Reducing Emissions from Your Dishwasher

Americans’ energy use has changed a lot since the days when a kitchen full of appliances was a symbol of success rather than just, you know, a kitchen. Although transportation is the biggest component of our household carbon footprint today, kitchens still use a lot of energy and water. The dishwasher is one kitchen appliance that uses both. Here’s how you can cut your dishwasher’s environmental impact.

The Environmental Impact of Dishwashers

Dishwashers are kind of an in-between appliance. Unlike coffee makers and Instapots, dishwashers are considered major appliances. But they aren’t the energy hogs that ovens and refrigerators can be. Like many small appliances, some people would argue that dishwashers are unnecessary, while others would rather go without an oven than a dishwasher. Fortunately for the latter group, dishwashers can provide a net environmental benefit.

Dishwasher emissions are lower than those of other major appliances in the first place: one study estimates 51-84 kg CO2/year. This estimate is based on the assumption of fewer than 150 washes/year – significantly fewer than most American families need. But even if your household generates a full load of dishes every day, running a modern, efficient dishwasher can be better than handwashing dishes – even if you use the more efficient two-basin handwashing method.

Buying the Best

Energy Star certification requires a minimum standard for efficient use of both water and electricity, but there’s a tradeoff between the two. The dishwashers that use the least water tend to be less energy efficient. The most energy-efficient dishwashers use more water. Whether you prioritize water or energy efficiency will depend on the source of your electricity and your local water resources.

In a coal-powered region with a sustainable freshwater supply, energy efficiency is more important. By contrast, a desert-dweller with renewable energy should prioritize water efficiency. You can use the EPA Power Profiler to find out how clean your region’s power supply is compared to the national average. The interactive maps on DWMAPS can identify your drinking water source. Earth911 compiled a buyer’s guide of the overall greenest dishwashers. There are good choices for every circumstance, even if you have a tiny kitchen or are immune-impaired.

Minimizing Impacts

Regardless of which dishwasher you choose, or even if you hang on to your old one, you can reduce the carbon footprint of your home appliances by the way you use them. If you want your dishwasher to generate fewer emissions than the two-basin handwashing method, follow three tips:

• Don’t pre-rinse before loading dishes into the dishwasher.
• Don’t select the “heat dry” setting.
• Don’t choose the “heavy” cycle over a normal wash, except for tougher loads.

Scraping dishes before placing them in the dishwasher will prevent clogged drains without wasting water. Scraped dishes will get just as clean in a modern dishwasher as pre-rinsed dishes. Heat drying may finish a load of dishes faster, and in some cases may make dishes sparkle a little more. But it uses energy unnecessarily. The “heavy” setting is also unnecessary for most loads. Even when dishes are hard to clean, a soak in vinegar water before running the dishwasher may be just as effective as running a “heavy” load.

Your choice of dishwasher detergent has environmental impacts, too. Detergents are petroleum-based, which gives them an outsized climate impact. Many also contain toxic ingredients and use excessive packaging. True Green Organics claims to make a petroleum-free dish cleaner and, although pricey, Blueland’s fragrance-free dishwasher tablets are EWG-verified and come in refillable plastic-free containers.

Choose eco-friendly tools like sustainable sponge alternatives and bottle brushes for the times when you need to wash things by hand. And remembering that the dishwasher can be used to clean a lot of things besides dishes can keep you from disposing of things like used sponges and bathroom items too soon or wasting water by handwashing household items.

End of Life

Although new appliances are more efficient than old ones, manufacturing also generates greenhouse gas emissions. Before you buy, make sure the efficiencies justify the upgrade. Energy Star generally recommends replacing appliances after 10 years. When it is time to replace your dishwasher, you might be eligible for rebates if you choose an efficient replacement.

Responsible disposal is part of sustainability. Often the retailer that sold your new appliance will collect your old one; before they do, make sure they are collecting for recycling and not disposal. Modern dishwashers contain more plastic than metal, so it might take some effort to recycle your old one. Check the Responsible Appliance Disposal program if your retailer doesn’t offer recycling.