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Tankless Water Heaters
Tankless Questions and Answers

What is a tankless water heater?

A tankless water heater is a device that heats the water as you use it. Unlike the traditional tank style water heaters used for many years now, the Tankless system does not store heated water. When you turn on a hot faucet in the home, the flow of water through the tankless unit initiates ignition, and the heater begins to make hot water. It stops making hot water when you turn off the faucet.

What are the major benefits of having a tankless water heater installed?

There are many great reasons to have a tankless water heater installed. Small size allows you to reclaim space in your home. The tankless system is about the size of a carry on suitcase. It is most commonly installed on the wall, which frees up floor space. Energy savings is another great reason, and ranks high on the list of positive things that a tankless brings to the home (more about that later). Dependability and long life is another trait that a tankless water heater has. All these benefits rank high on the list, but we feel the greatest benefit of all is the fact that with a tankless water heater, you will enjoy an endless supply of hot water. Although a tankless water heater is limited in the output of gallons per minute, your supply of hot water will never run out. This is especially appealing to large families who have struggled with the limited supply and recovery of a tank style water heater. We've seen countless large jetted/soaking bath tubs in homes that have used as expensive storage bins. If you have an 80 gallon tub, a 50 gallon tank won't even begin to fill it with a usable amount of hot water.

With a tankless water heater, you can fill and drain a large 80 gallon tub time after time. You will never run out of hot water, and the next person to use hot water can jump right in and go (no waiting for recovery. There is no recovery. The tankless heater makes it as you use it).

How does the relatively small tankless unit make so much hot water?

A standard 50 gallon gas tank style water heater has a 40000 btu burner, which heats about 35 gallons per hour. By comparison, an average gas fired tankless water heater has an 180000 btu burner, which will heat 4 gallons per minute (GPM), or 240 gallons per hour. More powerful tankless models will heat even more. An average electric tank style water heater can only heat 18 gallons per hour.

Is 4 gallons per minute of hot water enough for my average home?

The average water conserving shower heads that are common today have a maximum flow of 2.5 GPM. When you mix the hot and cold water at the shower to get a comfortable temperature, (about 103-104 degrees) you are taking 2 gallons per minute of hot water. (2 gallons hot, gallon cold). With this in mind, a basic tankless unit will supply enough hot water to run 2 showers at the same time. Other appliances vary in how much they take from the water heater.

I don't have gas. Can I have an ELECTRIC tankless water heater?

Although they do make electric tankless water heaters, they won't perform well here in the Pacific Northwest for whole house type operation. They can work well in cabins, coffee stands, mother-in-law apartments, etc, but in an environment where multiple users may be using hot water at the same time, they will not do well. The culprit here in the Pacific Northwest is COLD INCOMING WATER TEMPERATURE. Tankless performance is based on "Degree of Rise", or how many degrees the unit must heat the water to hit the target temperature. It isn't uncommon to see incoming water temperatures in the mid 40's in the middle of winter here in the Pacific Northwest. That means we have to raise the temperature of the water 75 degrees to get to our target of 120 degrees. This performance rule applies to both gas and electric tankless water heaters. The gas models are powerful enough to overcome this great temperature rise and still produce 4-5 GPM. The best an electric tankless can do here in our climate is about 3 GPM. ADDITIONALLY, the average home will not have the power available for an electric tankless unit without having extensive electrical work done. By comparison, an average 50 gallon electric tank water heater needs one 240 volt, 30 amp circuit. The electric tankless unit that will make 3 gallons per minute here in the PNW will require THREE 240 volt, 50 amp circuits. Of the 500 or so tankless water heaters we install each year, only 1 or 2 will be electric models. Electric tankless models do work well in warmer climates, like the southern states and tropical areas.

Is a tankless water heater NEW technology?

NO. Tankless water heaters have been in use for more than 50 years in other parts of the world. Although you could find a tankless water heater here in the USA 25 years ago, not many were sold. The big push for tankless started here in 2002-2003.

