New build - Underfloor Heating questions
Discussion
Hi guys,
As the title may suggest - I’m building a new house and am considering getting under floor heating installed. I have had a few quotes from some of the major suppliers (well according to Google search anyway
) but want to make sure that all this about cost savings and efficiency is true or if it’s just normal marketing by the under floor heating companies? My other worry is that I was told that the system won’t be able to properly heat up the larger rooms the same way a conventional radiator can? For those that have the system – do you have it on both the ground and first floor or just ground floor?
I’m currently leaning towards having the system installed on both floors but am getting conflicting advice from friends and family (particularly about being able to heat up larger rooms adequately) about the pro’s and con’s and just don’t trust the UFH companies to give me an unbiased answer.
Any advice appreciated.
p.s. what’s the consensus on ground source heat pumps? I haven’t read much about it until a brochure from a UFH company mentioned it. Anyone had any experience with them?
As the title may suggest - I’m building a new house and am considering getting under floor heating installed. I have had a few quotes from some of the major suppliers (well according to Google search anyway
) but want to make sure that all this about cost savings and efficiency is true or if it’s just normal marketing by the under floor heating companies? My other worry is that I was told that the system won’t be able to properly heat up the larger rooms the same way a conventional radiator can? For those that have the system – do you have it on both the ground and first floor or just ground floor?I’m currently leaning towards having the system installed on both floors but am getting conflicting advice from friends and family (particularly about being able to heat up larger rooms adequately) about the pro’s and con’s and just don’t trust the UFH companies to give me an unbiased answer.
Any advice appreciated.
p.s. what’s the consensus on ground source heat pumps? I haven’t read much about it until a brochure from a UFH company mentioned it. Anyone had any experience with them?
Ask Steve (GetCarter) - I'm pretty sure he installed it in his place: http://www.stevecarter.com/build/build.htm
A fantastic read if you have 30 minutes
A fantastic read if you have 30 minutes
Most stuff against UFH comes from people that don't really understand it.
The biggest anti is that if there is a sudden cold snap, it can take a while to warm up the rooms, which is true, but use a standard heat source to temporarily supply heat while the system catches up.
Otherwise, just don't install under units/wardrobes, and enjoy the use of all the walls free from encumberances, and having nice warm floors underfoot. Any UFH installer will be able to design a system to suit your build (just as they would with radiators), although the control system may be a bit more complex.
The biggest anti is that if there is a sudden cold snap, it can take a while to warm up the rooms, which is true, but use a standard heat source to temporarily supply heat while the system catches up.
Otherwise, just don't install under units/wardrobes, and enjoy the use of all the walls free from encumberances, and having nice warm floors underfoot. Any UFH installer will be able to design a system to suit your build (just as they would with radiators), although the control system may be a bit more complex.
I supply and install underfloor heating in New Zealand, powered with air sourced hot water heat pumps.
1 Underfloor heating is by far the best way of heating a house.
2 The system I install has reasonable capital cost with low running cost, but then electricity is relatively cheap.
3 The infloor pipes are installed in a 100mm slab (with insulation underneath) so it is an energy storage system as much as a heating system. (The heat pump is run during the day as it is more efficient and stores energy in the slab).
4 I've completed a two story house recently, the stairs go up from the main living area. The upstairs temperature is fine without any direct heating.
5 I also heat all the water with the same outdoor unit.
To give you an idea of costs. Electricity is about 8p per unit, the whole system in a single story house (total area 200 sq m) is around six thousand pounds (this does not include the cost and install of a hot water cylinder). In winter something like 25kW hours are used per day for house and water heating, but insulation and windows in NZ aren't very clever.
I don't get involved with ground source as it expensive to install, isn't necessary in NZ, and would be less efficient at heating water in the summer months.
The hot water heat pump itself can easily be 5 or 6:1 efficient under reasonable conditions, it appears it is still about 3:1 at freezing temperatures -
So your choice may depend on wherabouts you are, cost and availability of gas, cost of gas boiler, price of electricity, design of house etc etc.
With a gas boiler you you can always fit radiators upstairs - or if you have the first floor a concrete one where pipes can be fitted and then another thin layer of concrete poured on top (this give added heating to the downstair as the ceiling is also warm) then always fit infloor pipes if you can - simply because you can use any heat source for them. It just so happens at the moment an 11.9kW hot water pump costing fifteen hundred is easily the best soution for New Zealand. (That's 11.9kW output, they consume 2-2.5kW when house heatin)
1 Underfloor heating is by far the best way of heating a house.
2 The system I install has reasonable capital cost with low running cost, but then electricity is relatively cheap.
3 The infloor pipes are installed in a 100mm slab (with insulation underneath) so it is an energy storage system as much as a heating system. (The heat pump is run during the day as it is more efficient and stores energy in the slab).
