House heating; most efficient way.

I have a small 3 bed semi in Aberdeen.
New gas boiler. Radiators with thermostats in all rooms.
Heating comes on from 6.30 am to 9.30 am
Off all day with frost protect until 5 pm and then off at 9.30 pm.

Lets skip the best supplier for another time.
Question is; is it more efficient / cheaper, to keep the heating on a low temp during the day and overnight to avoid a big heat jump requirement when the heating timer kicks in?
We don't feel we need to be warmer during the day and night.

Thoughts folks

It will always be more efficient and cheaper to keep the heating turned off when the house is unoccupied. If you find it too cold when you return from work in the evenings, you could move the 'On' time slightly earlier. Having the heating on low while you are out will only succeed in keeping the sparrows on your roof warmer.

Turn it off when you don't need it, it'll be cheaper.

I don't know who came up with the idea that it's cheaper to leave your heating on low during the day, but it's rubbish unless you're on some weird tariff that gives you cheaper energy units during the day than in the evening. Not impossible, but rare.

JockyBrewer said:

Turn it off when you don't need it, it'll be cheaper.

I don't know who came up with the idea that it's cheaper to leave your heating on low during the day, but it's rubbish unless you're on some weird tariff that gives you cheaper energy units during the day than in the evening. Not impossible, but rare.

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Thanks. Good opinion.
Re weird tariff; my supplier promoted free electric between noon and 1 pm.
Ah ha; the free part was whatever I used in excess of what I usually used between noon and 1 pm.
A little bit naughty in how they phrased the 'offer'.

Another option is to add some smart radiator valves, so that you can program a heating schedule for each room, so you're only heating the rooms you're actually using. They're really quite cheap now (£27 per valve, plus you need a similar price gateway for the house: https://www.amazon.co.uk/SONOFF-Thermostatic-Radiator-Installation-Assistant/dp/B0CFXY26H1/).

My house has an Evohome system which was installed nearly 10 years ago, but paid for itself within a couple of years as at any given time we tend to only be in one room so heating the rest of the house is pointless. My system goes a bit further as it actually only turns the boiler on when heating is required, but it was quite a bit more expensive at the time. Starting over I'd definitely look at those SONOFF valves or similar.

JockyBrewer said:

Turn it off when you don't need it, it'll be cheaper.

I don't know who came up with the idea that it's cheaper to leave your heating on low during the day, but it's rubbish unless you're on some weird tariff that gives you cheaper energy units during the day than in the evening. Not impossible, but rare.

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The reasoning (and it's somewhat dependant on the level of insulation in the house) is that because you're keeping a low level of heat throughout the house, you don't get as much heat migration when one room is heated to a slightly higher level.

Otherwise (since cold air falls - often mistakenly described as hot air rising) you get draughts as cold air migrates to the warmer areas of the house making the heating system work harder to maintain the set heat levels there.

I am a low & slow myself. Your body also acclimatises to a lower range, which saves too.

Larse said:

The reasoning (and it's somewhat dependant on the level of insulation in the house) is that because you're keeping a low level of heat throughout the house, you don't get as much heat migration when one room is heated to a slightly higher level.

Otherwise (since cold air falls - often mistakenly described as hot air rising) you get draughts as cold air migrates to the warmer areas of the house making the heating system work harder to maintain the set heat levels there.

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Due to the constant energy losses while the heating is on, it does not stack up.

Cheapest way to heat a house is a log burner and good use of your hunter-gatherer skills.

LeeH said:

Due to the constant energy losses while the heating is on, it does not stack up.

Cheapest way to heat a house is a log burner and good use of your hunter-gatherer skills.

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I did say it was insulation dependant. You've got a heat leaky house, you may as well burn the money instead.

MashBag said:

I am a low & slow myself. Your body also acclimatises to a lower range, which saves too.

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I'm just going to run this by Mrs. Matt..........

My gas bills have dropped a fair bit after getting a wood burner. Yes,I have to buy logs but they seem to last ages and are more fun. There's also the cost of putting the burner in to consider. I have managed to forage a lot of logs and dried them out in the green house. As for the rest of it...if I'm home the heating is OFF...and the jumpers are ON!

Clint said:

I'm home the heating is OFF...and the jumpers are ON!

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When i am home alone i use one of these which i put close to me when working on my PC each bar is 400w so it costs around 10 pence per hour to run on one bar you don't need more than one bar its surprising how much heat they put out.

