Are Power Vent Water Heaters Better?

A selection of the best power vent water heaters to buy. Find out what power venting is, how it compares to atmospheric and direct venting, how it works, see the review of the top features, buying and installation tips.

Buying a high-performing water heater is a great decision to make, considering that the quality models and the professional installation are not cheap, service that can be expensive, and that average energy consumption of a North American household is between 14% and 20% - a great expense for heating only potable water.

Power vent water heaters: What makes them special?

You can purchase a tank-type or tankless unit, where the following venting types are used; atmospheric, direct vent, power vent, and power direct vent.

Power Vent model

The power vent water heaters (PV) are designed with the electric-powered blower mounted on top of the unit. With the assistance of the blower, combustion gases are mechanically moved to the outside while forcing the fresh air in. Due to the pressure created by a fan, the risk of negative pressure inside the home is significantly reduced, while the air quality is improved.

The blower assembly is factory installed, the vent pipe is sealed, allowing long runs, and except for the installation of the venting pipes, there is no other work needed. PV water heaters provide greater flexibility, so it is easier to find the location for the hookup.

Power vent water heaters are also called forced-draft or fan-assisted.

Differences between atmospheric and power vent models

Among these four venting types, the simplest one is atmospheric, which is also known as the standard type. This type uses the natural draft (buoyancy effect), and with the help of a chimney or vertical flue, products of combustion are effectively transferred outside.

The problem is the negative pressure which can develop and suck the flue gases back into the home, increasing the risk of carbon monoxide exposure. This type of water heater is usually less efficient and cheaper to buy.

Differences between direct and power vent models

Direct vent water heaters (DV) are similar to power vent models (PV), utilizing a sealed combustion chamber but not an electrically operated fan or a blower. They are usually equipped with a steel venting pipe (solid or flex), which moves the products of combustion outside to the atmosphere. They use the outside fresh air with an air intake pipe in a single or dual-pipe setup. This setup can also be seen on tankless models that have a sealed combustion chamber.

Direct vent water heaters usually move the exhaust gases through the horizontal vent pipe without the blower assistance and electricity. As the water heater is usually installed close to the exterior wall, the vent pipe is short. Direct vent is also cheaper but less efficient. As for the power vent, DV models do not require a chimney.

Power vent water heaters, compared to the above two types, are more advanced, cost more, and deliver more benefits, such as the higher energy efficiency - resulting in more savings, venting flexibility - for easier installation and no problems related to the back-drafting.

Power vent water heaters - Things to consider

• Buy a power vent water heater (PV) if planning to replace an old electric type with the high-efficient gas model.
  
• Use the PV water heater in areas with no access to the chimney or vertical vent, where the standard atmospheric model cannot be used, and in tightly built homes.
  
• Use the PV models when installing a water heater either near or away from the exterior wall because the long pipes and the blower guarantee correct venting.
  
• As the unit cannot operate without electrical power, install the unit close to the electric wall outlet (usually 120 V).

Note: When choosing the location for your PV water heater, consider the inlet and exhaust vent system piping and combustion air supply requirements. The venting system must comply with local codes and installed per manufacturer's specification. It must be able to run from the water heater to the termination with a minimal length and the number of elbows.

For the safe, professional and worry-free installation, contact the expert.

Popular manufacturers of power vent water heaters

If you are looking for an energy efficient water heater that uses the power vent and is coming from a well-known US or Canadian manufacturer, here are the recommendations: AO Smith, Bradford White, and Rheem.

AO Smith

Over 20 different models from AO Smith use power venting and both natural and propane gas. Most of the models utilize the low NOx burners, while only two have ultra-low NOx burners.

Power vent water heaters mainly come from the ProLine XE series, while only one is from the Vertex series, which is also the most efficient and ideal model to buy. The available sizes are in the range of 40 to 75 gallons, where the 50-gal unit is one of the most popular.

Vertex GPHE-50 is the power vent model with one of the highest energy efficiency - over 90% from all AO Smith gas water heaters.

The GPHE-50 is the 50-gal unit that is designed to produce a water flow of high 3 GPM for a continuous hot water supply.

The high water flow, first-hour rating of 124 GPH, and recovery rate of 95 GPH are great advantages over other models and are easily achieved using the unit's powerful burner with 76,000 BTU, advanced electronics, and fully submerged spiral heat exchanger.

The GPHE-50 water heater uses the combined vertical and horizontal vents through the outside wall bringing more flexibility during the installation. The vent pipes are made of PVC, PP, ABS, or CPVC material and have 4" diameter vents that can run up to a maximum of 128 feet. Other details can be found here.

The best selling from the AO Smith Proline XE series is coming from the GPVT group. The GPVT-50 model is the 50-gal model that also comes with great features and specs, including the energy factor of 0.72 and Energy Star compliance, first-hour rating of 97 GPH, and recovery rate of 56 GPH, making it great for 3-bath homes. According to the manufacturer, the GPVT-50 has an estimated energy cost of around $225 while Vertex $186.

Bradford White

The RC2PV50H6N model is coming from the High-Efficiency eF series, the most efficient PV model from Bradford White. The water heater has similar specs as the above Vertex from AO Smith. It utilizes a powerful and low-NOx gas burner that is able to provide up to 76,000 BTU, a high energy factor of 0.80, the first-hour rating of 120 GPH, and a recovery rate of 93 GPH.

