Air source heat pumps provide heat for piped heating systems and hot water much like a traditional boiler. The only difference is the temperature of the water delivered is slightly lower, meaning they need to be carefully designed to suit the property's specification. As stand-alone units they operate best in well-insulated properties and are well-suited to wet underfloor heating systems - often new build homes.
However, you can have the benefits of a heat pump with your existing radiators and no need to improve your insulation. Vaillant have been manufacturing heating solutions for over 100 years, and developing new innovations throughout that time. Their aroTHERM heat pump system has the option of an in-line miniature electric boiler, which tops up the heat from the heat pump to effectively operate exactly like a traditional boiler. So you can have the benefit of a super efficient heat pump, with no design or insulation worries.
Mitsubishi have a longstanding reputation in the heat pump market, and their Ultra Low Noise model displayed in Smarter Living is one of the quietest heat pumps on the market.