Sizing an On-Premise Laundry: Machines, Throughput and Floor Space

Bottom line: Size your OPL by throughput: measure weekly soiled weight, divide by available operating hours, then add 25% for surge; that number drives washer count and floor space.

The owner had measured the machine, not the soil pile. That 135-pounder would have sat waiting for work, because the facility only generated 200 pounds a day. I've walked into a dozen plants where the machine size was picked first and the flow chart second. You want the right answer? Count the pounds for a full week, include weekends, note how many hours you can actually run the equipment, then add a buffer for emergency stays or banquet blowouts. That number tells you how many pockets you need, which tells you the footprint for washing, drying, folding and staging. The machine is the last thing you choose, not the first. Hotel Laundry Service

I remember pacing off a warehouse in Tulsa back in 2008, checking the concrete pad for a 135-pound Milnor washer-extractor. The owner was thrilled he'd won it at auction. I had to point out that the machine was only half the problem—he hadn't measured the volume he expected to run through it, or the floor space to stage it properly. He ended up using the space for storage and sending the work out.

That's the thing about an on-premise laundry. Most people start by choosing a machine. You don't. You start by counting pounds, then figuring out what it takes to move those pounds through your building in the time you've got. The machine is just the heart of the system—and if the veins and arteries can't keep up, the heart doesn't matter.

In this guide, I'll walk you through the sizing logic I used for nineteen years running a 42-million-pound-a-year plant. We'll talk about weekly volume, peak-day demand, machine counts, drying capacity, and the floor space to make it all work. It's not a formula you can plug into an app—but it's close.

Start with Pounds per Week, Not Machine Sales Pitches

Before you call a single dealer, you need to know your soiled-pound number. That means weighing what you actually process in a typical week. You can do this with a scale and a logbook—no software needed. Each queen sheet runs about 1.5 pounds dry. A bath towel is a little under a pound. A pillowcase is a quarter-pound. Add them up across your operation.

For a 100-room hotel at 70% occupancy, with two beds per room and daily changing, you might see 2,800 sheets per week. That's 4,200 pounds just in sheets. Add towels, washcloths, bathroom mats, duvet covers—you're past 10,000 pounds before you get to the restaurant napkins. Healthcare is different: you have patient gowns, bed linens, surgical drapes, and often more stringent standards. But the starting point is the same—weigh the dirty stuff.

Once you have a weekly total, look at your actual operation. Do you have one big rush on Monday? Are you open 24/7? The weekly number is just the start. The next step is figuring out what the worst day looks like.

Peak Day Drives Machine Count

In my plant, Monday was always the beast. We'd get 40% of the week's volume delivered by noon. If you size for the average, you'll be buried by 10 a.m. The way you get to a machine count is to design for peak day, then hour by hour.

Take a healthcare facility that runs 8,000 pounds a week over six days. Average daily load is 1,333 pounds. But if Monday brings 2,000 pounds, that's your design number. Divide that by your usable hours in a shift—call it 7 to 8 hours after breaks, maintenance, and sorting. So you need to process 250 to 285 pounds per hour just on that worst day.

A 135-pound washer-extractor cycles in 45 to 60 minutes, including loading and unloading. That means one machine can do maybe 135 pounds per hour if the cycle is running flat out, but in real life, count on 80 to 110 pounds per hour after delays. So for 250 pounds per hour, you're looking at three 135s, not two. That's the difference between planning and wishing.

Matching Washers and Dryers—and the 1.5 to 2 Rule

People love to buy washers and then skimp on dryers. It's the same mistake every time. A washer takes 45 minutes to get a load done. A dryer takes 60 to 90 minutes to finish the same load, depending on the fabric and the extractor. To keep up, you need roughly 1.5 to 2 times as much dryer capacity as washer capacity. A 135-pound washer paired with two 135-pound dryers is the classic setup. Or one 135-pound washer with a 200-pound dryer if you can stack it.

The other factor is extraction. A washer-extractor with a high G-force spins faster, which leaves less water in the load, so the drying goes quicker. That's why you see Milnor or UniMac machines with G-force specs all over the place. If you're buying a 135-pounder, look for a G-force of 300 or better. It'll pay for itself in gas and time.

Floor Space: The Math Nobody Does Until It's Too Late

You can have the perfect machine count and still fail if there's no room to move a loaded cart through the aisle. A single 135-pound washer is about 6 feet wide and 5 feet deep. The dryer is similar. But you need clear space in front to load the door, and you need room to pull the door open. That's another 4 to 6 feet of aisle. So the real footprint per machine is more like 10 by 10 feet.

A rough rule of thumb: for every 100 pounds of daily capacity, budget 250 to 350 square feet of laundry area, including sorting, folding, and clean storage. That's a wide band because hotels, hospitals, and prison laundries all flow differently. If you have a tunnel washer, you trade breadth for length—a tunnel can stretch thirty feet or more.

And don't forget the separation between soiled and clean. In healthcare, TRSA Hygienically Clean and HLAC accreditation demand a physical barrier between the two zones. Even if you're not chasing accreditation, that separation keeps lint and bacteria where they belong. It's easier to plan it into the floor plate than to retrofit it later.

The Economics Check Before You Buy

One thing I see constantly: someone buys machines because they think they'll save money over renting. They don't run the full picture. Uniform rental commonly runs $4 to $15 per employee per week, depending on the industry and the garments. That price includes the garment, the washing, the delivery, the repair, and the inventory. When you run an OPL, you pay for the machine, the installation, the water, the gas, the chemicals, the labor, and the replacement linen.

I'm not saying OPL is wrong. I built a career on it. But you should size the equipment only after you've done a legitimate cost-per-pound comparison. If you're processing less than a few thousand pounds a week, it's hard to beat rental on cost alone. If you already have the space, the steam, and the staff, OPL can make sense. Just don't fool yourself by ignoring the real costs.

Comparing On-Premise Laundry Equipment Configurations

Frequently Asked Questions

What's the quickest way to estimate my needed washer capacity?

Weigh your soiled linens for a full week. Take the heaviest day's total, divide by the number of productive hours you plan to run (typically 7 to 8), and that gives you the pounds per hour you need. Then divide by roughly 100 pounds per hour for a 135-pound washer—that gives you the machine count.

How much floor space do I need for a 10,000-pounds-per-week OPL?

At 5 days a week, that's 2,000 pounds a day. Using the rule of 250 to 350 square feet per 100 pounds of daily capacity, you're looking at 5,000 to 7,000 square feet. That includes the laundry room, sorting, folding, and storage.

Can I use a washer-extractor for FR garments?

Yes, but home laundering doesn't maintain NFPA 2112 certification. If you're processing FR clothing in an OPL, you need to follow the garment manufacturer's care instructions, use the right chemicals, and have a quality assurance program. It's not a side project.

What's the difference between a washer-extractor and a tunnel washer?

A washer-extractor is a single drum that loads, washes, and spins out. A tunnel washer is a continuous batch machine that processes hundreds of pounds per hour—suited for facilities generating more than 5,000 pounds per day. Most OPLs are better off with washer-extractors because they're simpler and flexible.