Heating on or just on a few hours??

wrf12345

My combi has always been switched off for 8-9 months of the year despite warnings that the pump might fail. I turn it off and on at the power switch in winter and run it for an hour in the morning and late afternoon, except today when the temps have gone under zero in the house and I have had to run it for a couple of hours. It runs flat out because the thermostat does not work and costs a quid an hour to run. Today I am actually getting warmer using an infrared heater with the ch turned off, that costs a quid for four hours. No hot water and happy sleeping under two duvets in a cold bedroom with a lovely ice cold shower in the morning to wake me up, albeit with the bathroom heated by a wall infrared heater (10p electric for twenty minutes).

Infrared heats the person not the room, BTW, therefore actual efficiency in warming the person is far higher than most other forms of heating, but not very viable if you are entertaining guests. I have one on my desk and another on the wall near where I sit in the lounge.

macman

Why don't you just fix the 'stat so that the CH system works as intended when it was installed?
We're all striving to save energy at present, but not many of us want to go the whole Bear Grylls approach and abandon hot water entirely.
Gas is less than one third the cost of your electric heating, infra red or otherwise.

Sarah69

jrawle said:

I think there are two separate questions here. One is whether to keep the heating on all the time, or only for parts of the day.

The second question is whether to switch the boiler off at the main switch when it is not in use. I'll answer this first, and I'd say almost certainly no. They are not designed to be used like this, and doing so may shorten the life of the electronics or other components. There is an issue with the wasteful pre-heat function of some combi boilers. On most, this can be switched off. If you tell us the model of your boiler, someone can look it up and find out how to do that.

As for whether to leave the heating on low all day or or just for certain periods, that's been discussed at length on this forum many times, and in the end is largely down to personal preference. If you only heat the house when you need to, it'll lose less heat to the outside. The boiler will have to work more to warm the house up, but this will use slightly less energy than keeping it heated all the time. The difference won't be that large. Do you have programmable thermostat that lets you set different temperatures for different times of the day?

I’ve just looked on the annual service and it’s a Condensing Combi System Conventional, Make Potterton, Model Assure. Hope this helps. 

Astria

macman said:

Why don't you just fix the 'stat so that the CH system works as intended when it was installed?
We're all striving to save energy at present, but not many of us want to go the whole Bear Grylls approach and abandon hot water entirely.
Gas is less than one third the cost of your electric heating, infra red or otherwise.

With the current costs, people are becoming paranoid about what it might cost them if the system turns on/off by itself, so a lot of people are ensuring that the boiler only fires when they want it to, and keeping a close eye on the consumption.

For simple things like washing hands and doing the dishes, you don't need particularly hot water - room temperature is fine for most things unless they are particularly greasy or excessively dirty.

jrawle

Sarah69 said:

I’ve just looked on the annual service and it’s a Condensing Combi System Conventional, Make Potterton, Model Assure. Hope this helps. 

There must be more to the model number than this. Is there a label on the boiler itself? Anyway, I found the Potterton Assure manuals, and there is no mention of a pre-heat function. (In contrast, their Performa model does have this and it's explained in the manual.) That suggests your boiler doesn't have this feature, so you can leave the boiler powered up all year round and not worry about it wasting gas.

macman

But water at the sink tap won't be anywhere near room temp. It'll be coming off the rising main at near freezing point-not really ideal for washing up in. 
The DHW and CH won't come on 'by itself' if they are set up to the user's own requirements, and working properly. Having a broken room 'stat is really not an economy, given the trivial cost of replacing it.

Bark01

The only way you can be sure is to monitor it yourself.  I live in a flat with old double glazing and loads of loft insulation. Its not completely sealed and insulated but its probably better than most flats. In order for having the heating on low all day to wokr out cheaper you need a really well insulated building

My supplier website shows my hourly usage by day (i have a smart meter) so i can go back and look at usage per hour over time. Its very clear what the difference in cost is between heating my house form cold and keeping it at temp. 

When my heatings off and i don't use hot water my cost is 0. I can't remember the exact usage figures here so i'm just going to use generic units, but what i found is:

1) When I heat my house from cold in that hour my gas uses x units. For ease of maths lets say 6 unit
2) When my house is up to temp in takes 2/3rds of the above cost to keep it at temp, i.e 4 units
3) if i turn my heating off its takes around 2 hours for me to start feeling cold

For me its way cheaper to cycle my energy
Once my house is up to temp it takes 4 units so lets say over 12 hours that's 11*4 + 6*1 (for the initial heat) = 50 units
If I cycle my heating so its on for 3 hours (6*1 + 4*2) then off for 2 hours its = 38 units (24% saving)
If I cycle my heating so its on for 3 hours (6*1 + 4*2) then off for 1 hours its = 42 units (16% saving)