Lochinvar Gas Water Heaters
Review and Buying Tips
(updated 2018)

Lochinvar gas water heater

Check out the Lochinvar gas water heaters for efficient water heating, comfortable showers, and savings. A review of the models, types, and features.

Buying and installing a Lochinvar gas water heater can make a big difference in your home, especially if buying one of the latest and most innovative models. No matter the size, gas models can, in general, heat the water fast and easy, keeping up with the high demand for hot water than electric. The operating costs are lower, making them more affordable.

Lochinvar gas water heaters are available as the standard type for residential and light commercial water heating, or manufactured housing:


A great number of the above Lochinvar gas water heater models meets or exceeds the energy efficiency standards, NAECA and ASHRAE.

Also, they meet ANSI standards required for residential gas-fired water heaters. This is done by implementing the combustion technology that protects from the accidental ignition of flammable vapors outside the water heater. Shield Combustion System is Lochinvar's patented system that meets the above requirements.

Thanks to the Shield Combustion System, Lochinvar gas water heater is the high-efficient unit, providing great benefits to its customer and the environment.

The main components for all Lochinvar gas water heaters with the FVIR technology are the Lock-Shield Flame arrestor plate, made of the stainless steel, low NOx burner, and resettable thermal switch to protect the water heater from the heat created by flammable vapors.

Most models are equipped with the electronic gas control which utilizes the microprocessor to provide accurate temperature control, and LED status indicator for diagnostics. Low NOx gas burner is there to provide heating by burning the natural or propane gas and emit fewer greenhouse gases than the standard type. Some models have an ultra-low NOx burner.

Lochinvar models that are equipped with the pilot light to lit the main burner are using the piezo igniter while some, more advanced, are utilizing an electronic spark ignition and hot surface.

Lochinvar water heaters utilize glass lining for protection, which is applied to the inner tank surface, and magnesium high capacity anode rod is added for protection against corrosive water action. A magnesium anode rod is found in the majority of Lochinvar models, while those with the stainless steel construction do not have any.

Additional elements that are added for your convenience are the temperature and pressure relief valve as a safety feature and durable brass drain valve for easy fill and drain.

Lochinvar gas water heaters are available with the warranties of 6, 8 and 10 years.

Energy Saver

The Energy Saver group of gas water heaters is the standard type which uses the atmospheric vent system, and mostly standard features, making it the most affordable group, but with the lower energy factor of up to 0.62.

There are two groups of water heaters with the tank capacity ranging from 30 to 55 gallons in short and tall configurations and with the warranties of 6 and 8 years.

35-50 Series

This is the most advanced group of gas water heaters from Lochinvar. There are several models available utilizing 34 and 50-gallon tanks and gas burners with different gas inputs. Thanks to the high gas input of 199,000 BTU, the most powerful unit is capable of achieving a high First Hour Rating of 253 GPH, recovery rate of 293 GPH, and energy efficiency of 96%.

The units are equipped with the ultra-low NOx gas burners, resulting in less pollution and compliant with the strict emission law, as found in some states.

Models are equipped with advanced electronics which allows easy control (large screen) and diagnostics.

Features that are making them unique and different from most of the standard type gas water heaters are the stainless steel construction of the tank and heat exchangers, which has a helical shape for an enhanced heat transfer. The stainless steel construction eliminates the risk of corrosion, so the anode rod is not needed anymore.

Large Capacity

Large Capacity models are recommended for larger homes and applications. They include two tank sizes of 75 and 100 gallons. While they have high First Hour Rating of up to 170 gallons and a recovery rate of 81, the energy factor is low – around 0.6.

High Efficiency

High-efficiency Lochinvar water heaters are designed in sizes of 40 and 50 gallons in short and tall configuration.

All the models utilize atmospheric vents and automatic flue damper, including the thick foam and heat traps to increase efficiency.

The energy factor is higher than the one found on the standard type; it is in the range from 0.64 to 0.69. Only the 50-gal unit with the EF of 0.69 is Energy Star compliant, which also has the highest First Hour Rating of 84 gallons while the recovery rate is the same for all models – 42 GPH.

Other components are pretty much standard, and it includes the low NOx gas burner, electronic ignition, FVIR technology.

They are certified for potable water and space heating applications. The warranty is 10 years.

Ultra-Low NOx

Ultra-Low NOx residential gas water heaters produce less than 10 ng/j of NOx gases, thanks to the newly designed radiant burner system. This is what makes them environment-friendly and compliant with the strict emission laws, as present in some states.

Lochinvar water heaters with the ultra-low NOx gas emission are designed as atmospheric and power vent, in capacities from 30 to 50 gallons, short and tall configurations.

