Energy saving by reducing water temperature

[^woody^]

And yet if the system is not balanced, the turning the flow temperature down theory goes out the window.

 

[JonathanM]

My room stat will call for heat until it's set temperature is reached. Reducing the water temperature in the radiators will mean the heating will be on for longer so no net saving. Am I missing something here. Are the laws of thermodynamics different for some systems?

I'm assuming you have a boiler that runs on mains gas?

The main reason people are told to reduce the water temperature, is that the lower the temperature the water comes back to the boiler, the more efficiently the boiler works. If the water comes back from the radiators below about 54C, you start to see bigger savings. That's because some of the flue gases starts to condense on the cold part of the heat exchanger (where the water enters after it returns from the radiators), and that puts a lot of heat back into the boiler, which otherwise would have been lost through the flue.

However, old boilers like yours were not designed to condense. The condensate is corrosive and it can quickly eat away the heat exchanger in your boiler.

The opposite is true with modern boilers. They are designed to condense as much as possible, and their internal parts, especially the heat exchanger, are made from materials which are resistant to the corrosion.

 

[DP]

In that case, you shouldn't run the boiler at low temperature. Doing so can cause the flue gases to condense, and because they are acidic, they can corrode your heat exchanger. On newer boilers, the heat exchangers are made from metals which are resistant to the acidic condensate.

Resistant perhaps but still succumb to acidic condensate Hence on average 10-12 year life expectancy for alloy heat exchangers

 

[gas112]

Resistant perhaps but still succumb to acidic condensate Hence on average 10-12 year life expectancy for alloy heat exchangers

Yep aluminium heat exchangers are renowned for blocking up condense traps and pipe work

 

[Brigadier]

Yes sorry never gave that a thought, mine is wireless.

View attachment 290476

20 degrees?
Someone's doing alright for themselves!

 

[jeds]

May be this would be better suited to the gas and heating forum but I thought I'd stick it here instead. Can someone explain how turning down the circulation water temperature on my system will save me money. My room stat will call for heat until it's set temperature is reached. Reducing the water temperature in the radiators will mean the heating will be on for longer so no net saving. Am I missing something here. Are the laws of thermodynamics different for some systems?

The advice is to reduce HW temperature of combi boilers. Nothing to do with CH temp.

 

[Trazor]

20 degrees?
Someone's doing alright for themselves!

Please remember this is a portable unit, we switch the whole house off, apart from the lounge and bathroom.

The thermostat is kept in the lounge.

 

[Brigadier]

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[Trazor]

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Here ends any coherent discussion.

 

[IT Minion]

Here ends any coherent discussion.

The implication is that you are well off as you can afford to heat to 20 degrees given current prices.

 

[Brigadier]

The implication is that you are well off as you can afford to heat to 20 degrees given current prices.

And, or was a light-hearted ribbing, to boot.

Apologies if you were / offended, @trazor

 

[Trazor]

The implication is that you are well off as you can afford to heat to 20 degrees given current prices.

I fully understood the implication, but not the joke Gif...????

I wish I was rich enough to run the house at 20C, but it's just 1 room at 20C and the bathroom warms to what it does.
I have found, with the in home display, that this is the cheapest way for 2 of us.
We like a cold bedroom, and a warm bed........

Not offended Brigadier, just seemed out of context...............All is good.

 

[gas112]

just turned mine down mrs thought she was having a hot flush currently room at 22.5 so turned it down to 20 .
Still got window open upstairs as hate a warm bedroom

 

[IT Minion]

just turned mine down mrs thought she was having a hot flush currently room at 22.5 so turned it down to 20 .
Still got window open upstairs as hate a warm bedroom

Do you not have TRVs? Or is it heat leaking from downstairs?

 

[gas112]

Do you not have TRVs? Or is it heat leaking from downstairs?

yep trvs on all the rads upstairs prob set about 3 but the window open is right by the bed and keeps bed nice and cold and once in bed the other window also gets opened regardless of how cold it is outside goose down and feather quilt is the order of the day