6" liner into 8" liner?

[Woodburnnoob]

Hello, all. Trying to compare 2 quotes for liner installation. Recently purchased a Drolet Deco II wood stove, switching from a Vermont Castings Vigilant wood stove (came with the house). We currently have an uninsulated 8", stainless steel, flexible liner inside a brick chimney. Both chimney companies inspected the 8" liner and confirmed it was in great shape.

Company "A" is quoting a complete removal of the existing 8" liner, and installation of an insulated 6" SS flexible liner.

Company "B" is quoting inserting an uninsulated 6" SS liner into the existing 8" liner. This company stated that since the 8" liner is in great shape, they can safely install the 6" into the 8" liner. This setup would effectively act as a "double wall" pipe and negate the need for insulation.

Beyond the price difference (Company B - $1700, Company A - $2800), I want to make sure this is safe. Any guidance is appreciated. Thanks, in advance.

 

[brenndatomu]

This setup would effectively act as a "double wall" pipe and negate the need for insulation.

Double wall chimney pipe has insulation in it though...insulation shouldn't add that much to the job.
But the 8" will need to be very clean inside or it shouldn't be used.

 

[stoveliker]

double wall liner does not equate an insulated liner. That installer doesn't know what he's talking about.
I don't think it's unsafe to put a 6" in an 8", but it's not the same as having an insulated liner.

Go with the insulated liner, being in Maine and likely with the brick chimney exposed to the cold. Your stove will run better and the flue will stay cleaner.