do you think i should leave all lving areas open so? Would it cost much more.
I can't think why it would. Heat will always travel towards colder areas, so you would now have to put more heat into the room you are heating because that room is now also being used to heat the rooms around it, without a larger radiator (the floor) so needs a higher flow temperature.
You will need to somehow maintain a minimum temperature of the house so that you don't have a big gap to make up when you need the house warmer. A big gap means the heat pump works harder and is less efficient, possibly up to 40% less efficient.
If this happens, the system is not balanced so that the flow rates in each circuit are aligned with the heat loss for that circuit as per the UFH design.
do you have the UFH design documents?
do you have a diagram of all the components of the heating system?
@william1066 House kept at 21degrees.so what flow temp would be suitable for heating them 3 rooms. approx 120sq m including utility and bathroom. Its6deg outside and my sensor is telling me lwt is27degrees but desired temp on main screen is 36degree so presume the pump will heat up to weather compensated desired temp. A guy i know has his set to 40degrees all the time no weather compensation and seems v happy with it. Got designs but plumber did not follow them to a tee so not sure if they will be of much se to you. He said the plans were over specced, 26 loops on plans but i have 17. 242sqm house.
@newhouse87 I just looked at your photo, looks like you have 13 circuits, is this the only manifold in the house?, if so then you likely have 200mm centers for you UFH and likely close to 100m pipe per circuit, unless you have a lot of areas where there are not UFH pipes, e.g. where you have cabinets or other built in furniture/baths/showers etc.
This will likely limit the efficiency that you can achieve because with 200mm centers and quite long circuits you will need to run a higher temperature and likely quite a large deltaT
You really need the UFH diagrams, and the heat loss calculations to be able to get an optimal setup.
As mentioned before, you will also need to balance the system.
@william1066 have 2 manifolds, 17loops in total. Fairly sure it was 150mm spacing. How long should it take for lwt to get up temp, mine still at28 an hour in when desired temp is 37.
Unless you have specific circumstances requiring such a high temperature, you should be able to run the house about 1.5 to 2 degC lower with UFH than with radiators, as you have radiant heat 19.5 should "feel like" 21 with radiators.
He said the plans were over specced, 26 loops on plans but i have 17
I hope the plumber understands that for a heat pump things are different and that the new 17 circuit design still meets the criteria needed for a heat pump, which is high flow rate and lowish flow temperature.
Fewer circuits and larget spacing will means your UFH will be much slower to respond to demands for heat.
When you are installing UFH for low temperature heat sources such as heat pumps you need closer spacing, which means more pipe, which means more circuits (the latter because of max circuit length).
If you have 17 circuits, you must have a second manifold somewhere since I could only count 13 in your picture. Let us assume for a moment you have 17 circuits.
For your floor area, the following is likely.
@200mm centers that means, on average, up to 70m pipe per circuit. @150mm centers that means, on average, up to 95m pipe per circuit.
Both technically possible, though the second at the extremes of what is recommended.
Assuming your 11kW daikin is correctly specced, and you have a 242 sqm house, then at the design load (probably somewhere between 1 and -5 degC depending on where you live) you have a heat loss of 45 watts per square meter.
Assuming you need 40 watts per square meter @ outside ambient of 6 degC (it may be a bit more or less, but let us assume this)
@21 degC room temperature, you should get around 40watts per square meter emitted into the room from the floor, once the floor has reached a temperature of 25 degC
[If you have something on top of the floor, such as a carpet, you will get much less out the floor, maybe only 20-25 watts per sqm depending on how thick the carpet is]
If the floor is cold and the room is cold, then calculations get more tricky as the floor is heating up [thermal inertial], and the deltaT between the room and floor is different, and changing.
Having said all of that I did notice two of your pictures, which i think contradict each other.
Assuming that the daikin diagram is the correct one, then you should be able to run your flow much closer to 30degC, and gain about 30-45% in efficiency of the heat pump. So in theory leave it running nearly twice a long as you do now for the same cost, and likely more comfortable temperatures.
As an experiment, I would suggest two things
1 - run the heating twice as long as you do now, all day if possible, but set you weather compensation so the flow temp is around 35 degC or even less 2 - set you target room temp to 19.5
Unless you have specific circumstances requiring such a high temperature, you should be able to run the house about 1.5 to 2 degC lower with UFH than with radiators, as you have radiant heat 19.5 should "feel like" 21 with radiators.
