What Size of Ceiling Fan Do I Need to Cool My Room?

Determining the correct ceiling fan size for a room is important because fans are meant to move a certain volume of air.

So what size of fan works best in your room? If you aim to lower your energy bill and increase your comfort indoors, then choose the ceiling fan that moves the most air — this will be the fan with the greatest CFM rating. Your ceiling fan choice is also constrained by the size (in square feet) of the room in question, the length of the fan blades, the desired energy efficiency of the fan, and of course your preference in fan style and its installation or mounting method.

Table of Contents

For comfort’s sake, find the largest fan that fits your room size, then choose the most powerful fan you like that has the highest CFM rating possible in the price range you can afford.

An average 44-inch ceiling fan, for example, will move 3,600 to 3,700 cubic feet of air per minute.

To install a fan of this size in a small room means that you are buying far more air-moving capacity than is needed, but depending on how hot the room normally gets without a fan, you might need that seemingly oversized fan.

But make sure that the size of the fan will not dominate your tiny room.

The worst case scenario is buying an under-powered or small fan that cannot adequately move enough air to be effective for that size of room.

Room Size (Sq. Ft.)Room Type Recommended Blade Span Recommended CFM Rating
Under 75Nooks, Stairwells, Laundry Rooms, Walk-in Closets, or Small Bathrooms29-36″ Fans1500 CFM
100-256Bathroom, Breakfast Nooks, Utility Rooms, Small Bedrooms, Porches42-52″ Fans3000 CFM
256-400Medium Bedrooms, Kitchens, Dining Rooms, Dens, Patios44-52″ Fans4500 CFM
400+Master Bedrooms, Family Rooms, TV Rooms, Small Garages, GazebosFans Over 50”6000+ CFM
Over 400Great Rooms, Large Garages, Basements, and Open Floor PlansFans Over 62” or Multiple Fans if the Room is Rectangular6000+ CFM each
Fan Sizing Guide Cheat Sheet.

Airflow: Airflow is measured in CFMs (Cubic Feet Per Minute). This is the actual volume of air that the fan is capable of moving on high speed, and is dependent upon the blade pitch and the fan motor. Airflow is the most important point to keep in mind for comparing ceiling fans, as it describes how effectively the fan will function. The most powerful fans on the market will move around 10,000 CFM, while the average fan only moves about 4,000 CFM. You will find a dramatic difference in your level of comfort when sitting beneath the two fans.

Electricity Use: The amount of electricity a fan uses is measured in watts, and you are likely already familiar with the energy consumption of the average light bulb, also measured in watts.

As you compare fans, you will notice that the most energy guzzling ceiling fans rarely use more than 100 Watts.

On average, an adequate fan will use somewhere around 65 to 75 watts.

This number does not reflect the wattage of any integrated light fixture; this is a very important note, because a light fixture can use 2 or 3 times as much electricity as the motor.

In the past, some fan light fixtures consumed upwards of 300 watts, which completely eliminates all gains made by even the most energy efficient fan motor. Usually you can fix this energy oversight by either purchasing a light fixture that uses LED bulbs.

Calculate Fan Size by Room Size

Ceiling fans can be categorized in many different ways — style, colour, lights, mounting type — but when choosing a fan for a space you must consider the actual size of the fan: the diameter width or span of the fan blades.

How to Measure Ceiling Fan Size

Fan blade diameter is generally not measured from the tip of one blade to the tip of an opposing blade because few ceiling fans have an even number of blades.

So, ceiling fan size is measured as though the rotating fan were drawing an imaginary circle. The length from one side of the circle to its opposite side is the ceiling fan blade size.

Simply measure one blade from the tip to the centre of the fixture, then multiply that measurement by 2 to arrive at the fan’s size in inches.

Then choose the largest most powerful fan possible with the greatest blade pitch for your room size to maximize the airflow generated by its rotating blades.

[image from lampsplus.com]

I bought two fans, each with five 52-inch blades — the largest fans that fit into my small space. One is installed in an 80 sq. ft. bedroom and the other is in the 200 sq.ft. living room, and on the lowest setting they move a lot of air while costing very little energy to run. The blade pitch was minimal, but that was fine for my purposes. My ceilings are low and I do not require amazing airflow measurements in those spaces.

