What is a power vented hot water tank?

A power vented hot water tank is a type of water heater that uses a fan to push exhaust gases out of the home through a plastic pipe. This allows the tank to be located in places like a closet or attic where a conventional atmospheric vented water heater cannot be installed safely. Power venting makes a hot water tank more versatile in its positioning while also increasing efficiency and reducing energy costs.

How Does a Power Vented Water Heater Work?

A power vented hot water tank works very similarly to a standard atmospheric vented tank with one major difference – the addition of a fan to actively push exhaust gases out of the home. Here is a basic overview of how it works:

• Cold water enters the tank from the home’s water supply lines.
• The cold water sits at the bottom of the tank while the gas or electric burner heats it.
• As the water is heated, it rises to the top of the tank.
• When a hot water tap is opened, hot water exits the top of the tank while incoming cold water pushes up to take its place.
• The gas or electric burner activates to reheats the refilled cold water.
• Combustion gases from the burner are vented out through a plastic exhaust pipe rather than a vertical metal flue.
• A fan pulls the exhaust gases through the vent pipe and pushes them outside.

This active exhaust system allows the tank to be vented horizontally through the wall or even upwards into the attic. The fan provides the force needed to push the gases out over longer distances with turns and bends in the vent pipe. This gives greater flexibility in where the hot water tank can be located.

Benefits of a Power Vented Water Heater

There are several benefits that make power vented tank style water heaters advantageous in many situations:

• Flexible Installation – Since the exhaust can be pushed through plastic pipes over distances, the tank can be installed in places like closets, attics, basements and garages where a natural draft heater cannot.
• Increased Efficiency – The powered exhaust fan reduces heat loss compared to passive atmospheric vents. This increases fuel efficiency.
• Lower Costs – The efficiency gains allow a power vented heater to use less energy over time, saving on utility bills.
• Added Safety – Exhaust gases are sealed from living spaces and vented outside. This prevents carbon monoxide and other hazards.
• More Space – By fitting into spaces like closets and attics, power vented models free up floor space.
• Versatility – The tanks come in gas and electric models and a wide range of gallon capacities.

How Power Venting Works

The key difference in a power vented water heater is the addition of a fan assembly on the exhaust side of the appliance. This fan performs two important roles:

1. Pulling exhaust gases out of the combustion chamber.
2. Pushing the exhaust gases through the vent piping to outside of the home.

Without the fan, the hot exhaust would simply rise up through a vertical metal flue pipe. Cooler air would be drawn in behind it. However, the fan allows the exhaust to be pushed through smaller plastic piping that can travel horizontally and make turns before exiting the home.

The fan assembly includes the following components:

• An electric centrifugal blower fan
• A pressure switch to control fan speed
• An exhaust coupling to connect the vent pipe
• An intake coupling for combustion air

The blower fan spins rapidly to pull in the exhaust gases. The gases then pass through the fan blades which provide the pressure to push them through the output vent. The pressure switch monitors the exhaust flow and adjusts fan speed to maintain optimal pressure.

Power Vent Configurations

Power vented water heaters are available in a variety of configurations to suit different installation requirements:

Vertical Power Vent

A vertical power vent model has the exhaust outlet on top of the tank. It pulls the hot gases up through the top and pushes them out horizontally through the wall or vertically through the roof:

• Ideal for closets and alcoves where a rear exhaust is not possible.
• Can be vented through the wall up to 20 feet.
• Can be vented vertically through roof up to 40 feet.

Horizontal Power Vent

A horizontal power vent model has the exhaust outlet on the back of the tank. It pulls the exhaust out the back and pushes horizontally through the wall:

• Best for installations along a wall where a top vent is not practical.
• Exhaust can be vented horizontally through the wall up to 40 feet.

Power Direct Vent

A power direct vent model pulls in fresh air from outside and vents exhaust gases separately:

• Most efficient design since it doesn’t use indoor air for combustion.
• Requires two separate penetrations through the wall or roof.
• Both intake and exhaust can be piped up to 40 feet.

Power Vent versus Conventional Draft

Here is a comparison of some of the main differences between power vented and conventional atmospheric vented water heaters:

Power Vented	Atmospheric Vent
Uses a fan to push exhaust gases through vent pipes.	Relies on natural draft to vent through a vertical chimney.
Can be vented horizontally through walls or vertically through roof.	Must be vented vertically through the roof.
Typically plastic PVC or CPVC vent materials.	Typically metal B-vent piping.
Higher efficiency units due to reduced heat loss.	Standard efficiency units with more passive heat loss.
More flexible installation locations.	Limited to open spaces with vertical venting.
Higher equipment cost due to power vent assembly.	Lower equipment cost without power vent parts.

Power Venting Applications

Here are some of the typical applications where installing a power vented hot water tank would be advantageous versus a conventional vented model:

Closet Installations

Power vented models can be installed in closets since the exhaust can be vented horizontally through the wall:

• Frees up floor space in utility rooms.
• Keeps tank hidden away and out of sight.
• Short direct runs through the wall to outside.

Attic Installations

Power vented tanks are ideal for installing in attics by venting the exhaust vertically:

• Takes advantage of unused attic space.
• Keeps tank completely separate from living area.
• Exhaust can be vented through roof jack.

