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What’s the Difference between Condensing and Non-Condensing Tankless Water Heaters?


Get the Facts

  • Heating water accounts to about 30% of the average homes energy budget.
  • Tankless water heaters only provide hot water when needed saving you 40% on your energy bill.
  • They also produce more hot water, at a more consistent temperature.
  • Since a large amount of heated water is not stored, it cannot be depleted giving you continuous hot water even when running multiple appliances.
  • Tankless water heaters are a fraction of the size of standard heaters and can be installed on any wall.
  • These heaters also have a 20 year life span.

Understanding Tankless Water Heaters

Tankless water heaters are gaining in popularity and manufacturers are listening by offering new improved models. Tankless Water Heaters as the name insinuates do not have water storage tanks like traditional water heaters. In the tankless water heater, water is heated as it flows through its heat exchanger, which is heated through combustion. Combustion burn the hydrogen content of the fuel and produce hot gases. Steam or water vapor is one of these gases. When these vapors cool it becomes condensation. This condensation is different than what you might find on a drinking glass as it is corrosive. The combustion process fuel that is burned creates and energy that is used to heat the water. Lets explore the differences between condensing and non-condensing tankless water heaters.

Condensing Tankless Water Heaters

These water heaters extract heat from exhaust gases through different means and produce cooler gases around 100 degrees Fahrenheit. These cooling gases produce condensation inside the unit. The efficiency of the unit goes up because you can use cheaper ventilation materials as the gases are cooler. By capturing the residual exhaust heat to heat the water, the unit has achieved a higher efficiency. There are factors that need to be taken into account with this unit as it may not always condensate. Surrounding air temperature and air humidity can affect condensation. Since the exhaust gases have cooled inside the unit, the condensation is now inside the unit as well. This is where the heat exchanger comes into play. This part must be made of better materials to withstand the corrosive nature of the gases. These are usually made of stainless steel alloy. The collected condensation needs to be fully neutralized before it can be drained outside. This is usually done by special fertilization or dilution.

Non-Condensing Tankless Water Heaters

 Much like a condensing tankless water heater the non-condensing tankless water heaters will push the exhaust gases out a vent to the outside. They will cool outside the unit. These gases are around 300 degress and need special materials for the venting to withstand the temperatures and not corrode. These materials are usually very expensive.
View our Selection of Water Heaters Here.