Efficiency house in old building renovation? Other subsidies?

Hello,

has anyone had experience with using KfW 151/152 or KfW 430 to bring an old building up to the standard of an energy-efficient house?

A building from 1920 is to be renovated. In 1992, full thermal insulation was already installed on the facade and mineral wool was used for roof insulation. There is an extension on the house without additional insulation.
Currently, the house has a gas condensing boiler, which operates both heating with radiators and produces hot water for the bathroom. As part of the renovation, the house is to be equipped with underfloor heating. The extension will keep radiators, which is why (as far as I see) the gas boiler must be retained because a heat pump would not provide the necessary flow temperature.

I wonder if it is possible to benefit from currently available funding programs. Is it realistic to achieve an energy efficiency standard with such an old house?
Am I overlooking other subsidies that might be applicable to me? What is your opinion?

Best regards

The former program Kfw 430 consists of individual measures if you do not want to realize a KfW house. (Currently taken over by BAFA.) For a KfW house, the entire envelope area must be calculated; both gas condensing boiler or heat pump are possible here. The extension cannot remain uninsulated anyway if it is heated and therefore cannot be a criterion. In terms of the year of construction, I generally see no problem; I have many listed buildings in energy consulting as well as in later planning. Information on the energy consultant database can be found with KfW as well as BAFA.

Has anyone had experience with bringing an old building up to the standard of an energy-efficient house using KfW 151/152 or KfW 430?

I am currently renovating to a 55 house.

I wonder if it is possible to benefit from currently available funding programs. Is it realistic to achieve an energy efficiency standard with such an old house?

Everything is possible. But for 55, you need everything that is possible. New insulation everywhere (over-insulate old ETICS). New windows. Gas is usually not enough, heat pump + controlled residential ventilation.

Gas usually works without problems with solar thermal support in KfW55 with heat recovery from the ventilation system. A common heat pump is at first nothing more than wishful thinking. Only from the Energy Saving Ordinance 2013 do they pay off due to a political fundamental change, not due to better technology. I would make sure that the energy consultant calculates according to DIN 18599 and also documents the thermal bridge surcharge on the KfW form. This then also provides a statement about quality.

An energy consultant must look at this on site.

In addition to pure thermal insulation, you must also use shares of renewable energies: solar thermal or photovoltaics will be necessary.
Besides, the thermal envelope must be sealed, which could possibly be difficult with a (residential) basement and low ceiling height.

I think an energy-efficient house is definitely out of reach. The renovation measures alone to improve the living standards, including planning, are estimated to cost a total of 200,000 €. Which is not a big deal – the annual gas bill for hot water for 4 people, including heating inefficient outbuildings, was 1600 €. We could live with that.

The only item in the list where there might be something to gain would be new windows and exterior doors. What must be fulfilled to receive funding for those? Is that even possible if the building as a whole is not very efficient?