Variable speed blower, IMO, may be far less desirable. I don't think
fully variable speed adds much. I have an ECM, which like variable
speed, is an ECM motor. The big advantage to either is they use
substantially less electric than a conventional blower. How much
that saves depends on how much you use it and the elec rate. The downside
is that the motors have electronics in them, are more failure prone
and if they fail, instead of looking at a $150 motor, you're probably
looking at $600. I also had an ECM fan motor on the AC condenser outside.
It failed after just a few years. New one was like ~$350. I found
a conventional motor that would replace it for $90. IDK how many years
it would take to make up that difference in electric, but I suspect
it's a very long time, given the usage here. For a furnace blower in
a colder climate, the payback could be sooner, but I still suspect it's
many years. Say it's ten, is it worth it, given that if the motor fails
in six, you have to pay 4x more for a new one?



THIS is a very good point.

There is something to be said for simplicity and ease of repair.

mark