If you have a tankless water heater, you will never run out of heated water. This can be considered as the main reason behind the popularity of tankless water heaters. They also use less energy than traditional tanked water heaters. They do not have to keep around 50 gallons of water hot all the time and the water is heated whenever they are needed. The plumbers play an important role behind tankless water heaters. Since they do not keep the heated water, you will need to find an emergency servi