"The most common heating system in the US is a natural gas furnace connected to ductwork, with the hot air ultimately coming out of vents in each room. This heat pump is a great replacement for the furnace and air conditioner in these ducted systems."
The question is where do you have the exchange. The central / forced air tends to be a furnace in the basement. But its also viable to have a ductless mini-split heat pump ( https://www.energy.gov/energysaver/ductless-mini-split-heat-... ) that just moves the heat carrying fluid to a room and then have that room with an exchange.
> Ductless, mini-split-system heat pumps (mini-splits) make good retrofit add-ons to houses with "non-ducted" heating systems, such as hydronic (hot water heat), radiant panels, and space heaters (wood, kerosene, propane). They can also be a good choice for room additions where extending or installing distribution ductwork is not feasible, and for very efficient new homes that require only a small space conditioning system. Be sure to choose an ENERGY STAR® compliant unit and hire an installer familiar with the product and its installation.
> Like standard air-source heat pumps, mini-splits have two main components -- an outdoor compressor/condenser and an indoor air-handling unit. A conduit, which houses the power cable, refrigerant tubing, suction tubing, and a condensate drain, links the outdoor and indoor units.
> The main advantages of mini-splits are their small size and flexibility for zoning or heating and cooling individual rooms. Many models can have as many as four indoor air-handling units (for four zones or rooms) connected to one outdoor unit. The number depends on how much heating or cooling is required for the building or each zone. This can be affected by how well the building is insulated and air sealed). Each of the zones has its own thermostat, so you only need to condition occupied spaces, which can save energy and money.
> An optional wall unit heats and cools homes without ducts. Replace your expensive baseboard heaters and radiators with an efficient, ductless unit that blends into your home.
Current air-source heat pumps can't produce hot water at temperatures necessary to drive radiators.
I’m not against ducted systems or anything (Most houses in the US have them). But the laws of physics pretty much guarantee that a mini split will always be more efficient. Air ducts are harder to insulate and not that good at moving heat energy compared to sending refrigerant right to where you need it.