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

richardc1983

Northern_Wanderer said:

So, the manual for my Ideal Logic Boiler says not a lot about the eco/ economy setting, very helpful, indeed. It says to run the boiler in condensing mode you should set temp to eco mode or below but doesn't state a temperature for that setting.

Having now checked the boiler, economy setting is 70C so I've set it to 55C and let's see what happens tomorrow morning, it's pretty cold over night here just now and the house temp goes down to about 14C overnight (or did one night when I was up in the night).

My hot water is at 49C, has always been as I find it scalding above that and don't see the point heating water and then having to add cold water to a bath or dish bowl to cool it enough to use.

I'm aware that lowering the boiler temp will save gas but if I find the house slow to warm in the morning, should I just set the heating to go on half an hour earlier? Is that more efficient than turning the boiler temp up?

Thanks for the tips re condensing, didn't know anything about that although I was thinking to lower temp anyway.

I would not be turning it off overnight as the building mass will cool too much and then take a long time to warm back up. 

E.g if your comfort temp when the heating is on is 22c then try 18c overnight then 20c when you having the heating "on" 

Low and slow is the trick. Rather than off then low. If your house gets as low as 14c overnight it suggests low level of insulation. 

What temp do you find comfortable? 

Ultrasonic

richardc1983 said:

Northern_Wanderer said:

So, the manual for my Ideal Logic Boiler says not a lot about the eco/ economy setting, very helpful, indeed. It says to run the boiler in condensing mode you should set temp to eco mode or below but doesn't state a temperature for that setting.

Having now checked the boiler, economy setting is 70C so I've set it to 55C and let's see what happens tomorrow morning, it's pretty cold over night here just now and the house temp goes down to about 14C overnight (or did one night when I was up in the night).

My hot water is at 49C, has always been as I find it scalding above that and don't see the point heating water and then having to add cold water to a bath or dish bowl to cool it enough to use.

I'm aware that lowering the boiler temp will save gas but if I find the house slow to warm in the morning, should I just set the heating to go on half an hour earlier? Is that more efficient than turning the boiler temp up?

Thanks for the tips re condensing, didn't know anything about that although I was thinking to lower temp anyway.

I would not be turning it off overnight as the building mass will cool too much and then take a long time to warm back up. 

E.g if your comfort temp when the heating is on is 22c then try 18c overnight then 20c when you having the heating "on" 

Low and slow is the trick. Rather than off then low. If your house gets as low as 14c overnight it suggests low level of insulation. 

What temp do you find comfortable? 

My lounge temperature typically drops to around 14°C overnight at the moment, and is still a similar temperature when I've got home from work. What the morning temperature says about heat loss also depends on what temperature it started off at - in my case my lounge won't be above 18°C when I go to bed, and will often be a degree or two cooler.

I am not remotely convinced that heating should be left on overnight, even for people at home all day.

richardc1983

Ultrasonic said:

richardc1983 said:

Northern_Wanderer said:

So, the manual for my Ideal Logic Boiler says not a lot about the eco/ economy setting, very helpful, indeed. It says to run the boiler in condensing mode you should set temp to eco mode or below but doesn't state a temperature for that setting.

Having now checked the boiler, economy setting is 70C so I've set it to 55C and let's see what happens tomorrow morning, it's pretty cold over night here just now and the house temp goes down to about 14C overnight (or did one night when I was up in the night).

My hot water is at 49C, has always been as I find it scalding above that and don't see the point heating water and then having to add cold water to a bath or dish bowl to cool it enough to use.

I'm aware that lowering the boiler temp will save gas but if I find the house slow to warm in the morning, should I just set the heating to go on half an hour earlier? Is that more efficient than turning the boiler temp up?

Thanks for the tips re condensing, didn't know anything about that although I was thinking to lower temp anyway.

I would not be turning it off overnight as the building mass will cool too much and then take a long time to warm back up. 

E.g if your comfort temp when the heating is on is 22c then try 18c overnight then 20c when you having the heating "on" 

Low and slow is the trick. Rather than off then low. If your house gets as low as 14c overnight it suggests low level of insulation. 

What temp do you find comfortable? 

My lounge temperature typically drops to around 14°C overnight at the moment, and is still a similar temperature when I've got home from work. What the morning temperature says about heat loss also depends on what temperature it started off at - in my case my lounge won't be above 18°C when I go to bed, and will often be a degree or two cooler.

I am not remotely convinced that heating should be left on overnight, even for people at home all day.

