Motor HP Comparison: 1/2 Hp vs 1/3 Hp

Usually, you won’t be bothered with horsepower measurements. But while selecting the right motor for your HVAC system, a comparison between 1/2 hp vs 1/3 hp motors might appear.

So, which one is better between 1/2 hp vs 1/3 hp motors?

1/2 hp motors are stronger in power compared to 1/3 hp motors. They are used for slightly heavier operations than 1/3 hp motors. Since their workload would be more they have better build quality in general. If we compare their efficiency 1/2 hp motors can get more work done.

That’s the highlight of the whole discussion. Let’s get into the full version-

1/2 HP Vs 1/3 HP Motor: Quick Comparison

The fundamental differences between 1/2 vs 1/3 hp motors in a glance-

1/2 HP Vs 1/3 HP Motor: Detailed Comparison

Before jumping into a full-fledged 1/2 hp and 1/3 hp motor comparison, let’s have a look at the types of HVAC motors-

• Blower motor
• Compressor motors
• Combustion fan motor
• Condenser fan motor
• ECM (Electronic Control Module) motor

Now, keeping these variations in mind, let’s see how a 1/2 hp and 1/3 hp motor differs in action-

Build Quality:

The building quality of a motor greatly depends on the brand and the budget. Popular brands like Trane, goodman provides higher-quality materials for building their HVAC products.

But, in general, 1/2 hp motors have better building quality compared to 1/3 hp motors. This is because 1/2 horsepower motors are used in slightly heavier duties than 1/3 motors.

The inside build may not be that of a high-end one. But overall it should be of good build to withstand the power supplies. But like we mentioned earlier, your budget will vary the quality here.

1/2 hp motors are usually budget-friendly. You’ll find both 1/2 and 1/3 hp motors made from cheaper materials. But for a high-end product, the price will be higher than the average range. 

The same is true for 1/3 hp motors. You can get a 1/3 horsepower motor with better built by the same budget. In fact, a high-end 1/3 hp motor’s price will surpass any regular 1/2 motor too. 

Of course, it comes with the advantage of a good buildup.

Weight:

A few factors determine the weight of an HVAC motor. Firstly, it’s the motor design and the building materials. Depending on the motor design it can be heavy or lightweight. 

Another concerning factor is the case length of the motor. The longer it is the more it’s gonna weigh. Both 1/2 hp and 1/3 hp motors are on the lightweight side.

Because they are smaller in size. But 1/3 hp motors would be even lighter in comparison to 1/2 hp motors. The higher the horsepower is, the heavier the device would be.

So, if you want something lightweight, 1/3 HP disposals are definitely worth it. However, choosing the good ones is the key. So, here are some of the popular disposals for you to look at-

• Waste King L-111 Garbage Disposal is a great corded 1/3 HP disposal. You can’t really go wrong with this one.
• InSinkErator Garbage Disposal with Cord is a bit premium with better speed and efficiency. 

This information might come in handy when choosing a furnace blower motor size.

Power:

Horsepower is a unit of measurement. It is used to measure the power of machines like motors or engines. It calculates the rate your work gets done.

There are motors with higher and lower horsepowers. The more horsepower it has the stronger it is. You’ll hear about 5 hp or 4 hp motors. Those are quite powerful machines. Similarly, motors with 1/4, 1/5, and 1/6 hp are on the lower side in power comparison.

We were talking about 1/2 and 1/3 horsepower. Naturally, these numbers are lower than 1. 

This means a 1/2 hp motor has half the power a 1 hp motor has. A 1/3 hp motor’s power is even lower than 1/2 hp. The smaller the hp measurement is the weaker its power is gonna be. 

This is why a 1/2 hp motor will produce more air movement. Which means it can bring more air out of the machine. And that’s why many users replace their 1/3 HP garbage disposal with 1/2 HP!

You can check out our recommendation of 1/2 HP garbage disposals from here-

• FRIGIDAIRE FF05DISPC1 HP Corded Garbage Disposer is the best one we used! It even has a power cord attached to it.
• Waste Maid Garbage Disposal is another beast of a machine. It has been constructed with full stainless steel for extreme durability.

Now, let’s move on to the next part about the efficiency level.

Efficiency:

It’s important to match the power specification of a motor’s horsepower with the HVAC unit. You can’t pair up more powerful motors where motors with less power are needed.

In regular households, 1/2 hp motors are perfect for HVAC systems. They aren’t too big and perfect for lightweight duties. 1/3 hp motors are also suited for lightweight HVAC operations. Even more so compared to 1/2 horsepower motors. That’s why they are usually used in smaller households.

1/2 hp motors make little to moderate noises. But 1/3 hp motors tend to be noisier. They make sounds of fan flapping.

Cost:

1/3 horsepower motors are cheaper than 1/2 hp motors. But this might vary based on the different types of HVAC motor we’ve discussed earlier.

Putting the brand value aside, 1/2 hp motors are pricier for their machine power itself. After all, they are used for slightly heavier operations than 1/3 hp motors.

1/2 HP Vs 1/3 HP Motor: Which is For What?

So, which motor should you pick?

It purely depends on the functionality of your HVAC unit. But if your question is simply, which one is stronger, it’s definitely 1/2 hp motors.

Matching an HVAC motor with the appliances depends on quite a few things. The physical spec of the HVAC unit and motor speed matters greatly.

The direction of rotation, capacitor, and motor types are also to be taken into consideration. Calculating all these aspects by yourself can be pretty bothersome.

Better would be to take suggestions from a professional before making any changes. Especially if you wish to repair or replace the HVAC motor.

Frequently Asked Questions (FAQs)

What causes condenser fan motors to overheat?

An old worn-out condenser fan motor will overheat every now and then. The reason why it overheats can be because of a faulty capacitor. Electrical problems or debris in the outdoor unit can also be the leading cause. Neglecting the maintenance of your fan motor for a long time also leads to this issue.

What is a combustion fan motor?

Combustion fan motors are used for gas furnaces. These motors don’t contain a capacitor. It’s quite simple in design compared to other HVAC motors. That’s why it’s easy to troubleshoot these motors. But if it gets burned the whole motor needs replacement.

Which HVAC motor is more expensive?

Among all the other HVAC motors compressor motors are the most expensive ones. They can cost up to $1000. They are also the most complex type of motor. So, it’s hard to determine which part has failed if any problem arises. It’s a combination of two motors. A start motor and a run motor.

EndNote

That was all about Motor HP Comparison: 1/2 hp vs 1/3 hp. Hopefully, the discussion was of interest to you. 

It’s said that motors are the hearts of machines. If you don’t do some maintenance once in a while they might go bad. So, don’t skip it.

See you soon!

Tim David

HVAC tech with over 30 years of experience. Retired and doing repair work on the side around Madison County, AL.