Should I choose a split heat pump or a monoblock heat pump?

Monoblock Heat Pump:
All components — compressor, condenser, pressure valve, etc. — are housed in a single outdoor unit. The indoor system connects to it via a sealed water circuit.
Split Heat Pump:
Consists of two units: the compressor and condenser are placed outdoors, while the hydronic module — which includes elements like the expansion valve and heat exchanger — is located indoors. The two units are connected by refrigerant pipes.

Feature	Monoblock	Split System
Ease of Installation	Quick installation — only water pipes are needed; no F-Gas certification required	More complex — requires refrigerant piping and an F-Gas-certified technician
Maintenance	Single unit, easier access and servicing	Two units — more components to inspect and maintain
Freeze Protection in Cold Climates	Outdoor water pipes are at risk of freezing; glycol or antifreeze may be required	The entire water circuit is indoors, safer in very cold conditions
Efficiency and Energy Performance	Similar efficiency under comparable performance levels	Slight efficiency loss possible due to longer refrigerant lines
Indoor Space and Noise	No noise indoors, saves space	Indoor module generates noise and requires more space
Costs	Lower installation cost, simpler setup	Higher upfront cost, more complex installation

Monoblock: a practical solution for smaller budgets, simpler installations, retrofits, or when no F-Gas certified technician is available. Best suited for moderate climates with milder temperature variations.
Split System: recommended for colder climates or when greater flexibility is needed for indoor placement and system design. It can offer better overall performance but requires a higher initial investment.