Specs are compiled from manufacturer listings and verified buyer reviews and can change over time — please confirm the key details on the product page before buying.
If a standard 24-inch dishwasher simply will not squeeze into your galley, apartment, or RV alcove, the compact models below are built for exactly that gap — and they still wash a full day’s dishes. A quick honesty note before you read: this list uses flexible, human-like matching for the “about 20-inch width” size, so it accepts the nearest compact size (like 18 inches) rather than only the exact number you typed. Not every pick is the precise width searched, but each one serves the same purpose — a slim, under-counter machine that fits a tight space and cleans properly.
I’m Mohammad Maruf — the founder and writer behind KitchPrep. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
Whether you are retrofitting a rental or squeezing a machine into a weekend cabin, these picks cover 18-inch and 23-inch widths, 52 dB noise ratings, and heated-dry options. If you want the short answer, the quietest, best-loved compact in this roundup is the one worth hunting down first before you compare the rest of this list of the best 20-inch dishwasher.
Our Picks at a Glance
How To Choose The Best 20-Inch Dishwasher
Buying a compact dishwasher is really a measuring job before it is a shopping job. Get the fit wrong and the machine sits in your hallway forever. Get the fit right and the other specs — 52 dB noise, 8 place settings, heated dry — become details you can weigh calmly.
Measure the opening, not the old appliance
Pull out your tape measure and check the true width of the cabinet gap, the height under your counter, and the depth behind the door. A compact machine lands around 17.6 to 18 inches wide, which is the key number because it is what allows it to slide into a space a full-size unit cannot reach. If you are replacing a trash compactor or an old built-in, those slim widths are often the only thing that will drop straight in.
Decide how many place settings you actually load
A place setting is one person’s full set of dishes — plate, bowl, glass, and cutlery. Eight place settings is the standard compact capacity, which suits a couple or a small family running a load most days. If you cook with big stockpots and sheet pans, look for an adjustable upper rack, because raising it lets tall cookware clear underneath.
Weigh noise against your floor plan
The decibel figure tells you how loud the machine runs, and in a studio or open-plan kitchen it matters more than any wash option. A machine rated near 52 dB runs at roughly the level of a quiet conversation, which is calm enough to sit beside while it works.
Understand the drying and sanitizing extras
Heated dry uses a heating element to push moisture off the dishes so you are not towel-drying by hand afterward. Hi-Temp and sanitize cycles raise the wash water temperature — one compact here holds water up to 136°F — which helps on greasy bakeware and baby bottles. Energy Star certification simply means the machine meets federal low-energy-use guidelines, which trims running cost over the year.
Quick Comparison
| Model | Best For | Width | Place Settings | Noise Level | Amazon |
|---|---|---|---|---|---|
| Honeywell 18 Inch Dishwasher★ Best Overall | Tiny kitchens and RVs | 18″W | 8 | — | Amazon |
| COMFEE’ 18 Inch Built-in DishwasherQuietest Compact | Renters who want quiet | 17.6″W | 8 | 52 dB | Amazon |
| SPT SD-9254W Built-In DishwasherBuilt-In Classic | Compact retrofits | — | — | — | Amazon |
| Midea 18 Inch Built-in Dishwasher | Three-person households | 17.6″W | 8 | — | Amazon |
| SPT SD-9254SSA Steel Dishwasher | Spotless results, tight fit | — | 8 | — | Amazon |
| EdgeStar 18 Inch Wide Built-In Dishwasher | Replacing a trash compactor | 17.6″W | 8 | 52 dB | Amazon |
In‑Depth Reviews
1. Honeywell 18 Inch Dishwasher with 8 Place settings, 6 Washing Programs
Our pick — over 4★ from 100+ verified ratings; the strongest balance of quality and price.
The slim pick for kitchens so tight the only way in is under the counter
What makes this one the top of the pile is simple: it disappears into a space almost nothing else fits, then runs quietly enough that you forget it is there. The cabinet opening it needs is just 18 inches wide, and the whole unit measures 22.6″D x 18″W x 32.4″H — a footprint designed for the narrow slot between a stove and a fridge. It is ADA-compliant, which means it meets height-and-reach guidelines so the controls stay accessible from a seated position, and it is built in the under-counter style so the countertop continues right over the top of it.
Inside, you get 8 place settings of room, spread across a top cutlery rack, two main racks, and a large removable cutlery basket you can lift out to load on the counter. The tub is stainless steel, which holds heat better than plastic and stays a touch more hygienic cycle to cycle. You drive it from six programs — pots & pans, normal wash, china, quick wash, rinse only, and energy saver — and the 24-hour delay start lets you schedule a cycle for cheap overnight hours or for the moment you get home. It carries an Energy Star rating and a BEE star rating, so running it does not fight your power bill.
