How to Add a Power Vent to a Water Heater

Adding a power vent to your water heater is an effective way to improve its efficiency and performance. Power venting uses a fan to actively force exhaust gases out through the vent pipe, rather than relying solely on natural draft. This helps remove combustion byproducts more quickly, while also allowing pressurized fresh air to be drawn into the combustion chamber.

The key benefits of power venting a water heater include:

• Improved efficiency – Positive vent pressure decreases heat loss up the flue.
• Ability to use longer vent runs – A power vent can push exhaust much further than natural draft.
• Flexible venting options – Vent piping can be run vertically or horizontally.
• Reduced risk of backdrafting – Prevents combustion gases from entering living space.
• Higher hot water recovery – More heat stays in the tank rather than being lost up the flue.

However, power venting also introduces some safety considerations:

• Requires electrical wiring for the vent blower.
• Improper installation can result in flue gases entering the home.
• The vent blower must be properly sized for the water heater BTU rating.
• A control switch or relay should be used to activate the blower during operation.

With proper installation, a power vent is a great upgrade to improve hot water capacity and efficiency. Just be sure to take the necessary precautions.

Checking Compatibility

Before installing a power vent on your water heater, it is important to verify that the unit is approved for power venting. Most modern gas water heaters can accept a power vent, but older models may not be suitable.

Start by checking the rating plate on the water heater. Look for statements indicating it is certified for “Power Venting” or “Power Exhaust”. The instructions manual for the heater should also indicate if a power vent can be used.

If the water heater is compatible, you now need to determine the correct power vent kit for the make and model. Power vent kits are matched to the size of the draft hood and other features specific to each water heater brand and model. Refer to the manufacturer website or contact their customer support for assistance in identifying the right vent blower and components.

Providing the heater’s model number and serial ID will help ensure you get a properly matched power vent system. Purchasing a universal kit without verifying fitment may result in performance issues or safety risks if not adapted correctly during installation.

Take the time upfront to confirm power venting compatibility and acquire the proper venting kit to avoid problems down the road.

Preparing for Installation

Once you have confirmed compatibility and acquired the correct power venting kit, you can start preparing for installation. Proper planning and setup will make the installation process smoother.

The first step is to turn off the water supply and power to the water heater. Locate the shutoff valve for the water lines and turn it to the closed position. Unplug the water heater or turn off the circuit breaker that supplies power to it. This will prevent accidental activation during the installation process.

Next, gather the necessary tools and materials:

• Power drill and drill bits
• Hole saw or jigsaw for cutting vent hole
• Screwdrivers
• Pipe wrench
• Adjustable wrench
• Metal snips
• Utility knife
• Caulk and/or high-temp silicone
• Framing materials for vent box (if needed)

You will also need safety gear like gloves, eye protection, and possibly a respirator when cutting into the wall and roofing materials.

The power venting kit will include the vent blower, mounting hardware, vent piping, and electrical connectors. Read through the installation instructions to get familiar with the steps before starting.

Inspect the installation location to determine if any modifications need to be made before cutting into the wall. Make sure there is adequate space to mount the blower and route piping. Survey the exterior to plan where and how to run the vent pipe out of the building. Consider how to make a weather-tight seal between the pipe and roof or siding.

By turning off utilities, having the right tools on hand, and understanding the installation plan, you can setup an efficient workflow. Taking the time to prepare will allow the power venting project to go smoothly.

Installing the Power Vent

With the prep work completed, it’s time to start installing the power venting kit. This involves cutting into the wall, mounting the vent blower, attaching vent piping, and weatherproofing.

Start by cutting a hole in the wall to run the vent pipe through. The hole should be sized to fit the vent pipe diameter with several extra inches for clearance. Cut the hole in a convenient area near the water heater vent connection.

Use a hole saw for a clean circular cut if possible. For larger vents or odd shapes, a jigsaw will provide more flexibility. Outline the hole location and drill a starting point to insert the saw. Cut along the outline of the hole slowly and carefully.

Next, use the provided brackets, screws, or anchors to mount the power vent blower securely to the interior wall or an adjacent stud. Position it so the blower outlet aligns with the vent hole. Attach mounting feet if included with the kit to provide stability.

