Top 10 Things You NEED To Know About Tankless Water Heaters

Tankless water heaters have changed the plumbing industry since their inception in the 1860’s. Yes, you read that right. The first water heater was patented in 1868 ( ).In the 1890’s inventers were already experimenting with tankless water heater designs. Since those early days, both tankless and tank-type water heaters have only improved in design, efficiency, and popularity. For most people, tankless water heaters are a better fit for the house and the lifestyle they live. Unfortunately, the miracle of a tankless system isn’t the most reasonable system for every home. If you’re considering installing a tankless water heater, read this first.

1. Why are tankless water heaters called “instant hot water heaters”?

Tankless water heaters are sometimes called “instant water heaters” or “on demand water heaters” because they heat water so quickly. As soon as hot water is called for (caused by turning a hot water valve on) a burner kicks on, heating water that snakes its way through winding water lines inside of the heater.

Instead of a large storage tank that is constantly heating water to maintain the desired temperature, a tankless system has winding copper lines that allow the water as much time in the system as possible so the burners can have plenty of time to heat the water to the users satisfaction. Once the residual water that has been sitting in the system or in the pipes to the fixtures has been expelled through a faucet,the hot water should start flowing almost immediately. Having immediate access to hot water is one of the reasons that so many people are drawn to the tankless system. The convenience of having hot water makes life easier. Also, the lag time of waiting for hot water to heat up with a traditional system is a waste of water. Cutting down the time you must wait to receive hot water will make your home more energy efficient. If you really want to get as close as you can to instant hot water you can install a circulation pump. The pump works on a timer and water will circulate through the hot loop on a specific fixture or appliance for a few minutes before the set time to make sure the moment you turn the valve, you get hot water.

2. How long will tankless water heaters last?

This a very important factor to consider when looking at any water heater for your home, not just tankless systems. There are multiple variables that can play a factor in determining how long your water heater will last. With proper maintenance and water softening systems, there are stories of tankless systems lasting longer than 20 years. Of course, without proper maintenance your tankless water heater might only live a decade or less.

Quality of water in your area is a huge determining factor. In our part of Texas the water is very hard and contains minerals which are rough for plumbing systems. Unchecked water heaters can have a large amount of calcium, rust, and other minerals that reduce the life of your water heater and harm the rest of the plumbing system. So flushing your water heater can prevent that buildup and allow your tankless water heater to work for its full life span.

Flushing a water heater isn’t hard to do, doesn’t take very long, and produces amazing results. This practice alone can extend the life of your water heater for five, maybe even ten years. Flushing your water heater on a regular basis paired with a good whole-home filtration system can really push that water heater to peak performance and allow your water heater to run for decade after decade. Also, the other benefits of having a whole-home filtration system can include softer skin, healthier hair, and extended life of your plumbing system in its entirety. Learn more about whole-home filters here.

3. Are tankless water heaters really THAT efficient?

Yes. Tankless water heaters really are THAT efficient. They use less gas or electricity and water as well. You get savings from all angles with these systems! The savings of switching from a traditional to tankless will sometime recoup the cost of installing a tankless water heater. The time that takes to happen depends on the price of water and gas/electricity. There are traditional tank-type water heaters that are more efficient than the older models that you may have in your home right now, but the tankless models will always be more efficient. Water heaters have stickers on them that show you the estimated operating cost per year. However, that only includes the gas or electricity, not the water wasted too.

4. Will I have to change my gas system for a tankless water heater?

Possibly. There are many cases in which trying to retrofit a tankless water heater into the part of a house specifically design for a tank-type might not be easy, especially if trying to vent the gas through multiple floors. In the south, specifically very hot states, people can mount tankless water heaters to the outside of the house. They run all the pipes inside the house however, to utilize already existing insulation from the cold, in case of a freeze. Mounting a tankless water heater outside also allows your plumber to find much easier solutions for the gas exhaust problem. These are things to consider talking to your plumber about before taking the leap. Already existing gas lines may need to be rerouted to make the tankless system work properly. Which of course, will increase the price of installation.

5. Do tankless water heaters really give an unlimited supply of water?

Nearly limitless is a better phrase. Obviously you don’t want to turn your hot water on full blast and just let it run forever. But essentially, if you get in the shower after someone, you won’t need to worry if they used all the hot water. You’ll have your own nearly limitless supply of hot water to enjoy on your own. The reason is because with a traditional tank-type water heater, you can actually drain it faster than it can refill and heat up the new water that has entered the system. With a tankless system however, the water line runs from the city straight into the water heater and as it passes through the burner in the system, it gets hot almost instantly.

