What certification covers, what it does not, and what a certificate is evidence of.
Short answers on what certification means, who checks the checkers, what happens if an installer goes under, and who to complain to.
MCS is a scheme for certifying small renewable energy products and the companies that install them. It is worth understanding what the badge is evidence of before treating it as a guarantee.
MCS publishes a short document setting out what a certified contractor undertakes to do for its customers. It is worth reading before signing anything, because it describes what you are entitled to expect.
The MCS standards fix the method behind the numbers, so a quotation that follows them has certain things in it. What to look for, and what it usually means when one of them is missing.