Snow melts from the roof faster than at the neighbors'

I have noticed that the snow on my roof melts much faster than on the roofs of the neighbors. This surprises me because I have a low-energy house with insulated ceiling and double-ventilated cold roof. The neighbors have "normal" houses, with knee walls and insulated roof. Does anyone have an idea why my roof apparently emits more heat? I fear insufficient insulation.

Your insulation will be worse there, which would admittedly be strange for a low-energy house. Was a blower door test conducted? Have you already talked to the construction company about it?

Hello Krambambulli, that the snow melts off the roof is due to the warming of the roof, of course, but especially with a ventilated roof I wonder how that can happen. The insulation can be good and thick, but the problem with roofs is always the airtightness. With a leaking vapor barrier, warm air penetrates into the insulated intermediate space – and possibly also into the ventilation layer of your roof. But without seeing the situation on site and especially without knowledge of the planning, nothing more can be said. My predecessor mentioned it: Was there an airtightness test on the roof, and what were the results? Finally, something about "Niedrigenergiehaus": A house does not become an NEH solely through the thermal insulation calculation, because a lot can be fudged and improved by factors. You really have to consider and optimize all components. So it is therefore possible that the roof insulation of your house is thinner than that of the neighbors.

So if the snow melts faster than on the neighboring roof, then the thermal insulation is inadequate. Of course, it also depends on the roof pitch, are they the same? And how the houses are oriented to the sun, here too, there should be roughly the same conditions.

If this is roughly the same, then check the thermal insulation, were the required insulation layers actually installed, I have already seen cases where only 40 insulation mats were laid here, but 150 were billed. The customer could hardly verify this afterwards, everything is sealed anyway.

I see it that way and too much heat is lost here. I suspect that the wrong insulation was used. This botched construction is really severe. :(

In this situation, I would also be surprised that the snow on my roof melts faster than at the neighbor's. Just check the insulation here and that's not so easy now. But get to the bottom of the cause.