The honest catch is cleaning consistency. Some owners get spotless plates from the quick wash on the first try, while others find the results uneven and a small number run into an E4 error — a fault code the machine throws when it senses a water issue — or a leak inside the first month. That cleaning chatter points to a machine that rewards a proper load and the right detergent rather than one that rescues a badly stacked rack. Fit it well, level it properly, and it is a strong performer for the money.
Where It Wins
- 18-inch width slides into gaps a full-size model cannot reach
- Stainless steel tub holds heat and resists stains better than plastic
- Six programs including quick wash and a 24-hour delay start
- ADA-compliant design keeps controls reachable
- Energy Star and BEE star rated for low running cost
Watch For
- Cleaning results can vary load to load
- An occasional unit throws an E4 fault or develops a leak early
- No power cord in the box for some buyers
Reach for this one: if your only open slot is a cramped 18-inch gap and you want a stainless tub plus a delay timer without paying premium money.
Consider the next pick instead: if you would rather trade a little width for a rock-solid quiet rating and heated dry that arrives ready to put away.
2. COMFEE’ 18 Inch Built-in Dishwasher, Energy Star & NSF, Stainless Steel Tub
If quiet matters more than anything, this is the one that hums instead of rattles
Owners keep coming back to one trait above all: how little noise this thing makes. It is rated 52 dB, which is about the volume of a soft conversation, so an open-plan kitchen or a studio apartment can live with it running in the background. That noise rating is what wins people over here, and it holds up whether you are working from the next room or sleeping a wall away. The second thing folks notice is the interior room — it measures 22.6″D x 17.6″W x 32.4″H with adjustable legs, and the upper rack climbs up to 1.97 inches so tall pots clear underneath while the lower rack takes oversized plates and dishware up to 13.78 inches tall.
The feature list is fuller than the price tier suggests. You get six wash cycles — Heavy, Normal, Eco, Delicate, Quick, and Rinse — plus Heated Dry, Hi-Temp, and Sanitize functions. The heated dry delivers a cabinet-ready finish on every cycle except Rapid and Self-Clean, so no towel drying is needed. The Hi-Temp sanitation cycle holds water up to 136°F (58°C), which the maker says suits heavy soil, baby bottles, and children’s dinnerware. It carries both Energy Star and NSF certification, and one thing buyers confirm is exactly what it is not: this is not a standard 24-inch machine, and that is the point.
The recurring gripe is a small one and easy to plan around — there is no power cord in the box, so you buy one separately before install day. Fit it in a small kitchen or a tight counter run and it rewards you with quiet, clean cycles and heated dry that means the dishes are ready to stack the moment the light goes off.
Tub that earns its keep: the stainless interior stays bright and easy to wipe down, and the adjustable upper rack lets you reshuffle for a stockpot instead of hand-washing it.
Plan for the cord: budget for a separate power cord, and remember this unit fits a 17.6-inch opening, not a full-size 24-inch slot.
The quiet-apartment answer: pick this if you cook late, live in a small space, and want heated dry plus a sanitize cycle without paying premium money.
Look elsewhere if: you already own a 24-inch cutout or want a cord in the box on delivery day.
3. SPT SD-9254W Energy Star 18″ Built-In Dishwasher w/Heated Drying – White
A quiet top-mount that people mistake for the sound of rain
Some dishwashers announce themselves from three rooms away. This SPT does the opposite — owners describe it running so softly they have looked up thinking it was raining outside. That low hum is the trait this machine is loved for, and it is a genuine comfort upgrade if your kitchen shares a wall with a living room. It is a built-in top-mount design with a stainless steel tub, listed at 234 kWh of energy consumption per year and carrying an Energy Star rating and a BEE star rating, so the running cost sits on the light side for a compact.
It cleans a family load without drama too. The rack layout is generous for the size, the stainless tub wipes down easily, and the working filters are reachable when you need to rinse them. A heating function runs during the drying cycle to push moisture off the load instead of leaving puddles on every lid.
Now the trade-offs, and there are a couple worth knowing before you buy. This is a machine that wants a real installation — cabinet removal, a plumber, and an electrician in most cases — so factor that into your plans if you are not comfortable with plumbing and wiring. Over a long service life a small number of buyers have run into soap scum on a portion of a load, and the filter-cleaning routine is the task owners like least. Get the install right and keep the filters clear, though, and the quiet, steady performance is worth the setup effort.
