FAQs and Facts

Frequently Asked Questions and Answers

• Q: How do tankless water heaters work?

  A: Noritz & Rinnai water heaters work on demand. They only heat water when necessary. When a hot water fixture is opened or hot water is required by an appliance, the heater will sense the demand and heat water accordingly. Instead of wasting energy and money storing hot water when it is not needed, tankless water heaters provide only as much hot water as needed.

• Q: Will I get instant hot water with a tankless water heater?

  A: A tankless hot water heater heats water on-demand in a mere few seconds, but just like a tank water heater, it will take the same amount of time for the hot water to travel through the plumbing inside your home. If you would like to get instant hot water, there are recirculation pump systems available. Please ask your installer to see what options you may have in getting instant hot water in your home.

• Q: What is the difference between a storage tank water heater and a tankless water heater?

  A: Tank water heaters store and heat water at all times, thus incurring higher operating costs, whereas tankless water heaters only heat water as needed. In addition, tank heaters have a limited supply of hot water, while tankless heaters provide an unlimited supply of hot water.

• Q: How much is saved if a Rinnai or Noritz tankless water heater is used instead of a storage tank?

  A: The California Energy Commission estimates that a water heater uses approximately 25% of all energy consumed by any household. Using a Rinnai or Noritz gas tankless water heater will allow a home to use up to 50% less energy for water heating, which can cost up to hundreds of dollars per year.

• Q: Which model of Rinnai or Noritz gas tankless water heaters is right for my application?

  A: The best way to size a gas tankless water heater for any application is to estimate the peak flow capacity that will need to be supplied by the water heater at any time. For residential use, this will most likely be the maximum number of showers that may be used simultaneously, multiplied by the flow rate of the showerheads. This calculation should only be done by a qualified plumber or contractor. Once this maximum flow rate is calculated, consult the specifications for each heater to determine which models meet your demand.

• Q: How long do tankless water heaters last?

  A: On demand tankless water heaters can last up to 2-3 times longer than a traditional tank heater. They are extremely reliable as Rinnai and Noritz units are manufactured with the highest quality parts and put through very rigorous testing and quality control.

• Q: Do tankless require maintenance?

  A: Arnett’s Plumbing highly recommends protecting your tankless water heater from San Diego County’s hard water. Periodic water heater maintenance can significantly extend your water heater's life and minimize loss of efficiency. Read your owner's manual for specific maintenance recommendations and detailed warranty information. Options for protecting your Noritz or Rinnai tankless water heater are scale shields, regular de-scaling (flushing) or soft water treatment.

• Q: At what temperature should the water heater be set?

  A: The set temperature of the water heater depends on how it will be used. A comfortable shower temperature should not be much higher than 105°F (temperatures above 125°F are scalding). Lower temperatures will also prevent scale deposits from forming, which may affect the operation of the heater.

• Q: How do I change the temperature on the water heater?

  A: Not all tankless water heater come standard with a remote digital temperature controller, which allows you to adjust the water temperature. The controller is optional with the smaller models and can be added as an accessory if desired. The control panel can be wired and installed in a remote location; up to 300 feet away from the unit. The water temperature is displayed on the easy-to-use control panel, and can be adjusted using the up and down buttons.