Tankless Water Heater Review

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Before beginning this article only contains information on tankless water heaters that run on gas either natural gas or propane. The tankless units that run on electricity are not economical as most cannot produce the efficiencies and output as gas.

During a trip to Europe in 1998 I found out about these little suit case like devices called tankless water heaters. Up to that time I had only been accustom to the tank water heaters. While I was there I found out how they worked however, here in the States they were not very popular in 1998. It took sometime for these units to become popular and to find an installer to install them.

Fast forward ten years to 2007 when I purchased my first tankless water heater. Our old tank was eleven years old and I figured I had better start seriously looking into finding another tank or a tankless to replace it. The motivating factor was that the government was not going to extend the tax breaks on the tankless in 2008 so I purchased the tankless at the end of 2007. The model I purchased was the Rinnai R53i which supports multiple location use and has many features which eliminate some of the known issues that come along with other tankless water heater.

Update: April 2012 - The tankless is still going strong and have had no mechanical or electronic problems. We dis have an issue where a leave got sucked into the inlet and got caught up in the the fan. It was a weird sound coming from the heater but after taking it apart and cleaning out the fan the noise went away. Also, I once accidently layed up a large board near the intake and the unit started to make a funny sound while running. After realizing the issue I removed the board and there was no other sounds.

Note:There are new tax breaks on tankless water heaters *click here*.

Known Issues

1. Sandwich Effect - When turning on and off the hot water you will get hot water then cold water then hot water. This effect usually happens while doing dishes, shaving, etc.
2. Longer Wait - Tankless water heaters take longer for hot water to reach the user. This is caused by the tankless having to electronically gauge the incoming water temperature to desired output temperature. Also, it takes the burners sometime to get their output high enough to the users desired water temperature.
3. Only Supports Single Output - The cheaper models only handle a single output source. This is caused by the unit not being able to handle the request of two or more sources needing hot water at once.
4. Water Source Temp is Too Low - The incoming water source temperature is too low and the unit cannot make the water hot enough for the desired use. This is caused by temperature in colder climates where the incoming water temperature is too low for the unit to handle.
5. Electricity is Needed - Some models need power to run their exhaust blowers and gas ignitor. Usually tanks do not require any electrical and is not an issue when the electricity goes off.
6. Low Flow Does Not Turn on Unit - This is caused by some models not being able to detect low flow use. If you want to run the hot water without opening up the faucet on high some models cannot detect the low flow and will never turn on until flow rate is high enough for the unit to detect.

These are universally known concerns for tankless water heaters. The more important concerns are efficiency and payback. How many months will it take to break even with a tankless water heater?

Upfront Costs

The upfront costs for a tankless unit are greater than a tank. Besides the unit cost you may have other costs such as:
dollar

1. Gas Line Size - Tankless models that produce output for more than one source will need a gas supply line 3/4" inch or greater. This is an added cost of redoing the supply line for your entire house back to the gas meter. Also, the gas line to the house may need to be updated as well.
2. Water Supply Lines - Some tankless models that produce output for more than one source will need a water supply line 3/4" inch our greater. Updates to the water supply lines may need to be updated.
3. Water Valves - The tankless models also need the recommended water supply valves. These valves usually do not come with the unit.
4. Discharge And Intake - High efficiency models can get their air and discharge their gasses right out the side of the structure. However, there are certain building codes that require discharge and intake to be away from items like windows and doors. Location of the unit is critical as you will have to figure out the costs of where the discharge and intake can be placed. Going vertically up a chimney will cost more than horizontally out the side.

Efficiencies

A good rule of thumb on the tankless is to find one that is greater than 80% efficient.
Tankless water heaters are labeled as energy star as they only use fuel as needed.
Tankless water heaters also have the ability to use less energy during normal use as well. However, this would be based on how long the user uses the device and within reason.
Tanks usually have an efficiency curve. As they become less efficient as the older they get. This is caused by sediment build up in the bottom, burner wearing out, thermostat failure, hard water, and or anode tube failure. With a tankless proper care and maintenance is also required.

Longevity

With proper maintenance the tankless can last as long as 20 to 25 years. This is about double the life span of tank. The only issue is that there are more electronic gadgets inside a tankless that can make maintenance and diagnosis more expensive. However a side benefit is that if a part fails in a tankless, like the heat exchanger, it can usually be replaced instead of the whole unit. Tankless water heaters are more modular and parts can be changed out before purchasing a whole new unit. This also allows the tankless manufacture to add a longer warranty to their units.

Installation Location

Tanks take up a large amount of space and need a larger area. However, with tankless units they are able to be placed in small closets, outside the home, and or garage. However, when considering a location look at the costs of installing gas and water lines to the unit. Also, consider the air inlet and gas outlet location as there are building code requirements to follow.

I don't think I can afford a tankless. Now what?

If you cannot afford a tankless now and you do not need a water heater right away then I'd say save your money and wait. The tankless costs will keep dropping and as you wait you can look for a quality plumber to install one. As I mentioned before I waited for sometime to get a tankless as I was not about to throw out my six year old tank to get a tankless. Be patient and shop around.

