Having been in the industry for 30 years we have seen the use of heat in many a setting. Commonly used is a naked flame for heating windscreen repair resin or evaporating moisture. There could well be some changes and challenges ahead for the arguments for and against the use of heat with windscreen repair resins. We can only wait and see what the outcome of the new windscreen repair standard BS au 242b;2021 concludes when it is published. The drafts for public consultation made comment on naked flames with no conclusions to date it would seem. Here at GT we do not supply heat as we find that premium GT vacuum  and pressure windscreen repair kits and high quality windscreen repair resins eradicate the use of heat.