The bottom rack of a half-empty open dishwasher

It’s normal to feel guilty thinking of all the energy and water wasted when you turn on the dishwasher to clean just a few dishes.

With the average water bill in the U.S. being $40.92 and electricity 13.72 cents per kilowatt-hour, you can’t afford to be wasteful. 

In this state of confusion, you’ll want an answer to the question, “Is it wasteful to run a half-empty dishwasher?” 

This article will discuss water and energy usage when running a half-empty dishwasher. We’ll also advise on how to use your dishwasher efficiently. 

So, let’s get into it!

Is It Wasteful to Run a Half-Empty Dishwasher?

Running a half-empty dishwasher can be considered wasteful, or at least inefficient.

Doing so wastes half the energy and water the dishwasher consumes, while your dishes may not get clean.

Moreover, it risks breaking your dishes as they bump into each during the cycle. 

Energy and Water Usage for a Half-Empty Dishwasher

When running a half-empty dishwasher, there is always confusion between water and electricity usage.

While some claim running a half-empty dishwasher wastes water and electricity, others claim only electricity is the concern in such a case.

So, what’s the truth?

According to Cascade, a detergent brand, dishwashers are more energy-efficient than hand washing.

However, you must understand that this argument is based on a fully-loaded dishwasher. Can the same be said for a half-empty dishwasher?

The answer is a resounding no.

Let us explain why:

An average dishwasher load consumes about 1.5kWh of electricity. The energy consumed in heating a gallon of water from a faucet ranges between 0.1 to 0.15kWh. These dishwasher parameters are constant whether you run a half-empty or full-load dishwasher.

According to Cascade’s research, handwashing a single dish takes 15 seconds and consumes half a gallon (1.89 liters) of water. At this rate, you’ll have to hand wash between 20-30 dishes with running water to equal the 1.5kWh electricity used by the dishwasher.

A homeowner pre-rinses a mug before putting it in the dishwasher

Check out our article, “Dishwasher vs. Hand washing: Which is More Sustainable?” for more information.

Water Usage When Running a Half-Empty Dishwasher

A dishwasher, whether full or half-full, saves more water than hand washing. How is this possible?

According to the Environmental Protection Agency, an average dishwasher uses six gallons (22.71 liters) of water per load for a complete cycle. Therefore, it doesn’t matter whether you’re running a full or half-empty washer when it comes to water—you’ll use six or fewer gallons for newer Energy Star dishwashers.

But what about hand washing the dishes? Handwashing dishes uses a varying amount of water depending on factors like:

  • The time taken to wash the dishes
  • How long you keep the water running
  • Faucet sizes
  • Water speed

On average, handwashing dishes for two minutes uses four gallons (15.14 liters) of water. Therefore, handwashing dishes for four minutes uses eight gallons (30.28 liters) of water. This figure is twice the amount used in a dishwasher cycle, whether full or half-empty.

Worse still, most people use up to 27 gallons (102.21 liters) of water hand washing their dishes.

Based on this demonstration, if you intend to save water, using a dishwasher is the best option regardless of the load size.

Check out this article for other reasons why a dishwasher is the best option for water conservation.

A fisheye view from inside the upper rack of a dishwasher

How to Use Your Dishwasher Efficiently

Now that we’ve established that running a half-empty dishwasher is wasteful, let’s discuss how to use it efficiently.

Avoid Pre-Rinsing Your Dishes

Pre-rinsing dishes before loading them into a dishwasher is a common practice. This precaution was necessary for traditional dishwashers because they were too weak to get off all the gunk. However, this is unnecessary for modern dishwashers.

Modern dishwashers are powerful enough to take off most stuck-on food and grime. Therefore, pre-rinsing your dishes before loading them into a dishwasher is a waste of water.

Run Full Loads Whenever Possible

Growing up, you might have heard your mom say, “Never run a half-empty dishwasher!” 

Well, she was right! Running full loads every time is more energy-efficient than running two half-loads.

Closeup on the bottom rack of an old-school dishwasher full of clean plates and silverware

Also, it’s essential to place your dishes in the correct order for the best results. Ideally, always place them with the dirty side facing the dishwasher’s center.

Go for Energy Star-Certified Dishwashers

When upgrading your dishwasher, it’s advisable to pick an Energy Star-certified model. We all want to save our household energy consumption, and using Energy Star-approved equipment is one way to do that.

An Energy Star-certified dishwasher meets the energy efficiency standards set by the EPA. These dishwashers use 12-30% less energy and water, respectively.

a new modern white european style kitchen with matte black appliances
I personally made sure to get an Energy Star rated Samsung matte black appliance set when renovating our second netzero home a little while ago.