Basement Installations

Power venting allows basement installs by running the exhaust horizontally or vertically:

• Utilizes an unused basement space.
• Can horizontally vent through foundation or vertically through the roof.
• Keeps tank out of occupied upstairs space.

Garage Installations

Power vented heaters work well in garages by horizontally venting through a wall:

• Uses vacant garage space
• Venting keeps exhaust separated from interior living space.
• Short, direct horizontal venting through garage wall.

Power Vent Safety Features

All power vented water heaters incorporate safety features to allow their safe operation and prevent hazards:

Exhaust Temperature Sensor

Monitors the exhaust gas temperature and disables the burner if it detects overheating.

Vent Safety Switch

Automatically shuts down the heater if it senses restricted airflow in the exhaust vent.

Flame Arrestor

Prevents flames from backing up into the exhaust vent piping.

Pressure Relief Valve

Opens to release excess tank pressure buildup and prevent explosion.

Combustion Shut Off Device

Shuts off gas supply if pilot light goes out to prevent raw gas from accumulating.

Verified Venting

Certified for safe operation with specific venting brand pipes and configurations.

Common Power Vent Brands

Some of the major brands that manufacture power vented hot water tanks include:

Rheem

Makes EcoPower Hybrid models in both electric and gas. Offer horizontal and vertical power venting with efficiency ratings up to .70 UEF (energy factor).

Bradford White

Manufactures Defender Safety System models in gas and electric up to 40 gallons. Horizontal and vertical power vents available.

AO Smith

Produces ProMax line in gas and electric models up to 75 gallons. Multiple power venting configurations.

Lochinvar

Leading brand for commercial and residential power vented tank style heaters. Stainless steel and glass-lined tanks.

State

Well known for its Select Power Vent models for both homes and businesses. CleanBurn technology for increased efficiency.

Installation Requirements for Power Venting

Proper installation is critical to ensure the power vented water heater functions safely and efficiently. Here are some key requirements:

Venting

• Use only the approved vent materials and follow venting layout guidelines.
• Vent must terminate outside with proper clearances from windows, openings.
• Make sure vent run is within the maximum allowed vent length.
• Vent piping should be as short and direct as possible.
• Vent piping must be supported and sloped back towards the heater.

Gas Supply

• Properly size gas line piping to deliver sufficient gas volume to heater.
• Include a shutoff valve and union fitting for gas line connection.
• Leak test all gas connections and fittings.

Combustion Air

• Provide adequate air inlets to allow for proper combustion airflow.
• Maintain proper clearances around heater and Combustible materials.
• Direct vent models require a separate combustion air intake.

Condensate Drain

• Install a drain tube to safely collect and dispose of exhaust condensate.
• Drain line must be sloped down and have an open air gap.

Electrical

• Electrical supply must match voltage and amperage rating of water heater.
• Use proper wire size and install shutoff switch and fuse/circuit breaker.

Safeties

• Temperature and pressure relief valve must be piped to an open drain.
• Install carbon monoxide detectors when utilizing fossil fuel units.

Maintenance Tips for Power Vented Tanks

Performing periodic maintenance on a power vented water heater helps ensure a long service life:

Drain and Flush Tank

Annually drain the tank to remove sediment buildup. Flushing with a hose removes additional debris.

Inspect Burner and Pilot

Check burner flames are blue and consistent. Clean pilot orifice and replace if not functioning properly.

Check Venting

Verify vent piping is intact with no leaks or separation. Clean out any debris or blockage.

Test Safety Valves

Manually open T&P relief valve to ensure proper operation and discharge. Reset when closed.

Inspect Anodes

Check sacrificial anode rods each year and replace when 75% depleted to prolong tank life.

Clear Condensate Drains

Remove any buildup restricting condensate drain flow to prevent moisture damage.

Monitor Efficiency

Keep an eye on utility bills for unusual increases that could indicate performance issues.

Cost of a Power Vented Water Heater

Power vented tank style water heaters have a higher upfront equipment cost versus conventional atmospheric vented heaters. Here are some typical price ranges:

• Gas power vented: $900 – $1,500
• Electric power vented: $700 – $1,200
• Atmospheric vented: $400 – $900

While power vented models have a higher initial cost, keep in mind they can save on utility bills long-term due to greater efficiency. The ability to fit in more installation locations also adds value.

Key Takeaways on Power Vented Tanks

Here are some important summary points on power vented hot water heaters:

• Uses a fan to push exhaust gases through vent piping.
• Allows flexible venting options like through walls and roof.
• More installation location options versus conventional heaters.
• Higher efficiency with lower standby heat loss.
• Higher equipment cost but can save on energy bills long-term.
• Available in gas and electric models up to 80 gallons.
• Require proper installation and maintenance for safety and performance.

Conclusion

Power vented hot water tanks open up installation possibilities beyond conventional atmospheric vented heaters. The ability to vent horizontally or vertically gives greater flexibility in placement locations. Homeowners with spaces like closets, attics and garages can take advantage of the benefits of power venting. When properly installed and maintained, a power vented tank provides reliable hot water for households while achieving higher efficiency and lower operating costs.