How Long Does It Take a Water Heater To Heat Up?

The time required for a water heater to provide hot water depends on its size and whether it is powered by gas or electricity. Gas water heaters heat up faster. For example, a 40-gallon gas model usually heats up in about 30 to 40 minutes. If you have a larger capacity, like an 80-gallon gas heater, it can take about 60 to 70 minutes to provide hot water. 

On the other hand, electric water heaters take a bit longer due to their heating mechanism. A 40-gallon electric model might need about 90 minutes to heat up fully, and an 80-gallon heater could take up to two and a half hours. For more specific information on how long a water heater takes to warm in your case, consult an experienced plumber.

Factors That Influence Heating Time in Nevada

Type of Water Heater

Electric Water Heaters

These systems use heating elements inside the tank to heat the water, similar to the coils in an electric oven. Electric models are slower compared to gas because electricity heats up more gradually. A standard 50-gallon electric unit might take approximately 1 to 1.5 hours to fully heat the water from cold because each element (total of two in residential heaters) might only be capable of raising the water temperature at a rate of about 20 degrees Fahrenheit per hour depending on their wattage (between 3,000 to 5,500 watts).

Gas Water Heaters

Gas water heaters are faster than electric heaters because combustion of natural gas or propane generates a significant amount of heat quickly. A 50-gallon gas water heater with a burner that provides 40,000 BTUs of energy can heat the full tank from cold in about 30 to 40 minutes.

Oil Water Heaters

These are similar to gas heaters but use heating oil as a fuel source, which is combusted to generate heat. Oil-fired heaters are very quick due to the high energy content of oil. An average oil-fired heater with an 80-gallon tank might heat up within about 30 minutes if it uses a high-capacity burner.

Tankless Water Heaters

On-demand water heaters heat water as it passes through a series of coils or a heat exchanger instantly. The rate of heating depends on the flow rate of water and the temperature of incoming water. If you have a tankless system with a flow rate of 5 gallons per minute and it raises the incoming water temperature from 50°F to 120°F, it provides continuous hot water without the need to “recover” like tank-based heaters.

Solar Water Heaters

If you get solar panels installed on your roof to collect and convert sunlight into heat energy, it will be transferred to heat water stored in a tank. On sunny days in Nevada, water will likely reach the desired temperature in a few hours, but during cloudy or rainy days, it may not heat adequately, and thus, most systems are equipped with a backup heating source.

Capacity of the Water Heater

The time for water heater to heat also depends on how much water it can hold. Small capacity tanks (20-40 gallons) are sufficient for 1-2 person households and quickly recover between uses because they have less water to heat. If you get a 30-gallon electric heating system with elements rated at about 4,500 watts, it might take about 1 hour to raise the water temperature from cold (about 50°F) to a set point of 120°F. This is based on the ability of the heating elements to raise the temperature at a rate of about 25 degrees per hour per element.

A medium-capacity, 40-60 gallons gas heater equipped with a burner that provides about 40,000 BTUs can heat the entire tank from cold in about 30 to 40 minutes. These are ideal for families of 3-5 people. For a larger household, where most members use a lot of hot water all at the same time, a large capacity (over 60 gallons) tank is recommended. Heating a full 80-gallon electric tank from cold to hot could take approximately 2 to 2.5 hours.

Initial Water Temperature

The greater the difference between the incoming water temperature and the target temperature (set by the thermostat), the longer it will take to heat the water. Starting from a lower initial temperature means more energy consumption since the heating unit has to operate longer to achieve the desired temperature.

If you live in Northern Nevada, the incoming water might be near freezing (around 32°F) during the winters. Heating it to a comfortable shower temperature of about 120°F requires a lot of water heater heat-up time. If a gas water heater heats water at a rate of 50 degrees Fahrenheit per hour, and you are starting at 32°F, reaching 120°F will take about 1 hour and 46 minutes.  

In Southern Nevada, including Las Vegas, the incoming water stays around mid-40s to low 50s Fahrenheit. The same heater would only take about an hour to reach your desired temperature.

Insulation

Insulation around a water heater tank and its associated piping helps to retain the heat within the system. The better the insulation, the less heat is lost to the surrounding environment. Properly installed fiberglass or foam insulation also allows the heater to work less to reheat the water to the set temperature.

A well-insulated tank maintains the temperature of hot water for a much longer period compared to a poorly insulated tank. Look for a heater with an insulation R-value of R-24; the R-value indicates the material’s ability to resist heat flow. Higher R-values mean better insulation properties.

Regular Maintenance

Over time, your heater accumulates minerals, bacteria, and other debris. This is even more common in Nevada where most areas have hard water (i.e., water rich in calcium and magnesium). When these sediments settle at the bottom of the tank, they create a barrier between the heating element (in electric heaters) or burner (in gas heaters) and the water and prolong the warm-up duration.

Make sure to get the heater flushed or cleaned out by a Las Vegas plumber at least once a year to ensure all components function correctly.

Water Heater Not Doing Its Job? Call Active Plumbing & Air Conditioning in Nevada

If you are noticing inconsistency in the performance of your hot water system, contact Active Plumbing & Air Conditioning for dedicated service. We can help you make an informed decision about whether to repair or replace your heater after a thorough system check. Our licensed plumbing technicians take pride in suggesting practical and lasting solutions, rather than pushing for the most expensive option. Give us a call at (702) 553-1171 or contact us online.