Water Heater Heat Traps


Looking for ways to reduce your electric bill each month? A heat trap is a super simple way to retain about 60% of the heat from your water heater which in turn will reduce the amount of electricity required to heat your tank. In some states and local ordinances, these traps are now required because of their ability to save electricity.

In this article, we will be taking a look at what a water heater heat trap is, how it works, and recommended places to purchase one. We will also take a look at a few troubleshooting solutions to the most common issues someone with a heat trap may face. Let’s get started!

What Are Heat Traps?

In a water heater, cold water flows down the dip tube into the bottom of the tank where it will be heated by either a gas burner or an electric heating element. As the water is heated it moves towards the top of the tank where it will stay until you are ready to use it. When you open a faucet, the hot water is pushed out of the tank and more cold water is brought in by the drip tube.

Naturally, since cold water is heavier than the hot water that migrates to the top it stays in the bottom of the tank until it is heated. Any water left in the pipes will cool and some will sink back into the tank. Since this cooled water is heavier it will sink to the bottom cooling some of the other preheated water on its way down.

Because the inlets and outlets of a water heater are not sealed some of the heat escapes through these openings and this is part of the wasted electricity. Since escaping heat means that the hot water won’t stay hot for as long, it must be reheated again.

A heat trap is a simple pipe attachment that sits at the outlet of the water heater keeping the cold water from disturbing the preheated water until more water is needed. These heat traps can be homemade or purchased and come in many different styles:

  • U-shape
  • Loop Hose
  • Ball Style
  • Flap Style

The type of heat trap you will need depends on the type of water you have and your budget. It may also depend on if you decide to do this project alone or if you decide to hire a plumber to help out. Let’s take a closer look at the types of traps and how they work.

How Do Heat Traps Work?

When a water heater has to reheat water or the heat escapes from the tank it uses a lot of extra energy. The use of a heat trap lessens the times the water heater has to turn on to reheat water thus saving you money on your electric bill.


If your water lines come out of the top of your tank and turn off to the sides of your tank you will need to use a u-shaped attachment. This is a simple u-shape that attaches about an inch from the tank and hangs off the side of the tank keeping the cold water in the lowest part of the U. This trap is attached to the outlet of the tank. It keeps the cooled water in the pipes from back flowing into the tank and having to be reheated. This type of trap is the most simple and can easily be made at home if needed. These attachments are generally made out of copper pipes.

Loop Hose

Another type of attachment is a flexible hose that is attached to the outlet of the water heater and creates a loop above the tank. This type of trap is attached to the outlet of the tank and keeps the cold water in the lower part of the loop. The cooled water is unable to flow back into the tank and requires reheating. The loop is made from a flexible hose or bent from the preexisting copper pipe.

Ball Style

Newer types of water heaters may come with this type of heat trap already installed. This type of heat trap uses a small metal ball and a chamber generally made of two different types of metal to avoid erosion and wear and tear on parts. In this type of trap when a faucet is turned on the ball is pushed up in the chamber allowing water to escape out of the tank. Once the faucet is turned off the ball falls back into a gasket in the bottom of the chamber. This type of trap not only keeps water from back flowing into the tank but also seals extra heat from escaping the tank. These types of traps cannot be made at home and must be purchased from a hardware store.

Flap Style

The flap-style heat trap is widely recommended by plumbers and if you hire a professional to install one of these traps the flap style is most likely what will be installed for you. This type of trap works the same way as the ball style, it has a flap located inside the pipes and it opened when pressure is pushed on it and closed when the pressure recedes. The reason that most plumbers prefer this style of trap is that it doesn’t make a noise like a ball style, is easy to install, and can be purchased cheaply from a hardware store.

Where Can You Buy A Heat Trap?

Since heat traps were originally made by plumbers on sight many years ago as a trick to reduce waste many of the original ideas were thrown out and redesigned.


The U-shape for example is not something you will be able to find in a store but it can easily be made by leftover copper pipe you may have lying around, this is a great option for someone who doesn’t have the extra cash to purchase a premade heat trap but could use the reduction in their electric bill.

You may even see this type of trap on an older water heater if you’ve recently purchased an older home that hasn’t yet been renovated.

