central ac fan setting

ldj · Aug 21, 2013

Central ac in home, fan can be auto or on. Which is best and why?

Dblair · Aug 21, 2013

it's always better to keep the air circulating so
there aren't any hot or cold spaces but it costs
quite a bit more to keep that fan running . with the
air constantly circulating you can adjust the vents
to just the right temperature through out the home
if the duct work was figured correctly . the south
and west sides of your home are going to cool
harder.

Bruce SEKs · Aug 21, 2013

With the switch on fan, the fan will run all the time and keep moving air around. Automatic the fan comes on and off the air-conditioning. Personally like auto the best

Anonymous-0 · Aug 21, 2013

as said below, ON for circulation - but is cheaper to run auto and use ceilng fans for cirulation,

Hal/ Eastern WA · Aug 21, 2013

Most of the Summer I leave the furnace/air conditioning fan on all the time. The equipment is in the basement and it circulates cooler air that way without the AC compressor having to come on as often. It also helps keep the basement a warmer temperature. If I just leave the switch on automatic, it tends to get almost too cool for comfort in the basement.

I really appreciate the AC. Without it, sometimes our upper level would heat up to the 90"s. With the thermostat set at 78 degrees and the fan circulating all the time, the upper level stays very comfortable, at least to me. Maybe that is a peculiarity of my house.

I have never understood people wanting to set their thermostat at 75 in the Winter and 65 in the Summer. A little too warm in Winter and cold enough to almost need a sweater in the Summer. But I know people who figure that is the way things ought to be. I am glad I don"t pay their bills.

bobfeather · Aug 21, 2013

would be very interested in reply"s here
do not use our central air a lot, but when we do , turn thermostat down so air comes on ( compressor & fan ) when cool enough, turn thermostat up just wondering what everyone thinks re leaving fan run on " on " all the time would it not be hard on the motor / blower / bearings curiuos as I had to replace bearings in my furnace blower this spring
let me know your thoughts here guys thanks
bob

notjustair · Aug 21, 2013

I have always run the fan on no matter the season. In a hundred year old house you get lots of variance without it. I use air handlers with variable speed DC motors. They are much cheaper to run all the time and they run about half speed when the compressor isn't on. Those DC motors are much more expensive to replace but I have never replaced one yet. The compressor goes long before they do.

I have found I can keep the thermostat much less extreme with the fan on. If I am upstairs working and I am in a hot spot I might break down and turn the thermostat down cooler. The whole house is one temp with it on so I am not burning up in one room. With it off the upstairs is 5 degrees hotter no matter the season. With it on the most it ever gets is one degree.

Rick Kr · Aug 21, 2013

Same response as Notjustair.

Biggest thing as he said, keeps the whole house the same temp, otherwise the upstairs gets hot before the stat on the first level kicks the AC back on.

Rick

da.bees · Aug 21, 2013

If the ducts are in a hot attic,fan on picks up a lot of heat and humidity despite insulation on ducts. There are times when running fan all the time makes sense. Hal's arrangment is one. Another might be where a person has severe respitory ailments and chooses fan on and high effeciency filters to afford additional breathing comfort.
Here's a tip for those who like tinkering to save a little energy. Where the evap coil and air handler are in a hot attic,delaying fan off for 20 to 60 secounds (time is determined by seeing how long after compressor stops until supply air rises 10 degrees)scavanges the cold coil rather than alowing attic to heat it between cycles. Cheapest delay is clixon type for electric heat coils and fan. Delay is wired in paralell with fan cool speed wire and controled by Y on regular heat/cool and heat pump system. Most fossil fuel and electric furnaces delay fan off at end of heat cycles but not cool.

buickanddeere · Aug 21, 2013

Fan on to prevent air stratification. For the few scrawny bucks
to run the fan a few more hours of the day, just do it.
As previously stated, a variable speed fan is the best answer.
Keeping the fan running also reduces or prevents the
evaporator core from freezing.

Daryl in PA · Aug 21, 2013

If the indoor coil freezes, you have other issues.

john *.?-!.* cub owner · Aug 22, 2013

I have a little different setup than most people, it is a geothermal system with computer controls. the fan is D.C. powered and can be adjusted for almost any speed you want. In addition, my wife and daughter both have problems with many air borne allergies, so I use MERV 11 or 13 filters. during the summer I set my fan to run at about 1/4 to 1/3 the normal speed, and whne it calls for cooling, the fan comes up to normal speed. That both keeps the ir circulating and cuts down on the pollen, mold, etc. in the air. during the winter I slow the fan speed down to about 1/10th or so of normal speed to prevent drafts, but I still let it run continuous.

central ac fan setting

ldj

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Dblair

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Bruce SEKs

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Anonymous-0

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Hal/ Eastern WA

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bobfeather

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notjustair

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Rick Kr

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da.bees

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buickanddeere

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Daryl in PA

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john .?-!. cub owner

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