With the blower in place, you can now connect the vent piping between it and the draft hood outlet on the water heater. Use the included adaptors, couplings, and pipe lengths to assemble the run. All connections should be secured and sealed with silicone, metal tape, or locking bands per the manufacturer instructions. Slope horizontal piping slightly downward to allow condensation to drain.

Once assembled, run the vent pipe through the hole and determine the length needed to reach the exterior roof or wall. Cut to fit, allowing room for elbows and a termination fitting. Use additional silicone or caulk to seal the exterior penetration point around the vent pipe. This will prevent air, water, and pest infiltration.

Proper installation and sealing of the power vent assembly is critical to ensure combustion gases are vented safely. Take care to follow all directions when mounting components and making vent connections.

Electrical Connections

With the venting components physically installed, the electrical connections will need to be made to power the vent blower.

Start by running cable from the blower motor to a nearby power source. The junction box on the blower will indicate the voltage required, such as 120V. Route the cable through the wall safely using electrical conduit and secure with clamps. Ensure no sharp edges can cut the insulation.

At the power source, connect the hot wire to the black lead on the blower and neutral to white. Install a proper strain relief connector where the cable enters the junction box. Always confirm power is off at the circuit breaker before making any wiring connections.

In addition to power wiring, the vent blower should be connected to a control switch or relay. This allows the blower motor to engage automatically whenever the water heater burner activates. There are a few options for making this control connection:

• Line-voltage switch – Simple on/off control from a wall switch connected to the blower hot wire.
• Direct control board wiring – More complex but interfaces blower power directly with the water heater controls.
• Air pressure switch – Activates blower based on draft pressure but requires adjustment.
• Thermal switch – Turns blower on when high flue temp is detected.

Choose an appropriate control method according to the power vent kit instructions and your level of electrical knowledge. Proper control integration ensures the blower motor only runs when the water heater is firing.

If you are unfamiliar with making electrical connections, consult an electrician to wire the blower power and control switch safely.

Completing Installation

With the venting and electrical work complete, the final steps are to button up the installation and verify normal operation.

First, turn the water supply back on and reconnect any water lines that were disconnected from the heater during the work. Open supply valves slowly and check for any leaks. Repair as needed.

Next, restore electrical power to the water heater either by plugging it in or turning on the circuit breaker. You may need to reset the control board if it lost power.

Test the new power vent by drawing hot water and activating the water heater. The vent blower should turn on automatically within a few minutes as the burner ignites. Listen for normal airflow through the vent pipe. Check that exhaust gases are being pushed out properly.

Finally, complete the exterior finish work. Seal any gaps around the vent pipe penetration with additional caulk or expanding foam. Apply high-heat paint if necessary. Install rain caps or terminations that limit water and pest entry while maintaining vent flow.

Adding a power vent provides an immediate boost to hot water recovery and efficiency. But be sure to monitor system performance closely over the first few weeks of operation. This will confirm normal functioning and identify any potential issues to correct before vent problems arise.

Frequently Asked Questions

What are the disadvantages of power venting a water heater?

Potential drawbacks include increased installation cost, the need for electrical connections, and dependence on the vent blower working properly. Annual maintenance is recommended.

How difficult is it to install a power vent on my own?

Some DIY expertise in plumbing, electrical, and roofing work is beneficial.Experience with power tools and construction helps. Or consider hiring a professional.

Can I convert my old natural draft water heater to use a power vent?

Unfortunately, most older heaters lack certification and testing for pressurized venting. It’s best to upgrade to a new water heater designed and rated for power venting.

Is a permit required to add a power vent?

Permit requirements vary based on local regulations. Most areas require permits for vent modification and any new electrical wiring. Check with your local building department.

How much does it cost to have a plumber install a power vent?

Pricing will range from $500 to $1200+ depending on the complexity of the install, vent kit needed, and local labor rates. Get multiple quotes to compare options.

Conclusion

Installing a power vent on a water heater is a complex but rewarding project. With proper planning and attention to detail, you can successfully upgrade your existing water heater to take advantage of pressurized venting. Just be sure to confirm compatibility, use the correct venting kit, and follow installation procedures carefully. Added safety precautions are required, but the performance benefits make power venting worth consideration. Your improved hot water capacity will be noticeable every time you turn on the faucet.