This 50-gal PV water heater is equipped with a high-efficient dual pass heat exchanger system and ICON System for high performance, stable temperature, electronically controlled gas combustion, and smart troubleshooting system. The Hydrojet System reduces the sediment buildup so the unit can perform as designed.

The URG2PV50H6N model is the 50-gal model coming from the TTW Ultra-Lox NOx series, a series of Energy Star power vent water heaters that utilize the Eco-Defender Safety System for safe and reduced NOx gas combustion. The model is equipped with the ICON system to ensure the enhanced performance, accurate temperature control, and intelligent diagnostics for simpler troubleshooting. The Hydrojet Total Performance System guarantees efficiency and performance due to the reduced sediment buildup. It comes with an EF of 0.68, a recovery rate of 60 GPH, and the first-hour rating of 107 GPH.

Rheem

Power vented water heaters from Rheem are available in the Performance and Professional series.

The XG50T06PV42US model is available from the Performance series, an Energy Star model with an energy factor of 0.67, the first-hour rating of 88 GPH, and a recovery rate of 42.4 GPH. The greater advantages over simpler models are the self-diagnostic system that allows easier troubleshooting, low gas emission, and durable silicon nitride ignitor.

PRO50-38U is also built with the capacity of 50 gallons, has a lower recovery rate than the above model - 38.4 GPH, also a first-hour rating of 86 GPH and EF of 0.66. It comes with the Guardian System and ultra-low NOx radiant gas burner. The EverKleen system allows consistent performance and efficient work, protecting the system and elements from the sediment buildup.

Installing a power vent water heater

The vent pipe of the power vent water heaters can terminate horizontally through the exterior wall or vertically through the roof, with adequate supports along its length.

There are two venting options you should consider for your water heater:

A single vent pipe system can be installed as the concentric system (coaxial), a pipe within a pipe, where one pipe is used as a discharge and the other as an air intake pipe. When the internal air is used for combustion, a designated room has to be provided with access to the air with sufficient supply.

Water heaters with two separate venting pipes (two-pipe system) use one pipe to supply the air from the outside and the other to discharge products of combustion, also to the outside. These can run either horizontally or vertically.

When the pipes run vertically, it is important to install the elbow fittings (45 or 90 deg. bends) at the end of the pipes, which will prevent the rain or snow from entering. For horizontal termination, provide the slope downward to prevent potential condensate from coming back and affecting the blower operation.

If the water heater is installed in an unconfined space within the building, infiltrated air is usually adequate for proper gas combustion. If it is installed in a confined space, provisions for air ventilation must be provided.

Note: If the power vent water heater has to be installed as a replacement for the existing power vented unit in pre-existing venting, the proper inspection still has to be performed to ensure that requirements are met.

Venting tips

Buying a venting kit from the manufacturer or a supplier provides a worry-free installation, as they meet standards and safety requirements. Use the manufacturer guide and model specifications to determine the BTU rating, model, venting lengths, and other requirements so you can properly size the system.

For example, plastic pipes cannot be used on non-condensing tankless water heaters, only stainless steel, due to the acidic nature of the products of combustion.

PVC, ABS, or CPVC pipes are recommended for the tank-type storage tanks, and the most common sizes are 2", 3", and 4" in diameter, Schedule 40. These are also found in condensing tankless models.

Very flexible for installation, power vented gas heaters can be installed as far as 180' from the exterior wall and side-by-side with other furnaces or boilers.

When assembling the air inlet and vent outlet, both pipe diameters must be of the same size. This requirement applies to both 2" and 3" diameter pipes.

A limited number of elbows is recommended in any vent installation, but it depends on the length. Use the manufacturer's guide to determine the right length and the number of bends. Venting should be as direct as possible, with no reduction in the vent diameter.

Some manufacturer's manual guides explain that reduction in diameter at any point is allowed as long as the maximum and minimum length requirements are met.

When installed in the building, power vent water heaters cannot be connected to the chimney and share venting with other appliances as significant building depressurization will occur, affecting the performance of all gas combustion appliances.

All venting materials and components must be joined with the approved primer-cleaner and solvent cement, but do not cement the vent pipe to the heater. Rubber coupling and gear clamps are supplied with the water heater to connect the vent to the blower. These connections must be adequately sealed to prevent leakage of the products of combustion into the living area.

Required tools

• Power vent kit or PVC pipe and fittings
• Adjustable wrench
• Drill
• Saw
• Screwdriver
• Level
• Pliers
• Multimeter
• PVC tube cutter
• Caulk gun
• Electric wire

Drawbacks

You should be aware of several drawbacks:

• The power vent water heater should be installed away from the living room because the fan noise might be annoying. If the unit is installed professionally and in the right location, the noise can be minimized.
• Electricity must be provided to run the blower. During power outages, there will be no hot water.
• A sufficient amount of air must be provided, usually through the provisions on the wall or adjacent doors.
• PV units are more expensive than the direct or atmospheric vent types.

Conclusion

Professional installation of the power vent pipe system, with the unobstructed combustion and ventilation air delivery, is mandatory for safe and efficient operation for many years to come. The PV type is recommended for homes with no access to the chimney and where energy-efficient heating is required.