The Pros and Cons of a Tankless Water Heater

The Pros and Cons of a Tankless Water Heater

A tankless water heater can be a wonderful addition to a home. Instead of continuously storing hot water, tankless units heat the water when the faucet is turned on. These units are also called 'on-demand,' or 'instantaneous' water heaters. However, this type of water heater is not for everyone. Take a look at the pros and cons of an on-demand water heater to decide if this kind of water heater is right for you.

finger touching water heater

Pros and Cons of an On-Demand Water Heater


  • The Department of Energy states that for homes that use no more than 41 gallons of hot water a day a tankless water heater can be up to 34 percent more efficient than a traditional water heater.
  • In general, an instantaneous ENERGY STAR® qualified water heater will save the typical family $100 (or more) a year.
  • There are electric, propane and natural gas tankless water heaters.
  • By offering a continuous supply of hot water, these units are perfect for filling up a large whirlpool or garden tub.
  • Instantaneous units are much more compact than conventional water heaters.
  • Due to their smaller size, these water heaters can be mounted on a wall.
  • According to the Department of Energy, an on-demand unit can last 20 years (or more) and a conventional water heater with a storage tank usually lasts from 10 to 15 years. Replacing parts on an instantaneous unit is easy, which extends the life of the unit even more.


  • The upfront cost of the unit.
  • On-demand water heater installation is expensive.
  • Due to its high-powered burners, special venting systems are necessary with on-demand water heaters. Units that operate on natural gas frequently need a larger diameter gas pipe, which increases the cost of installation.
  • Smaller units cannot produce the amount of hot water needed in most households. These smaller units can only serve one faucet at a time.
  • Larger tankless units have the ability to provide sufficient water for an entire family. However, these units are much more expensive than the smaller units are.
  • If an on-demand water heater turns off following a task and you turn the hot water back on a few minutes later, you may experience a 'cold-water sandwich.' The hot water that remained in the piping after the first task will flow out and then cold water flows past the water heater before the unit is triggered to turn back on (Hot - Cold - Hot).

Whether you need an existing water heater repair or a new water heater installed, contact Stahl Plumbing, Heating & Air Conditioning today. Let our experienced professionals solve your problem quickly and efficiently. If you need assistance right away, please call 412-273-1000. At Stahl Plumbing, we offer emergency services 24/7.