Built for calm: the sound profile is the standout, and the stainless tub plus Energy Star rating keeps it efficient to run.
Install is not a solo job: expect cabinet work, a plumber, and an electrician, and set aside time for filter cleaning.
Worth it for: anyone who shares a wall with the kitchen and wants near-silent cycles in a slim footprint.
Think twice if: you want a snap-in replacement with no plumbing or electrical work.
4. SPT SD-9254WA 18″ Wide Built-In Dishwasher w/Heated Drying, ENERGY STAR
A slim body that swallows a big Sunday roast’s worth of pans
What impresses owners most about this Midea is how much it holds for such a narrow machine. The interior is built to take pots and pans up to 11 inches tall, and one buyer who felt the unit looked small on arrival changed their tune once they realized it was a built-in and started loading it. A couple running it every other day for just the two of them found room for big pots, pans, bakeware, and utensils, and households of three call the capacity a comfortable fit. The whole thing measures 22.6″D x 17.6″W x 32.4″H with adjustable legs, so it slides into a slim opening and levels out cleanly.
Under the hood the feature set is genuinely generous. Six programs — Heavy, Normal, ECO, Delicate, Quick, and Rinse — pair with Heated Dry, Hi-Temp, and Sanitize functions. The heated dry delivers a thorough, towel-free finish on every cycle except Rapid and Self-Clean, and the Hi-Temp sanitation cycle holds the wash water at up to 136°F (58°C), which the maker says suits heavy soil, baby bottles, and children’s dinnerware. A digital LED display shows you the cycle and the countdown, and there is a 1–24 hour delay start so you can run it during off-peak hours.
The honest caveat here is water. While the design, quiet running, and clean results win most people over, some units have arrived with a cracked sump pump housing that throws an E4 error and leaks — and one owner had to push hard on customer service before a refund came through. It is a minority of the fleet, but it is worth an inspection of that housing on arrival and a quick leak check after the first cycle. Nail those two boxes and this becomes a quietly excellent machine for the price.
Why It Earns Its Place
- Swallows tall pots and pans up to 11 inches
- Six cycles plus heated dry, Hi-Temp, and sanitize
- 136°F sanitation water suits baby bottles and greasy bakeware
- Digital LED display and 1–24 hour delay start
- Quiet running that owners compare to name brands
Where It Could Stumble
- Some units have arrived with a cracked sump pump housing
- Occasional water leaks reported
- Customer service resolution can be slow if something goes wrong
Choose this: if you want compact footprint with big-machine capacity and a 136°F sanitize cycle for serious cookware.
Check arrival carefully: inspect the sump pump housing and run a first cycle to screen for leaks before you commit.
5. SPT SD-9254SSA 18″ Wide Built-In Stainless Steel Dishwasher w/Heated Drying
The stainless under-counter that turns out spotless plates on the regular
Two things keep drawing praise for this SPT: how well it cleans and how solidly it is made. Long-term owners describe identical internals to double-priced big-brand machines, and one buyer liked it so much they bought the built-in after owning the portable version — same dishwasher, same happy result. It heats its own water to sanitize, dishes come out sparkling, and it is easy to install for anyone with basic plumbing confidence. That combination of clean results and sturdy build is the core of what you are paying for here.
It is packed with the conveniences you would want in a compact: a 1–24 hour delay start so you can schedule a cycle, an error alarm that displays fault codes for quick troubleshooting, a rinse-aid warning indicator that reminds you before you run dry, and a heating function during the drying cycle. It ships with a cutlery basket, dispenser, drain hose, inlet hose, and top-mount brackets, so most of what you need is in the box. The stainless exterior gives it a high-end look that sits comfortably next to other steel appliances.
Drying is where expectations need managing. A number of owners find dishes still wet even after running the “heated dry” and “sanitize” settings, and a few note that durability over the very long haul is a question mark — one past owner saw a door latch go after several years of service. It washes and sanitizes beautifully; just be ready to crack the door after a cycle or keep a towel handy for the odd stubborn lid.
What Buyers Love
- Spotless cleaning results owners call the best they have used
- Heats water to sanitize without needing a hot feed
- Delay start, error alarm, and rinse-aid reminder included
- Stainless body with a high-end look
- Simple install for experienced DIYers
Set Expectations
- Drying can leave dishes wet even on heated dry
- Door latch has been a weak point over very long service
- Manual is minimal and assumes some plumbing expertise
The clean-dishes pick: go for this if sparkling, sanitized results matter more to you than folding a towel into your routine.
Look elsewhere if: you expect a fully dry load straight out of the cycle every single time.