I think I can afford a tankless but I want to get more information.

This is a good approach. Tankless units are not for everyone and they are definitely not an item in which you would want to change your mind on. Here are some personal traits to consider before deciding.
Do not get one if you...

If you have a fear of new technology.
If you would find yourself being extremely frustrated that your hot water supply would be disrupted for a short amount of time.
If waiting longer for hot water would be an issue (15 - 30 seconds longer depending on model).
If you are planning on moving soon. However, it may help you sell your home faster by having energy efficient appliances.

Do get one if you ...

If you want to use less energy on hot water (within reasonable use).
If you love new technology.
If you can be patient with a new way of getting hot water.
If you want an endless supply of hot water.

I can afford a tankless and I am ready to get one. What if I dislike it?

If you dislike the tankless you can always go back to a tank. I am sure your installer will not have a problem charging you again for redoing the piping and installing a tank. However, I would think a lot about placement of the tankless and make sure that if you do go back that the piping could be easily redone.

I used this rule when making my decision. "If I did not like the tankless water heater or it did not save our family money, I could sell the unit on <web site for selling products here> and get part of my money back." E-bay is a great place to sell unwanted products and a good place to research costs on tankless water heaters.

Who should think about getting a tankless?

If you are building a new home and the utilities are not setup up yet.
If you already have the proper sized pipes installed.
If you fulfill #2 and your tank is close to the end of it's life.
If you are remodeling and you are planning on updating your plumbing and or updating your furnace and water heater.
If you are needing extra hot water that your tank cannot keep up with.
If you are looking to help the environment and use less energy and are not so concerned about up front costs.

My personal experience

It took sometime to choose a tankless, as I mentioned before, I was not going to get rid of a perfectly good tank. However, our tank did have a issue with it for as long as I owned it. The problem was that the thermostat would not work correctly. If the tank did not get used for 24 hours the water in the tank would turn cold. I did not mind this as I knew that I was using less energy and I could deal with this annoyance. When the tank turned eleven years old I started looking for a new hot water unit (tank or tankless). We settled on the Rinnai R53i (2007 model) to replace the tank. Our unit came with a digital control unit that I placed on my wall next to furnace thermostat. The digital readout shows the output water temp that you can adjust up to 140 degree output. Ours is always set to 110 as it's about the right temp for bath water and soaking dishes. One small issue that we have had to adjust is that it is not that practical to always run hot water when you wash your hands. The faucets in our house are single handle so even when we are not wanting hot water the single faucet design is too easy to be set to hot water or a hot/cold mix. This turns on the tankless too often. As we remodel we will go with a dual design faucet. We spent around $1,200 (around $800-$900 today) for the tankless unit and the valves. Other costs involved in the installation was a flex gas line, copper pipe and fittings, black pipe and fittings and labor. Since I knew the installer and helped out so I was able to get a discount on labor. Also my water and gas pipe were already sized correctly for a Rinnai tankless water heater. The total cost for everything was probably close to $1,500 minus a $300.00 federal energy tax discount.

My experience after installation are...

We see a slight increase in getting hot water to it's destination. It's not bad but we still notice a difference.
The sandwich effect is minimum as it has not bothered our family enough to be an issue.
The low flow effect has never been an issue for us and I have never noticed the unit not kicking on when we need it for small jobs.
This unit handles multiple uses just fine as we never had an issue with the unit not producing enough hot water.
The unit has worked great in the middle of winter in Michigan with temps in the single digits. We have never noticed a difference that the unit cannot keep up with the cold water coming into the house.
The tankless needs electricity to run the blower for pushing C02 gas outside and igniting the gas. However, if electricity would fail we have a generator that will run our furnace and our tankless just fine.

Our bottom line...

I see our gas usage has stayed about the same. However, that is not a bad thing as we had a new baby in first month of 2008 and with a new baby means more laundry, more dishes, and more baths. Also, I mentioned that the thermostat on our tank never kept the water hot over a period of time and so we were not using a fully functional water tank to begin with. There is no doubt we are using less energy for this tankless however, it is hard to gauge payback unless your life is not changing like ours. I am confident that if you do not over use the tankless you will see a drop in gas usage.

The last benefit

One last personal benefit for the tankless is, in theory, the tankless should never rust out and cause a major leak unlike a tank. This is also a benefit from having a tankless as you should never have to come home to water poring out the bottom of a tank.

Helping to Make A Decision
Hopefully you are getting some good information from this article as I wanted to not make this article too biased towards tankless water heaters. So to help give you more information in making a decision I thought I would give more on-line and publishings as well. Consumer Reports has an article on Tankless models in their October 2008 issue. They don't really rate any models but they do have some listed models and some good information in making a decision about getting one. What I found interesting in the article is that the model in picture is a Rinnai R85 but they never mentioned it in the article. I wished they would have put the tankless units together and rated them instead of trying to comparing them with a tank. As you can tell from this article it's hard to compare tanks vs tankless as apples to apples.

If you have any questions and or comments please feel free to ask as I will provide a Q & A as needed.

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