Which heating system is suitable for 160 m²?

Which heating system is recommended for a 160 m² bungalow with a room height of 2.50 m? We are currently leaning towards underfloor heating and gas. According to the heating engineer, underfloor heating should cost around €30 net (including material and labor). Control systems come extra, depending on the room. Is the price generally reasonable? I have no idea about the system, I was completely ... uninterested in this area. How expensive is an air heat exchanger (or similar) approximately? Which type of heating is most efficient in combination with underfloor heating?

...We are currently leaning towards underfloor heating and gas. According to the heating engineer, underfloor heating should cost about €30 net (including material and labor).

If there is no proper dimensioning/calculation, the price unfortunately says nothing at all. Heating surfaces and pipe hydraulics must match the room heating loads and the heat generator.

...Which type of heating is most efficient in combination with underfloor heating?

That always depends on the specific conditions of the construction project. Unfortunately, there are no general rules, as so many desire. In addition, efficiency must be defined. If it is exclusively about energy (kWh), then heat pumps are likely ahead, since the consumption is lower than the demand. For conventional heat generators, it is the other way around. If it is about total costs (investment or capital service for this as well as consumption costs), the price per kWh also plays a role. Best regards