Is the flow of hot water "Instantaneous?"

Tankless water heaters are commonly referred to as "Instantaneous" or "On Demand" water heaters. These names tend to insinuate that when you open the faucet, the hot water will be there "instantaneously". However, just like with your tank style water heater, the hot water has to travel through the pipes, whatever the distance is, before it comes out the open faucet. From the time you turn on the faucet, it takes about 3-4 seconds before the unit ignites and begins sending hot water into the pipes leading to the open faucet. Sometimes we end up relocating the tankless system, which helps shorten the distance, and thereby the time it takes to get hot water to your faucets. We can also shorten the time it takes by installing a recirculation system in conjunction with your tankless system.

I have a recirculation system on my existing tank water heater. Will that work with tankless?

Absolutely YES. There are several ways to accomplish recirculation. Some homes have a "Third Line" recirculation system where a water line has been routed from the water heater to the farthest faucet, and back to the water heater. This type of system uses a pump that keeps hot water circulating around this "loop". When any faucet in the home is opened, the hot water is instantly there. On a tankless recirculation system, the water doesn't really "re-circulate" back to the heater constantly, rather it works to keep hot water in the lines, and shuts off the water heater when that has been accomplished. Hot water does not re-circulate back through the tankless water heater. Another method of recirculation is to use a special pump that installs under the sink at the farthest faucet and it works to keep hot water there. All tankless recirculation systems use timers and thermostats to control the time and duration of operation. This affords you the best of both worlds: Convenience and Conservation.

Can the tankless unit be installed where my tank is now?

In most cases they can. However, a tankless water heater CAN NOT use the existing metal vent that your current gas tank style water heater uses. This means we need to be fairly close to an exterior wall of the home. Although we can vent them through the roof of single story homes, the preferred method is through the sidewall. In some cases, we prefer to completely relocate the tankless water heater to an area of the home that will facilitate getting hot water to your faucets quicker. There are also EXTERIOR mount tankless water heaters. These are popular for people with space limitations. The exterior mount system is being used less and less as we move forward. 5 years ago, 3 out of 10 tankless installs were exterior or "outdoor" models. Now we do about 1 in 10. This is due to the evolution of tankless water heaters being marketed here in the USA now. Newer models are more forgiving in how they can be vented.

How much does it cost to have a tankless water heater installed?

This is generally the NUMBER ONE question from people inquiring about tankless water heaters. There are a lot of things to consider when contemplating the price of a tankless system. The price will vary by brand, model, and ease of installation. It is our experience that the average price will fall somewhere between $2600 and $3600 plus tax for an average system. Top of the line systems (more horsepower and efficiency) will run a little closer to $3800/4200. Although these prices are 2-3 times more than the cost of the average professionally installed tank style water heater, you must look at all the facts before you rush to conclusions about the price of a tankless water heater.

