Forced air furnace

jim_51

I have a High Eff. forced air furnace with a two stage blower. Is it better to set the blower on low and let it run all the time? Or should I just let it cycle auto on and off?

Dale

Comfort vs $

If a FA furnace runs constant circulation an the lowest speed most people will be more comfortable. And, if you have a spaceguard or electronic air cleaner the air in the house is cleaner. However the low end blower motors use a fair amount of electricity and you electric bill may increase a dollar or two a day. Most people I know who have tri level homes leave the blower on. I advise people who are buying a new furnace who do that to spend the extra money and get the DC type blower which uses about 1/6 the electricity of the standard motor, this pays for itself at our elect rates in less than one year of 24/7 use.

HP80

A little first hand advice, I have a FA furnace and I run continuous fan. Actually my heating and electrical costs have dropped mainly because I have whole house comfort. There are a few things to consider before going ahead with continuous fan. Square footage (continuous works best at 2500 and under), do I have zoning( if you do continuous is not required) and application of conditioned area ie. do I have family in this space regularly or is it just a temperary (sleeping area) climate controlled area? Other factors that can greatly increase the efficency of your equipment are air treatments like UV and Steam Humidification. UV (the right type) when used with continuous fan can help people with breathing problems as simple as Hay fever and as complicated as asthema(not sure if this is spelled correctly) and if you use Steam Humidification look out for more savings during the heating season. Continuous fan allows Steam Humification to operate on it's own and allows you to drop your heating temperature by as much as 5 degrees($$$$ savings).
It is obvious that you have and understand that as far as FA furnaes 2 stage is the correct way to go, especially to avoid the single stage room purging of air, and I have been involved with variable DC motor packages for a little more than 10 years and have yet to see where the consumer would save after prepaying for the promised savings. Sorry to sound negative about the variable packages but the only one that I have seen that wins on these is the manufacturer, and I would love to hear any input that says otherwise. Ultimately the choice is yours.

D lux_2

it depends

If your furnace is older and the fan on speed is high all the time the temp. rise is likely to be off too cold as the air is moveing to fast past the excanger to pick up heat. This can cause condsate problims in the excanger oe the flue .Newer mod. sometimes run the blower in low speed or turn the blower off when there is a call for heat .

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

HP80

What is the model number and manufacturer of your furnace?

HP80

Do they really use low end blower motors in high end furnaces like this????? Two speed usually requires a little more R&D?

HP80

Can not be I don't know of too many older furnaces with 2 stage? Do you?

Glenn Harrison

Just about all furnaces made in the last 20 years...

and many other older than that are set up to run a lower speed for heating and a higher speed for cooling. However when you select fan on at the thermostat it energizes the fan relay for A/C and the fan runs on high. you have to have a furnace that is less then 10 years old in general to have the ability to run low speed fan with the stat set on fan on, and then it still varies between manufacturers and there units as to whether it's low or high speed continuous fan.

jim_51

Forced air furnace blower

For those who have asked the unit is a
Bryant Plus 90 Model 340 MAV 80,000 btu with a 1/3 h motor.