How do I know what size commercial dishwasher I need?

Count the racks you have to clear during your peak hour, not your daily average. Match that to the throughput band: roughly 20-40 racks/hr for an undercounter, 40-80 for a door-type, 150-400+ for a conveyor. The rush is what overwhelms a warewasher, so size to the rush.

Why not just buy the biggest machine to be safe?

Because oversizing is real money wasted — capital, water, energy, and floor space you will never use, plus bigger repair bills when something fails. A conveyor in a 60-seat bistro is paying for a fire truck to water a garden. Right-size to peak volume instead.

What happens if my dishwasher is too small?

Your dish pit becomes the kitchen's bottleneck. Racks stack up, clean plates and glassware run short on the line mid-service, and you end up pulling a cook off station to hand-wash or babysit a machine that cannot keep up. Undersizing costs you labor every single rush.

Is undercounter, door-type, or conveyor the most common choice?

Door-type. Most full-service restaurants land on a pass-through hood machine because 40-80 racks per hour covers a normal rush without the footprint and install of a conveyor. Undercounter and conveyor are the low and high ends of the range.

Does this decide whether I get a high-temp or low-temp machine?

No — that is a separate decision. Undercounter, door-type, and conveyor each come in both high-temp (hot-water sanitizing with a booster heater) and low-temp (chemical sanitizing) versions. Pick the machine class by volume first, then choose the sanitizing method; see our high-temp vs low-temp comparison for that trade-off.

Why do commercial dishwashers fail so often in South Florida?

Hard water. Scale builds on the wash and rinse arms until jets clog and dishes come out dirty, and it cakes onto booster and tank heater elements until they fail or stop reaching sanitizing temperature. Regular descaling of arms and heaters is the cheapest way to keep any warewasher alive here.

Can Berne service all three types?

Yes — undercounter, door-type, and conveyor warewashers, across Miami-Dade, Broward, and Palm Beach. $89 commercial service call, free with an approved repair, commercial dishwasher repair on 24/7 dispatch. When your machine is down mid-service, the dish pit is backing up by the minute — call and we will roll a truck.

Decision Guide

Undercounter vs Conveyor Commercial Dishwasher

There is no "best" commercial dishwasher — there is the one sized to your peak dish volume, and three wrong answers around it. Buy too small and a Saturday rush backs up the dish pit until you pull a cook to run racks. Buy too big and you have poured capital, water, energy, and floor space into capacity you will never touch. Warewashers sort cleanly by throughput in racks per hour.

Honest comparisonCommercial service call: $89Built from real service tickets11 years · 18 techniciansUpdated June 2026

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TL;DR

The short version.

Read these five lines if you don't have time for the full comparison below.

Size to peak dish volume in racks per hour, not your daily average — the rush is what overwhelms a warewasher.
Undercounter ≈ 20-40 racks/hr (bars, cafés, low covers); door-type ≈ 40-80 racks/hr (most full-service restaurants); conveyor ≈ 150-400+ racks/hr (high-volume, banquet, institutional).
Most operators correctly land on a door-type pass-through; undercounter and conveyor are the two ends of the range.
Undersizing costs you labor and a dish-pit backup every rush; oversizing wastes capital, water, energy, and floor space.
High-temp vs low-temp sanitizing is a separate decision from machine type, and South Florida hard water scales wash/rinse arms and booster heaters on all three.

At a glance

Undercounter vs Conveyor Commercial Dishwasher — side by side.

The quick comparison. Field-ticket detail and our verdict follow below.

Undercounter vs Conveyor Commercial Dishwasher comparison table
Spec	Undercounter	Door-Type	Conveyor
Capacity	~20-40 racks/hr	~40-80 racks/hr	~150-400+ racks/hr
Best volume	Low / bursty	Standard restaurant	High volume / continuous
Footprint	Under a counter	Corner / pass-through	Wall of floor space
Install cost band	Lowest	Mid	Highest (plumbing, electrical, vent)
Water / energy	Lowest	Moderate	Highest
Labor model	One person, batch loads	One person, lift-and-run racks	Dedicated dish crew, soil/clean sides
Common failure	Pump, wash arm, door switch	Booster heater, wash/rinse arms, hood limit	Drive motor/curtains, booster, tank heaters
Hard-water risk	Scaled arms + booster	Scaled arms + booster	Scaled arms, booster + tank heaters
Best for	Bar, café, small restaurant	Most full-service restaurants	Banquet, cafeteria, institutional

The comparison

Why this comparison, written by a service shop.

