Dishwasher Buying Guide: A Checklist Before You Buy

Updated October 16, 2026 · Appliance Den buying guide

Short answer: measure the opening first, then decide on size (standard 24-inch or compact 18-inch), how quiet you need it, how it dries, and how the racks fit your dishes. Check the ENERGY STAR label and the installation details before you order. Use the checklist at the end before you order.

1. Measure the space (before anything else)

• Width: most built-in dishwashers are made for a 24-inch-wide opening. Compact or “slim” models are made for an opening about 18 inches wide.
• Height: measure from the floor to the underside of the countertop at the front and back. Standard models fit a typical under-counter opening and have adjustable feet, but thick flooring added later can steal the height you need.
• Depth: check that the door can open fully without hitting an island, a range or a drawer pull, and that you can stand in front of it while it’s open.
• Read the installation guide of any model you shortlist: it lists the exact cut-out size, where the water, drain and power must come in, and the clearances it needs.

2. Standard or compact?

ENERGY STAR defines a standard dishwasher as one that holds at least 8 place settings plus 6 serving pieces; anything smaller is compact. In practice, a standard 24-inch model is the right call for most families; an 18-inch compact makes sense for a small kitchen, one or two people, or a second dishwasher. There are also countertop units that connect to the sink faucet when there is no cabinet space at all.

3. Noise: read the decibel rating

Noise is listed in decibels (dBA): a lower number is quieter. Because the scale is logarithmic, a few decibels make a real difference, and a 10 dB drop sounds roughly half as loud. If your kitchen is open to the living area or you run the dishwasher at night, put noise near the top of your list, and compare ratings measured the same way.

4. Tub and drying

A rinse aid helps any dishwasher dry better, especially those that rely on condensation.

5. Racks and loading

• Third rack vs. cutlery basket: a shallow top rack holds utensils flat and frees space below; a basket in the lower rack holds tall utensils and serving spoons. Many people prefer one or the other, so look at how you load today.
• Adjustable upper rack: lets you raise or lower it for tall glasses or large plates.
• Fold-down tines: make room for pots, bowls and baking sheets.
• Bring a dinner plate when shopping in person: check that your largest plates and favorite glasses fit.

6. Controls, filter and cycles

• Top (hidden) controls give a clean front but you can’t see the time left without opening the door, unless the model shows a light or display on the floor. Front controls are easier to read and harder to bump.
• Filter: many modern dishwashers use a manual filter you rinse every few weeks; it’s quieter. Self-cleaning (grinder) filters need less attention but can be louder.
• Cycles: you will mostly use normal, heavy, quick and rinse. A soil sensor that adjusts water and time to how dirty the load is is more useful than a long list of special cycles.

7. Energy and water

For a standard-size model to earn the ENERGY STAR label under the current specification (effective July 19, 2023), it must use no more than 240 kWh a year and 3.2 gallons per cycle; compact models must use no more than 155 kWh a year and 2.0 gallons per cycle. ENERGY STAR estimates a standard-size certified dishwasher costs about $50 a year to run. Its tips: scrape, don’t rinse (pre-rinsing adds water and energy), and run full loads, because a dishwasher uses about the same water and energy whether it’s full or half empty.

Sources: ENERGY STAR, “Dishwashers Key Product Criteria” and “Dishwashers” (energystar.gov, read October 16, 2026).

8. Installation: what to ask before you order

• Water: a dishwasher connects to the hot-water supply under the sink, usually through a shut-off valve and a supply line. Ask whether a new supply line and fittings come in the box.
• Drain: it drains into the sink drain or garbage disposal, with a high loop or an air gap as your local code requires. If you have a new disposal, its knock-out plug must be removed first.
• Power: some models come with a plug, many are hard-wired. Check which your kitchen has and whether a power cord kit is needed.
• Delivery: ask whether installation, haul-away of the old unit and any install kit are included, and what happens if the old one won’t come out cleanly.
• If you are not comfortable with water and electrical connections, have a licensed plumber or installer do it.

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