How long does it take a water heater to heat up?

How long does it take a water heater to heat up? The short answer is between 30 and 90 minutes. However, the details and specs can make a big difference when you have multiple family members who want to take a hot shower during short periods before work or school.

The first detail is whether you have gas, electric or some alternate form of water heater. Gas is much faster when heating water than electricity, and geothermal water heaters can cut heating times and costs even further. Hot water heater time also depends on the size of your tank, ambient water temperature, elevation and other factors.

Common Heating Averages for Different Heater Technologies

The times can vary between the instant availability of hot water in tankless heaters to more than 2 hours for solar water heaters to heat up on cloudy days. 

The average heat times times for various water heater technologies include:

Gas Heaters

Depending on tank size, gas heaters rise to the set temperature in 30 to 40 minutes.

Electric Heaters

Electric heaters can take twice as long to heat up to the temperature you set. You can expect heaters to take between an hour and 90 minutes. You can speed up the heating time by setting the temperature lower.

Tankless Heaters

Tankless heaters are designed to provide limitless hot water as the water heats up in the pipes during the time it takes to arrive at the faucet. The technology, however, is fairly new and prone to technical problems. The rewards are great, though, because you could enjoy as much hot water as you need.

Solar Heaters

Solar water heaters are usually connected to an electric water heater, so heating times are similar. However, if you don’t have backup energy storage, you might be unable to get hot water for a considerable time on cloudy days.

Hybrid Heaters

Also called geothermal and heat pump water heaters, hybrid heaters use thermal energy in the air and ground to generate heat. These models save on electricity costs, and they store water normally in tanks.

Hybrid pumps can take up to 2 hours to heat up, but you can switch over to electric mode and cut your waiting time in half.

Condensing Heater

This might be the best option for families that use natural gas extensively for heat and cooking. Condensing water heaters funnel the exhaust from those gas heating systems to heat water in a conventional tank.

Very little energy is wasted, and the tanks achieve a 90 percent efficiency rating. Heating times fall between the time it takes for gas tanks and electric tanks to recover.

High-recovery Heater

High-recovery water heaters usually have larger tanks, and they heat water faster than average — usually within 20 minutes.

All water heaters have this characteristic in common: Neglect of maintenance can result in longer wait times for the water to reach a comfortable temperature. Keeping your water heater in top shape extends its useful life and keeps the water heating at maximum capacity.

Things that Affect Your Water Heater’s Heat Time

How long does it take a water heater to heat up? There are many things that affect your tank’s recovery rate. These include: 

• First Hour Rating
• Heating source
• Water Heater Tank Size
• Water Heater Tank Condition
• Ambient heat and Inlet Water Temperature

The following are things that affect the heating times of different types of Water heaters:

All Heaters

Equipment condition, ambient air and water temperatures and tank size if applicable all affect recovery times. Specifically, recovery time refers to the time it takes to heat a full tank of water to the temperature you set. 

That’s often 100-degrees Fahrenheit, but many people decide to set the temperature at 90 degrees.

The heater’s first-hour rating tells you how many gallons the heater can heat in an hour. A high first-hour rating indicates a faster recovery rate. The temperature of inlet water is a prime factor. If the water is cold, it takes longer to heat.

Gas Heaters

Gas heaters often become clogged from debris, which reduces heating efficiency. Large water heaters might have an additional burner, which speeds up the recovery rate. 

Gas heaters are particularly susceptible to sediment buildup, which is mostly caused by hard water. Sometimes with gas heaters, sediment temporarily boosts recovery time, but you need to clean the unit for continued safe operation.

Electric Heaters

Electric water heaters are also highly vulnerable to sediment buildup, and flushing the heater can damage the heating elements. Larger tanks often feature two elements, and if one goes bad, you’ll experience big increases in recovery time. 

The signs of sediment buildup include:

• Rattling noises when water is heating
• Units that takes longer to heat
• Running out of hot water faster than normal
• Higher energy bills

Solar Heaters

Solar water heaters share some of the common problems like sediment buildup, and they have unique issues exclusive to solar heaters. 

Common issues that cause increased recovery rates in solar heaters include:

• Heat loss
• Improper orientation
• Water leaks
• Faulty sensor wires
• Collector-based problems
• Broken elements

Tankless Heaters

Tankless water heaters develop plugged heat exchanges, blocked air intakes and issues with the gas supply that could reduce heating efficiency. It’s common to develop problems if you are running too many appliances that use water at the same time.[1]

Dirty burners and a bad igniter or flame rod also compromise heating efficiency. It’s common to experience a burst of hot water followed by cold water until the system runs enough water to heat up. 

