Short answer: Before choosing a heat pump installer, ask how they check heat loss, radiator sizing, hot water, controls, outdoor unit position, handover and aftercare, and how those checks affect the final proposal.
Ask how the installer checks heat loss, radiator sizing, hot water, controls, outdoor unit position and aftercare.
A good proposal should explain the design assumptions in plain English and show what is included before the work starts.
It is also worth asking how handover is handled, what support is available after installation and how any grant position will be checked.
Ready to check your own home? Start with a design consultation so the next step is based on the property,
not a generic online assumption.