Roof with photovoltaic or other investment, any experiences?

Hi,

I am currently planning the modernization of our 29-year-old house.
Apart from recurring renovation work inside the house, no major (modernization) measures have been carried out so far.
We have additionally insulated the walls ourselves in the past.
Nothing else.

That means the house:
- still has the original roof
- the original gas heating system
- the original windows on the ground floor

What is already fixed and will be carried out in late summer/early autumn is the roof modernization according to [KFW] guidelines. That means the roof will be completely rebuilt and insulated.

Additionally, I have budgeted about 13,000 euros for a photovoltaic system.
However, I am still not sure how sensible the installation of a photovoltaic system really is.
The company I am in contact with recommended using the electricity and feeding the rest back into the grid.
My first considerations were actually to have a storage system to be able to use the electricity at night or during bad weather...
The location would be ideal for a photovoltaic system, as our roof faces southeast.

Therefore, I have now thought whether I should rather invest the money in a new heating system.
Our heating system has been in use since the house was built and has never caused any problems.
However, I think that new gas heating systems should work more efficiently and reduce gas consumption (I hope).
In addition, I would probably still have a few euros left over to possibly replace radiators.
Provided radiators can contribute to efficiency...

Maybe you have some advice or would share what you would do.

Regards

I'll start. Not too much on technology. New gas boiler, I think that's right. New radiators, why? Or are the old radiators so rusted? New Danfoss thermostats, yes to that. Those things eventually don't close well. Photovoltaics are burning money, better insulate the side walls and roof. 30 years, so the house is from 1987 1988. Are all windows still okay? Roof tiles good? Sealant on the base intact? Karsten

Have an energy consultant create a concept.

Advised: There is potential in the gas boiler, it doesn’t have condensing technology yet, does it?

Photovoltaics can also bring a return, as always it depends on the purchase price. Storage is a matter of preference and even with a lot of alcohol not nice to drink.

Photovoltaics are generally not a waste of money. That is more the case with thermal systems. The gas boiler might be due for replacement. However, I would first try to optimize the old one. Heating behavior, settings, and insulation can have a big impact here. Since you still want to do the roof, I would also mention the windows here. Likewise thermal bridges like the roller shutter box, for example. I would not touch the radiators at first. My approach would be to insulate what is possible first (basement ceiling?) and only at the very end have a suitable gas boiler installed if the old one breaks down. Without knowing more details, a ground-source heat pump might also be possible. But that is just guesswork.

After the first paragraph, I would have said: Insulate the roof! But you are already planning that.

Yes, I agree with the previous speakers:
- Check the gas boiler, renew if necessary
- Electronic thermostats
- Check the windows, renew if necessary (from this point on, no more without consultation, so you don't bring mold into the house).
- Assess the general condition, what still needs to be done now or in the next few years?

I would consider the photovoltaic system quite soberly as an investment object. Honestly evaluate the (personal time) effort and the concentration risk. I would probably then invest in a broadly diversified stock ETF and leave the photovoltaic system. But it might be different for you ...

Photovoltaics are all the more worthwhile the more of the electricity you can use yourself. Heat pumps and electric cars fit well with this. Gas heating and combustion engines less so.