1. Heat loss
An uninsulated house needs more capacity and hotter water in the radiators. Sometimes loft insulation or new windows do more than a bigger system.
2. The radiators
A heat pump runs efficiently with water at 45–55 °C. We check that each room heats up at that temperature; usually only one or two radiators need replacing.
3. Where the outdoor unit goes
It needs open air and a few metres from the neighbours’ windows. At the survey we choose the spot and check noise levels.