6. What is the maintenance like on a tankless water heater?

Maintenance is dependent on your water quality, the climate of where you live, and how much use the water heater experiences. If you live in our part of Texas, you’ll probably have to flush your water heater at least once per year just to be safe. We have hard water and those minerals need to be flushed out of the system to keep it running efficiently and to increase its lifespan. Homeowners can have water softeners installed to help the water quality, which might not require you to maintain your heater nearly as much.

If you’re reading this section and thinking to yourself “maintenance on a water heater?” I’m going to refer you to a video we made about water heater maintenance . Regardless of tankless or tank type, you NEED to maintain your water heater. If your water is more than 2 years old and has neer been flushed, don’t start flushing it now, it could cause more damage.

But the actual act of flushing one of these water heaters isn’t terribly difficult. It mainly just involves having the right equipment: a bucket, a circulating pump, and descaling chemicals or distilled white vinegar, ask your plumber what he or she prefers.

  1. Ensure you have flush valves, or a flush kit installed on your tankless system.
  2. Turn off your water heater
  3. Turn off the gas to the heater (if you have a gas system).
  4. Turn off the water to your heater.
  5. Open the flush valves to let water out of the system.
  6. Fill a five-gallon bucket with your anti-scale chemicals
  7. Connect a hose from your pump to your water in line
  8. Connect a hose from your water out back into the bucket to create a loop
  9. Turn on the pump and let the chemical cycle through the heater for 30 minutes to an hour.
  10. When it’s done cycling, reverse the steps listed above.

7. Can a tankless water heater support a large family?

Absolutely. The wonderful “near limitless” water supply we talked about earlier is ideal for a large family. Multiple showers in the morning or evening are a lot easier when you don’t have to worry about draining a storage tank down. It can also help with dinner time, cleaning dishes and laundry, etc. The luxury of a nearly limitless supply of is good for any family, regardless of water usage. But, if you’re always competing with family members to be the first one in the shower to ensure you have plenty of hot water, the switch to tankless might be beneficial for you. As always, every house is different, so to be safe, consult with your plumber before you buy a tankless water heater.

8. Do tankless water heaters save space?

They really do! Tankless systems are much smaller than larger tank-type water heaters. If you home has a place specifically built for a water heater you might not notice the size difference or it might not even be important to you. However, if your water heater is in your garage or attic, the smaller size will definitely be noticeable, and possibly might even make your home a little larger in terms of square footage. To really maximize those space savings you might even consider mounting your tankless system on the exterior of your home. Remember to ask your plumber for their advice on the matter, they may have some good insights as to why that might not be the best option for your particular home.

9. Will I have to buy any other equipment for my tankless water heater?

It depends on your situation. Every home, in every city, in every state is different. Therefore every situation needs to be inspected by a professional to make sure the install will indeed benefit your family. We have been to homes where the homeowners were wanting to replace their tank-type with a tankless system. Upon inspection we noticed that the exhaust systems would have to be completely changed in order to work with a new tankless system. It would’ve made the installation cost almost double the original price. The homeowners instead decided to just get a new tank-type water heater. Their new water heater is very efficient and they are very pleased with their decision. In that particular case they would’ve essentially had to buy a new exhaust system.

For people who really want to take instant hot water literally, they will have circulation pumps installed on showers that are used in the morning and faucets as well, so their morning ritual isn’t interrupted by waiting for hot water. In some cases, water softeners or filtration systems are almost a requirement due to the terrible quality of water in their area. Depending on your situation, adding a whole-home filtration system or a water softener can make your tankless-system close to maintenance free. That is a convenience that many people are will to buy, and sometimes considered a “must” by the homeowner.

10. How much more expensive are tankless water heaters than traditional water heaters?

Again, it depends. Tankless water heaters can range in price from around $800 to over $2,000. Not including the price of installation (and you’re going to want to hire a professional and reputable plumber for the installation. Never take a risk when it comes to natural gas). Small 20 gallon tank-type water heaters can be as inexpensive as $350 and 80 gallon tank-type water heaters can be as expensive as $2,500, not including the price of installation. If a lot of rerouting and other code upgrades have to be done to retrofit the tankless system, the installation will be more expensive. The people who end up buying tankless water heaters see the savings of the system and see how that can offset the initial cost of purchase and installation.


We hope this helped you understand some of the pros and cons of tankless water heaters and helped you think more about if tankless systems are beneficial for you or not. It is hard for us to speak for everyone since every homeowner has a different situation. If you have decided you want to get a tankless water heater, you should express this to your plumber and get a consultation to make sure this system is a good fit for your home. If it is going to be a diffiuclt installation, the savings might not be worth it.

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