4 I've completed a two story house recently, the stairs go up from the main living area. The upstairs temperature is fine without any direct heating.
5 I also heat all the water with the same outdoor unit.
To give you an idea of costs. Electricity is about 8p per unit, the whole system in a single story house (total area 200 sq m) is around six thousand pounds (this does not include the cost and install of a hot water cylinder). In winter something like 25kW hours are used per day for house and water heating, but insulation and windows in NZ aren't very clever.
I don't get involved with ground source as it expensive to install, isn't necessary in NZ, and would be less efficient at heating water in the summer months.
The hot water heat pump itself can easily be 5 or 6:1 efficient under reasonable conditions, it appears it is still about 3:1 at freezing temperatures -
So your choice may depend on wherabouts you are, cost and availability of gas, cost of gas boiler, price of electricity, design of house etc etc.
With a gas boiler you you can always fit radiators upstairs - or if you have the first floor a concrete one where pipes can be fitted and then another thin layer of concrete poured on top (this give added heating to the downstair as the ceiling is also warm) then always fit infloor pipes if you can - simply because you can use any heat source for them. It just so happens at the moment an 11.9kW hot water pump costing fifteen hundred is easily the best soution for New Zealand. (That's 11.9kW output, they consume 2-2.5kW when house heatin)
3 The infloor pipes are installed in a 100mm slab (with insulation underneath) so it is an energy storage system as much as a heating system. (The heat pump is run during the day as it is more efficient and stores energy in the slab).
I have underfloor heating upstairs and downstairs, bought a one off house 3 yrs ago ( design / build ) that was 1 yr old, we have a primary and secondary pump for the underfloor heating, what timing should I set these for ? Why two pumps ? I don`t fully understand the running of the heat pump during the day, isn`t the heat best left in the hot water tank ?
I have underfloor heating upstairs and downstairs, bought a one off house 3 yrs ago ( design / build ) that was 1 yr old, we have a primary and secondary pump for the underfloor heating, what timing should I set these for ? Why two pumps ? I don`t fully understand the running of the heat pump during the day, isn`t the heat best left in the hot water tank ?
As far as I am aware most in floor heating systems in the UK are rapid response ie the pipes are laid in a thin (40mm?) screed on top of insulation. This is fine for conventional heating such as gas, oil, coal etc as the floor will heat quite quickly (particularly as these boilers invariably have large outputs). Therefore it doesn't really matter when you heat the house as it will cost the same.
The important point about a heat pump is that the closer the temperature you want and the temperature you are grabbing the heat from, the more efficient it is.
You see floor heating with a deep slab means lots of storage capacity, and you only need 30 degree water to achieve a house at 20. A heat pump making 30 degree water when it's 10 outside can be 6:1 efficient - run it during the day and effectively store the energy for the night - like a giant storage radiator.
The domestic water heating is obviously to higher temperatures, and this is done by switching the underfloor off for an hour. This allows the heat pump to take the water in the cylinder up to 55 or 60. Switching back to the underfloor does not disturb this cylinder heat ie under no circumstances is 55 degree water cooled down to go through the floor as this results in a loss of efficiency when using a heat pump.
As you can't have water over about 45 in a floor conventional heating sources have tempering valves so some floor water is recirculated with only a limited amount of hot going in.
Hence, if you want to use a heat pump for underfloor (and hot water) heating then lay a deep slab and try and run the heat pump during the warmest part of the day, and probably only control it with a time clock.If you have conventional European thin slab heating then you would have to remember to turn it on early enough so the house warms up when you want it. With a deep slab you would tend to maintain the house at a reasonable temperature all the time rather than heating when it's cold.
The important point about a heat pump is that the closer the temperature you want and the temperature you are grabbing the heat from, the more efficient it is.
You see floor heating with a deep slab means lots of storage capacity, and you only need 30 degree water to achieve a house at 20. A heat pump making 30 degree water when it's 10 outside can be 6:1 efficient - run it during the day and effectively store the energy for the night - like a giant storage radiator.
The domestic water heating is obviously to higher temperatures, and this is done by switching the underfloor off for an hour. This allows the heat pump to take the water in the cylinder up to 55 or 60. Switching back to the underfloor does not disturb this cylinder heat ie under no circumstances is 55 degree water cooled down to go through the floor as this results in a loss of efficiency when using a heat pump.
As you can't have water over about 45 in a floor conventional heating sources have tempering valves so some floor water is recirculated with only a limited amount of hot going in.
Hence, if you want to use a heat pump for underfloor (and hot water) heating then lay a deep slab and try and run the heat pump during the warmest part of the day, and probably only control it with a time clock.If you have conventional European thin slab heating then you would have to remember to turn it on early enough so the house warms up when you want it. With a deep slab you would tend to maintain the house at a reasonable temperature all the time rather than heating when it's cold.
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