We had an ASHP fitted to replace an oil-fired boiler radiator heating and hot water system in October 2021. This was retro-fitted to a 20 year old, 4 bedroom detached property. The fan is outside the back door, and the hot water and expansion tanks and all other pipe work are in the garage, which is below the house. It is an 8Kw system.
We chose to have the ASHP connected to the existing radiator system, and not have the preferred underfloor heating system installed. This meant having to have some radiators changed for new ones with larger surface areas, but this caused minimal disruption indoors.
The whole job, from start to commissioning, took a working week to instal, and needed no planning permission. The existing (soon to be replaced) Renewable Heat Initiative grant will cover some 75% of the cost over 7 years, and the first quarterly payment of this grant has been received!