If you need specific suggestions for choosing a fan size to fit in your rooms, here’s a quick cheat sheet:

Ceiling Fan Size for Very Small Rooms or Spaces:

20″ to 36″ ceiling fans

For:

  • Nooks,
  • stairwells,
  • laundry rooms,
  • walk-in closets, or
  • small bathrooms.

If using in an outdoor patio or in a tiny bathroom, find a damp- or wet-rated fan designed to withstand frequent exposure to moisture.

Fans Size Small Rooms:

40″ to 48″ ceiling fans

  • For rooms smaller than 9′ x 9′
  • small bedrooms,
  • home offices,
  • dens, and
  • full bathrooms.

Look for a whisper-quiet ceiling fan, especially for in a bedroom.

Fan Size for Standard Rooms:

50″ to 58″ ceiling fans for cooling average rooms

  • 10’x 10′ to 16’x 16′ (100 to 256 sq ft) for example:
  • large bedrooms,
  • living rooms, and
  • large kitchens.

Powerful fans can easily cool rooms of 100-300 sq ft.

Under-sized and under-powered fans often result in a fan that is constantly running at high speeds, which increases energy consumption, delivers a stronger airflow which may be less comfortable, and can limit the life of the fan. Again, consider whisper-quiet fans when selecting fans for bedrooms.

Ceiling Fan Size for Large Rooms:

60″ to 72″ ceiling fans

  • 289 to 400 square feet rooms, like:
  • family rooms,
  • large living rooms,
  • large master bedrooms, and
  • outdoor patios (up to 400 sq. ft.) are best with 60″ to 72″ ceiling fans that have reasonable power and airflow (CFM).
  • again, having a whisper-quiet fan can be very significant in bedrooms.

Fans for Very Large Rooms:

Multiple 50″ to 58″ ceiling fans, or one 65″ (or greater) fan

A nice big, quiet fan works well in this bedroom.
  • For great rooms,
  • open attic space,
  • game rooms,
  • combination rooms,

consider multiple powerful fans with high airflow and blades of 50″ to 58″ for rooms greater than 400 sq. ft.

How To Calculate The Largest Size of Fan To Fit A Room

Choose a ceiling fan appropriately sized for your room. Larger fans are capable of moving more air than smaller models, as long as the blades are pitched sufficiently.

For rooms of 225 square feet, ceiling fans with a diameter between 36 and 44 inches is sufficient, but if you can go bigger and the space needs better cooling, install a larger fan with a powerful motor to rotate nicely pitched blades.

Larger rooms need a fan with a diameter of at least 52 inches or more. In rooms longer than 18 feet, multiple fans should be used for best results. You may add two fans to a slightly smaller area if you desire a certain aesthetic.

How to Space Two Fans Equidistantly in One Room

source: https://www.hansenwholesale.com/ceiling-fans/multiple-ceiling-fan-positioning/

Air Circulation Note

Ceiling hugger-fans (flush mount) provide as much as 40 percent less air movement than standard ceiling fans with a downrod amount.

For greater comfort, remember to focus on the blade sweep (width of the fan, blade tip to blade tip), blade pitch (a greater angle of the blade moves more air but requires a more powerful motor), and the resulting airflow (the higher the CFM, the better the cooling).

How to Choose a Ceiling Fan: Size Guide Considering Blades & Airflow

The short answer to how to choose the right-sized ceiling fan for any room is to keep this guidance in mind:

  • Ceiling fans work best in rooms with ceilings that are at least eight feet high, for safety and pragmatic purposes.
  • Ideally, install your ceiling fan so the blades are placed seven to nine feet higher than the floor and 10 to 12 inches away from the ceiling. In larger spaces increase this buffer zone to 18 inches.

Ceiling Height

When selecting a new or a replacement ceiling fan, measure the ceiling height to determine your fan style and mounting options.

When choosing your fan, you will come across the terms “downrod” and “flush” or “hugger” mount; the optimal fan height from floor to fan blades is approximately 8 feet. Many fans have multiple mounting options; if your ceiling is relatively low, your options are limited to the flush mount style.

As mentioned, your ceiling fan height (from floor to blade) should be at least 8 feet high, in an ideal situation.

