How to run boiler at lower temperature to save money? Turn down boiler or radiator?

ToTo_Man

Hi everyone,

I'm a newbie to the forum but have been following Martins money saving advice for many months now. My question relates to central heating.

I live with my parents and gran in an old detached sandstone building. The rooms are large and have high ceilings, and the house just eats up central heating like there's no tomorrow. We have a Vokera combination boiler, and have been advised that this type of boiler is inadequate for the size of house, however we cannot afford a new boiler so are stuck with it.

I am particularly thrifty. If it were up to my dad the heating would be on a lot more, however our gas & electricity bills are astronomical as it is. This means that I commonly sit in a room that is 12 degrees C. Guess you could say I've developed a thick skin to the cold! But even when the heating goes on, the hottest temperature many rooms in the house get to is 15 degrees C even with the radiator thermostats at max setting. This temperature is comfortable for me, any hotter and I start to feel stuffy. But I cringe at the fact that we are throwing so much money at getting the house to increase in temperature by a meager couple of degrees, hence my preference just to sit in the cold and save money. My parents are out at work and my gran has the comfort of her electric blanket, and when I get really cold I just run up and down the stairs a few times! Though I must admit it's a strange feeling when you are indoors and you can still see your breathe as you exhale! My dad is particularly cold blooded and as soon as he comes in from work, he changes into 2 thermal vests, 1 jumper, 1 zipper, 1 sheepskin over-sweater, a woollen hat and a scarf (funny but true!).

The house does not have any thermostats on the walls in any of the rooms, only on the radiator valves. There is an overall temperature control on the boiler (no numbers, just a round dial that goes from MIN to MAX). At the moment it is set close to max, probably approx 90%. In the first fortnight of October we got away with running it at 80%. At the moment it comes on at 6.30am and goes off at 11.30am. The distance of the rooms from the boiler determines how quickly the radiators heat up. E.g. the radiator in the kitchen gets to an acceptable temperature at 7.00am, but the radiator in my room does not get hot until after 9.00am. So my room is just getting to a nice temperature and then the heating goes off soon after. Once the heating goes off the house returns to its original cold temperature about 30mins later.

The flow and thermostat on each radiator are set to try to keep the rooms we use as balanced as possible in terms of temperature. Having a particularly large room and being furthest away from the boiler, the thermostat and flow on my radiator are constantly set fully open.

Instead of running the boiler at 90% from 6.30am to 11.30am, then from 5.00pm to 8.30pm, I am interested in trying to keep the heating on constantly from 6.30am to 9.00pm perhaps at 75% on the boiler. I can find out the difference in cost this makes by comparing meter readings, but want to know if I will be causing any damage to the boiler by running it at a lower setting? An engineer once told us that running the boiler at a lower setting forces it to work harder to keep the house heated. Instead he recommended running the boiler close to max and making any adjustments on the radiators.

Which way would be most effective at saving money:
A) running the boiler lower and the radiators higher,
running the radiators lower and the boiler higher?

As an additional question, is efficiency influenced by both the radiator thermostat and radiator flow valve settings, or is it mostly influenced by the radiator thermostat valve setting?

Thanks in advance for any input!

bluejosiah

I recently contacted http://www.energysavingtrust.org.uk/ using http://www.energysavingtrust.org.uk/Help-and-support/Contact-us they were so helpful. I've heard radio adverts for them too. I suggest you copy the above text and send it to them, I'm sure these are just the kind of questions they are able to answer!

mech_2

ToTo_Man wrote: »

The house does not have any thermostats on the walls in any of the rooms, only on the radiator valves. There is an overall temperature control on the boiler (no numbers, just a round dial that goes from MIN to MAX). At the moment it is set close to max, probably approx 90%. In the first fortnight of October we got away with running it at 80%. At the moment it comes on at 6.30am and goes off at 11.30am. The distance of the rooms from the boiler determines how quickly the radiators heat up. E.g. the radiator in the kitchen gets to an acceptable temperature at 7.00am, but the radiator in my room does not get hot until after 9.00am.

This bit catches my eye. Heat shouldn't take that long to get to the radiators. There should be a pump somewhere which moves the water through the boiler and the radiators. It sounds like it has failed/seized up. Is this possibly the case?

So my room is just getting to a nice temperature and then the heating goes off soon after. Once the heating goes off the house returns to its original cold temperature about 30mins later.

The flow and thermostat on each radiator are set to try to keep the rooms we use as balanced as possible in terms of temperature. Having a particularly large room and being furthest away from the boiler, the thermostat and flow on my radiator are constantly set fully open.

Instead of running the boiler at 90% from 6.30am to 11.30am, then from 5.00pm to 8.30pm, I am interested in trying to keep the heating on constantly from 6.30am to 9.00pm perhaps at 75% on the boiler. I can find out the difference in cost this makes by comparing meter readings, but want to know if I will be causing any damage to the boiler by running it at a lower setting? An engineer once told us that running the boiler at a lower setting forces it to work harder to keep the house heated. Instead he recommended running the boiler close to max and making any adjustments on the radiators.