  1. A tank style water heater is designed with a very specific life expectancy in mind from the start, and on average last 6-10 years. One of the most important pieces of any tank style heater is the ANODE rod. This device is usually made of magnesium, and it is the lowest property of metal in the water heater. Corrosion attacks the anode rod first since it is the easiest thing to "eat". If you buy a tank with a 6 year warranty, you get a 6 year anode rod. If you buy a 10 year warranty, you get a 2nd anode installed in the tank. If the tank manufacturers had their way, the tank would fail one day after the warranty expires. When a tank develops a rupture and begins to leak, it cannot be repaired. In today's dollars, a 50 gallon gas tank professionally installed will cost $1000-1300 plus tax.
  2. A TANKLESS water heater is built with longevity in mind. Every piece of a tankless water heater can be replaced. The average life expectancy of a tankless system is 20-25 years. In 20 years time, a home will need 3 tank style heaters (on average). When you compare the cost of 3 tanks installed versus the onetime larger cost of a tankless investment, it's easy to see the tankless is a much better value, ESPECIALLY when you consider the 30+ % energy savings a tankless will give you.
  3. THE GOOD PART: Incentives! There are some REALLY great incentives now for those installing tankless water heaters. The American Recovery and Reinvestment Act of 2009 (the "Stimulus Package") provides a tax credit for homes installing qualifying tankless water heaters. This credit is equal to 30% of the total job cost, up to a maximum benefit of $1500.00. For instance, if your tankless water heater project costs $3000.00 installed, your tax credit for that tax year is $900.00. THIS IS NOT A DEDUCTION type incentive. It is a true dollar for dollar CREDIT that is applied to your federal tax liability. Utility companies (like Puget Sound Energy) offer other incentives too. For instance, PSE will give a customer a rebate of $150.00 or $200.00 dollars (depending on the model) if you install a tankless water heater. PSE also has a "Fuel Conversion Rebate" of up to $950.00 for customers who currently heat their water with an electric tank that switch to any natural gas water heater. These incentive programs are always changing, so check with your utility company to see what is currently being offered. Learn more about the Stimulus Tax Credit here: www.energystar.gov . As of this writing, the Stimulus Package tax credits end on December 31, 2010.

    The average home will usually see about $1000.00-$1200.00 in real incentives. This brings the cost of your $3000.00 tankless project down to $2000.00 (not including tax). If you take the life expectancy of the tankless (25 years) and factor in the final price ($2000.00), your annual cost to have a tankless is around $80.00, compared to $120.00 per year for 3 tank style water heaters over the same period of time.

How much energy does a Tankless Water Heater save me?

Next to "Price", this is the second most asked question. Energy savings is one of those difficult things to calculate. Each home will see a different level of cost to operate a tankless water heater. Family size, habits, age of family members, and other factors will dictate the amount of savings, or in some cases additional costs associated with operating a tankless system. ADDITIONAL COST? You won't read about that in a tankless brochure. We at Washington Water Heaters feel that providing truthful information, regardless of if it's what a customer wants to hear, is the best approach. That is why you will hear us tell customers that a tankless system could actually RAISE your operating costs. The simple reason for this is that with tankless, now you have an UNLIMITED supply of hot water, so you could very likely USE MORE HOT WATER. However, if your habits don't change, the average home that uses a natural gas tank style water heater will see a 30% reduction in their hot water costs. Figure on a 50% savings for those using propane gas tank style water heater, and 60% for those using an electric tank style water heater. Our most common retrofit will be for those who use a natural gas tank. Those customers should expect an annual savings of $125-150.00. That doesn't sound like much, but if you calculate the savings over the life expectancy of the tankless water heater, that's more than $3000.00 in energy savings. And that's in today's dollars. We're pretty sure energy prices will be going UP in the future, which will compound the savings in an upward fashion. If you are using a propane or electric tank style water heater, your savings will be even more.

What brands of tankless water heaters do you sell?

We sell ALL the brands on the market today. Any number of factors will help dictate which brand and model of tankless water heater is going to be best for your home. For instance, we will look hard at the layout of the home and where the existing water heater sits. Your needs and budget will also factor in to a recommended brand. We like to find the right brand and model for your home rather than "force" a particular brand in just because that is the heater we stock. We stock them all. Brand has nothing to do with our profit, so we have no reason to steer you one way or another EXCEPT in how it will affect you and your family. With that said, and if all things are equal, the NORITZ line is one of our FAVORITES for traditional tankless type heaters, and the Eternal Hybrid when a customer wants TOP OF THE LINE warranty and efficiency. Noritz is the number 1 tankless manufacturer in the world, and they have been doing it longer than any other company (more than 50 years). You will pay a few dollars more the Noritz when compared to most other brands, but you get more for your money. We have installed every brand on the market. Without a doubt, we have the fewest problems with the Noritz line. 98% of all tankless brands are great, but Noritz is best. Want to hear about the other 2%? Give us a call.

