Tankless Water Heaters Explained

Tankless water heaters are known around the world as instantaneous, continuous flow, on-demand, instant-on water heaters, and POU (point of use) heaters. The chief advantages of tankless water heaters is a continuous flow of hot water and energy savings (as compared to storage water heaters). These water heaters heat the water as the water flows through the device, and do not retain any water internally except for what is in the heat exchanger coil.

Most tankless water heaters used today modulate the heat output based on the flow of water running through the unit. This is usually done through the use of a 'flow sensor', modulating gas valve, inlet water temperature sensor and an outlet water temperature sensor-choke valve and means that the occupants should receive the same output temperature of water at differing velocities.

Tankless heaters are more efficient than storage water heaters. The absence of a tank saves energy as conventional water heaters have to reheat the water in the tank as it cools off, called standby loss.

Tankless Water Heater Installation Requirements

The most important requirement of any whole house gas tankless water heater is the gas piping size. Gas piping is sized by CFH (cubic feet per hour) which is converted from the BTU input of the heater. For example, a standard 50 gallon storage water heater has an input btu of approximately 38,000 BTUs. In comparison, a whole house tankless water heater is 199,000 BTUs. When converting from a storage heater to a tankless heater the gas line will need to be upgraded to allow for the additional btu requirements. The unit will not work on an under sized gas supply and will void most warranties.

The exhaust venting will also require special vent piping depending on its location.
Dolphin Plumbing is factory trained installers of Rheem. Our plumbers can size the gas & vent piping correctly, and your warranty will be in effect since we are factory trained.
Contact Dolphin Plumbing for Installation and Service Pricing
(770) 942-4664

Tax Credit / Rebates
We can link to our vendors Tankless websites to their Tax Credit / Rebates page if they have one – bring up a new page that does not take the customer out of the Dolphin Plumbing website
Add other link or instructions for toilet and other installs that qualify for Tax Credits or rebates