Effects of the war on construction costs and interest rates?

So I would still prefer a small and inexpensive solution.

Buy a used oil heating system, used oil tanks, and an electric water boiler.

If you look around, that costs no more than a thousand euros. Add a wood stove and that's it. You can heat with heating oil and wood, haven't invested large sums in technology, and it's cheaper than gas. The electric water boiler can also be cheaply supported with solar.

The past has clearly shown that people are chasing very expensive trends.

Oil, gas, pellets, coal are all yuck.

How can you burn wood with an oil heating system?

I can't say how much consumption there will be, I get the key on the weekend. The purchase just went through.
The living area will be 110 sqm (after renovation). Currently wall-mounted radiators, plan is underfloor heating. House was built in '93, well insulated (according to the seller).

Then heat pump. With underfloor heating and decent insulation, the air-water heat pump works without problems. Especially when there is no gas connection at all and the connection costs 5k. In addition, the heat pump is heavily (45%) subsidized when replacing an oil heating system.

I just received a newsletter from sberbank that the interest rates for overnight deposits will be increased from 0.10% to 0.50% as of 28.02. That is about double compared to other banks with a similar rating ... and unlimited, even for deposits over 250k (previously 0.01%)

So, who wants? ;-)

By the way, the stock markets have largely recovered from the little shock yesterday. Oil prices are also back below the 100 mark.

How can you burn wood with an oil heater?

Open the oil heater, take out the oil, put in the wood, close the oil heater again. (That was a reference to the classic elephant/giraffe/fridge joke before someone comes along and wants to enroll me in special school :p )

I just received a newsletter from Sberbank stating that the interest rates for overnight deposits will be raised from 0.10% to 0.50% as of 02/28. This is about double compared to other banks with a similar rating ... and unlimited, even for deposits over 250k (previously 0.01%)

Honestly, even 0.50% interest does not reflect the current risk of an investment in Sberbank - at least for investments over €100k, since deposit insurance covers up to that amount. Everyone is currently avoiding it - and rightly so.