The actual heat pump for 9 HSPF, 4 ton and 14 seer rating cost $4,384.00. If you need to know the repair and replace cost here is the links. http://www.2myhvac.com/heat_pump_prices.html
Heat pumps all operate on the same principle - heat transfer. In case of an air source heat pump – heat is transferred from outside to inside your house. The RHPP grant can help you with costs over £1,300. Visit their site http://www.mrrenewables.co.uk/air-source-heat-pump.html