Tankless Water Heaters – General Information

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Tankless Water Heaters – General Information

Tankless Water Heaters

There are both pros and cons to the installation of a tankless water heater. You may have heard some of both sides already.  The information provided here is based on actual experience installing many tankless water heaters.

Our intention is not to persuade you one way or the other, but to inform you of what is involved with such an installation, and give general information about the option.  Then of course, if you are interested we would be willing to help with an installation.

General Information

First of all, you will want to make sure to understand the difference between “instant” hot water, and “continuous” hot water so that you are not disappointed.  Although tankless water heaters are sometimes referred to as instantaneous water heaters, “Instant” hot water can only happen at the point of use, so you would have to have a water heater under each faucet or fixture to avoid any wait time on hot water.  The only other way to achieve instant hot water is to have a recirculating system where hot water is constantly running through the house and ready to use at any fixture. Recirculation can be accomplished with a tank type or tankless water heater. If you have to wait a while to get hot water, a tankless water heater will not change that, because it is usually the distance of the fixture from the water heater that causes the delay and a tankless water heater will not change that.  In fact, it might even take a few seconds longer because the water heater will only start heating once water is flowing through it.  

However, if you are looking for “continuous” hot water or delivery at a constant temperature, then a tankless water heater is an excellent option.  Tankless water heaters can be set to a desired temperature, and they will continue delivering water at that temperature as long as the hot water is flowing through it.  This is a great advantage over a tank type water heater which loses temperature as water passes through it.

The fact that water is heated as it passes through the tankless water heater does create a disadvantage during the colder times of the year.  When there is a bigger difference between the incoming temperature and the temperature that the water heater is set to deliver, the hot water volume decreases.  The tankless water heater will still deliver the same temperature of water it is set to, but sometimes it might not provide enough hot water to effectively run more than two fixtures at a time.  

Tankless water heaters are also appropriately referred to as “On-Demand” water heaters because they only heat water when it is needed.  This is where they have the energy saving advantage. Tank type water heaters are always using a small amount of gas to keep the pilot light running.  This adds up over time. Whereas a tankless will only use gas when it is heating, and otherwise it sits dormant.

The fuel efficiency of a tankless water heater is often one of its selling points.  However, in Utah where natural gas prices are comparatively lower than at other places in the United States, average energy savings are only around $80-90 per year.  While that may not seem like much per year, when multiplied by the 20 year life expectancy of a tankless water heater, and it can add up to $1600.00. So it may take the whole life of the water heater, but eventually it can pay for itself, even in Utah.

As mentioned, tankless water heater life expectancy is usually more than double that of a tank.  A normal warranty on a tank type water heater is 6 years, whereas the warranty on the heat exchanger in a Navien water heater is 15 years.  

Installation Requirements

There are some real challenges with converting a tank type system to a tankless.  Tank water heaters use a draft vent flue, which is just a chimney for hot air to escape through.  Tankless water heaters are more efficient partly because they flue differently. They require air intake and exhaust piping, so the existing draft vent from a tank water heater cannot be used.  

Also there have to be modifications to the gas line.  A tank water heater is rated around 40,000 BTU whereas a tankless water heater ranges from 150,000 to 199,000 BTU.  This is because a tank water heater uses a smaller burner and heats water over time, whereas the tankless uses a heat exchanger which heats the water as it is passing through the water heater.  Before a tankless can be installed, careful calculations must be made on the gas system to ensure that there is adequate gas for the tankless. Ignoring this difference can result in insufficient gas at the appliances, which can cause them to fail, or to emit carbon-monoxide which is potentially lethal.  

Some cities require a permit and inspection with water heater installation.  We make all of the arrangements for the permit, and add the cost of the permit to the install.


Some routine maintenance is required for tankless water heaters. (Truthfully, tank water heater manufacturers recommend maintenance on tanks too, but most people are not aware.)  Tankless water heaters will not last as long without the maintenance. Annual maintenance includes cleaning of air and water filters, and clearing the condensate trap. Also the scale ought to be removed from the heat exchanger.  This is done by running an acid solution (even household vinegar will do) though the water heater for 15 to 20 minutes. We provide these maintenance services if you would want help. Having a water softener helps a lot with keeping the scale down, but even with soft water the heat exchanger should be rescaled every two years.

Rebate Available

Dominion Energy offers a rebate which can help offset the cost of transitioning to a tankless water heater.  The rebate is $300 for the Navien heaters (http://www.thermwise.com/home/ApplianceRebates.php)


Having installed Rinnai, Jacuzzi, Eternal and Navien tankless water heaters, we favor Navien heaters for a number of reasons. One reason is that they can use a PVC flue, which is much more affordable than the stainless steel flue at $75.00 per foot required by some of the others.  Navien also comes with a built in recirculation pump and small reservoir. It keeps enough hot water on reserve so when you turn on a faucet or fixture it can begin delivering hot water right away without the delay of initializing the heat exchanger.  Navien is one of the most compatible systems, so it makes for better transition from the tank. Furthermore, their track record is awesome. When installed correctly, they rarely have problems. For more information about Navien heaters, you can check out their website: .http://us.navien.com/Product/Category-NPE-A%20series/

Navien Heaters


Model NPE-180A = $1485.00

Model NPE-210A = $1564.00

Model NPE-240A = $1737.00

Because each house is different, installation costs vary, but a typical install is around $1500.00

Feel free to contact us with questions.  If you are serious about a tankless installation, we can do an evaluation of your house, including venting and gas line systems and create a modified gas plan for a non refundable fee of $45.00.

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