What measures are needed in a 1960s terraced house for a heat pump?

I want to convert a terraced mid-terrace house with the following key data from electric heating to an air heat pump:

- Living area 80 sqm (4 rooms, 1 bathroom)
- Fully basemented with laundry room and small workshop (the largest basement room with garden exit offers potential for a small granny flat or a party room)
- On the ground floor only the kitchen and living room. Upstairs are 3 bedrooms and the bathroom.
- Final energy demand of the building 224 kWh/(sqm a). According to the owner, the total electricity costs with night storage tariff are 150€ per month.

Since the terraced mid-terrace house is a real bargain in a good location and I no longer want to rent, I have considered the following measures:

1. The attic cannot be converted due to its low height, so I would lay 20cm walkable rock wool insulation boards on the floor (above is a Harz double roof)
2. Replace windows as well as front and balcony doors with triple glazing
3. Mill space for underfloor heating into the screed (approx. 40 EUR per sqm), install the underfloor heating and lay tiles over it. If the screed is not suitable for milling, the surface heating could be installed in the walls. The living area is not sufficient for huge radiators on the outside.
4. Install the following air heat pump: Viessmann Vitocal 200-S heat pump, 7.0 kW, Z016960, 300 L Vitocell 100-W, CVAA (only 35dB at 3m distance)

Then I would see if this is already sufficient. If not, I would additionally:

5. Build a wood stove in the living room for cold days
6. Insulate the two exterior walls (18cm WLS 025)
7. Insulate the basement ceiling (8cm WLS 024)

I don’t have enough space for pellets or oil. For the gas heating I would first have to have a gas connection installed and then I would have less space due to the radiators. Moreover, the heat pump can also cool, which is important to me.

As I am not an expert, my questions are: Is this completely unrealistic or could it work because the terraced mid-terrace house has fewer exterior walls? Have I overlooked a better measure or a more suitable/cheaper heat pump? Panasonic Geisha 5kW is louder, right? Would solar thermal with south orientation help at all?

I expect costs in the range of around 40,000 EUR (before deducting subsidies) for the first 4 measures plus bathroom renovation. But right now I pay the landlord 5,000 EUR per year and have significantly less than 80 sqm as well as no terrace with garden.

Best regards
Kaban

It is advisable to consult a specialist expert who is independent of sales. Heat pumps, especially air heat pumps, require heat-pump-friendly conditions that are unfortunately mostly not present in existing buildings. If these are not ensured, it can quickly become an economic disaster.

Right. Here I consider the framework conditions or the planning to be reasonable. With the planned insulation, it will not be a problem to achieve low flow temperatures with underfloor heating. But you really need to inform yourself thoroughly and/or get a true expert involved. Not with the motto: rough estimate and we've always done it that way

It might work. How does the masonry look? The biggest weak point after the planned measures is probably the basement ceiling. Insulating from below should be relatively easy, but closing off the stairs downwards is probably more difficult. Can you also position the outdoor unit in a way that it doesn’t annoy you or the neighbors too much?

I may have overlooked it, but how is the heating currently done? Night storage heaters?

Insulating the basement ceiling and top floor ceiling should definitely be done (no matter which type of heating will be used), the effort/benefit ratio should be best here.

Do you have construction plans and therefore know what was installed under the screed? I see this as a risk: the underfloor heating should lose as little heat as possible to the concrete slabs below. That would be a good heat storage, but with high inertia.

Is the current screed perhaps already cracked anyway? I mean, you are planning a complete renovation. A crew from the Czech Republic can remove the screed completely within a few days, then you can rebuild everything properly regarding insulation under the screed and underfloor heating, and take the opportunity to, for example, run network cables to all rooms or renew water pipes.

Is exterior wall insulation permitted considering the terraced housing? Are there mandatory regulations regarding uniform facade design?

Are the windows and doors still original from 1960?

before deducting the subsidy

Are you referring to the KfW subsidy? Then you have to work with an energy consultant anyway, who tells you what and how to insulate best. If you seal everything, don't forget ventilation.