The verdict up front: size to your peak covers, not your average. A bar or café clears low volume in bursts and belongs on an undercounter. A standard full-service restaurant lives or dies by a pass-through door-type machine, which is why most operators land there. A high-volume restaurant, banquet hall, cafeteria, or institutional kitchen needs a conveyor — rack-conveyor or flight-type — because nothing smaller keeps up. Undercounter and conveyor are the two ends of the range; door-type is the workhorse in the middle.

The numbers that matter are racks (or dishes) per hour at your busiest service, not over a whole day. An undercounter runs roughly 20-40 racks per hour and tucks under a counter like a residential unit, footprint and price to match. A door-type — the hood machine you lift a handle on — runs roughly 40-80 racks per hour and is the right answer for the bulk of sit-down restaurants. A conveyor pulls racks through continuously and runs 150-400+ racks per hour, but it eats a wall of floor space, a serious install, and real water and energy.

The decision driver underneath all of this is volume and labor. Undersize the machine and your dish pit becomes the bottleneck for the entire kitchen — racks stack, clean plates run short on the line, and you burn labor (often a line cook pulled off station) to wash by hand or babysit a machine that cannot keep up. Oversize it and you have spent on capital, water, energy, and floor you did not need. Note that high-temp versus low-temp sanitizing is a separate axis from machine type — any of these three comes in both — and we cover that trade-off in our high-temp vs low-temp comparison. This guide is about throughput and footprint.

Option-by-option

Each path — and what we see in the field.

Undercounter

An undercounter warewasher runs roughly 20-40 racks per hour and tucks under a counter like a residential unit, with footprint and price to match. It is the right machine for low, bursty volume — a glass rush at a bar, a small café lunch — clearing racks without surrendering a counter or a dedicated dish corner. It is the cheapest to buy, install, and run, and it slides under existing millwork. Stepping up to a door-type here buys capacity you won't use and a footprint you don't have.

Where Undercounter wins

Lowest cost to buy, install, run
The cheapest warewasher across purchase, install, water, and energy — ideal where volume is low.
Tucks under a counter
Fits under existing millwork without surrendering a dish corner — the footprint win for tight spaces.
Clears bursty low volume
Handles a glass rush or small lunch in batches without backing up.
Simple one-person operation
One person loads and runs batches — no dedicated dish crew needed.

Where this path goes wrong

Wash pump faults
The wash pump fails or weakens so plates don't come clean — a common, cheap undercounter ticket.
Wash arm scaling
Hard water scales the wash arm jets until they clog and plates come out spotted or dirty.
Door switch faults
The door switch fails and the cycle won't start — a quick, inexpensive fix.
Booster scaling (high-temp units)
On a high-temp undercounter, the booster heater scales like any other in our water.

Parts & service economics

An undercounter is cheap to buy and cheap to fix — a pump, a wash arm, a door switch. The failure we see most traces back to hard water: scale on the wash arms clogs the jets, and on a high-temp unit it cakes the booster element. Descaling discipline on arms and heaters keeps it off our after-hours board.

Door-Type

A door-type — the pass-through hood machine you lift a handle on — runs roughly 40-80 racks per hour and is where most full-service restaurants correctly land. It keeps a normal dinner rush from backing up the dish pit, one person can lift the hood and run racks through, and it fits a standard corner or a soiled-to-clean dish-table layout. Going undercounter here strands you in a rush; going conveyor here is paying for a fire truck to water a garden. It adds a booster heater and hood limit switches to the failure list — mid-range parts and labor.

Where Door-Type wins

Right capacity for most restaurants
40-80 racks/hr covers a normal dinner rush — the workhorse for the broad middle of full-service operations.
One-person lift-and-run
Lift the hood and run racks through; no dedicated dish crew required.
Fits a standard layout
Drops into a corner or a soiled-to-clean dish-table run without a conveyor's footprint.
Balanced install and operating cost
Mid-band on purchase, install, water, and energy — capacity without a conveyor's overhead.

Where this path goes wrong

Booster heater scaling
On high-temp door-types the booster scales in hard water and misses sanitizing temp or burns out.
Wash / rinse arm scaling
Scale clogs the arms so plates come out spotted or dirty — clear them on schedule.
Hood limit switch faults
The hood limit switch fails so the cycle won't run when the hood is lowered.
Wash pump and gasket wear
The wash pump and door gaskets wear with use — shared with the other classes.

Parts & service economics

A door-type adds a booster heater and hood limit switches to the list, mid-range parts and labor. Like every warewasher here, its lifespan comes down to keeping scale off the wash arms and booster heater — descale on schedule and the workhorse runs reliably through years of normal rushes.

Conveyor

A conveyor pulls racks through continuously and runs 150-400+ racks per hour — rack-conveyor for most, flight-type for the very largest. It is non-negotiable for high-volume restaurants, banquet halls, cafeterias, and institutional kitchens turning hundreds of covers, but it eats a wall of floor space, a heavier electrical and plumbing install, and real water and energy, run by a dedicated dish crew across soiled and clean sides. It is the biggest machine and the biggest repair: drive motors, conveyor curtains, multiple tank heaters, and a high-output booster.