If your lounge doesn't really recover at 70c flow temp then will be worse at 55c. I'd perhaps set to 16c night set back so the house isn't getting too cold and then maybe 18 or 19c when you are occupying it. It seems you prefer it cooler anyway. What do you set the thermostat too 

Ultrasonic

richardc1983 said:

Ultrasonic said:

richardc1983 said:

Northern_Wanderer said:

So, the manual for my Ideal Logic Boiler says not a lot about the eco/ economy setting, very helpful, indeed. It says to run the boiler in condensing mode you should set temp to eco mode or below but doesn't state a temperature for that setting.

Having now checked the boiler, economy setting is 70C so I've set it to 55C and let's see what happens tomorrow morning, it's pretty cold over night here just now and the house temp goes down to about 14C overnight (or did one night when I was up in the night).

My hot water is at 49C, has always been as I find it scalding above that and don't see the point heating water and then having to add cold water to a bath or dish bowl to cool it enough to use.

I'm aware that lowering the boiler temp will save gas but if I find the house slow to warm in the morning, should I just set the heating to go on half an hour earlier? Is that more efficient than turning the boiler temp up?

Thanks for the tips re condensing, didn't know anything about that although I was thinking to lower temp anyway.

I would not be turning it off overnight as the building mass will cool too much and then take a long time to warm back up. 

E.g if your comfort temp when the heating is on is 22c then try 18c overnight then 20c when you having the heating "on" 

Low and slow is the trick. Rather than off then low. If your house gets as low as 14c overnight it suggests low level of insulation. 

What temp do you find comfortable? 

My lounge temperature typically drops to around 14°C overnight at the moment, and is still a similar temperature when I've got home from work. What the morning temperature says about heat loss also depends on what temperature it started off at - in my case my lounge won't be above 18°C when I go to bed, and will often be a degree or two cooler.

I am not remotely convinced that heating should be left on overnight, even for people at home all day.

If your lounge doesn't really recover at 70c flow temp then will be worse at 55c. I'd perhaps set to 16c night set back so the house isn't getting too cold and then maybe 18 or 19c when you are occupying it. It seems you prefer it cooler anyway. What do you set the thermostat too 

I'm not sure what you mean by the part in bold?

I have though had the flow temperature for my heating set to 55°C from some point yesterday afternoon and this has been fine. Whether it would be sufficient if it was really cold outside I suppose I can't know right now, but as it stands I'll leave it there for the ~5% additional efficiency it may bring. Thanks for making me reassess this aspect  .

richardc1983

That's brilliant then if it's working for you. By recover I mean if the house drops in temperature  (whatever that may be) how long it takes to get back to a comfortable temperature for you. 

Ultrasonic

For context I used a total of 22.30 kWh of gas yesterday, and right now my IHD is showing 20.87 kWh for today (I won't be using any more gas now but I can't be certain if it's counted everything from today yet). These figures are whilst having the heating off overnight. Well, anti-frost mode I suppose but which means 5°C so it certainly didn't come on!

richardc1983

What's the weather been like where you are today. It's colder here tonight.. 

Ultrasonic

richardc1983 said:

What's the weather been like where you are today. It's colder here tonight.. 

I've not really been paying attention to the temperatures but I did put a warm hat on when walking into town after lunch. I live in Taunton by the way, and checking the forecast the overnight minimum is predicted to be 2°C.

Spies

Some data for you to mull over, outdoor temperature dropped to 4c, thermostat is in the living room and is set to 14c at 9:30pm, 18c at 10am and 19c at 5:30pm. 

Boiler flow temp was around 70c and I used a total of 46kwh of gas today (small amount used by hob). 

Graph attached to show temperature changes over time, I did have some solar gains from the sun today so maybe why the thermostat overshot slightly as its one of these that attempts to optimise, ie. Get to the set point by 10am rather than just coming on at 10am.

Ultrasonic

richardc1983 said:

That's brilliant then if it's working for you. By recover I mean if the house drops in temperature  (whatever that may be) how long it takes to get back to a comfortable temperature for you. 

I missed this earlier as I now realise we cross-posted. My energy use figures weren't in response to this but rather just giving some data to show that it was possible to be frugal with energy use without having heating on all the time.

Remember that for me I don't worry about 'the house' but the rooms I want to use - parts of it stay cooler as discussed yesterday. I didn't walk into my lounge this morning thinking it felt particularly cold by the way, and I can sit about 30 cm away from the radiator if I want to while the rest of the room warms up. That's what I do when I get home from work at the moment and the heating has been off during the day.