They are equipped with standard features such as the FVIR technology, electronic gas control with the microprocessor, large anode rod, heat traps, and others.

Ultra-low NOx Lochinvar water heater features the Honeywell gas control valve that allows better and accurate control of the improved economy. It also enables easy diagnostics and troubleshooting with the installed LED display.

The 50-gal unit with the atmospheric venting is the largest model, has 50,000 BTU, energy factor of 0.60, First Hour Rating of 91 gallons and recovery rate of 51 GPH. Atmospheric type models are available with the 6, 8 and 10-year warranty.

Ultra lox NOx models are also available as power vent models in sizes of 40 and 50 gallons. Due to the high energy factor of 0.70, they are considered as high-efficiency models. The 40-gallon model has the highest efficiency, also First Hour Rating of 76 gallons, while the recovery rate is lower than the above model – 43 GPH.

Power Vent

Power vented residential gas water heaters are designed in several sizes; from 40 to 75 gallons and with the power range from 40,000 to 76,000 BTU.

Lochinvar water heaters with the power vent are using the environment-friendly low NOx burner which is part of the standard FVIR technology.

Venting is very simple; power vented water heaters are using 120 VAC blower fan and the sidewall flue termination where the pipe is made of the cheaper PVC or CPVC material and can run up to 180 feet. Vertical venting is also an option; and based on the size of the water heater you will use 2, 3 or 4" vent size.

All the models are using standard 3/4" NPT water connection and side connection, so they can be used for space heating also.

The models are equipped with the durable and reliable hot surface ignition, control logic to provide an accurate temperature, LED for diagnostics, safety high limit switch, flammable vapor sensor and protection from the dirt and other contaminants.

The 75-gal model is the largest model which comes with the highest recovery rate of 80 GPH and gas input of 76,000 BTU but is not Energy Star compliant. The highest First Hour Rating of 119 gallons is found on the 50-gal unit, which also has the highest energy factor of 0.73.

All models are certified for both potable water and space heating and come with the 10-year warranty.

Power Direct Vent

Lochinvar water heaters with the power direct vent utilize the sealed combustion gas burning process to provide the fast recovery and high first-hour rating, and it is available in three tank sizes; 40, 50 and 75 gallons. The maximum gas input is 72,000 BTU, First Hour Rating of 129 gallons and recovery rate of 82 GPH, all found on the 75-gal unit.

All the models, except 75-gal model, are Energy Star compliant, due to the energy factor ranging from 0.68 to 0.73.

Power direct venting system is a 2-pipe vent system, where one pipe is used to remove the products of combustion outside and the other for the fresh air intake, needed for gas combustion. It can use 2”, 3” or 4” PVC, PP or CPVC vents.

All the models utilize the FVIR technology to prevent accidental ignition, low NOx gas burner for reducing gas emission, electronic ignition and LED for status and diagnostics and heat traps. Power direct vent water heaters are using the hot surface ignition to light the gas inside the combustion chamber.

Models can be used for both domestic water and space heating. The warranty is 10 years.

Balanced Flue Direct Vent

Lochinvar water heater is also available as the direct vent unit that features the sealed combustion and concentric vent system (a pipe within the pipe). The concentric or co-axial vent draws the outside fresh air through the outer pipe and inner pipe it runs the products of combustion out.

The advantage of these vent systems is in the flexible installation as it can rotate 360 degrees. The vent pipe and vent cap are included with the purchase of the unit.

Available models are with capacities of 40 and 50 gallons and maximum gas input of 47,000 BTU, First Hour Rating of 83 gallons and recovery rate of 51 GPH, found on the 50-gal unit. Thanks to the thick foam insulation and installed heat traps, the maximum energy factor found is 0.66 (40-gal unit).

Both models are using low NOx burner and the pilot light ignition. Except for the potable water heating, it can also be used for space heating.

Manufactured homes

Lochinvar water heaters that are specifically designed for manufactured homes can be found with the capacities from 30 to 50 gallons for direct vent models and 30 and 40 gallons for the atmospheric type. The maximum gas input of 38,000 BTU is found on the 50-gal DV unit, which also comes with the highest First Hour Rating of 67 gallons and recovery rate of 67 gallons, while the energy factor is only 0.56. 

All the models come with the low NOx gas burner, FVIR technology and electronic gas control with the LED status indicator.

A conversion kit is supplied with the unit, so it is convenient to convert the water heater from using the natural gas to LP or propane gas, but with a recommendation to call a technician for this job.

A 10-year warranty is offered with the purchase of the models.

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