Takagi - Noritz - Rinnai - Navien – Comparison of Tankless Water Heaters

Of the major brands of tankless hot water heaters Noritz, Navien, Takagi, & Rinnai, which brand is best? I recently asked a friend of mine this question. He installs and services tankless water heaters so I figured if anyone would know he would. Here is his reply.

All the major brands of tankless hot water heaters are very similar in construction, operation, and quality. Each brand has claims by the manufacturer that theirs is better, but nothing really stands out in my opinion, to differentiate between the brands.

Noritz advertises its "Dual Burner" technology as a big advantage. Is that a significant advantage over the others? I don’t think so. Since all of the brands modulate the flames I don’t think having two small burners is any better than one larger burner. In fact, if I had to choose I would take the single burner since it is simpler and I think simpler is better.

Rinnai, Noritz, and Takagi are all made in Japan and Noritz and Takagi both share some components, and they have similar warranties. Rinnai uses a different venting system than Noritz and Takagi. Do I think its better? Not really.

I do like the fact that Rinnai tankless water heaters have a built-in condensation trap. Sometimes installers forget or just don't bother to include the condensation trap when installing a tankless water heater because of the additional cost. This can result in a much shorter life expectancy for the heat exchanger. Unless the customer knows something about tankless heater installations he would have no idea that it was missing. Vent condensation is highly corrosive and should not be allowed to drip on parts of your water heater.

Navien tankless water heaters are made in South Korea. Navien is better established in Canada. The Navien units have unique and interesting features, like a built in small buffer tank that lets you obtain low flows of hot water and eliminates cold water sandwiches.

Navien heaters have 98% efficiency while the other major brands have about 94%. Is the 4% difference significant? It would not be enough for you to notice on your utility bill.
Navien, Noritz, Rinnai and Takagi are mechanically very similar. They all deliver roughly the same amount of hot water for the gas or electricity used. The warranties are all pretty much the same.

I personally like Takagi because of their excellent service. They even have a toll free number 24/7 that I can call when there is a problem. When your hot water heater stops working on Friday night, and you can’t get any help until Monday morning you can become quite frustrated.

I feel that the most important thing when buying a tankless water heater is to be sure that heater is installed correctly; it is not like your standard storage type water heater where you connect a couple of pipes up and you are done.

With a tankless hot water heater It is very important to purchase it and have it installed by a plumber that is experienced with tankless water heaters particularly with the brand you are purchasing. If you experience problems in the future, you will be glad you did.

Another tankless water heater comparison article: Compare Bosch, Takagi, Noritz & Rinnai

Best Home Improvements – Home Improvement Idea for Your Kitchen and Bath

If your home has long hot water pipes then it can take a long time to get hot water, which can be quite annoying. However, an easy, low cost solution to get you your hot water much more quickly is available. It’s a solution that speeds up your hot water, and saves you thousands of gallons of water a year.

A hot water demand system is the answer. Hot water demand systems are small pumps located under a sink furthest from your hot water heater. When you want hot water you just push a button and the system speeds the hot water from your hot water heater to your fixture without running water down the drain.

The water that has cooled off in the hot water pipes, is returned to the water heater through the cold water pipes. When the hot water reaches the the pump at the fixture it stops pumping and no hot water gets into the cold water pipes. Turn on your hot water and you have nearly instant hot water.

Other fixtures that share the same main hot water trunk line will also have faster hot water from the demand system. If your plumbing happens to be looped from fixture to fixture in a daisy chain fashion then all of your sinks will have faster hot water. By placing the system under the sink in a bathroom the shower and tub are also only seconds away from hot water once your demand system has finished its pumping cycle.

Hot water demand systems work fine with tankless water heaters as long as they have enough power to turn on the tankless hot water heater. Tankless heaters need a minimum hot water flow rate to turn on, typically ½ gallon to ¾ gallon per minute. Most recirculating pumps can’t produce a flow rate high enough to turn on tankless heaters.

Tankless water heaters require longer waiting times for hot water since they have to heat the water from scratch unlike storage water heaters. This makes demand systems even more important when you have a tankless water heater.

Solar water heaters work with hot water demand systems as well. Any kind of solar water heater will work with hot water demand pumps. If you are green enough to have a solar water heater on your home then you certainly should have a hot water demand system. In my opinion water savings is just as important as energy savings.

By reducing the amount of water you run down your drain you reduce the amount of sewage that must be processed and treated. That saves you more money and further reduces your carbon footprint.

If you have a septic system it reduces the load on your system saving you potential septic system problems.

This is an easy inexpensive home improvement project that saves you time, water, energy, and money and provides you with the convenience of fast hot water. Not many home improvement products can claim that.

Hot water demand systems for providing your home with instant hot water can be purchased online for less than $200, and some systems can be hooked up to your plumbing system with just supply hoses like the ones already on your fixtures. You don’t even have to turn off the water to your house.

A very easy and inexpensive home improvement project for the do it yourselfer and the novice alike. Possibly one of the best home improvements a homeowner can make.

Best Home Improvements

Motion Sensing for Residential Hot Water Demand Systems

Using a motion detector to start your hot water demand system can have unexpected results.

Demand systems are meant to be activated and then used quickly. Hot water in your piping cools off quite rapidly. Since a demand system shuts off the pump when hot water reaches it, if you don’t use the hot water quickly it will soon become “warm” water and to get hot you will still need to run more water out of the pipes and down the drain.

How the hot water demand system behaves a short while after being used depends mainly on how long since the system was last used. If the water hasn’t cooled to below 96 degrees the pump will be locked out and won’t start until the water in the pump cools to below 96 degrees F. You will be forced to purge the warm water from the pipes to obtain hot water and end up running that water down the drain.

If the water has cooled to just below 96 degrees… say about 90 degrees, then the pump will run again until it sees a sudden increase in temperature or if it senses water hotter than 96 degrees and then shut off again. Now however, there will be 90 degree water filling the cold water line.

If you begin using the hot water mixed with cold, after a short time the warm water will be purged from the cold water line and you may need to re-adjust the temperature to add more hot and less cold water. More details about how the hot water demand system behaves in different situations. It pretty much depends on the water temperatures in the piping.

Using a Motion Sensor

As you can see, any significant wait after you have tripped the motion sensor can cause an inconvenience and or end up wasting water.

Another thing to consider when using motion sensors to control your demand system is what happens when someone enters the bathroom while you are taking a shower? Depending on your plumbing layout and how long since the pump was last run, it could cause a fluctuation in water temperature like flushing a toilet sometimes does.

This is especially true when you have a tankless water heater. Since tankless water heaters take time to heat the water, typically 10 to 20 seconds, if the heater has been off for a few minutes you may experience a brief “cold water sandwich”.

Before you decide you want a motion sensor to activate your demand system you might consider how often you enter your bathroom when you don’t want hot water. Each time the pump runs and you don’t use hot water you are wasting energy and increasing your water heating bill. This is especially true with tankless water heaters. It doesn’t take many firings of the heater to use more energy than a standard tank type water heater loses in standby loss.

The same things hold true when using a timer based system. You can have the demand pump turn on automatically at say 7:30 a.m. every morning, but if you push the snooze button a time or two you are still going to need to run the pump again when you get to the bathroom.

Since the piping is warm you will get hot water faster but you pay the price in extra energy consumption.

For some people motion sensing to control the delivery of hot water is a welcome convenience, but for many others it would just be a wasteful nuisance.