Do I leave the thermostat fan switch in Auto with a variable speed furnace?

MrDisco wrote: ↑
One thing I'm confused about is the relationship between the blower motor and the fan selector on the thermostat. Do I leave the fan selector in 'Auto' and let the furnace control when the fan should kick in? Also with these type of furnaces (in this case a Trane) does the fan run 24/7, just at varying speeds depending on how much cooling/heating is required?

everylittlecent wrote: ↑ if you leave in auto the fan comes in when the furnace/ac kick in,
if you leave it in the ON position then the fan is on irrespective of whether the furnace/ac in working.

some newer thermostats have a Circulate mode. my honeywell has this. this turns the fan on for about 20-30 mins i think every hr irrespective of whether the furnace/ac is on. I have mine set for this as I feel it even outs the airflow. my nbr has it set for ON during summer months. It all depends on how your comfort level is. with the DC motor the fan draws very little current so your hydro bill isnt affected too much

MrDisco wrote: ↑ I'm having a new 2 stage furnace installed with a variable speed motor (it wasn't what I originally purchased but it's 2022 and nothing goes to plan now days).

One thing I'm confused about is the relationship between the blower motor and the fan selector on the thermostat. Do I leave the fan selector in 'Auto' and let the furnace control when the fan should kick in? Also with these type of furnaces (in this case a Trane) does the fan run 24/7, just at varying speeds depending on how much cooling/heating is required?

MrDisco wrote: ↑ I think what's tripping me up is the difference between a variable speed and a constant torque and how those relate to fan operation. My assumption is that if left in auto, the furnace will turn on the fan as needed, and adjust the fan speed accordingly, compared to a constant torque that will turn on the fan but it comes on at its full speed. Is that right?

I have a regular honeywell programmable TS which only has an auto/on selector. I guess that's my next question - do HE furnaces need a newer TS?

MrDisco wrote: ↑ I think what's tripping me up is the difference between a variable speed and a constant torque and how those relate to fan operation. My assumption is that if left in auto, the furnace will turn on the fan as needed, and adjust the fan speed accordingly, compared to a constant torque that will turn on the fan but it comes on at its full speed. Is that right?

I have a regular honeywell programmable TS which only has an auto/on selector. I guess that's my next question - do HE furnaces need a newer TS?

newlyborn wrote: ↑ It is a personal preference. I personally like the FAN to run 24X7 by selecting it "ON' from the thermostat. When fan is on "ON" it runs on continuous one speed irrespective of blower being variable or constant torque. Blower ramps up / down only when heat or cool is ON.
By having blower continuously ON without heat / cool cycle it balances the temperature through out the house and you have more consistent temp besides lesser stale air. If you add a little baby oil spray or any other fragrance on the filter, it gives an excellent results of freshness throughout at the min cost.

GoodFellaz wrote: ↑ what about people who open their windows in the summer for fresh air? is it advisable to keep the fan running when you open all your windows or does that waste hydro and ineffective?

GoodFellaz wrote: ↑ what exactly does that mean "not make the needed impact" is it a good idea to open windows all day long in the spring when you leave the furnace setting to Fan Always On? or is it a BAD IDEA? everyone tells us to keep the fan always running, but doesnt the windows open do the exact same thing in the spring/summer time if we need fresh air?