On Demand Water Heater FAQs

On Demand Water Heater

On Demand Water Heater FAQs

How much will I save on my monthly bill?
Obviously everyone’s experience will be different.  A lot depends on how much hot water you use and the utility rates in your area.  Results have shown that an On Demand Water Heater costs about 40% less to operate than an electric water heater, and about 30% less than a natural gas water heater.

 Why do I have to wait to get hot water after turning on the tap?
For the same reason why you have to wait for hot water to get to the tap with a conventional water heater – the hot water has to flow to the faucet.  The wait time is primarily determined by the distance between the water heater and the faucet.  A typical On Demand Water Heater produces hot water within a few seconds of first water flow from a cold start.  Keep in mind that you have to wait for all the cold water sitting in the pipe, in front of the hot water, to flow through the faucet before the hot water can.  For example, if your kitchen sink is 50 feet from the hot water heater and the water flow rate is one gallon per minute, it should take approximately 90 seconds for hot water to reach your sink.  Because an On Demand Water Heater is small it can be placed very close to the faucet which can drastically reduce the wait time.

Can an On Demand Water Heater be installed in the same place as my old hot water heater?
Yes, as long as there is an adequate supply of air (for combustion) and proper venting for the exchanger.  You may want to think outside of the box a little bit.  On Demand Water Heatersare generally smaller and can be installed in places where a conventional heater cannot fit.  The digital temperature controller can typically be installed in any room.  Placing the heater closer to where you will actually use the hot water will decrease the amount of time it takes for the hot water to reach the faucet.

On Demand Water Heater

 Do I have to worry about the exchanger overheat and causing a fire?
Some On Demand Water Heaters utilize an overheat limiting film wrap.  The film is wrapped around the entire exchanger and monitors its temperature.  Should the exchanger become too hot the heater will simply shutdown.

 What is the minimum clearance on the back, sides, top, bottom, and front for an On Demand Water Heater?
Always refer to the installation manual for exact measurements.  Typically you need a minimum of a foot on the top and bottom of the heater and a half an inch on the sides.  Most heaters mount directly to a wall.

 How will I know if the burner is working correctly?
You will have hot water!!  Seriously On Demand Water Heaters are sophisticated devices that have built in self-diagnostics.  Most include a sensor that detects incomplete combustion within the exchanger.  N such an event, the unit may try to correct the situation itself or alert you to the fact via a diagnostic display.

Can an On Demand Water Heater be used to heat a pool or spa?
While an appropriately sized On Demand Water Heater could provide the necessary hot water, the chemicals used would damage the components of the water heater.

 Can I install an On Demand Water Heater myself?
As with any major appliance, it’s installation should be performed by a licensed contractor who is trained to handle the plumbing, gas, electrical and venting aspects of an On Demand Water Heater and is aware of all local and national codes.

 Is there a standing pilot?
An On Demand Water Heater does not have a pilot light.  It uses an electrical ignition system that generates a spark when water flow is detected.  The spark in turn ignites the main burner – very similar to the way modern gas stoves or gas grills are ignited.

Can I convert the water heater from one type of gas to another?

No.  You have to be careful to make sure you purchase a heater that meets the specifications of your fuel supply.  Note that not only the type of gas is important but also the maximum flow of the gas.  Again refer to the installation manual for details.

Where in my home can I install a On Demand Water Heater?

An On Demand Water Heater can be installed almost anywhere.  The installation guide will provide the details you need to know if a particular location is appropriate.  Note that electric On Demand Water Heaters do not have the same venting requirements that gas powered heaters do.

How much more does an On Demand Water Heater cost?
A On Demand Water Heater will cost about 2 to 2-1/2 times as much as a standard water heater to purchase and install.  

What size gas line does an On Demand Water Heater require?
It depends – check the installation manual.  In most cases, a gas On Demand Water Heater will require a ¾” gas line to provide a sufficient gas supply to the burner.  If there is sufficient pressure and the gas line is short enough, there are some cases where a ½” gas line can be used, which is the most common size used in the United States. This can make switching from a conventional heater to an On Demand Water Heater faster, easier and less expensive.  Always check with a licensed plumber to make sure you are abiding by local gas-pipe size and licensing rules and codes.

What is the minimum water flow rate required to operate on demand water heater?
Different units have different specifications.  In most cases the water flow sensor needs to see a demand somewhere in the neighborhood of 0.4 to 0.6 gallons per minute of water flow in order to ignite and around 0.26 gallons per minute to stay in operation.

On Demand Water Heater

Continue reading my Tankless Gas Water Heater Reviews including How they work, What makes them green, FAQs, Tips and tricks and please visit my Tankless Gas Water Heater Store.

Please see our other review posts for this living green product:

Best Features of Tankless Water Heaters

How Does a Gas Tankless Water Heater Work

What makes a Tankless Gas Water Heater green

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