ᐅ Suitable Heating Concept for a KfW 40 Energy-Efficient House?

Hello everyone,

I am in the initial phase of planning a 75 sqm (800 sq ft) bungalow without a basement. I have an offer for a KfW 40 energy-efficient house equipped with an air-to-water heat pump Vaillant aroTherm plus uniTower with VWL 105/6, a central ventilation system with heat recovery, and a 190-liter (50-gallon) hot water storage tank. Additionally, a photovoltaic system with 7.9 kWp and a battery storage of 5.24 kWh would be installed.

The house is planned only for me, with a maximum of one additional person. I work a lot from home, and my comfort temperature is around 22–23°C (72–73°F). I would prefer a system that requires little effort or adjustments regarding settings, etc.

From your perspective, does this offer make sense, or would a different heating system be more advisable?

Good luck

So, the heating system is way, way, way too large! And to enjoy it properly, you need an HVAC technician who knows what they’re doing, which is probably not the case here.

Save the money on an air-to-water heat pump and underfloor heating and opt for an alternative system. Air-to-air heat pump plus better insulation. Window glass heating. Infrared heating.
That’s what I would do for such a small house.

@RotorMotor Thank you for your quick response. So my gut feeling was correct. Would the smallest unit from the VWL 35/6 A model series with uniTOWER be more suitable?

I am quite certain that even the 35mm (1.4 inches) pipes are much too large for the small KfW40 house. We have the 75mm (3 inches) pipes, which are twice as big, on a 200m² (2,150 sq ft) house, and they are far too large for our home.

Hello @nordanney, my problem is that I don’t know which system would be a suitable alternative… The only thing I’m sure about is that I need a photovoltaic system because of Baden-Württemberg. I have no experience with IR (infrared?). With an air-to-air heat pump, it might be that I don’t find the airflow comfortable. I already don’t like it in a car when warm air is blown at me… But maybe my impression is not realistic.