Then & now
1868
An early instant gas water heater appears in England
- From Roman baths to wall-mounted tankless
- U.S. homes with tankless: 1% to 6.5%
- How to make modern equipment last
A Mr. Tankless field guide · Then & now
The history of water heaters.
From Roman bath furnaces to today’s wall-mounted tankless systems, hot water has always been an engineering story. Here’s how we got here, and how to help modern equipment last.
- NJ Plumbing License #9366
- Tankless specialists
- Water treatment & service
The timeline
Hot water has a long history.
There’s no single “first water heater.” People heated water long before written records, but a few milestones stand out.
01
Ancient Rome: a furnace heats the bath
Bathhouses used a hypocaust to circulate hot air below floors, and the same furnace could heat water held in a tank for the hot bath.
02
1868, England: hot water on demand
Benjamin Waddy Maughan’s gas “geyser” is widely credited as an early domestic instantaneous water heater.
03
1889, United States: automatic storage
Engineer Edwin Ruud developed an automatic gas storage water heater, putting stored hot water within reach of more homes.
04
20th century: the tank becomes standard
Insulated tanks, thermostats, safety controls, and gas or electric heat made hot water an everyday expectation.
05
Today: tankless returns to the original idea
Modern sensors and heat exchangers bring instantaneous heating into a compact, controlled appliance.
A shift in American homes
The tank still leads. Tankless is growing.
Share of occupied U.S. homes reporting a tankless main water heater in the EIA’s Residential Energy Consumption Survey. These are survey snapshots, not annual sales.
- 20051.0%about 1.1 million homes
- 20152.5%3.0 million homes
- 20206.5%8.03 million homes
Efficiency & lifespan
Efficient by design, when it’s sized right.
In high-use homes, around 86 gallons a day, the DOE estimates an 8–14% advantage. Actual savings depend on the model, fuel, draw pattern, and installation.
A well-maintained tankless heater can last 20+ years, versus roughly 10–15 for a typical storage tank, though no individual unit is guaranteed to reach that age. Efficiency also isn’t the same as a guaranteed cut in your utility bill.
24–34%potential efficiency advantage for gas on-demand heaters in homes using 41 gallons a day or lessSource: U.S. Department of Energy
Choose the fuel that fits
Three ways to go tankless.
Natural gas is often a practical whole-home choice where gas service exists, but the lowest total cost depends on utility rates, sizing, venting, and upgrade costs. We assess the actual house first.
Natural gas
Strong capacity for multiple fixtures; condensing models recover more heat from exhaust. Needs correctly sized gas piping, approved venting, and often a condensate drain. Best when your home already has suitable gas service.
Propane
Similar combustion-based operation where utility gas isn’t available. The tank, deliveries, fuel pricing, and approved venting all enter the overall cost.
Electric
No combustion vent, and compact for a sink or modest demand. Whole-home units can need substantial electrical capacity, especially with cold New Jersey inlet water.
Make it last
Good water. Longer life.
In parts of northern New Jersey, hard water leaves calcium and magnesium scale behind. The right treatment starts with your local water report and, where useful, a hardness test.
One option is the 3M Aqua-Pure AP430SS scale-inhibition system on the cold-water feed. It doses polyphosphates that help keep hardness minerals from depositing on hot surfaces. It isn’t a filter that catches calcium or a substitute for a softener where the heater maker requires one, and its cartridge generally needs replacing every six months, or sooner if flow drops.
Like descaling a coffee maker, professional flushing circulates a manufacturer-approved solution through the heat exchanger. The DOE says intervals range from twice a year to once every three years, depending on the manufacturer and conditions.
Tankless maintenance
What a good service visit checks.
Ignoring scale can restrict flow, reduce performance, and shorten service life. A sensible visit covers:
- Heat exchanger flushingPlus inlet-screen cleaning, as the manufacturer specifies.
- Scale controlCartridge age, water hardness, and whether the treatment suits your water.
- Combustion and ventingAlong with condensate and error history, where applicable.
- Flow and temperatureFlow rate, outlet temperature, leaks, and accessible isolation valves.
Make it affordable
Upgrade now. Pay over time.
Flexible financing, utility rebates, and current promotions help make the work your home needs fit your budget.
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Hot water has evolved. Your installation should, too.
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