Is it true that you have to have electrical power to use a gas fired tankless water heater?

For the most part, yes There are a few left with standing pilot lights, but all the major manufacturers have switched 99% of their product line to electronic ignition. Another reason you need power is the modern whole house tankless water heaters have a sealed exhaust system and a fan that pushes the exhaust out the vent pipe. Tankless units also have a built in freeze protection system, which requires a small amount of electricity when the heater is plugged in. Although losing power is rare, we do recommend that every tankless owner purchase and install a simple Battery Backup device (UPS) and plug the tankless power into it. These battery backups are usually used with computers, and will run a tankless water heater for 20-40 minutes in the event of a power outage, and they also protect the tankless water heater from power surges. The biggest reason for the battery backup however, is to ensure you don't lose hot water if you happen to be IN the shower when the power goes out. There are no battery backup devices that will run an electric tankless water heater.

Why do YOUR tankless water heaters only produce 4-5 gallons per minute, when your competitors have told me they sell systems that will give 10+ gallons per minute? I have also read about 10 gallon per minute models on the internet and seen them at the box stores.

This is a great question, and one we are VERY happy to explain. Manufacturers have decided to inflate their perceived performance by listing a model's MAXIMUM gallons per minute. Some even put the design max into their model number. For instance, a very popular Noritz tankless water heater is the NRC 111 DV. This model is rated for a maximum output of 11.1 gallons per minute at 120 degrees. Here is the "sneaky" part. To get 11.1 GPM out of the heater, the incoming water temperature must be 90 degrees. Incoming water temperature here in the Puget Sound is going to vary from 45-55 degrees. We use the 45 degree mark because we don't want to "Over Promise, and Under Produce". We would rather have you find out you are getting slightly MORE hot water out of the system than the other way around. To really find out what a tankless system will do here, you take the incoming water temperature (45 degrees) and subtract that from the desired output temperature (120). This tells you the degree of rise (75). Then go to the performance chart. The Noritz Chart below is figured for 120 degree water in mind, and shows that with these parameters, the NRC 111 DV will produce 5 GPM. You can also see that the NR 98 heater will give you 4.5 GPM with the same numbers. Use this same basis on all manufacturers? performance charts and you will see that 4-5 GPM is pretty much the standard for residential models here in the Pacific Northwest.

I have heard about this new ETERNAL HYBRID water heater. Is that a tankless, or is it a tank?

The Eternal Hybrid is both a tank, and a tankless (hence, HYBRID). This unit takes the benefits of a tankless water heater's powerful burner and couples it with a small holding tank (less than 2 gallons). The biggest difference between a true tankless and this Hybrid style heater is you CAN run a Hybrid out of hot water. The reason for this is that a true tankless water heater WILL NOT allow more water to pass though it than it can heat to your desired temperature. When the tankless water heater hits the maximum flow of GPM at your desired temperature, it restricts output flow to maintain the temperature. The Hybrid does not have this safeguard. When you exceed the flow and temperature with the Hybrid, it continues to do the best it can, but it allows more GPM to pass through the heater, resulting in a drop in temperature, and eventually (if the demand for higher flow is made) run completely out of hot water. Don't get us wrong, we LOVE the Eternal Hybrid. The dreaded "Cold Water Sandwich" is eliminated with the Eternal. Recirculation system temperature is much more stable with the Eternal than with a traditional tankless system, due to the small holding tank. Another popular Eternal Hybrid feature is the 20 year heat exchanger warranty. The Eternal Hybrid has become our top selling system for those customers wanting TOP of the line performance.

What is a "Cold Water Sandwich?"