He said the plans were over specced, 26 loops on plans but i have 17
I hope the plumber understands that for a heat pump things are different and that the new 17 circuit design still meets the criteria needed for a heat pump, which is high flow rate and lowish flow temperature.
Fewer circuits and larget spacing will means your UFH will be much slower to respond to demands for heat.
When you are installing UFH for low temperature heat sources such as heat pumps you need closer spacing, which means more pipe, which means more circuits (the latter because of max circuit length).
If you have 17 circuits, you must have a second manifold somewhere since I could only count 13 in your picture. Let us assume for a moment you have 17 circuits.
For your floor area, the following is likely.
@200mm centers that means, on average, up to 70m pipe per circuit. @150mm centers that means, on average, up to 95m pipe per circuit.
Both technically possible, though the second at the extremes of what is recommended.
Assuming your 11kW daikin is correctly specced, and you have a 242 sqm house, then at the design load (probably somewhere between 1 and -5 degC depending on where you live) you have a heat loss of 45 watts per square meter.
Assuming you need 40 watts per square meter @ outside ambient of 6 degC (it may be a bit more or less, but let us assume this)
@21 degC room temperature, you should get around 40watts per square meter emitted into the room from the floor, once the floor has reached a temperature of 25 degC
[If you have something on top of the floor, such as a carpet, you will get much less out the floor, maybe only 20-25 watts per sqm depending on how thick the carpet is]
If the floor is cold and the room is cold, then calculations get more tricky as the floor is heating up [thermal inertial], and the deltaT between the room and floor is different, and changing.
Having said all of that I did notice two of your pictures, which i think contradict each other.
Assuming that the daikin diagram is the correct one, then you should be able to run your flow much closer to 30degC, and gain about 30-45% in efficiency of the heat pump. So in theory leave it running nearly twice a long as you do now for the same cost, and likely more comfortable temperatures.
As an experiment, I would suggest two things
1 - run the heating twice as long as you do now, all day if possible, but set you weather compensation so the flow temp is around 35 degC or even less 2 - set you target room temp to 19.5
-- Attachment is not available ---- Attachment is not available ---- Attachment is not available --
Thats 2 manifolds,id imagine some loops run near100m, not all i hope. I ddnt post them 2 diagrams however. Why would my boiler have flow this morning when no call for heat or dhw, is that cycling? flow rate last night at 33 with 7 loops open.what do you mean run heating twice as long, the heating turns off when stats get up to 21 in living areas. 19.5 feels little chilly to sit in at night so try to have at 21. during coldest days i had house at 22 and was v nice but was using up to70kwhs a day when temps below freezing and, was that usage pretty normal so and i overreacted?
Unless you have specific circumstances requiring such a high temperature, you should be able to run the house about 1.5 to 2 degC lower with UFH than with radiators, as you have radiant heat 19.5 should "feel like" 21 with radiators.
He said the plans were over specced, 26 loops on plans but i have 17
I hope the plumber understands that for a heat pump things are different and that the new 17 circuit design still meets the criteria needed for a heat pump, which is high flow rate and lowish flow temperature.
Fewer circuits and larget spacing will means your UFH will be much slower to respond to demands for heat.
When you are installing UFH for low temperature heat sources such as heat pumps you need closer spacing, which means more pipe, which means more circuits (the latter because of max circuit length).
If you have 17 circuits, you must have a second manifold somewhere since I could only count 13 in your picture. Let us assume for a moment you have 17 circuits.
For your floor area, the following is likely.
@200mm centers that means, on average, up to 70m pipe per circuit. @150mm centers that means, on average, up to 95m pipe per circuit.
Both technically possible, though the second at the extremes of what is recommended.
Assuming your 11kW daikin is correctly specced, and you have a 242 sqm house, then at the design load (probably somewhere between 1 and -5 degC depending on where you live) you have a heat loss of 45 watts per square meter.
Assuming you need 40 watts per square meter @ outside ambient of 6 degC (it may be a bit more or less, but let us assume this)
@21 degC room temperature, you should get around 40watts per square meter emitted into the room from the floor, once the floor has reached a temperature of 25 degC
[If you have something on top of the floor, such as a carpet, you will get much less out the floor, maybe only 20-25 watts per sqm depending on how thick the carpet is]
If the floor is cold and the room is cold, then calculations get more tricky as the floor is heating up [thermal inertial], and the deltaT between the room and floor is different, and changing.
Having said all of that I did notice two of your pictures, which i think contradict each other.
