ᐅ Selecting Gas Heating Capacity: 20 kW Instead of 14 kW

Created on: 8 Oct 2020 18:43
H
Hausbaer
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?
H
Hausbaer
8 Oct 2020 20:44
Ok. Yes, I expected these answers. I will initially not have the additional radiators installed and possibly add them after the construction.
K
knalltüte
8 Oct 2020 20:57
Hi, you might want to reconsider the 14kW capacity. Our demand is 5.3kW (according to the energy consultant) for about 300m² (3,230 ft²)!

So, calculate the heat load for each individual room first, then size the heating system accordingly. Without a heat load calculation, it will just be done "as usual," which doesn’t always mean well suited or properly sized!
H
Hausbaer
8 Oct 2020 21:01
I believe 14 kW is the lowest (max) capacity in the Wolf gas-solar series. We are building with GU. For now, we are bound to the construction and performance specifications there.
Mycraft9 Oct 2020 13:40
With 20 kW you can also heat the other half of the semi-detached house right away, so yes, if possible, go for the 14 kW. Or you create a basement and sell your excess heat to your neighbor.
H
Hausbaer
20 Oct 2020 21:46
So the company insists on the higher capacity and otherwise refuses to provide any warranty for the radiators.
Ötzi Ötztaler
20 Oct 2020 21:47
Insist on a room-specific heating load calculation according to DIN xxx