Mounting Options

Flush Mount (or hugger): Mounted to the ceiling, this option is ideal for rooms with low ceilings or where a low profile is wanted or required. These ceiling fans are mounted flush to the ceiling, with no extra attachment.

Example of a flush mount or hugger ceiling fan type.

Downrod Mount: This mounting option is best for rooms with high ceilings, of 8 feet and up. Many ceiling fans (other than fans explicitly flush mount) include a downrod. Check the packaging for a downrod and note the size — for extra-tall ceilings, you may need a longer downrod than provided.

Important: If your ceiling fan has a light fixture, reduce the length of the downrod by 12 inches.

source:homedepot.com

See below to help calculate the ideal downrod length. These are a guide, not a rule:

9-ft ceiling6-to-12-inch downrod
10-ft ceiling12-to-18-inch downrod
12-ft ceiling24-to-36-inch downrod
14-ft ceiling36-to-60-inch downrod
16-ft ceiling48-to-84-inch downrod
18-ft ceiling60-inch downrod
20-ft ceiling72-inch downrod

Depending on the height between the floor and your ceiling, you’ll have a different selection of fans to deliberate over. For vaulted ceilings, make sure the tips of your fan’s blades are at least 18 inches away from the walls and ceiling.

The Takeaway
  • For rooms with tall ceilings, you’ll want to choose a fan with a downrod of adequate length, as the image above shows.
  • For optimal air circulation and proper functioning of the fan, the fan blades should be positioned 8 inches or more from the ceiling, and 18 inches away from the surrounding walls.
  • For safety, the bottom of the fan needs to be at least 7 feet above the floor.

Size, or Pitch? What to Consider When Picking Ceiling Fan Blades

All about the right angle: the look of a ceiling fan’s blades are less a feature and more a design preference — the fan’s ability to move air is determined by the pitch of the blades.

What is the Fan Blade Pitch?

Blade pitch is the slope of the fan blade. In other words, it is the angle (in degrees) of a ceiling fan’s blade tilt.

Blade pitch is important because the higher the tilt, the more the motor works to push the air when the fan is rotating. The greater the blade pitch, the more air the fan can move. Thus, the greater the fan’s blade pitch, the greater the fan’s ability to move air (increased CFM).

In order to feel that your fan is moving enough air effectively to cool you down on those muggy summer days, look for a fan that has a blade pitch of 12-15 degrees.

10-11slight pitch
12-13medium pitch
14-15steep pitch (this fan needs a powerful motor)
Slightly pitched blades can work well too, if the fan motor is powerful enough to generate and maintain a nice breeze.

Design Considerations

Many fans these days have reversible blades, so if you feel like changing the finish, you can reverse them — a two-for-one! The number of blades and blade shapes are also constantly changing. Some fans have as many as nine blades, for a helicopter style, and some trendy fans are going for the 3-bladed propeller look. You can’t go wrong with the traditional four or five-blade classic ceiling fan, so choose whichever fan you like. The important choice is the fan motor and blade pitch.

What Size Ceiling Fan for Outdoor Living Space

What about the perfect ceiling fan for an outdoor room? On an open or screened porch, a ceiling fan can provide a refreshing breeze on still summer days. Ensure your fan is rated appropriately for damp or wet locations, and look for one that has weatherproof fan blades, too. Wet-rated fans are suitable for coastal or rainy areas, but damp-rated fans (for bathrooms, for example) shouldn’t come into contact with water.

A Short Word on AC vs. DC Motors

AC (Alternating Current) motors use electricity to produce a rotating magnetic field to spin the rotor. This is the common, affordable motor with which most are familiar. Accordingly, AC-powered fans offer more design and style options on the market. AC Motors are also quiet when installed properly, reliable, and most ceiling fans are equipped with them.

DC (Direct Current) motors convert electrical energy to mechanical energy, and utilize up to 70% less electricity. But are often more expense to purchase upfront. DC motors are light in weight, whisper-quiet to run (great for bedrooms), and boast a longer motor life thanks to efficiency advancements.

Why would anyone want to use ceiling fans to cool themselves when they already have an air conditioner, you might ask. Aside from their efficiency, ceiling fans take up less space making them ideal for cramped spaces, renters, and for use in bedrooms.

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