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?



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As for direction / speed a piece I did on that - http://thehtrc.com/2014/faq-ceiling-fan-direction-summer-winter which goes from basics to common exceptions

The biggest things though to keep in mind: if your not in the room it does no good to have it on. The next is just like ducted, the unit pushes out the conditioned air which creates the mixing, it isn't up to the ceiling fan to do that while it is running

Thank you.  Good information about the ceiling fans.

Using a ceiling fan as part of a team to bring your maximum home cooling comfort. Adding a ceiling fan can allow you to actually turn up the thermostat, saving you energy and money.

Another way to conserve energy and cost is to make sure your ceiling fan is only on when the room is occupied.

Running a ceiling fan actually heats up air. Allison Bailes has some great articles on it.  I would set fans to slowest speed if you are having issues with the mini splits distributing air throughout the room. Otherwise you might be making them work harder depending on where they draw in the return air. Most units draw return air in the top and conditioned supply air out the bottom. You could be making it hard on the system by mixing the air w a fan. Try turning the fans off for a day and see if that helps.

Through evaporative cooling on the OPs skin, OP may be able to have a higher set point _due_ to the cooling felt on the skin from the fan.

While yes, the motor _does_ give off heat, the cooling felt is IMHO higher than the heat contributed.

(Of course, if it's a closed/sealed/unused room this is a moot point but while the space is occupied the fan will be appreciated by the occupant.)

You can run air conditioner and ceiling fan together but, if you are using it in right way then it will reduces the load on ac and even lower your cooling costs. If it is very hot then yes, you must drive a ceiling fan and air conditioning at the same time. A good ceiling fan allows the air conditioner to operate at a higher temperature. Much of the discomfort in a warm room comes from the silence in the air. A ceiling fan can relieve much of this silence. However, if you still have any more question on this then contact to White Mechanical, Inc. a professional residential HVAC services experts to get all your answers.

The big difference I see between these units and central AC in my region (Upper Midwest) is that minisplits tend to be installed up high in rooms, whereas central units are located in the basements. The mini split (if located up high) is well positioned to put cold air in at the right spot, whereas a central unit located down low has more difficulty pushing that air up as well as the registers will typically be on the floor. My experience has been that folks that have mini splits installed up high (typical) generally don't need their ceiling fans much, whereas they are  much more helpful for central systems. 

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.

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.

Now I am confused.  Everyone has a different opinion.  

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.




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.


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