ᐅ New Construction Preparation for Future Experience Documentation

Hello,

Construction is scheduled to begin for us at the end of October or beginning of November.

We are building a KfW 55 standard house with a gas boiler and a 5m² (54 sq ft) solar thermal system for hot water, installed by a general contractor.

I would like to prepare for a possible photovoltaic system that might be added later.

Is it best to install an empty conduit from the attic to the utility room for this purpose, or should the electrician run a suitable cable without connecting it?

I want to make the house relatively future-proof with simple measures. We have a gas boiler, and I saw in the specifications of another general contractor that they leave two conduits in the utility room for the possible future installation of a heat pump. Are there other things along these lines that can be done now with little effort but could provide significant benefits later?

I would also like to have a 400V (approximately 230-240V 3-phase) line, or at least an empty conduit, installed to the carport, as I expect electric cars to become standard in the coming years or decades.

Thank you!

Take two 20mm (¾ inch) conduit pipes. The cables should be sized according to the power output of the photovoltaic system and depending on how large your installation is planned to be in the future.

Thank you for the quick reply!

Otherwise, I would have simply chosen the cable with the largest affordable cross-section.

Is it worth installing a larger storage tank for the gas boiler from the start, in case modules for heating support are added later? If gas prices skyrocket or there are significant subsidies, it might pay off at some point.

No. No buffer tank for heating support. It’s not worth it — even with gas prices twice as high.

Depending on the size of the photovoltaic system, you will likely need to properly size your electrical panel. You should also allocate space in the utility room for a possible battery and other equipment.

We are only installing the solar system for hot water to meet the KfW55 standard. With the €5,000 repayment grant and the subordinated loan, it makes financial sense for us.

These are probably all things I can discuss with the electrician during the final selection process.

Is it worth having a 400V (400 volts) line installed to the carport right away, or would an empty conduit be more practical?

I think you might as well have the cable installed at the same time... the price is obviously quite high there as well, but for a saving of €10.50 I wouldn’t want to deal with the hassle later.