On Thursday, July 26, 2018 at 10:24:05 AM UTC-4, wrote:

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

And also factor in that for my condenser fan, the $350 price was the lowest
price I could find online. If you can't do the repair yourself, have to
call an HVAC guy, that motor could be $500 plus labor and the replacement
would have the same crappy electronics in it. IDK if an HVAC guy would
put in a split phase motor instead or not. It takes a bit of smarts for
one thing, to look up the specs on the two and find the equivalent one.

The furnace ECM I think is paying back faster, the electric bills in winter
are lower, but I've also put in LEDs, etc that could be part of it. But
the biggest savings were in the gas bill for the furnace and elec bill in
summer with AC. Gas bill went down by ~40%, elec bill probably about the
same.