Why Hot Water Habits Matter More Than You Think

Water heating is one of the largest single energy loads in a typical American home — often second only to space conditioning. As part of your home's three biggest energy systems, it deserves the same attention homeowners give to their furnace or air conditioner.

What makes water heating unusual is how much of its energy cost is driven by behaviour rather than equipment. You could own a highly efficient water heater and still waste significant energy through habits like running excessively long showers, washing laundry in hot water unnecessarily, or leaving the thermostat set far higher than needed. The good news: the same logic works in reverse. Changing how you use hot water — before spending anything on new equipment — is often the most cost-effective first step.

14–18%

Share of home energy used by water heating

According to the U.S. Department of Energy, water heating typically represents 14–18% of a home's total energy consumption.

~2 min

Shower reduction needed for meaningful savings

Cutting shower time by just two minutes per person per day can reduce hot water consumption by hundreds of gallons per person annually.

90%

Of washing machine energy used to heat water

The U.S. Department of Energy estimates that roughly 90% of the energy a washing machine uses per cycle goes toward heating the water, not running the motor.

Proven Practices to Cut Your Hot Water Energy Use

These recommendations are grounded in how water heaters actually work: every gallon of hot water you draw from the tank is replaced with cold water the heater must warm up again. Reducing demand at the tap directly reduces how hard the heater works.

1

Set your water heater thermostat to 120°F (49°C).

Many water heaters ship from the factory set to 140°F, which is hotter than necessary for most household uses and increases standby heat loss — energy lost simply from the tank sitting idle. Dropping to 120°F reduces that ongoing loss without meaningfully affecting shower comfort or dishwasher performance for most households.

Example: A family that lowers their tank from 140°F to 120°F can reduce water heating energy use by roughly 4–22%, according to U.S. Department of Energy estimates, depending on usage patterns.
2

Shorten showers by two to three minutes.

The shower is typically the largest single draw of hot water in a home. Every minute of showering uses roughly 2 gallons of hot water with a standard showerhead. Trimming shower time is one of the fastest ways to reduce both water heating energy and overall water consumption without any hardware changes.

Example: A household where two people each shorten their daily shower by two minutes could reduce hot water draw by more than 1,400 gallons over a year.
3

Switch to cold water for most laundry loads.

Modern detergents are formulated to work effectively in cold water, and the energy used to heat water for a warm or hot wash cycle is substantial — it accounts for the majority of a washing machine's energy use per cycle. Reserving hot water for heavily soiled items only eliminates unnecessary heating.

Example: Switching a household that does five loads of laundry per week from warm to cold water can cut washing machine energy use by a significant margin for those loads, according to the U.S. Department of Energy.
4

Fix dripping hot-water taps promptly.

A tap dripping at one drop per second wastes roughly 3,000 gallons of water per year — and if that tap is on the hot side, it continuously draws from the water heater tank. This is a quiet, persistent form of energy waste that's easy to overlook because no single drip feels significant.

Example: Replacing a worn washer in a dripping bathroom faucet — a common DIY-accessible repair — eliminates this ongoing loss entirely at minimal cost.
5

Insulate your first few feet of hot water pipes.

Heat dissipates through uninsulated pipes between the water heater and your taps. Foam pipe insulation is inexpensive and simple to apply to accessible pipes, and it reduces the time you spend running water waiting for it to warm up — which in turn reduces waste.

Example: Adding foam pipe insulation to the first three to four feet of pipe leaving your water heater tank is a straightforward task for most homeowners with basic tools.
6

Use the dishwasher instead of hand-washing when possible.

Counterintuitively, a fully loaded, efficient dishwasher typically uses less hot water than washing the same dishes by hand under a running tap. Hand-washing often involves prolonged hot-water flow, while a dishwasher uses a measured, contained volume per cycle.

Example: Running a full dishwasher load instead of hand-washing after a large family meal can use noticeably less hot water while requiring less time and effort.

Quick Actions You Can Take Today

You don't need to overhaul your plumbing or buy new appliances to start reducing your water heating load. The following actions require little to no cost and can be done in minutes. For a broader look at habits across your whole home, see our complete home energy efficiency guide.

high Check your water heater's thermostat dial today and lower it to 120°F if it's set higher.
medium Set a two-minute timer on your phone during your next shower to benchmark your current average.
high Switch your washing machine's default temperature setting to cold for the next week and observe results.
medium Check all hot-water taps in your home for drips and schedule any repairs needed.
medium Pick up foam pipe insulation at a hardware store and wrap the first few feet of pipe leaving your water heater.

Always consult your water heater's manual or a licensed plumber before adjusting thermostat settings on gas or electric units. Some thermostat controls are located inside panels that require professional access.

When Habits Aren't Enough: Knowing When Equipment Matters

Behavioural changes have real limits. If your water heater is more than 10–12 years old, is poorly insulated, or requires frequent reheating cycles, equipment-level improvements become worth considering. Regular maintenance — like flushing sediment from the tank — can improve efficiency noticeably. See our guide on water heater maintenance tasks you can do safely for what's genuinely within DIY reach and what isn't.

If you're evaluating a replacement, understanding the trade-offs between tankless and storage tank water heaters will help you ask the right questions. But start with habits — they cost nothing and deliver results immediately.

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