On Dec 21, 11:04*pm, Some Guy wrote:
Tony Hwang wrote:
Just wondering if anyone has replaced their conventional furnace
/ HVAC fan motor (PSC, single phase, etc) with one of the new
ECM motors to realize a reduction in your electricity bill.
Don't even bother. It is DC servorized motor with matching control
logic board. High efficiency furnaces are made to take advantage
of this variable speed motor.

Everything you're saying is true, but it doesn't mean that
fundamentally ECM motors are more efficient regardless in what type of
furnace they're used in.

Even if all I do is use it as a constant-speed replacement for a 50%
efficient PSC motor, it will use less electricity.

The question is - how much, and what is the over-the-counter cost of a
suitable ECM motor (not the HVAC-contractor-installed price).

Also they are not as reliable as ordinary motor.

That is probably true, and along the lines of planned obsolescence
that's designed into modern residential HVAC systems.

I've worked at and with a lot of companies engaged in all kinds of
product design during my career. But I never heard any discussion of
planned obsolence, which IMO is largely an urban legend. There is
a real tradeoff between what it costs to make, how much you can sell
it for, and longevity. In my experience, that is where the tradeoff
is made.
If you made a product that deliberately lasted 10 years, while it
could last 20, it wouldn't be long before a competitor whose product
did last 20 would start eating your market share because their product
was superior. That's how free markets work.

The typical funace lasts 20 years. Given the cost, that seems a
reasonable lifespan. How many customers would be willing to pay say
30% more for one that lasted another 5 years? Or 50% more for one
that lasted another 10? Most people don't even plan to be in their
homes that long today. Given that the energy situation and technology
is constantly evolving, I don't see a problem with the lifespan or
value proposition presented by today's furnaces.