi drops about 20 degrees from out flow temp to return temp (of ideally 50-55 degrees for full condensing efficiency.

Are you saying the return temp should ideally be 50-55? If so, how do you respond to this section from the article I linked?

The correct temperature setting is 'as low as possible'. Boilers can commonly operate between 30-80°C flow temperatures. They start to reach their higher efficiency figures at 45°C flow temperature, but that can be too low for older properties.

Unless I’ve misunderstood, you’re suggesting 50-55 return temp for peak efficiency, and the article is implying 25??

Hi Op, flu gases condense below 55 so return needs to be below this and ideally below 50.
As I understand it most boilers dont become more efficient below about 45 return unless they are specially designed to run at very low temps in which case a return of 35 can give 97% efficiency .

In short a flow of 65 will give optimal efficiency im most cases.
Going colder of course uses less gas but takes longer to heat the house.

Temp compensation kit allows the boiler to run at different flow, ie 75 on a cold morning start up reducing to 50 once the house is warm.

I feel like I’m reading a foreign language looking at these posts! Am impressed with those that understand this.

Now I’m unsure what to do. Old cottage. Radiators (here when I moved in, how do I know if they’re micro-something?). New combination boiler fitted just over 12 months ago. I can’t wrap my head around the various posts, so not sure what to do.

I don’t expect anyone to explain, but if someone can point me to what to look for online then that would be great!