under floor heating

kuttann

hello all

I bought a house in the northern part of england. It is a 3200 sqft house and has underfloor heating (wet)on both floors.
most of the time, no one is at home during the day time. But i was told that i should not put the boiler on timer and is cheaper to leave it on 24/7. is this true?
all the rooms have individual thermostats..but even when all of them are off the boiler (worcester bosch) keeps on humming. is it normal? is it burning gas?

thanks in advance

Premier_2

The more the boiler burns, the more it will cost you.

If the boiler is off, it won't burn anything (ignoring any pilot light that you may have)

zooks

I think the OP was refering to the amount of work (and gas burnt) a boiler has to do to heat a large house from cold rather than just leaving it on low.
Ive also wondered whats the most efficient way run the heating. Anyone?.

Premier_2

zooks wrote: »

I think the OP was refering to the amount of work (and gas burnt) a boiler has to do to heat a large house from cold rather than just leaving it on low.
Ive also wondered whats the most efficient way run the heating. Anyone?.

You've been a member here for 3 years, and it's been discussed many times in that period.

If it were cheaper to keep something hot continuously rather than just heat it up as required, they would have designed an electric kettle to work that way by now.

aelitaman

The problem that the op has is the time that the floor takes to heat up. Depending on the level of insulation, thickness of screed, what covering is placed on the screed, etc. Also there is the fact that the water used to heat the floor is at a much lower temperature than water used for radiator heating so takes longer to get the same amount of energy into the same room.

For the above reasons this means that it can take 24 hours to get a room up to temp depending on the outside temperature. So there is no option you can not set it to come on 1 hour before you arrive home from work and expect the house to be warm. You have no choice but to run it 24/7 with the resultant big gas bills.

kuttann

thanks aeilitaman...

but do you know why the boiler keeps humming even when none of the the rooms are active( i know this because the thermostat has only the green light).

i read some where that since water is at a lower temperature it is less energy consuming...is it true?

Andy_WSM

kuttann wrote: »

thanks aeilitaman...

but do you know why the boiler keeps humming even when none of the the rooms are active( i know this because the thermostat has only the green light).

i read some where that since water is at a lower temperature it is less energy consuming...is it true?

Maybe the boiler has a circulation pump that continues to run so it can monitor pipe temperatures - just a wild guess...

Also, yes, the lower running temperatures make the system more efficient - i.e. less losses. Also, with underfloor heating you tend to have slightly lower room temperatures as the heat rising into the room makes you feel more comfortable, so another small saving here.

macman

Premier wrote: »

You've been a member here for 3 years, and it's been discussed many times in that period.

If it were cheaper to keep something hot continuously rather than just heat it up as required, they would have designed an electric kettle to work that way by now.

Hear hear!
I'm sooo bored of this topic of leaving your boiler/hot water on 24/7 still coming up several times a week, could we not have a sticky for this to try and stem the flow?

aelitaman

kuttann wrote: »

thanks aeilitaman...

but do you know why the boiler keeps humming even when none of the the rooms are active( i know this because the thermostat has only the green light).

i read some where that since water is at a lower temperature it is less energy consuming...is it true?

I should add that if I would you I would try to have the system timed as opposed to on 24/7.

Based on the assumption (rough guide really) that radiators run about 60C and UFH at about 30C what I would do first is to double the time I would normally use to allow radiators to come on.

So if I run the CH for 1 hour before coming home from work then with UFH I would allow 2 hours.

But the compensation is that with such a large amount of concrete (ground floor) being heated you have a very large heatbank (stored energy) that will continue to heat the house for a longer time than small radiators. So you may be able to turn the heating off before going to bed or leaving for work a lot earlier than if you had rads.

The only certain thing is that you are going to have to experiment if you do not want to run it 24/7.

aelitaman

kuttann wrote: »

thanks aeilitaman...

but do you know why the boiler keeps humming even when none of the the rooms are active( i know this because the thermostat has only the green light).

i read some where that since water is at a lower temperature it is less energy consuming...is it true?

Is your boiler heating the hot water tank?

Can you put your hand close to the flue exit to see if the boiler is actually burning gas or just humming?

Some boilers will cycle for a period of minutes after the thermostat tells them no more hot water required so that they can cool the boiler down - so use the ufh, then when up to temp turn the thermostat right down to a low temp 10C or soemthing like that then say after an hour feel the CH hot water pipe that exits the boiler and if it is warm then you have a problem call heating engineer, if cold then the boiler may be humming but it is not heating water. You could also look at the gas meter when the boiler is humming but not meant to be heating water if the Gas meter is ticking over with no other gas applicances on then again you have a problem, thermostat not shutting down boiler or boiler not responding to shut sown request.