Loop Hose

The loop style is another style you may not be able to find easily in store but it was created alongside the u-shape when heat traps were becoming more popular. I did some digging and was able to find a really good loop-style trap with Supply House, an online supplier that can also be used for individuals.

If you are limited on space, a flexible hose can be used to create your own loop. Holdrege's stainless-steel water heater connector comes in several different sizes and the price varies depending on size.

The ¾” copper loop they have manufactured by Sioux Chief holds a four and a half star rating and is recommended for its easy-to-install style. This loop is retails for less than twenty dollars as of now. You can check out the reviews and purchase this loop here.

These connectors are reviewed to have extremely good flexibility and amazing quality. They also have a lifetime warranty.

Ball Style Heat Traps

The ball style is slightly easier to find because it is a newer design for heat traps. They're also fairly cheap at less than 15 bucks and work quite well. Click here to check current prices.

Flapper Style Heat Traps

Camco makes this great flapper-style trap that has a dielectric insert that is meant to help corrosion on galvanized metals. You can find this style of heat trap for less than fifteen bucks here.

Troubleshooting Heat Traps

Just like with any project, you may run into a few issues when installing your new heat trap, let’s take a look at some of the most common ones you may face.

Flow Restrictions

Sometimes when installing a ball-style heat trap you may notice lower pressure coming from your tank. This is generally caused when a ball can not move freely and becomes trapped. This is usually caused by a small mistake during installation and can easily be fixed by reinstalling the ball and ensuring no debris is present inside the attachment.


Another common problem is small leaks coming from your new trap, this is also most commonly caused by incorrect installation or sometimes a faulty trap. Remove the trap and inspect it to be sure it isn’t faulty and reinstall.


Blockages occur in many parts of the water heater and the heat trap is no exception. If you have hard water, you are more than likely to develop calcium buildup at some point or another. Adding softener to your water can lessen the likelihood of having this problem. However, if it does occur in your water heater be sure to check your trap too!

Heat Trap Installation Tips

As mentioned before just about anyone can install these heat traps but there are a few things to note before taking on this project.

If you have absolutely no experience at all with plumbing, please don’t attempt to install the u-shape or loop style unless you are using the flexible hoses mentioned above. The copper must be bent and sautered with these styles and should only be done by professionals.

The ball and flap styles are the easiest to install and can be done by just about anyone. Before you begin a few of the supplies you may need are:

  • Your desired heat trap
  • Teflon tape or joint compound
  • Pipe wrench
  • Towels
  • Bucket
  • And of course, this guide

Once you’ve gathered all the materials you should locate and turn off the breaker switch to the water heater. You do NOT want to get electrocuted especially around all this water.

You’ll need to drain about 2 gallons of water from your tank to access the pipes needed to install the trap. There are two ways to drain your tank, the relief valve or the drain valve, this is where the towels and bucket will come in handy.

Use the instructions provided with the traps to install them properly and use Teflon tape to ensure a good seal on the pipes and prevent leaking. It’s important to remember that the blue tape should be used for the cold-water side and the red tape should be used for the hot water side.

If you are using a joint compound instead, apply a thin layer of the compound to the threaded side of the nut and be sure to coat all of the threads. Joint compound generally takes 5-10 minutes to set but you should read the container to be sure.

Now, you can use your wrench to tighten up the nuts but remember not to over-tighten them. Be sure to use your wrench only on the thick part of the nut and not on the threads, this can damage and strip them making it impossible to properly tighten them.

Finally, you can go switch back on the power and enjoy your finished home improvement project!

Dielectric Heat Trap Installation

Water Heater Heat Trap Installation (Dielectric Heat Trap)


Saving a few dollars each month on your electric bill adds up at the end of the year, installing a simple heat trap on your water heater may help you save those dollars.

It’s a very easy-to-install project that should only take about half an hour depending on your skill level however, even the most inexperienced handyman or woman can accomplish this project. There are several different styles to choose from so you’re sure to find the right one for your style!

So, should you install a water heater heat trap? Absolutely! There is no reason a homeowner shouldn’t look for easy ways to save money. You can also insulate the pipes of your water heater to create even more savings. Be sure to share this project with a friend and help them save money!

B. Boyer

I love learning about water heaters, especially repairing and diagnosing water heater problems. I started this water heater website to help others fix, repair and diagnose water heater problems.