The Laundromat Owner's Guide to Water Heating Systems

Your water heater is one of the most critical pieces of equipment in your laundromat. It's also one of the most expensive to replace. Here's what you need to know about selecting, sizing, and maintaining water heating systems for commercial laundry.

Sizing Your System

The water heater must keep up with peak demand — every washer running hot simultaneously. Calculate total hot water demand: gallons per cycle × number of machines × cycles per hour during peak. Add a 20% buffer. Undersized heaters produce lukewarm water during busy periods, leading to customer complaints about cold washes. When that complaint comes in, rule the heater out first, then work through our commercial washer troubleshooting guide for the machine-side causes.

Tank vs. Tankless

Tank water heaters store heated water and deliver it on demand. They handle peak loads well but consume energy maintaining temperature between uses. Tankless (on-demand) heaters only heat water when needed, saving energy — but may struggle with simultaneous high-demand situations. For most laundromats, a properly sized tank system is more reliable. Some operators use a hybrid: tank for base demand, tankless for peak overflow.

Gas vs. Electric

Gas water heaters are the standard for commercial laundry. They heat faster, cost less to operate (gas is typically cheaper per BTU than electricity), and recover faster between heavy draws. Electric is simpler to install and maintain but significantly more expensive to operate at laundromat scale.

Efficiency Ratings

Look for condensing water heaters rated 95% or better thermal efficiency. Standard atmospheric models run at 80–85%, so 15–20 cents of every gas dollar goes up the flue. New DOE standards effective October 2026 require 95–96% on new commercial gas units. A high-efficiency replacement can pay for itself within a few years through gas savings alone, which puts it on the same list as the energy-efficient upgrades that pay for themselves.

Maintenance

Annual professional inspection of burners, flue, and safety systems. Monthly check of temperature output at the most distant machine, the same test our laundromat plumbing basics post recommends. Flush the tank annually to remove sediment buildup (sediment reduces heating efficiency and shortens tank life). Check the anode rod annually — this sacrificial component prevents tank corrosion and should be replaced when significantly worn.

Warning Signs

Inconsistent water temperature, longer recovery times, unusual noises (banging, popping), and visible corrosion or leaks are all signs your water heater needs attention. Address these early — a water heater failure during business hours is an emergency that shuts down your entire operation.