Insulation of the top floor ceiling

Was heat for heating purposes generated only with the gas and wood?
With us, that is not the case, so it is hard for me to say how much is actually due only for heating.
You can only calculate an average over a few years to know whether such a measure has actually paid off.
Additionally, some winters are colder and longer than others.
In the end, I consider it quite difficult to find out when the actual zero hour will be or even when it was.

Wood only for heating (in one apartment a wood stove, in another apartment a wood-burning stove), gas naturally for heating + hot water.

I see it similarly to you. You can't determine it exactly, only estimate more or less accurately.
Too many factors play a role. Ventilation behavior, room temperature, etc.

But I think it will pay off over several years. I will see then. We have only been living in the house for 1.5 years... I'll just see how things develop.
€740 is definitely not such an amount that you couldn't take the risk ;)

Regards
Specki

I just insulated the top floor ceiling as well, similar ceiling construction, but I do use the attic as a storage room for all kinds of things.
Therefore, I used a mixture of walkable EPS boards with OSB on top and mineral wool.
The effect is already clearly noticeable; the house is simply much warmer with the same heating or the heating can be turned down.
It pays off quite quickly; with old houses like ours, you can roughly save 1/3 of the heating costs with proper insulation of the top floor ceiling compared to uninsulated. The comfort gain, hopefully also in summer, comes as a free bonus on top :-)

So I have now laid about 3/4 of the area with 180 mm insulation. And yes, I can feel it. Not so much in the back rooms, since I have electronic thermostats, they will probably just run a bit less. But in the front living room/kitchen I notice that I have to put less wood in the stove to keep our temperature constant.

I'm curious how it will affect the gas costs overall. Wood consumption has already decreased :)

The last quarter will be laid next week. Unfortunately, there is still a lot of stuff up there that first needs to find a new place....

Regards Specki

One aspect has been overlooked here. You have a fully boarded roof with roofing felt, which we call Harzer Unterdach. That is diffusion-tight. At the same time, your attic becomes colder due to the insulation. The risk of condensation therefore increases. That is why it would be important for the door to the attic to close relatively airtight, and I would also take a look at the ventilation of the attic space.

It could also happen that the door to the attic becomes damp on the warm side, as it is probably not insulated.

One aspect has been too briefly addressed here. You have a fully boarded roof with roofing felt, which we call Harzer Underlay. That is diffusion-tight. At the same time, your attic becomes colder due to the insulation. The risk of condensation forming therefore increases. That is why it would be important that the door to the attic closes relatively airtight, and I would also take a look at the ventilation of the attic space.

It could also happen to you that the door to the attic now becomes damp on the warm side, as it is probably not insulated.

Yes, the roof is fully boarded with roofing felt, but with all the penetrations for ventilation and otherwise, it is not airtight in the slightest. When it is windy outside, the wind whistles through properly. It is almost always nearly outside temperature under the roof, except in summer, when the sun shines strongly on it, then it is significantly warmer there. Therefore, the air exchange to the outside is always ensured. Also, the attic does not really become colder now, since it already had almost outside temperature anyway.

I can only repeat once again. We already clearly feel the insulation in the front area where we heat with wood!

Regards
Specki