Hello,
in our case (120 sqm (1300 sq ft) living area with underfloor heating, 60 sqm (650 sq ft) basement corridor area with standalone heaters), a 14 kW Wolf gas-solar heating system is planned. We are considering installing standalone heaters in two rooms in the basement, which is fully insulated. However, the plumbing company argues that the 14 kW system is not sufficient and recommends a 20 kW unit.
I find this a bit confusing and believe I have read that oversizing can lead to higher operating costs and increased wear (among other reasons, due to the minimum modulation level).
For now, I have declined this proposal. Presumably, it would make more sense to calculate the actual heating load instead of just "going for it." However, I think increasing the heating capacity just because of two standalone heaters is exaggerated.
Is there anyone in this forum who has an opinion on this?
in our case (120 sqm (1300 sq ft) living area with underfloor heating, 60 sqm (650 sq ft) basement corridor area with standalone heaters), a 14 kW Wolf gas-solar heating system is planned. We are considering installing standalone heaters in two rooms in the basement, which is fully insulated. However, the plumbing company argues that the 14 kW system is not sufficient and recommends a 20 kW unit.
I find this a bit confusing and believe I have read that oversizing can lead to higher operating costs and increased wear (among other reasons, due to the minimum modulation level).
For now, I have declined this proposal. Presumably, it would make more sense to calculate the actual heating load instead of just "going for it." However, I think increasing the heating capacity just because of two standalone heaters is exaggerated.
Is there anyone in this forum who has an opinion on this?
If there is KfW funding, I received a supplementary sheet for the builder from our energy consultant. It states that a room-by-room heating load calculation according to DIN 12831 should be performed.
This calculation determines the heating load of the entire building based on the target temperatures of the individual rooms and the heat losses/U-values of walls and windows. In our case, the heating load was just under 6 kW and your 14 kW gas heating system would therefore be oversized by a factor of two. That might not be such a big issue with gas, as it would be with a heat pump, but choosing a 20 kW unit is simply unreasonable.
This calculation determines the heating load of the entire building based on the target temperatures of the individual rooms and the heat losses/U-values of walls and windows. In our case, the heating load was just under 6 kW and your 14 kW gas heating system would therefore be oversized by a factor of two. That might not be such a big issue with gas, as it would be with a heat pump, but choosing a 20 kW unit is simply unreasonable.
T
T_im_Norden21 Oct 2020 11:20Is this a heating engineer or someone from the house construction company? Today, the most important factor for a heating system is the minimum output, and for the 20 kW (68,000 BTU/h) version, it is far too high. If he claims he doesn't see any issues with that, he either doesn't know what he's talking about or is deliberately withholding information.
T_im_Norden schrieb:
Is this a heating engineer or someone from the house construction company?
Today, the most important factor for a heating system is the lowest output, and the 20 kW (about 68,000 BTU/h) version is far too powerful.
If he claims he sees no issues, he either doesn’t know what he’s talking about or is deliberately leaving out information. He is from the subcontractor of the house construction company.
I get the impression they have had negative experiences before where something didn’t work properly, which is why they prefer to oversize the system to make sure it definitely gets warm...
Hausbaer schrieb:
I have the impression that they have had negative experiences before because something didn’t work, so they prefer to oversize to make sure it will definitely be warm...That’s exactly the case. An oversized heating system always works, even without the effort of a detailed demand analysis. The result is not always efficient, but the customer will be warm. They won’t complain just because the system isn’t as efficient as it could potentially be.Efficiency was therefore improved elsewhere – in terms of labor input relative to the revenue generated.
T
T_im_Norden22 Oct 2020 06:36If the heating load for each room is properly calculated, there is no reason to over-dimension the system "just to be on the safe side."
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