For standard storage tank water heaters, it is generally more efficient and convenient to leave the unit on all day. Because modern tanks are highly insulated, maintaining a constant temperature takes less energy than reheating a full tank of cold water from scratch.
Extended use can gradually lead to a significant rise in electricity usage, contributing to high electricity bill causes. Over time, the constant operation can cause wear and tear on the heating element and other components.
To effectively control Legionella bacteria, the CDC recommends storing hot water at 𝟏𝟒𝟎∘𝐅 (𝟔𝟎∘𝐂) and maintaining circulating hot water above 𝟏𝟐𝟎∘𝐅 (𝟒𝟗∘𝐂).
Only heat the hot water twice a day
Try heating the water for an hour in the morning and an hour in the evening. Start the water heating about an hour before you need it. For example, if you shower at 08:30, start heating the water at 07:30. If you wash up in the evening at 19:30, then start the water heating at 18:30.
A 40-gallon water heater typically provides about 8 to 15 minutes of uninterrupted, hot shower time. While the tank holds 40 gallons, the actual hot water lasts longer because it is mixed with cold water, allowing for 4-5 average-length showers back-to-back if they are short (5-7 minutes).
A 10-minute shower typically uses 20 to 25 gallons of hot water. Because showers are usually mixed with cold and hot water to reach a comfortable temperature, the actual volume of hot water drawn from your heater will usually be slightly less, while a low-flow showerhead can reduce this amount by up to 50%.
A 4 bedroom house typically needs a hot water tank between 180 to 270 gallons (around 700 to 1000 litres), depending on the number of bathrooms and occupants. This size ensures enough capacity for typical daily use without excessive energy waste.
In winter, you should set your water heater between 120°F and 130°F (49°C to 54°C). This range strikes the perfect balance between keeping your hot water warm enough to offset the cold incoming groundwater and keeping your energy bills and scalding risks in check.
For most customers, we recommend turning on your furnace when the weather is consistently below 18° Celsius, which usually happens to be around the end of September, or early October. Some homeowners try to put off turning on their furnace as long as they can to save money, which is okay if you're healthy adults.
When working in the heat, drink 1 cup (8 ounces) of water every 15–20 minutes. This translates to ¾–1 quart (24–32 ounces) per hour. Drinking at shorter intervals is more effective than drinking large amounts infrequently. Do not drink more than 48 oz (1½ quarts) per hour!
The most dangerous and common bacteria that grows in hot water heaters is Legionella (specifically Legionella pneumophila). It thrives in warm water environments (especially between 90∘F90 raised to the composed with power F90∘F and 108∘F108 raised to the composed with power F108∘F) and can cause a severe form of pneumonia called Legionnaires' disease if aerosolized water droplets are inhaled.
The first signs of Legionnaires’ disease typically appear 2 to 14 days after exposure to Legionella bacteria. Early symptoms are often flu-like and include:
Yes, it is perfectly safe to turn off your hot water heater for a week. However, to prevent bacterial growth like Legionella and avoid damaging the system, do not drain the tank.
Signs a Water Heater is Going Bad
It takes time for your home to warm up and cool down. If you're not sure how long it takes, try turning the heating on about 30 minutes before you need it. You should turn it off 30 minutes before you'll stop needing it.
Extreme heat is the leading weather-related killer, causing more fatalities each year globally and in the United States than all other extreme weather events—such as hurricanes, tornadoes, and floods—combined.
We asked our social media community when they usually start to turn on their heating. More than half (58%) people said they leave it as late as they can before they turn the heating on. And a third (33%) said they already had the heating on by mid-September.
The global temperature forecast from ECCC indicates that 2026 will likely be among the four hottest years on record, comparable to 2023 and 2025, and approaching 2024, the hottest year ever recorded.
You might wonder what temperature a water heater should be set to. Most experts suggest the ideal hot water setting range is between 120-140 degrees Fahrenheit.
Cold Water Takes Longer to Heat
During winter, the water entering your home is much colder than it is in warmer months. Because of that, your water heater needs more time and more energy to reach the set temperature.
Turning the thermostat up can make the water hotter, which means you might mix in more cold water at the faucet to reach a comfortable temperature. This can slightly increase effective volume through mixing, but: It does NOT increase the actual amount of heated water stored.
A small (50- to 60-gallon) storage tank is usually sufficient for one to two three people. A medium (80-gallon) storage tank works well for three to four people. A large tank is appropriate for four to six people.
Keep the top of the tank free of dust, debris and flammable products such as paint, gasoline, solvents or adhesives. Also, never use these products near a water heater or any other natural gas or electric appliance because vapors from flammable liquids can ignite.
The Home Depot offers traditional water heater tanks and modern tankless units, both powered by either gas or electricity. Depending on your selection, the average cost for standard tank installation is generally between $1,600 to $2,400. Tankless installation can range from $2,400 to $5,400.