Why You Shouldn’t Replace Ceiling Fan Blades With Longer Blades

Ceiling fans come in many variations. Some have long blades and some have small. But is it ok to replace the shorter blades on a fan with longer ones?

You can put longer blades on a ceiling fan but it is not recommended. Longer blades increase the load on the fan’s motor, causing it to burn out. Even if you manage to run the fan without damaging the motor, it is likely to be less energy efficient.

If you are interested in knowing why it is a bad idea to replace ceiling fan blades with longer ones, continue reading.

Why do people want to put longer blades

There are many reasons why people want to replace their fan’s blades with longer ones. The main reason is to get more airflow. Sometimes, the fan you bought may not be delivering enough wind speed to feel a breeze effect. Sometimes, there is no airflow a all. In such cases, people have two options;

  • Replace the blades with their longer versions
  • Buy a new fan

It is much cheaper to buy new blades than to replace the entire fan. However, trying to save a few bucks like this can cost you more.

Problems with putting longer blades on a fan

There are many reasons why you shouldn’t replace fan blades with longer ones. Here are they;

Risk of the motor burning out

Even though ceiling fans are seemingly simple machines that move air for better ventilation and convenience, many thought has gone into their design. Its parts like the motor, blades, housing, etc are made with their energy efficiency and airflow in focus. A fan you buy is a combination of different optimized parameters to give it good performance. Changing any of these parameters, say blade span, of the fan will affect its working.

For example, the pitch of the fan blades determines how much airflow it produces. You get more airflow for more blade pitch. However, larger blade pitches increase the drag on the fan’s blades and thus increase the load on its motor.

Likewise, a longer fan blade will move air over a large area. This means that it has to overcome more air resistance, which means spending more power. As the air resistance increase, the fan’s motor will come under increased load. Even though most motors can withstand extra load by a margin, the long-term use can burn out the windings on it.

Longer blades aren’t effective

Fitting longer blades to the fan won’t necessarily increase its airflow rate. The additional drag on the fan slows down its rotation, and in effect, the fan will deliver more or less the same airflow as with the previous blades.

For example, let’s say you want to replace 52-inch blades with 60-inch ones. The new blades will now cover an additional 224 square inches of the area, which is almost 30% more than the initial area covered. So, the fan will need almost 30% more power to run at its normal speed. Since the current to the fan is regulated, this additional load causes the fan to slow down, which nullifies any benefits you expected to get from the longer blades.

Voids fan warranty

The motors of most fans are covered under a lifetime warranty. But if you use longer blades and the motor gets damaged, that comes under causing intentional damage, and this is not covered under warranty. So by using longer fan blades, you are losing the warranty coverage of your fan.

Then there is the Homeowners insurance. Most insurance policies cover damages from DIY projects if they are sudden and accidental. But many won’t cover if the damage is due to faulty workmanship.

They will not fit correctly

You are less likely to find longer blades that correctly fit your current ceiling fan. Since blades are tailor-made to suit particular fan models, most blades you see won’t fit your fan model. In addition, there is the issue of color. It is tough to find third-party fan blades that match the color and finish of a fan. So the chances of finding matching blades are grim. That being said, if the fan model you have is also available in larger sizes, you won’t have any trouble finding the right blades. For example, the Monte Carlo Maverick fan is available in 52, 60, and 80-inch sizes, so you can buy matching 60-inch blades for your 52-inch fan. Whether they will work or not is entirely another matter.

Even if you manage to fit the longer blades to the fan, they can stay loosely connected and cause rattling noise and other issues.

There is also a good chance that you will need to do some drilling and customizations to install the new blades. More often than not, this can unbalance the blades, and as a result, the fan will start wobbling. You can use a balancing kit to rectify this issue.

Do bigger blades move more air

Yes, bigger fan blades move more air than smaller ones, provided they are fitted to a large motor. Blade span by itself doesn’t increase airflow. Long blades on a small motor will cause it to run slower instead of moving more air. But with the right motor, large fan blades move considerably more air and cover more area. For example, a 52-inch outdoor ceiling fan can cool up to 100 square feet, whereas a 60-inch fan can cool up to 225 square feet of outdoor area.

There are also fans called High Volume Low Speed (HVLS) fans which have huge blade spans but rotate slowly. Even with their slow rotation, such fans can move large volumes of air. The motors they use are powerful even though they are designed to run slow. So this is much different from putting larger blades on a fan and having it run slow. BigAss fans are a good example of such high volume low-speed fans.

Do more blades make a ceiling fan better?

You can find ceiling fans with three or more blades. There are also some models that have just one blade (crazy, isn’t it?) More blades don’t equate to more airflow, though. In fact, it is 3 and 4-bladed fans that move more air, and they are more energy-efficient. This is because more blades restrict the amount of air movement between the blades.

But a fan with more blades is generally quieter. This is because more blades smoothen the airflow, thus reducing the air resistance on each blade. So what if you replace the blades of such a fan with longer blades, will it still damage the motor? Yes, even if the possible drag on such fans is lower, putting longer blades can still damage the fan.

What is the right solution to increasing the airflow of a ceiling fan?

If your ceiling fan is delivering less airflow, the first thing to do is check whether it is running in the right direction. For you to feel airflow the fan should run in the counter-clockwise direction when looking at it from the floor. Most fans come with a reverse switch, it is possible that your fan is running in the wrong direction. If the fan is spinning clockwise, reverse its direction using the toggle switch found on its motor casing or by using the pull chain (there are usually two pull chains, one to change the fan speed and the other to reverse its direction.). Cleaning the fan blades too helps to improve its airflow.

If the fan still doesn’t move enough air, your only option is to buy a new fan. A larger fan will deliver more airflow. However, if you are looking for wind speed, the chilling breeze effect created by a fan, then you need to buy a smaller fan with high CFM. Such fans spin faster to produce high airflow, and this fast spinning also increases the wind velocity that creates the chill effect.

Charles John

Experienced HVAC technician with 8 years of experience in the industry. Capable of handling all sorts of heating and cooling equipment as well as proficient in operational management, construction-related techniques such as preventative maintenance, electrical troubleshooting and AutoCAD

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