Where Conveyor wins

Continuous high throughput
150-400+ racks/hr keeps up with banquet, cafeteria, and institutional volume nothing smaller can match.
Flight-type option for the largest
Flight-type machines scale to the very highest-volume institutional kitchens.
Soiled/clean crew workflow
Designed for a dedicated dish crew working soiled and clean sides continuously.
Keeps a high-volume pit clear
Prevents the permanent dish-pit backup a door-type would hit at this volume.

Where this path goes wrong

Drive motor / conveyor curtain faults
The drive motor or conveyor curtains wear or fail — the signature conveyor breakdown and a longer wrench-time bill.
High-output booster scaling
The high-output booster scales in hard water and misses sanitizing temperature.
Multiple tank-heater failures
Several tank heaters scale and burn out — more heating elements means more to fail.
Wash / rinse arm scaling
Scaled arms clog and dishes come out dirty — the same hard-water root cause, at scale.

Parts & service economics

A conveyor is the biggest machine and the biggest repair: drive motors, conveyor curtains, multiple tank heaters and a high-output booster, and a longer wrench-time bill when any of it fails. Bigger machine, bigger repair — and on the coast, descaling discipline on arms and heaters is the single cheapest thing you can do to keep it running.

Which operator picks which

Operator profiles — and our honest recommendation.

No platform is universally better. The right pick depends on your account type, ownership horizon, and operating style.

Bar, café, or small low-cover restaurant
Undercounter. Your volume comes in bursts — a glass rush, a small lunch — and an undercounter clears it without surrendering a counter or dish corner. Cheapest to buy, install, and run, and it slides under existing millwork. A door-type here buys capacity you won't use.
Standard full-service restaurant
Door-type pass-through (hood machine). Where most operators correctly land. At 40-80 racks/hr it keeps a normal dinner rush from backing up, one person runs racks through, and it fits a standard corner. Undercounter strands you in a rush; conveyor is a fire truck to water a garden.
High-volume, banquet, or institutional kitchen
Conveyor — rack-conveyor for most, flight-type for the very largest. When you're turning hundreds of covers or feeding a cafeteria line, only continuous-flow throughput keeps up. It demands floor space, heavier install, and more water and energy — but a door-type at this volume means a permanent dish-pit backup.
Tight-footprint operation (small Miami kitchen)
Undercounter, or a compact door-type only if the corner exists. When floor space is the binding constraint, don't force a conveyor or full door-type into a kitchen that can't give it clearance. Size honestly to the space and volume — an undercounter that fits beats a bigger machine that blocks the line.
Multi-unit operator standardizing across locations
Spec by each location's peak covers, not one blanket model. Standardize the brand and sanitizing type for consistency, and size the machine class (undercounter / door / conveyor) per location — a downtown high-volume store and a suburban café have different peak racks per hour.

Cost of ownership

What it costs to actually own each one.

All three qualify for the Berne $89 commercial service call, and the repair economics scale with the machine. The failure we see most across every warewasher in South Florida traces back to hard water: scale builds on wash and rinse arms until the jets clog and plates come out spotted or dirty, and it cakes onto booster-heater and tank-heater elements until they burn out or stop hitting sanitizing temperature. An undercounter is cheap to buy and cheap to fix — a pump, a wash arm, a door switch. A door-type adds a booster heater and hood limit switches to the list, mid-range parts and labor. A conveyor is the biggest machine and the biggest repair: drive motors, conveyor curtains, multiple tank heaters and a high-output booster, and a longer wrench-time bill when any of it fails. Bigger machine, bigger repair — and on the coast, descaling discipline on arms and heaters is the single cheapest thing you can do to keep all three off our after-hours board.

Berne's perspective

We service both. Here's what we think.

Operators ask us to recommend "the best commercial dishwasher," and the honest answer is that there isn't one — there is the machine sized to your busiest service, and three expensive mistakes around it. We coach it by the rush, not the day: count the racks you actually have to clear during your peak hour, then match the throughput band. Under that line an undercounter is the correct, cheaper, smaller answer and anything bigger is dead capital. In the broad middle a door-type is the workhorse for a reason. Above the line — banquet, cafeteria, institutional, genuine high volume — a conveyor is non-negotiable, footprint and install and all. Pick the sanitizing method (high-temp or low-temp) separately. And whatever you run, in our hard-water market the machine's lifespan comes down to keeping scale off the wash arms and booster heaters — neglect that and you will meet us mid-rush with a dead booster and a dish pit climbing toward the ceiling.

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