Home purchase consultation energy costs

I looked at a semi-detached house, which I also like, the location and the plot are okay. Built in 1994, insulated, heated with gas, and hot water is also provided by gas, underfloor heating on the ground floor and the upper floor, the attic is finished with a total of 5 windows, also the remaining rooms have windows on the gable side.

The windows are made of wood but double-glazed, how is that, can they be kept, or do they need to be replaced soon?

A small extension to the house was well built afterwards, with its own WC and walk-in shower.

The basement is dry and clean.

It has a solid wood staircase.

The price for this house amounts to 325,000 euros, with the broker and the rest approximately 365,000. Equity capital is 200,000.

The energy certificate is rated D around 108 kWh, is this value good or rather bad, how can such a value be changed? For example, installing new windows?

And where can I get good financing, what should I pay attention to?

I would definitely keep the windows in, unless they are scratched or otherwise damaged.
A rating of D is ok. (Nonsense like A+++ for electrical appliances does not exist.) In detail, of course, it always depends on how the rating was determined, especially whether it results from consumption or from a calculation.

Since you specifically asked about energy costs, you are probably concerned with an economic consideration. In general, any major measure will not lead to energy savings that will ever pay off in a lifetime. For that, an initial rating of D is simply already "too good."

The only sensible option might be insulation of the floor ceiling, but even that might already be present.

Regarding the financing question:
With that equity, you can get good financing anywhere. Go to two local banks and one broker, then choose the best offer, done.

What interest rates are currently acceptable? I don't know how it is measured, but I have the energy certificate with me if that helps. There are radiators in the basement as well as in the attic. Approximately how high do I have to calculate the heating costs? Currently, I pay about 30 euros per month for a 68 sqm. And what advantage does it have that the hot water is centrally heated by gas?

In general, the just over 100 kWh per m2 is a good value for the age and also overall acceptable, and there are only rarely energy-saving measures that are worthwhile.
Which type of energy certificate is meant: consumption certificate based on the actual energy bills of the users or demand certificate. In the latter case, a theoretical value is calculated based on the building data.

I guess you have the consumption certificate.

Possible measures:
1994 as the year of window installation is exactly on the border between insulating glass and thermal insulation glass.
Until around 1993 there was only simple insulating glass, and from 1995 only the new one. In between, both are possible.
The heat loss through thermal insulation glazing is only 1/3 of the previously used one. Which one is installed is not easily seen. But it can be found out with the lighter test. Just search for it on YouTube or similar. For windows without thermal insulation glazing, the glass (only the glass, not the frame) could be replaced with new ones. Costs are about 120-170€ /m2 window. However, you only recover the costs after about 10-15 years. If thermal insulation glazing is already installed: leave everything as it is.

Gas heating with central hot water preparation with storage is standard. Everything else, electric boilers or instantaneous water heaters, is uncomfortable or more expensive. If the heating system is also from 1994 and has not yet been replaced, I would set aside 8,000 EUR for a replacement with a new one.

Gas and electricity costs will be significantly higher than in your apartment. Calculate rather with 20,000 kWh = 1,000 € gas and 2,000 kWh = 600 € electricity per year.

I am currently not completely up to date on exact interest rates, but under the mentioned conditions, I would guess below 1%.

Everything has been said.

Thank you very much, the gas system is from 2016 so quite new, the windows have double glazing, and inside they have installed a kind of ornament like a cross in the middle.

Attached is this energy certificate. I was only a bit worried about these windows and thought that a lot of heat is lost because of them. Also, I will not use the heating in the basement, or rather not use it as living space, possibly in the attic there are two radiators, and the rest is underfloor heating.