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Are you trying to decide whether a traditional tank or a tankless water heater is best for your home? If so, there are plenty of things you should consider when making this important decision. Here, we’ll go over some of the pros and cons of each type of water heater to help you make an informed decision before you start shopping.

How do tank and tankless water heaters work?

Traditional water heater: This water heater stores and preheats between 30 and 50 gallons of water inside a tank. This preheated water is used every time someone takes a shower, runs the dishwasher, does laundry, etc. When some of the preheated water supply is used, the tank refills itself and heats the water again so that there is always a reserve available for use.

Tankless water heater: A tankless water heater is different in the way that it uses a source of heat, either electric or gas, to heat up or cool water as needed. Rather than storing preheated water within a tank, the water is heated as you need it. 

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Tankless Vs Tank water heaters – Pros and Cons

Tank water heater

tank water heaterWater Heater “After”, by Brian Cantoni on flickr [CC BY 2.0]


  • One benefit of having a traditional water heater is the lower initial installation cost. Traditional water heater installation can be as little as half the cost to install a tankless water heater. Along with cheaper installation, traditional water heaters are also easy and inexpensive to replace. If anything ever goes wrong with your water tank, it is much easier to replace or have maintenance done to it, and you can do the majority of the maintenance yourself – you would only need to pay for replacement parts. 


  • Traditional water heater tanks run out of hot water. If you have ever been the last in your family to take a shower, this is a familiar and dreaded experience. However, if you find yourself running into this problem, it can easily be resolved by purchasing a larger tank. This will allow your heater to store more preheated water so that it is readily available when you need it, and less likely to run out. However, this will increase your energy and water bills, due to more water being heated.
  • Another con of traditional tank water heaters is that they typically have higher utility bills, due to the inefficiency of the water heating process. This type of water heater is consistently heating your water no matter what your needs are, and there isn’t any real way to regulate how much water is heated. This can greatly increase your utility bill, especially in the winter. You are able to control the temperature of the water, but it takes time to adjust the heating temperature. This leaves little control over regulating your water and electric utility bills.
  • Finally, traditional water heaters have a shorter lifespan than tankless heaters. They usually last for anywhere between 10 to 15 years if they are taken care of and regular yearly maintenance is performed. This means you will have to purchase multiple tanks over time, which could add up to the initial cost of a tankless water heater. Traditional water heaters are also bigger and therefore take up more space, so you need to make sure you have dedicated space for yours to be installed. 

Tankless water heaters

Tankless water heaterstankless hot water heater installation 004, by Roger Mommaerts on flickr [CC BY-SA 2.0]


  • This type of heater offers hot water on demand, so you determine when you need hot water, and how much you need. They generally provide two or three gallons of hot water per minute as needed. This helps save money on your water and gas utility bills, as it provides more control over how much energy is being used to heat the water. Energy.gov points out that homes using 40 gallons or less of hot water can be 20 to 30 percent more energy efficient than homes with conventional tank water heater units.
  • Tankless water heaters last much longer than traditional varieties. They can last for more than 20 years, which is nearly double the lifespan of traditional water heaters. Also, since tankless heaters are smaller – they don’t take up much space at all – they can be easily installed in more places. This is great for small homes or apartments.


  • One con of having this type of heater is the higher cost of installation. It can cost anywhere from $2,800 to $4,500 to install a tankless water heater, including the unit itself. Of course, the price depends on the model you choose and where you purchase it from.
  • Tankless water heaters don’t have the same flexibility as a tank water heater, and it’s usually quite difficult or impossible to have multiple tanks running simultaneously. A solution to this is to look at bigger tankless units that consume and preheat more water.
  • Another con to consider with tankless are the fluctuations in water temperature that owners experience when momentarily closing and reopening a hot water source. This is known as the cold-water sandwich effect. When the hot water heater is in use, and then the hot water source is shut off, the water in the line starts to cool. This creates a momentarily unpredictable water temperature when a hot water source is opened again. You can learn about the cold-water sandwich effect in this short video

Deciding on which type of water heater is best for you will depend on several factors, such as how much water you plan to use, your lifestyle, and your budget. If the initial cost of a tankless water heater is not out of reach, it could save you money in the long run. Yet a traditional water heater is best for those on a tight budget, and the easy and affordable replacement options make it appealing. For more information on all types of water heaters, visit h2ousegeek.com

Tankless vs Tank water heater : Everything You Should Know was last modified: July 6th, 2019 by h2ousegeek

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