How to install Heat Traps on Water Heaters - Instructions

What are the heat traps, installation tips, and problems that can affect comfortable water heating?

Heat traps and thermosiphoning

Heat trapsHeat traps

Heat traps are elements installed on the electric and gas-powered water heaters and are used to prevent heat loss from inside the storage tank when the flow stops while increasing the overall efficiency.

The heat energy is lost through the thermal expansion when hot water from the storage tank rises through the cold water inlet (dip tube) and out through the plumbing.

This is also known as natural convection and thermosiphoning. The heat dissipation process can be tested by touching the cold water inlet, and if it feels warm or hot, the thermosiphoning is in action. That means either the water heater does not utilize the heat traps; heat traps are broken or improperly installed.


Today, most tank-type water heaters such as Rheem, AO Smith, State, American, Bradford White, and others are equipped with two heat traps (hot and cold pipes) to increase energy efficiency, while those without can be retrofitted. The most used types are with the metal nipples with the flaps or balls inside.

The heat traps with the flaps are better due to the smaller size and quiet heater’s operation, while the ball type can usually get stacked and reduce water flow.

Some plumbers prefer making the heat traps by bending the pipes into a U-shape, also known as a gooseneck. The most frequent problems related to the heat traps are flow restriction, lack of hot water, and noise, especially if you have a recirculation loop. Shaping the pipe into a gooseneck has its advantages over the factory-installed one; there are no moving parts that can get stuck and reduce the water flow.

Installation instructions

If you require professional assistance, contact your local water heater expert! Get FREE estimates here

  • Turn the power off to the water heater.
  • Drain approximately 2 gallons of water on the drain valve or relief valve.
  • At the top of the water heater, remove the pipe connecting nuts from the pipe nipples using the pipe wrench.
  • Apply Teflon tape or joint compound to the heat trap before making connections and insert the heat traps into both hot and cold pipes.
  • Use the pipe wrench on the steel body of the element, not on the thread.
  • Reinstall the connecting nuts onto the pipe nipples.
  • Never apply heat directly to the fitting if the pipe connecting nuts are sweated onto the pipes.
  • Recommended are those heat traps that have a self-cleaning fitting or dielectric inert thermoplastic lining that prevents corrosion. They have a color-coded cold inlet (blue) and hot outlet (red).
Find Trusted Plumbers & Get Free Quotes