6. EdgeStar 18 Inch Wide Built-In Dishwasher
The narrow one that slips into a trash compactor’s old spot
If you are tearing out an old trash compactor, this is the machine that was practically built for the job. At 17.75 inches wide it slides into a slim gap a full-size unit cannot touch, and its dimensions read 32.5″ H x 17.6″ W x 22.4″ D at 52.9 lbs, so it drops straight into a tight under-counter slot. Owners describe it washing like a much larger machine, holding more dishes than the compact body suggests, and running quietly enough — 52 dB, near conversational volume — that you forget it is on.
what separates it from the other compacts is a safety feature the others do not carry: a leakage sensor that automatically shuts off the water flow the moment it detects a leak, protecting your floor and cabinetry from water damage. For a built-in appliance sitting full of water over a wood subfloor, that automatic shut-off is real protection. You get 8 place settings with a silverware basket and cup tray, six wash cycles — Heavy, Normal, ECO, Glass, Rapid, and Rinse — and three options covering Sanitize, Hi-Temp, and Heated Dry. The finish is black with a stainless interior, and at 258.33 kWh per year of energy consumption it carries a BEE star rating.
Two things to weigh honestly. Installation experience splits — some buyers call it super easy, others find it more of a fuss, so plan a couple of hours or hire help. And the heat dry runs weak, meaning dishes are often still wet at the end of a cycle; the drying is not this machine’s strong suit. The cleaning itself draws strong praise, so if you can live with a little towel work, the leak protection and compact fit make this an easy pick for a condominium or tight galley.
Leak protection you can rely on: the automatic shut-off sensor is the standout feature here and a real safeguard for a built-in water appliance.
Dry it yourself: the heat dry runs weak and dishes come out wet, and install can take a couple of hours.
Made for this: tight condos, galley kitchens, and anyone replacing a trash compactor with a dishwasher.
Skip if: you want a load that comes out bone-dry without a towel.
Understanding the Specs
Width and Fit
The width is the number that decides whether a compact dishwasher works in your kitchen at all. Compact builds land around 17.6 to 18 inches wide, which is why they slide into a gap a full-size unit cannot reach. Measure your cabinet opening before you buy, because a machine that is even an inch too wide will not fit no matter how good its specs look.
Noise Level in Decibels
A decibel is a unit of sound volume, and dishwasher noise usually lands near 52 dB — roughly the level of a quiet conversation. In a studio, an open-plan kitchen, or an apartment with thin walls, a lower decibel number means you can run a cycle while watching a movie without turning up the volume.
Place Settings
A place setting is one person’s complete set of dishes. Eight place settings is the standard compact capacity and suits a couple or a small family. If you cook with tall pots and sheet pans, look for an adjustable upper rack so you can raise it and clear deep cookware underneath.
Heated Dry and Hi-Temp
Heated dry uses a heating element to push moisture off the dishes so you skip the towel drying. Hi-Temp and sanitize cycles raise wash water temperature, and one machine here holds water up to 136°F, which helps on greasy bakeware and baby bottles. Energy Star certification means the unit meets federal low-energy-use guidelines.
FAQ
Will an 18-inch dishwasher fit where a 24-inch one couldn’t?
Do I need a plumber and electrician to install one?
How many place settings do I actually get in an 18-inch machine?
How quiet are these compact dishwashers in decibels?
Is heated dry worth having or will my dishes still be wet?
Can I use regular dish soap in a built-in dishwasher?
What does the E4 error code mean on these dishwashers?
Should I hook my compact dishwasher to cold or hot water?
Do compact dishwashers save water compared to washing by hand?
How long do these compact dishwashers typically last?
Final Thoughts: The Verdict
For most small kitchens, the winning 20-inch dishwasher is the Honeywell 18 Inch Dishwasher, because its 18-inch width drops into gaps almost nothing else reaches, its stainless tub and six programs cover everyday loads, and the 24-hour delay start fits real life. If your priority is the quietest possible cycle with heated dry and a sanitize function, the COMFEE’ 18 Inch Built-in Dishwasher is the pick for you. And if you want big-machine capacity and a 136°F sanitize cycle in a slim body, the Midea 18 Inch Built-in Dishwasher is the one to reach for — with a check of the leak sensor and heated dry in the EdgeStar if protecting your floor from water damage matters most.
Measure your opening before you order, confirm whether a power cord is included, and match the machine to the water supply it was designed for. Measure the opening, confirm the power cord, and match the water supply, and a compact dishwasher earns its counter space.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of September 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
As an Amazon Associate, KitchPrep earns from qualifying purchases. This does not affect which products we feature.
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