brass monkey wrote:

There must be a lot of cash to be made in this insulation game.

Had a few of them pounding the streets here, I usually hear them
trudging up drives and knocking doors from several houses away, peek out
to see who they are and can ignore them when they reach me.

I heard my neighbour open the door to the last one, opening line "Hello
sir, I'm not selling anything" ... "Yes you are" ... "No, I'm not" ...
"who pays your wages then?" ... ended up with the guy demonstrating how
badly cut out for the job he was by storming off down the drive slagging
off the neighbour for all to hear ... then trying his luck at the next door!

That said my parents have had CWI installed for free, which I assume was
from the same sort of outfit.