Direct Vent Water Heaters:
Buying and Installation Tips

Are you looking for a hot water solution that's efficient, reliable, and space-saving?

If so, direct vent water heaters (DV) might just be the answer!

What makes direct vent water heaters unique?

Gas water heating systems with a direct venting offer a range of benefits that make them a popular choice for homeowners. With their sealed combustion chambers and efficient heating technology, they provide constant and reliable water heating. Plus, they're easy to install and require minimal maintenance.

In this article, we'll take a closer look at the many benefits of direct vent water heaters, so you can see why they're such a great choice for your home.

As water heating energy use accounts for about 20% of total energy use, and with higher fuel prices today, buying the best direct vent water heater for your home requires research and knowledge. It's important to understand how they work, the main parts, installation requirements, and service and maintenance costs.

Whether you're buying a gas water heater for a new or old house, it's crucial to consider proper location and venting, regardless of the fuel type or unit. If you're purchasing an electric type, you don't have to worry about venting, combustion gases, and additional expenses.

Tank water heaters - venting types

If you're in the market for a tank-type water heater, you'll need to choose from one of four venting types: standard or atmospheric, direct vent, power vent, or power-direct vent. Keep in mind that each of these options requires a venting system to remove flue gases and provide fresh air for gas combustion.

Choosing the right type depends on the unit's location, installation requirements, and local building codes.

The atmospheric type is the most common and cheapest to buy and install. It uses a vertical metal vent pipe or chimney to naturally move flue gases from the unit and up through the vent and outside, thanks to the temperature difference (hot air rises).

The power vent water heater (PV) uses a power blower to move exhaust gases outside the house, using PVC, CPVC, or ABS pipes. These units are more expensive but highly efficient and provide greater installation flexibility.

Power direct vent models are a combination of power and direct vent models, where the blower is used to remove gases outside. They are used when the external wall is far away from the unit, requiring longer pipes.

Direct vs. atmospheric vs. power venting

Direct vent water heaters require an ample supply of fresh air for proper combustion and ignition. The combustion air is typically drawn from outside through the vent pipe.

They utilize a sealed combustion chamber to ensure safe transfer of combustion products through the horizontal pipe and external wall. A second pipe, also airtight, is used to draw fresh air in.

A direct vent setup addresses two common issues found in atmospheric models: backdrafting and negative pressure within the room where the unit is installed.

Compared to power vent models, a direct vent system is much quieter because it does not have an electric blower. However, it is typically more expensive than the standard type.

Note that venting pipes must be installed in accordance with local codes and the manufacturer's instructions to ensure proper venting.

Direct vent water heaters - Buying tips

No chimney needed

Direct vent water heaters are an excellent choice for those who want reliable, efficient, and safe hot water solutions. If you're looking for a water heater that doesn't require a chimney or electrical source, a direct vent water heater is a perfect choice. Not only does it provide hot water during power outages, but it's also designed with a sealed combustion chamber that eliminates back-drafting, making it safe and silent.

For those who don't mind using electricity, the power-direct vent models are a great option. They use an electric blower for exhaust and provide excellent performance. Additionally, direct venting is better than power venting because it eliminates pilot outages caused by air pressure changes.

With DV models, you won't have to worry about Carbon Monoxide leaks or insufficient indoor ventilation. They draw fresh air in from the outside, making them safe to install almost anywhere as long as there is an outside wall.

Application

Direct vent water heaters offer homeowners the flexibility to choose from a range of installation options. Depending on the recommended pipe length, some types can be installed close to an outside wall, while others can be located further away.

Direct venting is available in both tank-type and tankless units, making it a versatile option for any home. With direct venting, homeowners can enjoy reliable and efficient hot water while avoiding issues like back-drafting and negative pressure.

Safety

Direct vent water heaters provide safe and efficient water heating, thanks to their sealed combustion chambers that prevent fumes from entering the home. As these units draw in fresh air from outside, there is no risk of using air from inside the house. This makes them a great choice for homeowners who prioritize safety and indoor air quality.

Easy installation

Direct vent water heaters can be equipped with steel pipes, as well as PVC, CPVC, or ABS pipes, making for an easy and cost-effective installation. The orientation of the pipes can be either horizontal or vertical, depending on the installation requirements.

In the case of vertical pipes, the warm/hot exhaust fumes, which are lighter than cool air, are naturally moved up and out due to the temperature difference.

