Registered installers are trained and approved to HETAS standards and can self certify that their work complies with the relevant Building Regulations. If you were to use a company that is not HETAS registered, you must apply to your Local Authority Building Control Department for a Building Notice. You must then pay the appropriate fee (possibly up to £300.00). Should there be a problem and the worst happens and HETAS do not have a record of a HETAS Certificate at the property, then I’m afraid it can void your insurance. After your installation a copy of your Certificate is forwarded to HETAS who will notify your Local Authority on your behalf. Please note that just because a company is HETAS registered it does not always guarantee quality, well installed work.