If your unit is older, you might have set the minimum flow rate too high. You must set a minimum flow rate for the water to heat up within the allotted travel time as water moves to the faucet or shower head.

Hybrid Heaters

Hybrid or heat pump water heaters, depend heavily on environmental conditions for heating efficiency. These heaters channel heat from the air and ground, and they need periodic changing of the air filters. They also require unique installation conditions and extra space for efficient operation.

Changes in the environment can affect the heating capacity of hybrid water heaters, and they’re also susceptible to the same threats as electric heaters.

Hybrid heaters require 1,000 cubic feet of surrounding air and sufficient clearance between air intake and discharge vents. Hybrid heaters also require vertical space because the heat pump is located on top of the tank.

Simple mechanical failure of the pump is always a possibility, and ambient air temperature shouldn’t fall below freezing. When operating in heat pump mode, the water heater won’t recover as fast as when using the electric resistance motor. In cold climates, these heaters require a bigger compressor that cuts off at lower temperature.

Condensing Heaters

Condensing water heaters are more efficient than other heaters, but that comes with an expanded need for maintenance. Condensing boilers produce condensation, and that liquid has to drain away from the tank. 

The excess condensation can cause water leaks, which reduce heating efficiency.

The boilers need the water supply to be at a lower temperature than standard water heaters to kickstart the condensing process. However, extra efficiency can be generated by extracting more heat from the flue gases.

Things to Consider When Replacing a Water Heater

When replacing a water heater, recovery rate is one of the most critical things to consider. According to an article posted at washingtonpost.com, you should consider the following tank sizes for the proper heating capacity to accommodate different family sizes:

• Families of three people: 30-gallon tank
• Families of four people: 40-gallon tank
• Families of five people: 50-gallon tank
• Larger families: 80-gallon tank

Benefits of Choosing a Gas Water Heater

Gas water heaters are economical – Gas water heaters are less expensive to operate than electric water heaters.

Better Recovery Rates – Gas heaters are now available with adjustable flames that speed up the recovery rate in busy households. That means you can operate with a smaller tank with a minimum of inconvenience. Tankless gas water heaters will speed up the recovery rate even further.

More reliable – Natural Gas is more reliable than electricity. Your natural gas supply typically isn’t affected by power outages. 

Better Flow rates

Benefits of Choosing an Electric Water Heater

The benefits of using an electric water heater include the following:

Cheaper Installation Costs – Electric water heaters are relatively easy to install, and the upfront costs are lower than any other type of water heater. Gas water heaters cost many hundreds of dollars more than electric heaters to install.

Safety – Electric water heaters free you of the worries about gas leaks or explosions. Those aren’t common, but people still worry.

No Need for a Gas Line Connection – Gas Lines are available in most – but not all — areas of the United States. Almost every home has a connection to the electrical grid or generators for electricity.

Long-lasting Service – Electric water heaters generally last longer than gas heaters. You don’t need to worry about maintaining a pilot light, which quickly deteriorates over time.

Additional Tech to Generate Faster Recovery Times – You can ensure a faster recovery rate by choosing a water heater with two large-wattage heating elements. You can add a secondary heater to heat your water supply to achieve the same results. Another option is adding a heat pump, which breaks the rules by transferring heat to the water instead of generating it.

Benefits of Alternatively Powered Water Heaters

Alternatively powered water heaters usually run a bit more expensive than traditional models, but these heaters provide other benefits to compensate for the high upfront costs. 

Solar water heaters 

• Reduce energy expenses
• Decrease reliance on the grid
• Protect water and air quality

A solar water heater increases the value of your home, and it appeals to the ever-increasing number of environmentally responsible consumers.

Tankless water heaters

• Save money over time by heating only the water that is needed
• The technology guarantees that hot water is always available, a tremendous benefit for large families

Condensing water heaters

• Generate 90 percent efficiency ratings. 

This means you only waste 10 percent of your total energy. That’s good news for environmentalists and people who just want to realize savings on their utility bills.

Hybrid water heaters

• Save money over time by borrowing energy from the environment instead of generating it. 

You can switch over to electric operation if you need a faster recovery time, but most families quickly learn how to schedule their water usage to take the maximum value of environmentally generated heat.

Final Thought on How Long Does It Take a Water Heater to Heat Up

Success in life depends on balance. Water heater recovery rate, which is the top concern of some people when replacing a water heater, remains just one part of the equation.

You might discover that small changes in your routine will ensure an adequate supply of hot water so that you can focus on some of the other benefits of different water heaters.