Hello,
we are currently struggling with our heating system. It is warm everywhere in the house—both on the ground floor and in the heated basement room—around 21-22°C (70-72°F). However, the temperature in all rooms in the attic is noticeably lower, usually about 2°C (3.6°F) difference. This is problematic because a) it is too cold and b) it also affects the bathroom.
We have already tried various measures. We adjusted the heating curve, the manufacturer’s service performed a firmware update, and the hydraulic balancing was done again... but the problem remains the same. The attic stays consistently about 2°C (3.6°F) cooler than the other floors. The heating technician said this is normal because of the many windows and that it always tends to be cooler in the attic. He advised us to simply increase the supply water temperature. But that can’t be the solution, right? Although this raises the temperature in the attic, we then have to lower the temperature on the ground floor because otherwise it becomes too hot. The 2°C (3.6°F) difference always stays the same. We have solid ceilings and walls, underfloor heating everywhere, and the room thermostats turned up fully.
Is this really normal, or is the heating technician just trying to sell us that because he has no other ideas? What is your experience? Do you also have such temperature differences?
we are currently struggling with our heating system. It is warm everywhere in the house—both on the ground floor and in the heated basement room—around 21-22°C (70-72°F). However, the temperature in all rooms in the attic is noticeably lower, usually about 2°C (3.6°F) difference. This is problematic because a) it is too cold and b) it also affects the bathroom.
We have already tried various measures. We adjusted the heating curve, the manufacturer’s service performed a firmware update, and the hydraulic balancing was done again... but the problem remains the same. The attic stays consistently about 2°C (3.6°F) cooler than the other floors. The heating technician said this is normal because of the many windows and that it always tends to be cooler in the attic. He advised us to simply increase the supply water temperature. But that can’t be the solution, right? Although this raises the temperature in the attic, we then have to lower the temperature on the ground floor because otherwise it becomes too hot. The 2°C (3.6°F) difference always stays the same. We have solid ceilings and walls, underfloor heating everywhere, and the room thermostats turned up fully.
Is this really normal, or is the heating technician just trying to sell us that because he has no other ideas? What is your experience? Do you also have such temperature differences?
B
Bieber081524 Mar 2017 15:56Surface temperatures are not exactly easy to measure, and the values obtained here are probably not reliable. Supply and return temperatures should be easier to measure. Flow rates can be determined at least relatively by using the indicators on the heating circuit distributor.
Obviously, measurements should be taken under steady-state conditions. In this case, that means waiting a long time after changing the settings (and turning off outdoor temperature control, instead operating manually).
Obviously, measurements should be taken under steady-state conditions. In this case, that means waiting a long time after changing the settings (and turning off outdoor temperature control, instead operating manually).
P
Peanuts7426 Mar 2017 09:22Bieber0815 schrieb:
Surface temperatures are not that easy to measure accurately; the values obtained here are probably unreliable. Supply and return temperatures should be easier to measure. Flow rates can at least be estimated relatively using the flow indicators in the heating circuit distributor.
Naturally, measurements should be taken under steady-state conditions, which means waiting a long time after adjusting the settings (and disabling outdoor temperature control, instead operating manually).Why is measuring surface temperature not that straightforward?
B
Bieber081527 Mar 2017 09:14For non-contact measurement (radiation methods), it is necessary to know the (temperature-dependent) emissivity of the surface. If this is low, there is a significant influence from the surrounding radiation.
With contact or adhesive thermometers, there is always feedback between the object being measured and the thermometer (heat flow).
If you want to evaluate a underfloor heating system where the temperature difference between supply and return is only a few degrees, and the measurement is carried out by a layperson (or tradesperson) without experienced physicists present, using an extremely expensive measuring device, I tend to consider the measured results (with regard to the intended use) as worthless.
It is better to measure directly in the medium itself. This is straightforward as long as access is possible, and the measured temperatures are then very accurate. The remaining uncertainty relates to the condition of the system (stationary?).
With contact or adhesive thermometers, there is always feedback between the object being measured and the thermometer (heat flow).
If you want to evaluate a underfloor heating system where the temperature difference between supply and return is only a few degrees, and the measurement is carried out by a layperson (or tradesperson) without experienced physicists present, using an extremely expensive measuring device, I tend to consider the measured results (with regard to the intended use) as worthless.
It is better to measure directly in the medium itself. This is straightforward as long as access is possible, and the measured temperatures are then very accurate. The remaining uncertainty relates to the condition of the system (stationary?).
P
Peanuts7427 Mar 2017 10:45Okay, the analysis or interpretation is a different matter. But with a thermal imaging camera, you should at least be able to measure a difference in surface temperature when the supply temperature is increased by 5°C (9°F) or more. If, using the same "measurement method," the surface temperature does not change—even when measured by an amateur—that should raise some doubts.
Of course, I don’t know the ideal values for things like window frames or the roof, but even a layperson can often detect leaks.
Of course, I don’t know the ideal values for things like window frames or the roof, but even a layperson can often detect leaks.
K
Knallkörper27 Mar 2017 14:31Bieber0815 schrieb:
For non-contact measurement (radiation methods), you need to know the (temperature-dependent) emissivity of the surface. If it is low, the surrounding radiation has a significant influence.
With surface-mounted or glued-on thermometers, there is always feedback between the object being measured and the thermometer (heat flow).
If you want to evaluate a radiant floor heating system, where the difference between supply and return temperature is only a few degrees, and the measurement is done by a layperson (or tradesperson) in the absence of experienced physicists using very expensive equipment, I tend to consider the results (for the intended purpose) worthless.
It is better to measure directly in the medium. That is straightforward, as long as you have access, and the temperatures determined are then very accurate. The only uncertainty remains the system condition (steady state?).Let's keep things in perspective. The goal is to measure whether the surface temperature changes with an increase in the supply temperature. For this, the emissivity does not play a significant role, and certainly not its temperature dependence. Just stick a piece of black insulating tape on the surface, and that’s it. And you worry about accuracy in a contact measurement because of heat flow? Between screed and, for example, a Pt100 sensor? Seriously? If I were 15 years older, I’d ask: What’s wrong with engineers these days, do they only see obstacles??? Do you also call in an "experienced physicist with very expensive equipment" at work whenever you need to measure something minor?
P
Peanuts7427 Mar 2017 14:36Exactly, the good camera still records for a "long" time when you briefly touch the floor with your hand. A temperature difference of more than 5 degrees Celsius (9°F) in the initial reading should be noticeable to any layperson. To what extent the surface temperature should then change is not so easy to predict, but even with bare feet, you can clearly feel the difference...