As you are having problems getting heat from the boiler to the radiators, I think you want the boiler water temperature as hot as possible and then make the adjustments on the radiators.

But do try and find out if the pump is working.

Which way would be most effective at saving money:
A) running the boiler lower and the radiators higher,
running the radiators lower and the boiler higher?

For the moment try B, but if you manage to resolve the issue of heat not getting to where it should, you may wish to change the settings again.

As an additional question, is efficiency influenced by both the radiator thermostat and radiator flow valve settings, or is it mostly influenced by the radiator thermostat valve setting?

Thanks in advance for any input!

I'd say efficiency is affected by the thermostat as that controls the room temperature. The other valve isn't very useful in normal usage if the radiator has a thermostatic radiator valve.

ToTo_Man

Thanks for the advice.

Yesterday for interest I decided to run the heating all day to see how much it would actually cost. Boiler set to 90%, and I adjusted the radiators throughout the day until I achieved a constant and bearable warmth throughout the house. Some of the older radiators are quite finicky to adjust. Set the thermostat to 2 and they're cold but set to 2.25 and you get substantial heat. Took me from 7am to 3pm to fine tune the system, but the results are very interesting!.....

Now almost all of the radiators are operating hotter at a given temperature than they were before I adjusted them all. E.g. I get adequate heat from the radiator in my room with the thermostat set to 1.75 compared to having it set to 4 before hand. I'm not sure of the reason for this overall apparent gain in efficiency. Perhaps two or three radiators were previously set too high, and taming these down has boosted the rest of the system. My father couldn't believe the results, it's the first time he's come in from work and not had to put extra layers on! The catch however is the cost.....

Yesterday's gas consumption from 6am to 8pm (14hrs) was 283kWh, which by my own calculations costs £11.85 before the DF discount (the spreadsheet I downloaded from this forum gives exactly the same estimate).

The day before last, when we ran the heating from 7am-12pm and from 5pm-8.30pm (8.5hrs) on the original radiator settings, gas consumption was 249kWh, which cost £10.43 before the DF discount.

Both costs are very high when you consider that electricity is to be added on top of this. Our current monthly direct debit is much lower than this, even though they only just recently increased it by 15%. I don't know how we'll be able to absorb another increase (based on my figures it could be as much an 80% increase!).

The temperature of the house was however much more comfortable yesterday, and it doesn't seem to be that much dearer considering the extra hours the heating was on for. And I'm hoping that this increase is partly due to the fact that I didn't get the radiators dialled down enough until halfway through the day, so I am repeating the experiment today. If it doesn't get any cheaper today, the next day I am going to try just having the heating on from 6am to 9am and running a fan heater in my room, to see how much this increases the electricity and reduces the gas by. It could be the case that this is what I do from now on and just save the central heating for the weekend as a treat!.......

Umski

That does sound very expensive. A couple of questions - is the loft insulated? This can make a huge difference to the amount of heat that is conserved. Same thing for cavity wall insulation if possible. Then last thing is to check for drafts and seal them up - this is very inexpensive :j

Secondly is there a possibility of installing a system thermostat? The reason I ask is that my parents had a simialr issue where they were turning the boiler on and off adhoc but they like it nice and warm (I'm guessing >22C!). I installed a thermostat which turns the boiler off when the coldest room gets up to temp (21C) - this way the control is such that each room gets up to temp on the rads and turns off, then the whole system is controlled by the system stat. The system stat is programmed so that a constant temp is maintained during the day, which uses no more gas than if you cycle between extreme cold and normal. At night it drops to a lower temp in case it is really cold (17C)

I have a similar set-up in my own place where the lowest the temp will get is 17C. When we go away I turn it off but then the house can take a few days to get up to temp in that situation even if the stat says it's normal - basically because the walls and furniture absorb the heat...

Very last thing to check on the rad stats is whether they are sticking - mine do this sometimes so the rad won't heat up at all because the pin is stuck making it think it's up to temp

Mazio_2

The radiators have to be balanced as well normally the outlet side the one without the active control valve just 1 that rotates and seems to do nothing it can normally be removed by pulling it up (be carefull though they break easily) there should be an adjusting screw this determines how much water goes through the radiator the problem is if the ones near the boiler are set full open they will take most off the heat and pressure this then means further down the system there is not enough pressure or hot water so the radiator will take along time to heat up or remain tepid.

So normally the radiators close to the boiler should be restricted and the ones further away should be fully opened. But be carefull and take note how many turns you make on each rad incase you have to return them to the original positions also they may have by now seized up and if you move them they could start leaking.

cuden

Have you tried self bleed radiator valves? Just a small amount of air in the system can mean that your radiators do not heat up as quickly, nor do they stay hot. There is a company called Aladdin that make self bleed valves, my dad bought some as he has oil heating which is very expensive, he says that his bills have decreased by 30% just by using these things. I've ordered a few - they sell them on an ebay shop much cheaper than anywhere else.(radiator valves online)

ToTo_Man

Hi, thanks everyone for your advice. I've recently undertaken some experiments and have continued this thread here: http://forums.moneysavingexpert.com/showthread.html?t=1341797