How to Install a Hybrid Water Heater – Basic DIY Installation Tips

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If you are planning to install a hybrid water heater yourself and looking for an easy-to-use guide with DIY tips you have come to the right place. This DIY installation guide is for beginners and handymen with some plumbing and electrical knowledge.

The DIY installation comes with many benefits, including savings, the ability to work at your own pace, and using tools that are available to most homeowners.

Note: Before you start replacing an old water heater and installing a new hybrid one, make sure to turn off the electricity and water supply. If you have a gas model, turn off the gas supply too. Safety first.

Also, check with your city/township building department if you need a permit.

Where can I install my hybrid water heater? Can I install it outside? How about a garage, basement, or attic?

The best location for hybrids is near the center of the water heating system or close to the most demanding application.

Hybrid water heaters are electric devices designed for indoor use only and should not be installed in cold and unprotected areas and in smaller rooms with insufficient space and air supply. They are designed to draw heat from either surrounding indoor or outdoor air.

Hybrids can be installed in garages, basements, laundry rooms, and attics but must be protected from lower temperatures, potential water leaks, and property damage. Your new water heater needs to be placed in an unoccupied space to operate efficiently, meet the minimum volume requirement and have air temperatures between 40 and 90 F, which is ideal.

Hybrids are recommended mostly for areas with mild climates and where the surrounding temperature is over 34 F but does not exceed 145 F. Still, check your unit’s specs.

In cooler climates, hybrids should be installed in basements near the furnace or boiler to take advantage of the surrounding warm air. Another great benefit of installing a heat pump in the basement is the ability to remove the moisture and reduce humidity since the unit acts as a dehumidifier.

Only heated garages can provide enough heat for efficient operation in colder regions. But be careful there since the water heater uses electricity to remove the heat from the air so that it might cost you more.

In warmer climates, a garage is often warmer than any other room, so placing a water heater there would make sense.

If the unit cannot supply you with sufficient heat, installing a backup heating source would solve the problem.

Installing a hybrid unit close to the bedrooms and living spaces is also not recommended due to the noise it makes.

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How much space does a hybrid water heater need?

An average hybrid water heater with the capacity of 50 gallons, such as the Rheem ProTerra, comes with a size of 62” x 22” and weighs approximately 180 lbs. They are very similar to electric water heaters but with an addition of the heat pump on the top, making them taller than a typical tall electric unit.

Most manufacturers recommend approximately 100 sq. feet or a ten by ten room, with a height that can accommodate a tall unit. That means crawl space, attics, and rooms with a low ceiling are not suitable for this installation.

Installation requirements 

For the installation requirements, check the manufacturer’s instructions.

Here are some important things to consider:

Due to similarity with the electric water heater, hybrids can usually be plumbed at the same spot and might require slight adjustments to plumbing and electrical connections.

Most hybrids, such as AO Smith Voltex, require a 240 VAC single phase and 25-amp power supply.

To operate effectively and without ducts, hybrid units require at least 700-750 cubic feet of surrounding air space and with no additional ventilation required. If the unit is installed in a smaller room, a proper connection to the adjacent room must be provided. Installing louvered doors, for example, would allow your heater to pull the air from the nearby room.

If the hybrid is ducted, it can be installed in any room size as long ducted to the outdoors or has adequate space. Also, to ensure ideal performance and efficiency, hybrids require at least 6 inches of clearance at the top, back, and sides and 12 inches at the front of the unit.

Note that some hybrid water heaters won't turn on the fan if the minimum incoming water temperature is not met, including the minimum and maximum air temperatures. In the case of a problem with the unit, an error message will be displayed.

Required tools and material

  • Hacksaw or pipe cutter
  • Adjustable pipe wrench
  • Multimeter
  • Pliers
  • Screwdrivers
  • Measuring tape
  • Level
  • Copper pipe
  • Copper fittings
  • Solder material
  • Torch
  • Drain hose for draining
  • Dolly cart
  • Electric tape
  • Teflon tape
  • Wire nuts
  • PVC pipe and connectors for condensate
  • PVC glue
  • Drain pan
  • Shutoff valve

Installation tips

  • Remove an existing water heater (use instructions below).
  • Clean up the spot and prepare it for a new installation.
  • Place your new hybrid water heater. Use the same location as the previous unit and set it onto the drain pan.
  • Connect the plumbing using unions and install shut-off valves for easier service, maintenance, and replacement (if not already installed). Flexible connections, such as PEX, are recommended.
  • Provide a proper condensate and TPR valve drainage. Use a rigid or flexible pipe with a downward slope for proper drainage.
  • Fill the tank. To start the process, make sure a drain valve is closed, and a shut-off valve is open, so cold water can freely enter the tank. Open a nearby hot water faucet to allow air to escape the system and prevent future issues. Also, your water heater must be full of water before running the unit; otherwise, it can get damaged (dryfire).
  • Connect electrical wires to the junction box. Once you reconnect the power, turn the breaker switch on.
  • Run the unit. Set the thermostat to 120 F to activate the unit. A water heater filled with water and free of any codes on the control panel means everything is running smoothly, and it’s a matter of time when you will get hot water.

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It is not hard to remove an existing water heater, but due to its weight, it requires a hand truck and another pair of helping hands.

Here is a step-by-step guide on how to disconnect an old unit:

  • Turn off the power at the breaker box.
  • Drain all the water from the tank. If not sure how, use this guide.
  • Shut off the water supply.
  • Disconnect your water heater from the household plumbing.
  • Disconnect all the wires, but first, double-check that there is no electricity.
  • Once the old unit is removed, make sure to prepare a site as described above.
  • Bring your new hybrid water heater in and make necessary changes if needed. Follow the instructions and make sure there is required clearance around for the proper air intake and filter service.
  • As opposed to typical electric water heaters, hybrids require condensate disposal. The drain lines must be pitched downward, away from the unit, and into the suitable drain. If not, a condensate pump must be used.

If you don’t know what to do with your old water heater, check out these ideas.

Tip: Some hybrid water heaters have side water connections, so if it is different from your old unit, you need to make necessary changes according to the local codes.

Other things to consider when installing a hybrid water heater

If this is a new installation with a closed water system, you need to install a thermal expansion tank to prevent excessive pressure buildup.

Temperature and pressure relief valves – T&P with the discharge pipe is required by the code, and they are used to prevent excessive pressure buildup inside the tank.

In order to prevent scalding burns, install a mixing valve that ensures safe water temperatures anytime.

Install a drain pan under the water heater to collect any drippings and protect the property from damages due to condensation or leaks. A drain valve should be two inches wider than the heater and piped to the drain. If required by the code, secure the unit with the seismic strapping.

If water heating pipes are exposed to low temperatures, insulate the pipes using foam sleeves or any other approved type.

Important: Never run your water heater if the tank is not full of water; otherwise, you’ll risk heating elements dry fire. Once the tank is filled with water, check for leaks, and open the nearby hot water faucet to let the air escape.


Hybrid water heaters are expensive, so as the installation. Expect to pay at least 25% more than for the standard electric type. While installation costs depend on many factors, including the location, labor cost, material, brand, or model, hybrid installation can cost you between $300 and $1500 on average.

Need help?

If installing a hybrid water heater is too complicated for you or you don’t feel confident working on the electrical device, don’t worry; you can always call for professional assistance.

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