ᐅ Individual Room Control for Air-to-Water Heat Pump and Underfloor Heating
Created on: 31 Jan 2023 20:20
W
Waldbewohner
Hello,
this is more of a general question rather than related to a specific construction project.
I have increasingly heard from acquaintances that heating engineers/general contractors often recommend an electronic radiator thermostat (ERT) when heating with an air-to-water heat pump. We have also already received such an offer.
However, it seems that the whole internet is of the opinion that an ERT is not only pointless but even counterproductive.
I find it hard to judge, but the explanations sound convincing.
1) In solid construction, after a certain time, the entire space within the thermal envelope is heated to roughly the same temperature anyway. So it is pointless to turn off the heating in rarely used rooms because they are heated through the other rooms.
2) The entire masonry, screed, etc., makes the heating behavior very sluggish, and the low flow temperatures do not allow targeted "boosts." Therefore, it is more sensible to simply keep the entire underfloor heating running constantly and operate the heat pump in the "comfort range" at the lowest possible flow temperature.
3) As in point 2: increasing the room temperature at the thermostat by 2°C (3.6°F) takes many hours to become noticeable due to the sluggish system. So if it’s too cold in the evening, adjusting the thermostat doesn’t help anyway.
I am not an expert, but this sounds plausible.
Is an ERT really counterproductive and should it be avoided in solid construction with an air-to-water heat pump?
this is more of a general question rather than related to a specific construction project.
I have increasingly heard from acquaintances that heating engineers/general contractors often recommend an electronic radiator thermostat (ERT) when heating with an air-to-water heat pump. We have also already received such an offer.
However, it seems that the whole internet is of the opinion that an ERT is not only pointless but even counterproductive.
I find it hard to judge, but the explanations sound convincing.
1) In solid construction, after a certain time, the entire space within the thermal envelope is heated to roughly the same temperature anyway. So it is pointless to turn off the heating in rarely used rooms because they are heated through the other rooms.
2) The entire masonry, screed, etc., makes the heating behavior very sluggish, and the low flow temperatures do not allow targeted "boosts." Therefore, it is more sensible to simply keep the entire underfloor heating running constantly and operate the heat pump in the "comfort range" at the lowest possible flow temperature.
3) As in point 2: increasing the room temperature at the thermostat by 2°C (3.6°F) takes many hours to become noticeable due to the sluggish system. So if it’s too cold in the evening, adjusting the thermostat doesn’t help anyway.
I am not an expert, but this sounds plausible.
Is an ERT really counterproductive and should it be avoided in solid construction with an air-to-water heat pump?
W
Waldbewohner1 Feb 2023 10:08akanezumi schrieb:
When it comes to a cooling function, the situation might be different. In that case, an ERR could definitely make sense (whether with or without KNX doesn’t really matter at first). Could you perhaps explain that in more detail? Or recommend search terms for further reading or websites? I’m interested in the background information.
What would the usage profile look like then?
In winter, would everything be set to “manually off with no power” as Michert described, and in summer only the room that needs cooling be regulated down?
With “manually off with no power,” wouldn’t the other rooms also receive the cooled water?
R
RotorMotor1 Feb 2023 10:21halmi schrieb:
However, this doesn’t change the fact that constantly adjusting the settings is completely counterproductive for an efficient heat pump operation. After hydraulic and thermal balancing, there is no more overheating. What makes you assume that?
In my house, this statement definitely does not apply.
As I said, solar gains and their use make rooms measurably warmer.
A thermal balance is constant, but life isn’t, and neither is the weather.
From my point of view, regulating is very helpful here.
What good are solar gains if I keep adding heat through the heating system?
What many people seem to confuse is that a good COP (Coefficient of Performance) or annual performance factor is considered the most important thing.
For me, the total energy consumption matters much more, because that’s what affects both the environment and the wallet.
Waldbewohner schrieb:
In winter, set everything to “manual power off” as described by Michert, and then in summer only regulate the room that needs cooling? With a heat pump that has a cooling function, the priority of where the water should flow changes twice a year.
That manual adjustment can get really annoying.
@Waldbewohner
Your considerations in the initial post are generally correct.
The efficiency ratio (ERR) works very well for older buildings with radiators to save energy. In new constructions with underfloor heating, however, it is rather ineffective.
For the cooling function, it can make sense. However, I don’t really consider the few degrees it can achieve as true cooling, but at most a mild tempering. Everyone has to decide for themselves whether it is worthwhile.
Your considerations in the initial post are generally correct.
The efficiency ratio (ERR) works very well for older buildings with radiators to save energy. In new constructions with underfloor heating, however, it is rather ineffective.
For the cooling function, it can make sense. However, I don’t really consider the few degrees it can achieve as true cooling, but at most a mild tempering. Everyone has to decide for themselves whether it is worthwhile.
You distribute the solar gains throughout the entire house using an active heating system; when it’s off, they simply won’t be transferred. The room overheats because of the solar gains, not because of the underfloor heating. In this case, turning off the heat pump does not help at all.
R
RotorMotor1 Feb 2023 10:38halmi schrieb:
You distribute the solar gains throughout the house using a running heating system; if it’s off, then you don’t. The room overheats because of the solar gains, not because of the underfloor heating. Turning off the heat pump doesn’t help at all in that case.If the sun only shines on the floor, that might be true, but I don’t think that’s the case. If the sun shines on the walls, furniture, kitchen countertop, etc., the room would need to overheat through the supply temperature to then transfer heat via the underfloor heating. So that doesn’t really make sense.Regarding people, while I’m working, I generate about 100W just by being present, plus the computer and monitors. So that’s around 300W of heat output. That’s about what the underfloor heating provides. Therefore, if I’m not in the room, I need the underfloor heating; if I am in the room, I definitely do not.
Similar topics