I have central heating and a gas fired boiler and a few years back installed a Tado thermostat. It is similar to the one sold by Hive (control your heating from your phone) in being able to turn the heating down/off when no-one is home and back on again before getting home. (great if you remember) But the Tado is much smarter. My wife and I both have the app on our phones but we never have to touch it. As soon as the last person leaves the house Tado starts turning the heating down. The further you are from home the further it reduces. Then, just like magic, it starts firing it up again as one of you start heading home so it’s nice and toasty again when you get home.
This saved us a fortune on heating when my wife was a childminder and I was in the office every day. She used to go to toddler groups twice a week, library drop ins once a week, music clubs on tues and Thursdays one week then mon and weds the next week, it would have been impossible to set a normal thermostat to cope with these schedules.
It is still useful now even though one of us is at home a lot of the time in that you just don’t have to try to remember to keep turning it on or off or up and down.

How much do people pay in heating costs per day I wonder.
I work from home so we have the heating on all day. But even today, with the heating on all day (well not constantly, but on the thermostat), it totalled £4 and was about zero degrees all day outside. We have a pretty-well insulated 4-bedroom 1980s build (gas central heating).

Im an all electic with a wet radiator system. 1940 built 3 bed. It moderately well insulated. When my parents were in it they had the heating in 24/7 and it cost a fortune to run.
Si i installed a Drayton smart system to teplace my old boiler time clock. Each rad has its own thermostat.
In short i can programme each room to be at the right temp at the right time for our needs. Eg the shower room suts at a constant 16c when we aint using it. But it is programmed to come up to 18c from 04.30 to 0600 so that the room praks at 18c when we need our showers.
However i have done a lot of tinkering with the programming especially the temps when we are out.
In my case if i leave the stats set at 16c the house never drops delowbthat. Even in this weather (-4) sort of ticks over using minimal heating.
If i switch the heating off completely it takes more enrgy to bring it up to 16c from say 8 or 10c than it does to keep it at ticking over at a constant 16c.
This is all dependent on your level of insulation. And how exposed your building is to wind. And will vary from property to property. How long you are out yhe house. Etc. whats freaky is the effect other properties can have on yours. The house next door was empty for a while last so the heating was off. When the new people moved in their heating wwent on and my usage dropped by 3%. Which shows how much i was leaching out through the partition wall.
In short if you can afford it. Get a smart controller and tune your house.
The ither thing i do is run the boiler slower for longer. Currenyly my boiler is set at 55c not the usual 70c. Temp in the rooms is more constant and take less enrgy over the day. If i feel its not keeping up i turn the boiler up 5C till the cold snap is over and drip it back to the lowest temp where it will keep up with the outside temp.
Also. You need to make sure the fitters set your boiler up to condense properly. If not its costing you money. Problem can be boilers get set up to make sure they run to prevent callbacks. Not always to run well. Take a look at heat geeks on ewetoob. They are predominantly heat pump geeks but they do explain a lot about heat losses and maximising condensing boiler.

Frisp said:

If i switch the heating off completely it takes more enrgy to bring it up to 16c from say 8 or 10c than it does to keep it at ticking over at a constant 16c

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I'm curious at to how did you measured this, because it violates some pretty basic laws of physics (thermodynamics)

Well its about thermal mass and thermal batteries. If you keep your heating ticking over then you're able to maintain temperature very efficiently. If you turn everything off and everything chills down including your walls then it takes a hell of alot of energy to heat all that back up again as the walls, floors and ceilings just act like a big thermal sink. Due to thermal mass there is a lag for the walls to warm up and cool down, but if they are already warm then all you're doing is keeping the heat in the room topped up. Of course all this depends on the thermal properties of your walls, floors, windows and ceilings, so material they're made of, levels and effectiveness of your insulation. If you have very poor insulation and a leaky house then you're on a hiding to nothing, but if you have decent level of insulation then the building itself will hold onto energy quite well and act as a thermal battery and you can exploit this if you have a clever enough system.

Of course if you're out of the house for a long time then it's always going to be best to not maintain a temperature. But if you're just popping out and about for a few hours or so then it can be more efficient to keep the heating on while you're out rather than letting everything chill down and having to heat it all up again.

I have gas central heating and a nest smart thermostat set to auto and it works great. It manages the temperature in my home pretty well and very efficiently. Takes a bit to get there as it has a learning function so early on I had to continually tweak things but it learns and over time manages a schedule.

I'm not even using all its features as the geofencing only works off my phone and I've not added the phones of all my other family members but it detects when people are in and seems to manage quite well. It also tracks the outside temperature and uses information from weather forecasts to try to predict demand and manages it proactively and in the most efficient way.

Larse said:

since cold air falls - often mistakenly described as hot air rising

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Are you sure?

MashBag said:

Are you sure?

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Cold air falling and hot air rising are two sides of the same coin.

Agentgonzo said:

Cold air falling and hot air rising are two sides of the same coin.

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I know that. You know that.

But I think some people prefer the world a bit flatter.