Hello,
When considering underfloor heating for my new build, my father-in-law recommended the underfloor heating system from Athe-therm (specifically the OptImus model). In this system, metal plates are placed above the heating pipes to ensure better heat distribution.
He installed this system himself a few years ago, mainly because his old underfloor heating from anno ducto caused some tiles to feel cold while others were warm. As a child, my wife used to slide around on the warm tiles while playing.
I assume this issue is not as pronounced with current systems as described here. I recently asked my brother-in-law if their floor had cold and warm spots—that is, if you can tell where the pipes run and where they don’t. He said you can feel this by hand during winter.
My question is: Is it normal for a modern underfloor heating system to have cold and warm spots? (This is not related to the ambient air temperature but only to surface contact warmth.)
If this is not unusual, I will definitely consider the Athe-therm system in my planning.
When considering underfloor heating for my new build, my father-in-law recommended the underfloor heating system from Athe-therm (specifically the OptImus model). In this system, metal plates are placed above the heating pipes to ensure better heat distribution.
He installed this system himself a few years ago, mainly because his old underfloor heating from anno ducto caused some tiles to feel cold while others were warm. As a child, my wife used to slide around on the warm tiles while playing.
I assume this issue is not as pronounced with current systems as described here. I recently asked my brother-in-law if their floor had cold and warm spots—that is, if you can tell where the pipes run and where they don’t. He said you can feel this by hand during winter.
My question is: Is it normal for a modern underfloor heating system to have cold and warm spots? (This is not related to the ambient air temperature but only to surface contact warmth.)
If this is not unusual, I will definitely consider the Athe-therm system in my planning.
Hello,
I think people have a misunderstanding about underfloor heating. The days of having "warm" tiles are over since standards like KFW 55/40. The amount of energy transferred through the floor into the living space is usually so low that the supply temperatures are around 24, 25, or 26 degrees Celsius (75, 77, or 79°F), which is also optimal for heat pumps. This always feels cold! If you are worried about "cold" spots on the floor, you simply install pipes with a 10cm (4 inches) spacing. This ensures that the temperature is evenly distributed across the floor.
If there actually are warm or cold areas, it’s because the piping was cut back and, for example, spaced at 20cm (8 inches) intervals. To deliver enough energy to the room, the supply temperature was raised. This resulted in large pipe spacing combined with high supply temperatures, causing warm and cold zones. People who experienced this simply were not informed beforehand.
I installed my first underfloor heating in 1994. The 10cm (4 inches) spacing I insisted on was discouraged by the installer at the time. He said it would only be expensive and that the house would also warm up with 20cm (8 inches) spacing…
There are no warm/cold zones with 10cm (4 inches) spacing! A few years ago, a dishwasher leaked in the house, and holes had to be drilled into the screed for drying. During this, thermal imaging cameras were used to photograph the floor to avoid drilling into the heating pipes. It clearly showed how evenly warm the floor was.
I think people have a misunderstanding about underfloor heating. The days of having "warm" tiles are over since standards like KFW 55/40. The amount of energy transferred through the floor into the living space is usually so low that the supply temperatures are around 24, 25, or 26 degrees Celsius (75, 77, or 79°F), which is also optimal for heat pumps. This always feels cold! If you are worried about "cold" spots on the floor, you simply install pipes with a 10cm (4 inches) spacing. This ensures that the temperature is evenly distributed across the floor.
If there actually are warm or cold areas, it’s because the piping was cut back and, for example, spaced at 20cm (8 inches) intervals. To deliver enough energy to the room, the supply temperature was raised. This resulted in large pipe spacing combined with high supply temperatures, causing warm and cold zones. People who experienced this simply were not informed beforehand.
I installed my first underfloor heating in 1994. The 10cm (4 inches) spacing I insisted on was discouraged by the installer at the time. He said it would only be expensive and that the house would also warm up with 20cm (8 inches) spacing…
There are no warm/cold zones with 10cm (4 inches) spacing! A few years ago, a dishwasher leaked in the house, and holes had to be drilled into the screed for drying. During this, thermal imaging cameras were used to photograph the floor to avoid drilling into the heating pipes. It clearly showed how evenly warm the floor was.
Okay, good information about the spacing, I didn’t know that before.
However, it still doesn’t seem to be standard to work with 10-15cm (4-6 inches) spacing. From what I’ve read, 10cm (4 inches) spacing is used in bathrooms and near window walls, while in other rooms it’s usually 20cm (8 inches).
Others say that you can’t really feel the difference because the flow temperature is so low that the tiles always feel cool.
Smaller spacing apparently allows for even lower flow temperatures, which should reduce energy costs. However, in this context, the discussion usually refers only to heat pumps. I assume that the potential energy savings would be similar with a gas condensing boiler.
So either something like (5-10-15cm (2-4-6 inches) spacing), or maybe using these heat conduction plates. I could imagine it ends up being the same. But I really don’t know!
Maybe someone has experience with dry systems and heat conduction plates to achieve similarly low flow temperatures with larger spacing (20cm (8 inches)).
However, it still doesn’t seem to be standard to work with 10-15cm (4-6 inches) spacing. From what I’ve read, 10cm (4 inches) spacing is used in bathrooms and near window walls, while in other rooms it’s usually 20cm (8 inches).
Others say that you can’t really feel the difference because the flow temperature is so low that the tiles always feel cool.
Smaller spacing apparently allows for even lower flow temperatures, which should reduce energy costs. However, in this context, the discussion usually refers only to heat pumps. I assume that the potential energy savings would be similar with a gas condensing boiler.
So either something like (5-10-15cm (2-4-6 inches) spacing), or maybe using these heat conduction plates. I could imagine it ends up being the same. But I really don’t know!
Maybe someone has experience with dry systems and heat conduction plates to achieve similarly low flow temperatures with larger spacing (20cm (8 inches)).
A smaller pipe spacing leads to lower supply temperatures, regardless of the energy source (heat pump, gas, oil, wood).
In my current house, I use wood, solar thermal, and a gas condensing boiler, all connected to a buffer tank from which the underfloor heating and domestic hot water draw energy. In my bathroom, I installed the pipes with a spacing of 5cm (2 inches), and elsewhere I used 10cm (4 inches).
Personally, I don’t see any advantage in using metal plates. I believe that self-leveling screed, which perfectly surrounds the pipes, is more effective. The additional cost of the piping is negligible compared to the overall expenses. In my ground floor, I have about 2500 meters (8200 feet) of piping, which cost around 1200€. Since I don’t know how the technology will develop, I would definitely opt for closer spacing to keep the option open to switch the energy source in the future. For example, if I want to change from gas to a heat pump in 15 years, I can do so without having to modify the screed.
But that is just my personal approach.
In my current house, I use wood, solar thermal, and a gas condensing boiler, all connected to a buffer tank from which the underfloor heating and domestic hot water draw energy. In my bathroom, I installed the pipes with a spacing of 5cm (2 inches), and elsewhere I used 10cm (4 inches).
Personally, I don’t see any advantage in using metal plates. I believe that self-leveling screed, which perfectly surrounds the pipes, is more effective. The additional cost of the piping is negligible compared to the overall expenses. In my ground floor, I have about 2500 meters (8200 feet) of piping, which cost around 1200€. Since I don’t know how the technology will develop, I would definitely opt for closer spacing to keep the option open to switch the energy source in the future. For example, if I want to change from gas to a heat pump in 15 years, I can do so without having to modify the screed.
But that is just my personal approach.
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