Assuming that the daikin diagram is the correct one, then you should be able to run your flow much closer to 30degC, and gain about 30-45% in efficiency of the heat pump. So in theory leave it running nearly twice a long as you do now for the same cost, and likely more comfortable temperatures.
As an experiment, I would suggest two things
1 - run the heating twice as long as you do now, all day if possible, but set you weather compensation so the flow temp is around 35 degC or even less 2 - set you target room temp to 19.5
-- Attachment is not available ---- Attachment is not available ---- Attachment is not available --
Thats 2 manifolds,id imagine some loops run near100m, not all i hope. I ddnt post them 2 diagrams however. Why would my boiler have flow this morning when no call for heat or dhw, is that cycling? what do you mean run heating off twice as long, the heating turns off when stats get up to 21 in living areas. 19.5 feels little chilly to sit in at night so try to have at 21. during coldest days i had house at 22 and was v nice but was using up to70kwhs a day when temps below freezing and, was that usage pretty normal so and i overreacted?
I'm not going to try and add to any of the technical advice you've had but ...
Up to 70kWh to heat a 240 m2 house to 22 deg at below zero outside temps is in the right ball park, even for a new house. My house, although not new, is quite well insulated and about 2/3 the size of yours. I heat the whole house to 21 deg and use 45kWh or so in similar conditions. You may be able to improve things a bit but I doubt you'll see drastic improvements. Definitely worth doing what you can though.
the way in which heat is transferred into the room
the way in which the human body perceives the 3 different categories of heat
As a lab-technician, you'll already know that heat can be transferred by conduction, convection and radiation.
A radiator heats the room primarily by convection (despite the name!). The cold air rises past the surface of the radiator, picks up heat, travels across the ceiling and then falls onto the occupants on the other side of the room. Thus the hotter air is high up, and the floor has a cold draught across it.
However, UFH transfers the heat mainly by radiation. The larger the mass of an object in the room, the more of that radiation is absorbed.
If the surface of a floor heated by UFH has reached a pleasant 25-26°C then a human will feel warm. But the air temperature at your thermostat will be reading about 19°C.
To achieve the same result with a radiator requires an air temperature of around 21°C
Don't just look at a thermometer in the room. It has a relatively low mass compared with a human, and is measuring air temperature transferred to it by conduction from the air molecules.
Warning... pinning this up on the staff room wall will provoke furious debate. Do so at your peril!
This post was modified 2 years ago 5 times by Transparent
@transparent tell all that to the girlfriend 🤣 . Its what your body gets used to swell i suppose. My friend has his set to23.5 and he wanted it bit higher even. Thinking my system may be performing ok, just need to do balancing with weather compensation, trying to find the thread derek m had on it. If its easy to follow ill attempt it.
is the most any flowrate should be is 2.5l/min for 100mloop, loop length/40 is the standard im reading. my biggest sun room longest loop has alot of glass and laminated timber in the room so was thinking of increasing that to see if it would heat up quicker. Presume higher flow rate wont cost me more energy usage?
is the most any flowrate should be is 2.5l/min for 100mloop, loop length/40 is the standard im reading. my biggest sun room longest loop has alot of glass and laminated timber in the room so was thinking of increasing that to see if it would heat up quicker. Presume higher flow rate wont cost me more energy usage?
As it has been pointed out previously by other forum members, the primary objective with heat pumps is reasonably continuous operation at low LWT, not high LWT to heat a room up quickly. You should therefore seek to get the rooms up to temperature, and then keep them at that temperature, varying the heat energy supply to match the varying heat energy demand. The higher the desired room temperature, the more heat energy that will be required, and the more expensive the system will be to run.
Many modern cars provide a mpg indication, which may not be totally accurate, but at least gives an indication of fuel consumption. If you were to drive such a car at 30 mph, and then push down on the accelerator to speed up to 70 mph quickly, you will no doubt see that the mpg indication drops quite dramatically. If instead, you gradually push down on the accelerator, it should be possible to bring the car up to 70 mph, but still maintain a reasonably high mpg reading.
This is how heat pumps should be operated for best overall efficiency.
The quantity of heat energy that is transferred by the heat emitters (UFH heating loops in your case), is primarily dependent upon the LWT, not the water flow rate, so to heat a room up quickly will require a higher LWT. Increasing the LWT means that your heat pump will need to work harder and will be less efficient, thereby costing more to run.
At the end of the day the choice is your's, you can heat rooms up quickly at greater expense, or you can heat rooms more slowly, at lower expense.
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