ᐅ Air-to-Water Heat Pump: Indoor or Outdoor Installation?

We are planning an air-to-water heat pump for a new build. My questions:

1. Indoor or outdoor installation of the air-to-water heat pump, which is more cost-effective or efficient?

2. Besides monoblock units, there are also so-called split units. Which option is more cost-effective in the long term?

1. These systems always require fresh air from outside. With a split system, only part of the air is brought indoors. There are heat pumps for indoor use for domestic hot water, but as far as I know, not for heating.

2. Monoblock.

There are efficient and less efficient units available in both types. Good monoblock units start at around 3000 EUR (5 kW Panasonic) if you purchase them yourself (+ installation + hydraulics with hot water storage). Another advantage is simple installation, no annual HVAC maintenance, and the possibility of doing some work yourself. Replacement costs at the end of the unit’s lifespan would then only be about 3000 EUR plus 2-3 hours for a technician, rather than 10,000-20,000 EUR. Have fun doing the math.

For efficiency, the design of the underfloor heating system and its optimal operation later on are at least as important as the unit itself.

Of course, complete units for indoor installation are available. So far, I am very satisfied with them...

Ashes on my head, yes, that's correct – outside air is then directed indoors.