The amount of time it takes for a water heater to heat up depends on the size and type of water heater being used, as well as its setting. A large tank-style water heater may need up to an hour to heat up, while a smaller, more efficient tankless water heater can heat up much quicker — sometimes within minutes. Higher settings require more energy and therefore take longer than lower settings. It is important to note that the water temperature should never exceed one hundred twenty degrees Fahrenheit, regardless of the setting on your unit.

On average, a tankless water heater takes between 15 and 30 seconds to heat up. It can take longer or shorter depending on the tankless water heater model and water temperature. Some tankless water heater models have adjustable thermostats that allow you to save energy by setting the hot water output to the desired temperature. Depending on how the system is configured, the tankless unit can heat up once it receives a call for hot water or maintain a steady temperature, allowing you to enjoy continuous hot water all day long.

The main difference between a tank and a tankless hot water heater is the way in which they heat water. A tank hot water heater uses an insulated storage tank to heat and store a predetermined amount of hot water, ready for use when needed. In contrast, a tankless hot water heater uses sensors to instantly heat cold water as it enters the unit, delivering an uninterrupted supply of heated water on demand. Generally, the life expectancy for a tank-type hot water heater is 8–12 years, whereas a tankless model can last up to 20 years or more. Tank type units also tend to require more energy due to the need for storage of preheated water, whereas their tankless counterparts are more energy efficient because they only run when hot water is being demanded.

Tankless water heaters are becoming increasingly popular due to their high efficiency and long-term savings. Compared to traditional tank water heaters, tankless systems don’t use a storage tank to hold hot water, so they don’t waste energy continuously reheating the same amount of water and provide instant hot water in unlimited amounts. This means they are much more efficient than standard hot water tanks and can save you money over time in terms of energy costs. With a tankless water heater, you only pay for what you use and can save up to 50-70% on your monthly energy bill.

They also have a much longer lifespan since they only work when the hot water tap is turned on; this prevents them from undergoing the same wear and tear as a tank unit. Additionally, without taking up much space, they can be installed at nearly any location indoors or outdoors depending on preference.

Furthermore, tankless water heaters require less maintenance than tank water heaters, as they don’t have an anode rod or other components to be replaced. They are also much, much quieter compared to a traditional tank water system. 

Lastly, tankless water systems can last up to 20 years or more vs a traditional water heater lifespan of 8-12 years.

A tankless water heater helps save space and money on energy bills, however, there are some drawbacks. Lower-cost units only produce 2-4 gallons per minute, so for bigger households or for homes with multiple bathrooms and/or fixtures, this may not be enough hot water to meet their needs. Additionally, the initial cost of purchasing a tankless water heater is usually considerably more than a conventional storage tank model. Also, depending on the model selected and its location within the home, additional new venting systems may need to be installed which increases installation costs. Lastly, they require professional installation in order to meet warranty requirements so the extra labor doesn’t come for free either.

Despite these few drawbacks, we believe the benefits far outweigh them over the life of ownership. See the FAQ above for benefit analysis.