This is a term used to describe what can happen with a tankless water heater when you turn the hot water on and off frequently. As we learned earlier, it takes about 3-4 seconds from the time you turn on a faucet before the tankless heater is actually on and sending hot water into the water lines. This is due to the sequence of ignition, and then the time it takes to send the water through the heat exchanger and out into the pipes. Now with this knowledge, let's take a look at a scenario where you may experience the CWS. Let's say you are in the shower enjoying the endless hot water. For whatever reason, you decide to turn off the hot water (maybe you have "scamper" out and grab a bar of soap) Anyway, the water is off for 15 seconds and then you turn it back on and resume your shower. Just like when you started your shower, the water heater has to go through the 3-4 second ignition and startup again, which introduced 3-4 seconds of cold water in between the previously heated water, and the current hot water flow that is heading your way. Depending on how far the water heater is to the shower, at some point you will feel that 3-4 second cool down until it clears the line. Although you will definitely feel a cool down in water temperature, it doesn't go completely ice cold as some would have you believe (like tank manufacturers). In reality, it is a small price to pay on occasion for the huge benefits of tankless.

Can I buy the tankless equipment from you and install it myself?

We hear this question at least 3 times a week. The short answer is probably not. Allow me to clarify. We are more than willing to sell you a tankless water heater in a box. Can you install it yourself? 99 out of 100 cannot. The actual act of mounting and connecting a tankless water heater isn't the hard part in the whole tankless equation. That is simple plumbing, and anyone with basic knowledge of plumbing practices, and who has basic plumbing tools, can get that part of the project done. The hard part of a tankless retrofit is knowing how to size the system, where to install it, how to vent it, and what to expect performance wise based on the choices you have before you. We also have to determine if the current gas meter is of sufficient size to handle the added BTU load that a tankless will bring, and many other factors must be considered before a positive endorsement can be made for switching to tankless. Tankless water heater installation is a "Specialty Niche" of the plumbing trade. A contractor that specializes in tankless water heaters (like Washington Water Heaters) is very much a specialist. I can't tell you how many times we get the call to go fix a newly installed tankless water heater that a plumber just installed. Since we do the majority of the warranty repairs in the Puget Sound, we get these calls from the manufacturer's representatives. We arrive and in most cases quickly see that it isn't an issue with the heater itself, rather an installation error, or the customer was never told what they could really expect out of the system. This scenario doesn't necessarily mean the original plumber is incompetent. It simply shows that this plumber doesn't do enough of them to really become familiar with all the do's and don'ts of tankless. It is like going to a neurosurgeon if you need an operation on your foot. A podiatrist and a neurosurgeon are both MD's, but they don't specialize in the same medicine. At Washington Water Heaters, we are THE plumbers who SPECIALIZE in tankless water heater system design, repair, and installation in the Puget Sound region.

I had my furnace serviced the other day and my furnace man said he can install a tankless for me.

Don't do it. Not only does the same rule apply as we discussed above, there is another very important factor to consider when deciding on who should do your tankless water heater installation. In the State of Washington, you must be a Licensed Plumber or Apprentice to do any plumbing work for hire. If you want a valid warranty on your expensive tankless water heater, it has to be installed 100% to code. If you have anyone other than a licensed plumber do the install for you, it has not been installed to code in accordance with Washington law.

  • (ref 2006 Uniform Plumbing Code, Section 218), "Plumbing: The business, trade, or work having to do with the installation, removal, alteration, or repair of plumbing systems or parts thereof."
  • The Revised Code of Washington, Section 18.106.020 states that "No person may engage in or offer to engage in the trade of plumbing without having a journeyman certificate, specialty certificate, temporary permit, or trainee certificate and photo identification in his or her possession... )

There are no licensing requirements for HVAC technicians. Plumbers in Washington have to accumulate a minimum of 6000 hours of OJT and then pass a very stringent test to become licensed. Then they must perform continuing education every 2 years to maintain their license. By contrast, a HVAC Technician has no licensing or education requirements to work in Washington. Don't trust your complex tankless project to anyone who doesn't specialize in that trade, and who isn't licensed to do so.