How best to run central heating this winter?

After reinstating our internal walls downstairs and adding a lot of insulation I was interested to see how the temperature fluctuated throughout the day/night so I brought my high-low thermometer in from the greenhouse. Over the last 5 weeks since the CH has been back on (6:15-8:00, 16:00-22:00) the max high has been 21.2C and the min low 18.5C.

I can't really see how keeping the heating on to maintain a constant 20-21C would benefit as the temp isn't dropping much at all in either of the unheated 8hr periods.
 
My heating comes on twice a day 06:30-08:30 and 16:30-18:30 which normally heats the house up to temperature in ~15mins. I normally set the thermostat to ~18C and, if it's cold, then the house normally looses 2-3C during the day and maybe 4-5C overnight.

If I'm working from home during the day then I just hit the advance button and the heating will go on and off as needed to maintain the temperature.
 
My house is old and takes ages to warm up as first you have to get all the internal surfaces/bricks warm before you feel any air temp rise.

So having it on all the time helps. But all that heat is escaping very quickly and not doing much. It takes ages for it to warm up but defiantly uses less gas using it intermittent to take the chill off than it being on all day.

I'm not in HVAC just know that having the heating on when I'm not in is completely pointless unless I want to warm up outside :D
 
Dangerous Dave said:
I currently run our heating at 20.5c during the day 05:30 to 22:00 with a set back of 16c overnight.

We recently replaced our heating system and went with over sized radiators in combination with weather compensation to keep a low flow/return temperature even today where it was -1 this morning the radiators were ticking over with a flow temp of 53c.

A modern boiler only condenses when the return temperature is under 56c so due to the old design of systems that initially had non condensing boilers they ran at 70-75c with a flow/return differential of 11c rather than a modern condensing boilers 20c. If you run a modern boiler at 75c in these systems without either rebalancing the radiators and/or oversize them the boiler will never go into condensing mode which can give you an additional 10% in efficiency.

Taking into account the milder winter our system is saving around 30% compared to our old system, actual gas usage is down 49%.
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Glad to hear you're clued up. The number of people who are running their condensing boilers without them ever condensing is ridiculous. I'd guesds it was 99% of people!!

Simon said:
My house is old and takes ages to warm up as first you have to get all the internal surfaces/bricks warm before you feel any air temp rise.

So having it on all the time helps. But all that heat is escaping very quickly and not doing much. It takes ages for it to warm up but defiantly uses less gas using it intermittent to take the chill off than it being on all day.

I'm not in HVAC just know that having the heating on when I'm not in is completely pointless unless I want to warm up outside :D
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So you have no evidence...I'm afraid you're incorrect.
 
I'm hot-bloodied, and the only time I feel really cold is when I've just got out of the shower on winter mornings. Instead of turning the whole house heating on, I just use one of those little £20 heaters from Argos. Run it at 3kW for 5 minutes to dry me out, then at 1.5kW for another 5 minutes while I'm getting dressed.

Evening - I just give the boiler a manual blast when it's 15C indoors. Outdoor temps have to hit ~3C and below for that to happen though. 18C indoors is more than enough for me. Can't stand it when it's 27C in the office, but luckily my current colleagues will let me have my window open.

Night time - no heating at all, all year round, with the window open. It would have to be lower than -5C outside before I close the window.
 
dirtychinchilla said:
Glad to hear you're clued up. The number of people who are running their condensing boilers without them ever condensing is ridiculous. I'd guesds it was 99% of people!!



So you have no evidence...I'm afraid you're incorrect.
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I know thermodynamics though
 
It depends on the house. With a ultra low U value host it may be close and then you get efficiency gains from new heating systems and condensing boilers.

In my 1902 house I can assure you leaving the heat on all day is just burning money as there will always be high levels of heat loss.
 
Danish heating is a big boiler for a load of houses with pumped in heat. Very much like russia.

Not sure how these methods apply to a single house ?
 
That's not quite true. They do use district heating, and to a much greater extent than in the UK, but that's the way the energy market is heading now.

They pump hot water straight to your house in Denmark, heated by waste heat from power stations. In their homes, they use weather compensation, which means that the heating will be on pretty much all day every day when their heating is not switched off.
 
And my old house with heating on all day being cheaper than only when I need heating ?

That district heating example is irrelevant for 99% of people in UK. And even then it's still no more efficient to have it on all day than only when you use it.
 
There's a surprising amount of district heating in the UK to be fair!

If you want temporary comfort, which takes a while to kick in, yes you'd be better off heating the house only when you need it.

If you want a constant temperature in your house that will keep the house warm all the time whilst using less energy, what I'm saying is correct. If you do research about weather comp, which does what I'm suggesting, you'll find that most people save a reasonable amount of money using weather comp.
 
I have my heating on permanently throughout winter, 21-22 during morning and evening when wife says shes cold, and 17 during day when house is empty. I live in a detached 1970s, timber framed, brick clad bungalow so it looses heat rapidly, but leaving the heating on uses more gas for the first week as it's heat the structure up, but it also retains it a lot longer when it's off. Our boiler doesn't come on that often, and i'm spending £50 a month on gas.

Once a building has heat in it's structure it takes less heat energy to make it feel warmer, which means less usage.

My old house I use to only heat in the evenings and it was a lot more to heat as it lost more heat from the structure not getting warm.

I'm currently trying to insulate my house better but not sure on what to do with the walls as they're timber framed. Any ideas appreciated.
 
You can't create energy from no where. If the structure is warm then the heat loss to outside is greater.
 
Also look into turning off or turning the thermostat on the radiators down on rooms that you dont use or need. Like the down stairs loo or box room and keep the door closed. I found this saved about 20%.
 
For most people having the heating on demand rather then low all day (whilst in or out) will save them money. Its much easier to have a smart thermostat that knows when your in or out and as such won't heat the empty house.

I've tried it in my house and with a smart thermostat set to 21c when I'm in has saved 30% over a constant low.
 
Yes and this take huge amounts of emergency to maintain the temperature.

After about an hour of having the fire on in my lounge the walls finally equalise and they the air temp Rockets up. However as soon as you turn off the heating the walls will just lose their heat to the outside

This is the issue with making everything warm all the time. Sure your heating system doesn't have to work as hard when you get in and want it warm. But it takes a load of energy just to keep it ticking over ready for when the real heating demand is needed
 
Dirtychincilla is right, its all about efficiency, i work for a heat pump design & installation company and Flow rate is the key.

If you want to spend a few a little money and use weather compensation you will never look back.
 
How does flow rate affect:

A- district heating
B- the insulation value of your house

Sure lower flow rate, lower temperatures and making sure boiler is always in confessing mode (hence the benefit of weather comp) but that doesn't address the OPs question.
 
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