Navien ComfortFlow™ Technology Explained

Navien is one of the rising stars of tankless water heater industry that has come up with some truely promising products in recent years. It makes condensing gas water heaters exclusively, which are more expensive than normal units but can produce more hot water with less gas. One of the things that make Navien appealing to people who want to refurbish their home’s hot water system is the ComfortFlow Technology. Needless to say that you couldn’t be too informed about this feature if you have or are consdering to get a Navien.

What is its Purpose?

The ComfortFlow Technology is built into some Navien tankless water heater models to deal with the hot water delays as well as the notorious cold water sandwiches that can really ruin your time in shower. Hot water delays happen because the water heater is at some distance and it is taking time for hot water to come all the way to your bathroom. Cold water sandwiches happen when you close the tap for a few seconds for some reason and your tankless unit stops because the water use has stopped. When you open the tap, it takes time for the tankless water to sense the water flow and readjust the water tamperature so you get sporadic hot and cold water for upto a minute. The ComfortFlow Technology is basically a built-in recirculation pump and a buffer tank for keeping the water inside the water heater and the pipes hot all the time so that you never get cold water.

How does it Work?

This is how the recirculation pump in select Navien tankless water heater models work. There must be an additional water pipe running back from the farthest hot water outlet back to the water heater. When the water inside this water line gets cool, it is sensed by the water heater as a sign that there is cold water inside the hot water line. The water heater starts heating water and and sends it into the hot water line until the temperature inside the return line rises. There is also a buffer tank between the heat exchanger and the hot water lines. The buffer tank is kept hot all the time. This sort of cushions that delays in the tankless water heater’s reactions. This dual measure ensures that the water in the pipes is always hot when you open a tap and you get hot water in seconds.
You can easily switch between internal circulation mode and external circulation mode. The internal mode will disable the recirculation pump and only keep the buffer tank hot. This significantly reduces the effectiveness but it also reduces the running costs.

Is ComfortFlow Good?

This system should work to remove delays and temperature fluctuation when properly installed but it does burn some extra gas and it makes the installation more complicated just as it makes Navien tankless water heaters some of the most expensive in the market.
Some of the best tankless water heaters built by companies such as Rheem and Rinnai have a lower activation flow rate that lets them better react to changes in water flow rate and have features that keep the hot fumes inside the unit for upto a minute so that water heats up much faster if you are opening and closing tha tap in small intervals. Navien’s ComfortFlow Technology is basically an alternate way of solving these issues.

What Navien Models have ComfortFlow?

Navien’s NR-180A, NR-210A, NR-240A, NPE-180A, NPE-210A and NPE-240A models come with the ComfortFlow System. To make sure that the model has this feature, you simply need to check to see if there is an ‘A’ at the end of the model number.

What Else Do You Need to Know?

Navien tankless water heaters need to be installed by a contractor who knows about the unique system of this brand’s tankless units. The recirculation system needs a line running back to the water heater from the farthest faucet. If that is not done when putting this water on your wall, you will not be able to enjoy the instant hot water privilege that makes the high price tag on this water heater justified.

Just like the installer, the use needs to know how the unit works to take full advantage of its special features. Reading the manual carefully is imperative so that you know exactly how to activate, adjust, shut down and program the hot water circulation. It can be programmed to run at certain times of the day so as to reduce gas use.

If left to run continuously, Navien’s built-in circulation pump can add to your bills, though that is never going to be a considerable addition. The fact that it has to keep the water hot all the time means, your Navien tankless water heater will run by itself from time to time although there is no hot water use. Do not be surprised if you witness fumes coming out of the vent pipe one day when walking in your yard and knowing nobody’s home.
You can find out more at Navien Website and