I am having an ASHP, radiators and pipework installed to replace storage heaters. How can I check whether the proposed pipework and pump can cope with the heat demand? The installer is proposing a single circuit with 14 radiators with a combined heat demand of around 8kW. I hear heat pumps getting bad press, but feel sure the problems arise through bad design in one or more of the heat loss calculation, heat pump size, radiator sizes and distribution system. The first three I feel more confident about, but not the distribution system design. Are there any rules of thumb or guidance anyone can offer? Thanks.