We just had 2 mini split air conditioners put in our home, which previously did not have air conditioning.  We have ceiling fans in every room and I am wondering how to use the fans in conjunction with the air conditioners that are at ceiling level.  Should the fans be on summer mode?  What speed is good to use to enhance the distribution of the cool air in the rooms?  

We usually keep the fans on high to keep the air moving, but with the air conditioners, I am not sure if the warm air near the ceiling is making the compressors work more.  

Any advice out there?

Thanks.

Beverly

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  • Ceiling fans are like open fireplaces. Unless you have a potbelly stove or other high delta t heating device that causes temperature stratification layers, it's an outdated, very inefficient, human comfort device. 

    If you have them and must use them, only use them when you are present. Recognize that they add heat while cooling humans through accelerated evaporation. 

    I've removed all the cords from mine, they tend to get left on in unoccupied rooms for days at a time.

  • That depends on the configuration of your mini split AC also. I think you have found your answer till now but when I was confused with the same situation, I took help of the commercial air conditioning service NJ professionals. Asked my query online and they helped me a lot even they visited my home and did the whole HVAC inspection.

    Commercial Air Conditioning Services
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  • Ceiling Fans vs. Air Conditioning.

    Though installing numerous ceiling fans in your hope may be the cheaper option, it’s clear that air conditioning works in ways they just can’t match on a fundamental level. Air conditioning, while more expensive, just works. It has the ability to adjust the temperature of the air in your home to a cooler level and create a comfortable environment. Ceiling fans, on the other hand, simply circulate air. This air cools the skin, which can help your body to cool itself, but it doesn’t have a cooling effect on the room or house.

    If you think that running a ceiling fan while running the AC only stands to make it more effective, you’d also be wrong. Because modern AC units and homes are equipped with elaborate duct work and much more robust ventilation for even cooling, a ceiling fan only messes up the flow and prevents the cold air from making its way back to the air conditioner to be cooled and recirculated again. In this sense, an air conditioning unit can be likened to the human heart. It pumps out air to each room in the house, much like the heart pumps out blood to the extremities. Theoretically, if you turned on a fan in one of your extremities, the blood would be trapped and have a tough time making it back to the heart. The same can be said about the air in your house.

    While ceiling fans may make air circulation less effective in modern homes, particularly ones with AC units installed in 2005 or later, ceiling fans in homes with air conditioners from 1995 or earlier are actually recommended to increase air flow. The bottom line, however, is that ceiling fans don’t improve an existing air conditioning units output or temperature, though some may enjoy the feeling they provide.

  • Good opinions in these replies!  I'll just add a few:

    * Experiment.  It's your house and how you feel in it should drive your decisions.  If it was my house, I'd start by turning the fans off.

    * There is no "best way" to go.  We don't know the size of your rooms, the layout, the insulation levels, your building airtightness, or even what climate you're in.  So all we can do is guess.

    * In some of the climates where I live, ceiling fans are very helpful for moving air around, which helps avoid stale pockets, which can help keep mold at bay.  It's not just a comfort thing.

    Good luck,

    Blake

    • Thanks.  A very reasonable, practical answer.  We have done our experimenting and ceiling fans, on low, seem to make us comfortable.  

  • Among the various opinions expressed here, I offer a few 'truths'...

    Ceiling fans are mostly for cooling PEOPLE, not rooms. Evaporative cooling. Turn off the fan when the room is unoccupied.  Walter mentions another benefit: to help mix air in rooms with volume ceilings. Whether or not that's necessary or even useful is debatable, largely depending on the home's design and mechanical system design -- both beyond the scope of this discussion I think.

    Aside from evaporative cooling, ceiling fans improve comfort by disrupting the boundary layer of air that forms on the ceiling. This reduces the ceiling temperature, which in turn reduces radiant heat. This effect is greatest when you're prone, such as lying down. Even if ceiling is only a few degrees warmer than the air in the room, your body will 'feel' that in the same way you feel hot when facing a fireplace in a cold room while your backside still feels cold. 

    As and aside, disrupting the air film (boundary layer) at the ceiling will slightly increase the ceiling assembly u-value (i.e., reduces R-value by a fraction). However, don't let that stop you if it allows you to raise the thermostat. Increasing the setpoint by only 1 degree will way more than offset the (tiny) additional load caused by proper air mixing.

    Ceiling fans do generate heat, BUT, today's fans are far more efficient than even 10 years ago. In particular, fans with DC motors use a tiny amount of power on the lowest speed settings (some models pull as little as 3W on low!).  And with recent improvements to blade design, you get the full effect without ever turning the fan to high. Check out Energy Star's database of certified fans.

    Bottom line: I strongly advocate DC ceiling fans in rooms where you spend the most time, using one of the lower speed settings. This may also help mix supply air from the mini's, but either way, there's no benefit from leaving the fan on when the room is unoccupied.

  • This is one of thouse topic where you ask 10 people and get 12 different opinions. I will give you 5. :)

    There is no clearly right answer. Some if this depends on who you are where your house is and what type of house it is.

    In my opinion if you have a ceiling height over 10 feet I say the fan runs 24/7 with the AC.

    If having a lower electrical bill is somewhat more important than comfort and you are willing to set your thermostat higher and turn the fan on medium as you enter and off as you exit each room. That will save you some money.

    If comfort is more important than the electric bill, run the fan on low with the AC.

    I find we never set the fans above the slowest speed. Between the noise and papers flying around the higher speeds are just annoying.

    I find the “winter” setting spinning the blades backward makes me less comfortable and the fan soon gets turned off.

     

     

    Walta

  • Now I am confused.  Everyone has a different opinion.  

  • Don't use the fans! They generate heat and mix the stratified high warm air with the low cool air which is already where it needs to be (where the occupants are). Mini-split air handlers do an excellent job of moving the air and need no assistance from a paddle fan. Plus why waste the money running the fans, let the super efficient heat pump do all the work.

  • If you are using air conditioning, a ceiling fan will allow you to raise the thermostat setting about 4°F with no reduction in comfort.” If you turn on your ceiling fans, turn your air conditioner up 4 degrees to 80 degrees. The ceiling fan will keep you just as cool, at a reduced cost. However, if you have more queries on this then contact residential air conditioning installation experts at White Mechanical, Inc.

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