Use an installer with experience of church buildings. Churches are not like houses or offices: they have tall ceilings, stone walls, limited insulation, heritage constraints, and usage patterns that most commercial heating engineers do not encounter. An installer who has worked in churches before will understand the faculty process, know how to mount equipment without damaging historic fabric, and size the system correctly for a building that is heated intermittently rather than continuously.
Ask for references from other churches they have worked on, and contact those churches to ask whether the system performs as promised. Check that the installer holds the relevant certifications for the technology: Gas Safe for gas systems, MCS for heat pumps, NICEIC or equivalent for electrical work.
If you are not sure where to start, your diocese may maintain a list of approved or recommended contractors, and we can <a href="/enquiry">introduce you to an installer</a> who knows churches.