For horizontal pipes, the sealed combustion chamber facilitates the extraction of the products of combustion and air intake. A venting system with minimal turns and pipe fittings is recommended to allow for installation in smaller spaces.

To prevent blockages, condensation, and vapor hazards that can cause property damage or affect proper unit operation, the vent system must terminate with the appropriate clearances as specified in local codes.

Note: During installation, all vent-air intake joints should be properly sealed with the provided sealant.

Popular direct vent water heater manufacturers

Direct venting is a common feature among gas water heaters manufactured in the US and Canada. However, despite their prevalence, most of these units are not Energy Star compliant due to their low energy factor. It is important to consider the energy efficiency before making a purchase to ensure that it meets your needs and energy-saving goals.

Rheem

Rheem, a popular manufacturer of water heaters, offers several types of direct vent heaters that use coaxial vents for easier installation in residential and manufactured homes.

Rheem's direct vent water heaters are designed for horizontal venting only and come in two sizes: 40 and 50 gallons. The adjustable coaxial vent provides flexibility in installation, as it can swivel 360 degrees. Horizontal and vertical kits are also available for longer venting, up to 48" max. To protect against corrosion, Rheem uses Rheemglas tank lining, premium anode rods, and the EverKleen system to reduce sediment buildup.

One model, the PROG50-36N RH60 DV, is a 50-gallon unit from the Professional Classic series. It offers a Recovery Rate of 36.5 GPH, a First Hour Delivery of 50 GPH, and an energy factor of 0.51.

Another model, the XG50T06DV36U0, is a 50-gallon unit from the Performance series with better specs. It has a Recovery Rate of 36.4 GPH, a First Hour Rating of 78 GPH, and an energy factor of 0.63.

AO Smith

AO Smith offers a greater number of models with direct venting than Rheem. These water heaters are available in natural gas and propane versions, and utilize a low NOx gas burner. They come with a standard 6-year warranty and do not require electricity to operate. Direct vent models are also available for manufactured homes.

The GDVT-50 is AO Smith's top DV model. This 50-gallon unit has a 47,000 BTU gas burner providing an energy factor of 0.65, a first-hour rating of 83 GPH, and a recovery rate of 51 GPH.

The GDV-50 has a weaker gas burner with a power of 40,000 BTU, resulting in a lower first-hour rating of 77 GPH and recovery rate of 43 GPH. However, it has a slightly higher EF of 0.66.

Bradford White

The Defender Safety System DS models use a coaxial vent pipe that is suitable for homes and rooms where there is insufficient air for gas combustion. The pipe can rotate for added flexibility. Telescoping vent kits allow for lengths of up to 8 feet, while flexible vent kits allow for lengths of up to 100".

Defender Safety System High Input DH models, like the DS models, do not require electricity and use a co-axial direct vent system with the same length capability. However, they offer greater recovery, have larger tanks (up to 75 gallons), and provide side connections for space heating.

Required tools for installation

• Direct venting kit
• Adjustable wrench
• Drill
• Saw
• Screwdriver
• Level
• Pliers
• Multimeter
• PVC tube cutter
• Caulk gun
• Electric wire

Conclusion

Direct vent water heaters offer a safe and efficient alternative to traditional venting methods. They are particularly suitable for residential homes that lack access to a chimney or are located far away from the water heater, or where an electrical plug is not nearby.

It is important to ensure that direct venting is installed professionally and per codes to ensure safe and efficient operation. The absence of a blower in these units requires a clear path in the vent pipe with no obstructions, which should be taken into consideration during installation.

FAQ

How do I know if a direct vent water heater is the best option for my home?

Direct vent water heaters are a good choice if your home does not have access to a chimney or the chimney is far away from the water heater. They are also a good option if you do not have access to an electrical plug near the water heater.

Can a direct vent water heater be used with propane gas?

Yes, many direct vent water heaters can be used with either natural gas or propane gas. However, it is important to make sure that the unit you choose is compatible with the type of gas you will be using.

Can I use a direct vent water heater in my RV or mobile home?

Yes, many manufacturers offer direct vent water heaters designed specifically for RVs or mobile homes. These units are typically smaller in size and have specific venting requirements to ensure safe operation in a mobile environment.

The size of the water heater will depend on the size of your RV or mobile home and your hot water needs. It is important to consider the First Hour Rating and Recovery Rate when choosing a unit to ensure you have enough hot water for your needs.