Use the Eco Mode

Are you among the people who always use the high-temperature program? If so, you’re doing it the wrong way and wasting energy.

Most dishwashers have an eco mode setting that uses a lower temperature to clean the dishes. This mode saves energy and water without compromising efficiency.

It’s worth mentioning that some dishwashers don’t have eco mode. If this is your case, you’ll have to match the program to the load’s needs in terms of temperature.

Air Dry the Dishes

Air drying your dishes is an excellent way to save energy. Although the heat-dry setting is faster and more convenient, it uses a lot of energy.

Therefore, if you don’t mind waiting for your dishes to dry, turn off the heat-dry setting and let them air dry. This measure will save you significant money in the long run.

Tips for Optimizing Dishwasher Loads

Optimizing dishwasher loads will help ensure that you’re using the appliance efficiently, saving water and energy.

Here are some tips for maximizing the effectiveness of your dishwasher:

  • Scrape, Don’t rinse: Modern dishwashers are designed to handle food particles. Instead of pre-rinsing your dishes, simply scrape off excess food before loading them into the dishwasher. This saves water and time.
  • Sort utensils properly: Place utensils with the handles facing down to avoid water pooling in them. Mix up the placement of forks, knives, and spoons to prevent nesting and ensure thorough cleaning.
  • Load larger dishes on the sides and back: Place larger items like pots, pans, and baking sheets on the sides and back of the dishwasher. This ensures that water and detergent reach smaller items in the front more effectively.
  • Face dirty surfaces inward: Position plates and bowls so that the dirtiest surfaces face the center of the dishwasher. This maximizes exposure to the spray arm, improving cleaning efficiency.
  • Don’t overload: While it might be tempting to fit in as many dishes as possible, overloading can hinder the dishwasher’s effectiveness. Make sure there’s enough space between items for water and detergent to reach all surfaces.
  • Use the top rack wisely: The top rack is ideal for glasses, cups, and smaller items. Angle glasses and cups slightly to allow water to drain properly.
  • Check spray arm movement: Before starting the dishwasher, ensure that the spray arms can move freely. Items blocking their rotation can lead to uneven cleaning.
  • Regular maintenance: Keep your dishwasher in top condition by cleaning the filter, checking for clogs in the spray arms, and wiping down the door gasket regularly. A well-maintained dishwasher operates more efficiently.

Dishwasher Mistakes to Avoid

For efficiency, here are some dishwasher mistakes to avoid:

  • Overfilling the machine – although running full loads is recommended, overloading the dishwasher reduces its efficiency. An overly-filled dishwasher can’t clean between plates and other items, meaning some dishes will come out dirty.
  • Blocking the sprayer – the sprayer is responsible for cleaning the dishes. Therefore, it won’t work properly if obstructed by a spoon or other utensil.
  • Using too much detergent – some people think using more detergent will get them cleaner dishes. Unfortunately, that’s a fabulation since too much detergent means more suds, which limits water circulation. It also leaves residue on your kitchenware.
  • Leaving the door open – we’ve all been guilty of this at some point. Leaving the dishwasher’s door open emits steam, making it use more energy. Moreover, the vapor is a recipe for mold if it condenses on kitchen appliances and walls.
  • Placing the dishes incorrectly – while the top shelf is safer for cups, glasses, and bowls, the bottom rack is suitable for pots, pans, and plates. This arrangement makes your dishwasher more efficient since the bottom rack is for rigorous cleaning while the top gives gentler cleaning.

Watch the video below to learn how to load your dishwasher correctly:

Screenshot from a video showing how to load your dishwasher correctly
Courtesy of Boulevard Home

Frequently Asked Questions

Here are several of the most frequently asked questions pertaining to running a dishwasher.

Can you run a dishwasher that’s not full?

It would be best not to run a dishwasher that’s not full because it wastes energy and will expose you to high electricity bills. Furthermore, you risk breaking your utensils by running a dishwasher that’s not full.

Can you run a dishwasher with a few dishes?

You risk cracking your dishes if you run a load with a few pieces. When you run a dishwasher with a few dishes, they bump into each other, increasing their chances of breaking.


Running a half-empty dishwasher is wasteful because it uses the same energy and water as running a full load. Thus, it’s advisable to run full loads in your dishwasher to save energy.

However, running a half-empty dishwasher saves more water than hand washing. Finally, it would be best not to overfill your dishwasher as this reduces cleaning efficiency.

Now that you know about dishwashers, check out this article to find out if dishwasher pods are bad for the environment.

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