Date: 15/09/2019
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Are You a “Fan” of Changing Seasons?

audio, podcast, fans

In the fall and spring of each year, fan direction, fan rotationremembering to change the direction of rotation of your ceiling fans may make a bigger difference than you think!  Knowing which direction they should rotate can sometimes be trickier than it seems. Suppose the directions say the blades should turn clockwise, does that mean clockwise when you’re looking down the shaft of the fan from the top?  Or does it mean clockwise when you are below looking up at the fan? They’re not the same! So here is the definitive way to know how to set your fans for any given time of year or situation.

Heat Rises

First, you need to remember one basic principle: heat rises.  Whether it is summer or winter, whether you’re running your air-conditioner or heat, the warmest air will always tend to pool toward the ceiling and the cooler air will always tend to pool towards the floor. This is even true if your air-conditioning vents are set in the ceiling or your heating vents are set in the floor.



Fan Blades Are Angled

If you look at the fan blades, you’ll notice they are not set exactly horizontally in the fixture. They are angled slightly. If you imagine the blades as big spatulas mixing up a cake batter, you can envision that if the blade moved in one direction, the strokes of the spatula would be angled upward.  Moving in the opposite direction, the spatula strokes are angled downward.

Where Do You Want the Air to Go?

In the summertime – or any time you are feeling too warm – you want to feel a breeze of cool air.  The best way to do this is to be sure the fan blade is “scooping” up the cooler air below and wafting it upwards. In other words, the “spatula” should be stroking upwards.  In the wintertime – or any time you are feeling too cool – you want that warm air trapped up by ceiling to come down and surround you.  So you want the fan blades to be pushing the air downward.

How Do You Change It?

fan switch, change fan rotationYou are never really changing the angle of the blades – they stay stationary inside the fan fixture. However, there is usually a small, two-position switch somewhere near the fan motor (towards the center mechanism, not on the blades).  Turn the fan on and observe which way it is “scooping” the air: upwards or downwards.  If it needs to be changed, turn the fan off and wait for it to come to a stop. Then flip this switch in the other direction, and turn the fan back on.  Never try to flip this switch while the blades are still rotating!

Use Fans Year-Round

Most people have no problem using ceiling fans in the summer to create a “wind chill effect” – in other words, to increase evaporation from the skin, which makes us feel cooler.  But many avoid using their fans in cooler months for that same reason.  But if your ceiling fan is spinning the correct direction (as described above) you can save as much as 15% on heating costs... just turn the fan to a lower speed setting to minimize the wind chill effect.  Look at it this way: you’ve already paid to heat the air that is now trapped near the ceiling… why not spread it around to help warm the people in the room? This is even more critical if you heat the room with a form of localized heat – such as a space heater or wood-burning stove.     

Saving Energy, Money, and Feeling More Comfortable

By having fans rotating the correct direction at any given time of the year, you can save money on your heating and cooling costs because you’ll be saving energy.  You’ll be able to set your thermostat higher in summer and lower in winter and still feel comfortable.  By moving the air, fans help to “mix” the various layers of cooler and warmer air that naturally stratify due to physics.  This will help your HVAC system run more efficiently and increase your comfort, no matter the season.

Important Tips

If your ceiling fan does not have a way to “winterize” it (e.g., to change rotation direction), consider replacing it with a model that does. Also, don’t forget to clean the fan blades and replace any burned out light bulbs (if your model has lights) while you’re flipping that switch. Ceiling fans should only be used in rooms with ceilings at least 8 feet high.  For optimal performance, the fab blades should be 7-9 feet above the floor and 10-12 inches below the ceiling.  Larger ceiling fans can move more air than smaller fans, and a larger blade will also provide comparable cooling at a lower velocity than a smaller blade.  Some large rooms are best served by installing 2 or more ceiling fans. We recommend fans that have earned the EnergyStar® label - they move air up to 20% more efficiently than standard models.

air filtersHere’s another tip for the changing seasons: Remember to schedule an HVAC maintenance tune-up to ensure there are no surprises later in the dead of winter or the heat of summer.  And, we can’t preach it enough: the most important thing you can do to keep your HVAC system running more efficiently and prolong its life is to change your air filters. Set up reminders every 3 months and never miss a filter change.

If you live in the Nashville or surrounding area, Interstate AC Service can get your HVAC system ready for whatever lies ahead. Call on us at (615) 832-8500.

Important Tips & Advice



You often don't think about your heating or air-conditioning system until something goes wrong. But there is so much you can do to help keep your system from breaking down. We regularly post information to help you learn what you can do to keep your system running, to save money and energy.  Search our many posts, videos, and podcasts, for valuable information that is never a sales pitch. Subscribe to receive an email when something new is posted, so you won’t miss any important tips.

Choosing a Repair Company

Whether you’re talking about heating or cooling, repairing or replacing a system, you want a company that can advise you reliably based on what is in your best interest, not based on what is convenient or what earns them the most money (commissions). We'll help you choose the best solution to fit your needs. Check out our many posts at HVAC News You Can Use and our podcasts.

Going Green

We're concerned about the environment and know all the latest technologies - such as geothermal systems, LED lights, and smart thermostats - that can reduce energy and put more "green" in your pocket!  We've provided HVAC systems in certified LEED buildings and written many posts on ways to Go Green.

The Sign of Service

We are a repair company performing a full range of commercial and residential heating, air conditioning, energy management and comfort products service, maintenance, and installation. We are a locally-owned company serving Nashville-Davidson County and the surrounding counties including Williamson, Rutherford, Wilson, Sumner, Robertson, and Cheatham.

Who We Are

Our service technicians are fully trained and experienced.  We can tackle the most complicated system to the simplest of systems – from large commercial plants to single-family homes.  Our ownership group of Eddie Hutton, Tony Anderson, Roger Eldridge,  Swaney Powers and Alan Seilbeck have over 125 years combined experience as leaders in the HVAC industry.


We are proud of our dispatchers that respond to your telephone call. When your system is down they make things happen. Our trucks are loaded with most parts needed for a quick repair. You can call day and night 7 days a week. Our normal weekday hours are 7:00AM to 5:00PM. Click on the button below to schedule a service call online. Emails and forms can only be answered weekdays from 7-5.”  

615-832-8500 Online Service Call


Did you know you should service your HVAC on a regular schedule – just like you would your car?  We have specialized maintenance programs to ensure the clean, energy efficient and safe operation of your HVAC systems.  This helps minimize service interruptions/breakdowns and maximize your equipment's lifespan.  All maintenance contract customers are assigned a primary technician that will get to know your facility and equipment and will treat it like his own.  You’ll receive discounts on repairs or new installations, and get priority service when it is cold or hot outside and you need service promptly.  Plus, maintenance contract customers are never charged overtime rates for emergency services after-hours, weekends or holidays. We’ll teach you how to save on maintenance costs by showing you things you can do yourself and when you need a technician. Here are some good posts:  Repair vs. Replace, Things to Try Before Calling for Service, Springtime Tips that Pay Off.


Our team takes on HVAC projects for office, school, retail and industrial facilities. Check out these case studies:

Replacement of a 250-ton Cooling Tower

Ductless HVAC at Brentwood Middle School