Keeprite bryant and carrier offer single stage with ecm motors.
Single stage furnace with ecm motor.
I m sticking with single stage as all the contractors recommended them.
This increased precision results in a home that is more consistently heated both in different areas of the home and over time.
And the ecm motor will have greater electrical efficiency.
Variable speeds unlike an on off psc motor a furnace ecm motor can operate at a range of outputs between zero and 100 percent.
A variable or multi speed furnace monitors the temperature of your home and then adjusts the speed of the blower motor sometimes referred to as an ecm motor in very small increments.
With a 40k low stage the 2 stage will not be a reduction in comfort or gas efficiency over a single stage furnace.
Be sure to not use the built in staging timer if you go that route.
Instead either use a.
Is it worth getting it with a emc motor i do not have the fan on all year round and the furnace is only on 5 6 months for winter and on and off for 2 months of the summer.