A question about underfloor heating
Discussion
Are there any heating experts here that can give me a definitive answer to this question?
I live in a modern, well-insulated house that has tiled floors throughout and has gas-fired, water pipe underfloor heating which works a charm. Can anybody advise me whether it is more economic to leave the heating on all the time during the winter or put it on a time cycle, something like 0600-2200.
I've lived in the house for four years using the time-cycle method but I've had a few people (not heating experts) suggest that it is more economic to leave it on all the time because of the extra energy it uses when re-heating from cold if it's turned off at night. Given that it takes 12-24 hours to warm up from cold at the beginning of the season I'm wondering if I could save myself some money if I changed my routine.
Any tips much appreciated.
I live in a modern, well-insulated house that has tiled floors throughout and has gas-fired, water pipe underfloor heating which works a charm. Can anybody advise me whether it is more economic to leave the heating on all the time during the winter or put it on a time cycle, something like 0600-2200.
I've lived in the house for four years using the time-cycle method but I've had a few people (not heating experts) suggest that it is more economic to leave it on all the time because of the extra energy it uses when re-heating from cold if it's turned off at night. Given that it takes 12-24 hours to warm up from cold at the beginning of the season I'm wondering if I could save myself some money if I changed my routine.
Any tips much appreciated.
Yes it takes a long time to heat up from cold, but not from warm which it will be when in use on a time clock.
If I set them up I usually do it similar to a radiator system. On for 1st thing in the morning, then off till mid-day, on for an hour or two, then back on for the evening.
I suppose it will depend on how much you use the house during the day, what temp you want in the house, what your heat source is for the water, if the heat source is doing anything else, eg hot water.
If I set them up I usually do it similar to a radiator system. On for 1st thing in the morning, then off till mid-day, on for an hour or two, then back on for the evening.
I suppose it will depend on how much you use the house during the day, what temp you want in the house, what your heat source is for the water, if the heat source is doing anything else, eg hot water.
Tuna said:
It completely depends upon how quickly your house goes cold when the heating goes off.
The house is mostly a large open living space with a high ceiling and does drop temperature pretty quickly. It can get pretty cold round here, -5 degrees last night (southern France, near Pyrenees). The hot water is on a separate circuit with its own boiler and that is on all the time.Given that the temperature does drop quickly are you saying it would be better to leave it on all the time?
The house cools down due to losing (wasting) heat to the outside; the rate at which it cools will fall as its temperature drops, as the rate depends on the difference between interior and exterior. So, the amount of energy lost per hour will actually reduce over time, until the heating goes back on. If you were to leave the heating on constantly, the rate of loss would remain steady, at its highest rate, so you will waste more energy. Energy taken in reheating the floor structure, walls etc is simply replacing the energy lost over time, and this would be nothing compared to that lost keeping the heating on constantly.
Stegel said:
The house cools down due to losing (wasting) heat to the outside; the rate at which it cools will fall as its temperature drops, as the rate depends on the difference between interior and exterior. So, the amount of energy lost per hour will actually reduce over time, until the heating goes back on. If you were to leave the heating on constantly, the rate of loss would remain steady, at its highest rate, so you will waste more energy. Energy taken in reheating the floor structure, walls etc is simply replacing the energy lost over time, and this would be nothing compared to that lost keeping the heating on constantly.
Exactly this. The amount of heat lost from your house isn't constant. The driving force in moving energy (heat) from inside your house to the outside is the differential between the two. IE if you keep your house nice and warm all the time then you will actually lose more energy than if you let it cool down (and thus lower the differential with the outside).The other thing to bear in mind is that modern condesing boilers are far more efficient at full load than at part load. So unless you let your heating system actually cool down and give your boiler the opportunity to run at full whack for a while it will be relatively inefficient.
Tuna said:
It completely depends upon how quickly your house goes cold when the heating goes off.
Time really isn't a factor in heat loss calculations unless your heating system is undersized and will struggle to bring the temperature back up in a reasonable amount of time.Can you set it to run at a set-back temperature (say 12'C) while unoccupied? If sp then I'd go for this...you'll save energy by not keeping you house warm when you're not there and with a set-back temperature you will prevent it getting so cold the system struggles to heat the house back up to temperature (and you will prevent condensation that very cold temperatures can produce).
Thanks all for the info - it sounds like I'd do best to carry on with the timed cycle. I guess the fact the the default settings for the Siemens programming device are 0600-2200 also suggest this is the best way.
I have got an override where I can select holiday mode which just keeps the chill out of the house if you're away for a few days.
Anyway, I'm off to turn the heating up it's going to be -8 degrees tonight.
I have got an override where I can select holiday mode which just keeps the chill out of the house if you're away for a few days.
Anyway, I'm off to turn the heating up it's going to be -8 degrees tonight.
I can't add anything to the debate about a heating cycle - but as you live in France I am interested in the cost of gas, the cost of daytime electricity, size of house and depth of concrete slab. why? because you would save lots of energy by using a hot water heat pump instead - however this may not be economic due to the capital cost.
A hot water heatpump could be 5 or 6:1 efficient, ie pay for 1 unit of electricity and get 5 or 6 units of heat. But - you need a reasonable depth of slab to store enough energy as the heat pump works best during the day.
A hot water heatpump could be 5 or 6:1 efficient, ie pay for 1 unit of electricity and get 5 or 6 units of heat. But - you need a reasonable depth of slab to store enough energy as the heat pump works best during the day.
jaybkay said:
I can't add anything to the debate about a heating cycle - but as you live in France I am interested in the cost of gas, the cost of daytime electricity, size of house and depth of concrete slab. why? because you would save lots of energy by using a hot water heat pump instead - however this may not be economic due to the capital cost.
A hot water heatpump could be 5 or 6:1 efficient, ie pay for 1 unit of electricity and get 5 or 6 units of heat. But - you need a reasonable depth of slab to store enough energy as the heat pump works best during the day.
I pay 1,100 euros a year for gas which does the heating and all the hot water. Electricity works out about 900 euros a year and I spend about 200 euros a year on logs, so a total cost for energy of 2,200 euros. If I was here for the long term I'd certainly be consider the heat pump - two or three people here I know that are building are going that route and one guy in the village who has a HUGE house had it installed about a year ago at a cost of around 20,000 euros. You do get about 6 or 7,000 euros from the taxman as there are various schemes to encourage people to adopt the newer technology.A hot water heatpump could be 5 or 6:1 efficient, ie pay for 1 unit of electricity and get 5 or 6 units of heat. But - you need a reasonable depth of slab to store enough energy as the heat pump works best during the day.
So far as I can see my concrete slab above the pipes is around 30mm with a 28mm thick tile on top - don't know whether that's good or bad.
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