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5/8 HP vs 3/4 HP Garbage Disposal: Which Should You Choose

Household garbage disposals manly come with four horsepower ratings; 1 HP, 3/4 HP, 1/2 HP, and 1/3 HP. But there are also a few models with 5/8 HP motors. How are these 5/8 HP garbage disposals different from 3/4 HP models, and which is the right fit for you?

3/4 HP garbage disposals have more grinding power than 5/8 HP ones, and hence they can grind tougher food wastes. If you cook only once a week, a 5/8 HP garbage disposal is the right choice. If you cook more often, a 3/4 HP garbage disposal is the one you need.

If you are interested, here are some top garbage disposals in the 5/8 HP range (View them on Amazon) and some in the 3/4 HP range (View them on Amazon).

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Significance of 5/8 HP garbage disposals

Understandably, a higher horsepower motor grinds better. But that doesn’t explain the need for making a whole new category of 5/8 HP disposals. They aren’t much different from 1/2 HP disposals in terms of grinding power, then why do companies go through the pain of introducing a new line of garbage disposals and making it hard for customers to choose a product?

The answer is simple. The 5/8 HP garbage disposal models are made by InSinkErator, and they all belong to their premium Evolution series. InSinkErator introduced 5/8 HP garbage disposals as an alternative to 1/2 HP units with premium features. If you check the Evolution series, there are no 1/2 HP garbage disposals. So, for a customer looking for a 1/2 HP garbage disposal but with premium features like noise insulation, 5/8 HP garbage disposals tick all the boxes.

Best 5/8 HP garbage disposals

All the popular 5/8 HP garbage disposals are made by InSinkErator. Here are the best picks;

1. InSinkErator Evolution Select

InSinkErator Evolution Select

Evolution Select is the most popular 5/8 HP garbage disposal. It is available exclusively through HomeDepot. It is powered by a permanent magnet motor that runs at 1725 RPM. It is very quiet thanks to SoundSeal technology by InSinkErator. It uses a 3-bolt mounting assembly to connect it with a kitchen sink. It is compact in size, measuring only 12.25 inches in height.

Check specification sheet

2. InSinkErator SpaceSaver

InSinkErator SpaceSaver

InSinkErator SpaceSaver has exactly the same features and specifications as the Evolution Select garbage disposal. The only difference is that this model is sold exclusively through Lowes.

Another difference is the warranty and price which change from time to time.

Check specification sheet

Differences between 5/8 HP and 3/4 HP garbage disposals

Since 5/8 HP garbage disposals were introduced as an upgraded version of 1/2 HP models, they aren’t much different from 3/4 HP disposals in anything other than their grinding power.

But this small difference is significant to the customer since you cannot grind as many things with a 5/8 HP disposal as you can with a 3/4 HP unit.

For the sake of comparison, let’s consider two very similar garbage disposal models; Evolution Select and Evolution Select Plus. The only major difference between them is the grinding power. There are also differences in their warranties and pricing; the higher HP model tends to have more warranty and price. But these differences, the price, and warranty of garbage disposals, change yearly, so they cannot be used for a sensible comparison.

But when you consider an InSinkErator 5/8 HP garbage disposal and a 3/4 HP garbage disposal by another brand like Waste King, the differences are many. The latter tend to have less noise insulation and slightly lower build quality. However, Waste King 3/4 HP disposals generally have longer warranties and lower prices than the 5/8 HP disposals by InSinkErator. Another difference is the type of motors these disposals use. 3/4 HP Waste King disposals use high-speed permanent magnet motors that run at 2800 RPM, whereas 5/8 HP InSinkErator disposals use induction motors that run at 1725 RPM.

Common features in 5/8 and 3/4 HP garbage disposals made by InSinkErator

The garbage disposals of both these horsepower ratings come with a lot of similar features. Here are they;

Noise insulation:

Both 5/8 and 3/4 HP garbage disposals by InSinkErator come with SoundShield noise insulation. The insulation layers and the anti-vibration mounts of these garbage disposals have considerably reduced the noise coming out of them. They are around 40% quieter than a standard garbage disposal without any noise insulation.

Click here for a list of the top 10 quiet garbage disposals

Multi-stage grinding

Another feature shared by 3/4 and 5/8 HP garbage disposals is multi-stage grinding. This is a feature seen only in premium garbage disposals. Here, the food waste entering the garbage disposal undergoes multiple stages of grinding. This helps to cut the food wastes into smaller particles that can easily pass through drain pipes without causing clogs.

This feature also lets you grind fibrous vegetables like celery, otherwise not advisable to be put in standard garbage disposals. Since the fibers of these vegetables are cut into tiny sizes through multiple grinding stages, they won’t clog the drain pipes.

High build quality

Like I said before, the 5/8 HP garbage disposals in the market belong to the premium category. So, their build qualities are also the best. Both 3/4 and 5/8 HP garbage disposals by InSinkErator come with a stainless steel grinding chamber and stainless steel grinding components. Their grinding components are resistant to rust and are made to withstand constant contact with water.

When you compare a 5/8 HP InSinkErator garbage disposal with a 3/4 HP model of Waste King, the latter doesn’t have noise insulation or multi-stage grinding. But the lack of multi-stage feature is somewhat compensated by Waste King’s high-speed motors, which run almost twice as fast as InSinkErator’s. Waste King 3/4 HP disposals are also good in build quality even though they use time-tested corrosion-resistant plastic grinding chambers instead of the stainless steel ones.

InSinkErator Evolution Compact

Evolution Compact

Waste King 3200 garbage disposal

Waste King 3200

Which garbage disposal should you choose?

A 5/8 HP garbage disposal is good for a household of two people who cooks only once a week. If there are three to four people and they cook more often, you need a 3/4 HP garbage disposal.

That being said, there are garbage disposals of other sizes as well. You can choose from 1/3 HP, 1/2 HP, 3/4 HP and 1 HP garbage disposals. Here is a detailed guide for what size garbage disposal to choose for further reference.

Additional reading:

My name is Thomas Anderson, author of DisposalQA. I have 15 years experience working as a plumber in CA, and this is where I answer common questions about garbage disposals.