Water heater research

How Tankless Water Heaters Work

(Last Updated On: April 13, 2020)

how tankless water heaters workThe idea behind the tankless water heater is that it heats the water coming into your house as you need it without it heating water held in a tank continually. They save energy, and money, without it being lost for standby operation. Cold water is drawn into the heater when the hot tap of a sink or a bath is turned on, where a flow sensor activates the gas burner (or equivalent), which warms the heat exchanger.

The incoming cold water then circles around the heat exchanger and then leaves the heater at a set temperature. A sealed and dedicated venting system will take care of any combustion gases generated by the heater.

Benefits of the Tankless Water Heater.

  1. Instead of maintaining a full tank of water being heated at all times, tankless water heaters are more energy efficient.
  2. Certain companies manufacture water heaters that feature a secondary heat exchanger that uses 9 or so % than conventional tankless water heaters.
  3. On demand only – they only heat water when it’s needed.
  4. Tankless systems come in two varieties, the point of use is small, and heats sinks. Their size means they can fit inside a cupboard, and their closeness to the outlets means the water won’t cool down. The second variety is the whole house heaters.
  5. Comes in various types; gas, electrical, propane, or natural gas. The gas and propane powered models will give out more power than the electric models.
  6. Increases your homes value with the use of premium and energy smart technology.
  7. Some heaters feature copper for maximum heat efficiency and uses upto 40% less energy than a traditional tank.
  8. They take up less space than traditional tanks, and they never run out of hot water.
  9. The tankless water heaters last longer than tank heaters.
  10. No potential flooding if ruptured.

Drawbacks of Tankless Water Heater

  1. They can cost up to three times as much as a traditional tank heater, so that’s something to consider.
  2. The hot water output is split among the fixtures of your house that demands its use – the shower, the bath, the hot water taps, water radiators etc.
  3. If you’re using a gas powered heater, you might need a larger gas line to supply the unit with the fuel to power the heat exchanger.
  4. Venting (gas & propane) requires expensive stainless steel tubings to work properly.
  5. Additional circuits might be needed for the electrical models.
  6. Greenhouse gases with regular gas powered heaters.
  7. Lag time might occur with whole house heaters.

What are the other things to consider?

How much can water heating cost? It’s around 20% of your home’s budget. Buying a tankless water heater isn’t an easy choice besides the benefits it brings to your door. An electric whole house heating unit can cost $500-$700, even if its installation is far cheaper, whereas the gas models which are expensive to install, can cost much higher, at around $1,000 or at $2,000 depending on the model you’ve chosen.

The good news is natural gas is less expensive now than it used to be, and is expected to surpass electricity in the coming years.


Tankless water heaters have many benefits to homeowners. They might be more expensive to buy and install, but in the long run they can provide your home and family with less bills. The best thing for you to do if you decide to follow the advice and information provided will be comparing the Energy guide stickers on your current system and the tankless model that suits you the best – type, power system, etc – then weigh the costs of getting a tankless unit into your home. Then figure out the costs itself, and the payback period – the amount of time to make the money back – might take a little time, but it will get there.

You can read our reviews for tankless water heaters at tankless.reviews!

Tankless Reviews was created with the goal of helping people to understand the benefits and practical knowledge related to tankless water heaters. After purchasing my very first tankless heater years back, I realised that other people needed to hear about the incredible money-saving ability of this household item, and wanted to share my lessons with you!