Installing a hot water tank typically takes 2 to 4 hours for a straightforward, direct replacement. The process includes about 45–60 minutes to drain and remove the old unit, 30 minutes to position the new one, and 1–2 hours to secure connections, fill the tank, and test the system.
Tank to Tank Installation: On average, replacing a gas or electric water tank with a similar model takes two to three hours. It takes between 45 to 60 minutes to drain, disconnect and remove your old water heater.
Electric water heaters: About 1-2 hours for a full tank. Gas water heaters: Usually 30-40 minutes. Tankless water heaters: Almost instant, since they heat water on demand. Recovering after use: Most tanks need about 20-30 minutes to reheat water after a shower.
How Long Does It Take for a New Water Heater to Start Working? A new water heater typically takes 30 to 90 minutes to heat water to the set temperature after installation. Gas models usually heat faster, reaching hot water in 30 to 40 minutes. Electric units may need 60 to 90 minutes.
Naturally, tanks that heat more gallons of water typically have a higher price point, so the larger the tank size, the more you can expect to pay. For example, the average 40-gallon water heater installation cost runs between $1,000 and $2,500, while its 80-gallon counterpart runs between $2,650 and $3,910.
A: Traditional tank water heaters usually last 8–12 years, while tankless units often last 15–20+ years.
Professional labor costs for installation make up over half of the total cost of a new water heater. In general, tankless water heaters are more expensive to install than storage tank models, particularly if you're replacing a tank model with a tankless one because of the additional labor needed.
If a standard showerhead is fitted, it will use around an extra half a gallon each minute, accounting for a 25-gallon emittance every 10 minutes, or 50 gallons throughout a 20-minute shower. *1 gallon = 4.54 litres.
During installation, air can get trapped in the water lines and the water heater tank. Running the water helps purge these air pockets, preventing potential disruptions in the flow and ensuring the water heater functions optimally.
Best Water Heater Brands Ranked
What Next After a New Water Heater Installation?
To help us save every drop of water, showers should be kept to four minutes or less. Wondering if cutting a couple of minutes off your shower really helps? The answer is yes!
Showers & Bathtubs
The average shower uses about 2 gallons of water per minute. If there are four people in your household and each person takes a 10-minute shower daily, that's 80 gallons of water.
Water heaters typically need replacement every 8 to 12 years for traditional tank models, and 15 to 20+ years for tankless units. If your heater is approaching the 10-year mark or showing signs of wear, it is usually recommended to replace it proactively to prevent sudden leaks and costly water damage.
The Average Timeframe for Hot Water System Replacement
For a straightforward, like-for-like replacement, the process typically takes between 2 to 4 hours. This is the most common scenario we encounter.
For larger households, multiple showers, laundry, and dishwashing may run at the same time. Hot water demand could reach 10–12+ GPM. A high-capacity tankless water heater—or even two units installed in parallel—may be the best solution.
A brand new water heater typically takes 30 minutes to 2 hours to fully heat a fresh tank of water. The exact time depends on your specific unit type:
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.
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.
You may be surprised by how many gallons per minute your shower uses — on average, it's 2.1.
Family needs
For example, the needs of a family of two with one bathroom and a clothes washer should be adequately met with a 30-gallon water heater. For every additional bathroom in your home, add another 3-1/2 gallons to the tank capacity.
Your water heater relies on its heating element or burner to do the heavy lifting. If either of these parts starts to wear out or fails, the water inside your tank won't reach the temperature it should. This can cause your hot water to run out surprisingly fast, even if you haven't changed your usage.
For most families of four, a 50-gallon water heater is the perfect size and will provide plenty of hot water, provided your household routines are slightly staggered.
Some of the most reliable tank water heater brands in 2026 include Rheem, A.O. Smith, and Bradford White. These manufacturers have long histories of producing durable, efficient heaters with strong warranty coverage. Rheem is known for overall dependability and wide availability, A.O.