Lochinvar Line

Lochinvar EnergyRite Commercial Gas Water Heaters (ERN series)

Atmospheric-vent 81%-thermal-efficiency commercial gas water heaters. 75-100 gallon, 300-850 MBH input.

Updated May 2026 · Lochinvar Water Heaters

EnergyRite is Lochinvar\'s atmospheric-venting commercial gas water heater line. Standard pick for restaurants, hotels, multi-family, salons, gyms, car washes — light commercial applications needing 300-850 MBH input and 75-100 gallon storage. 81% thermal efficiency; lower upfront cost than condensing ARMOR but lower operating efficiency.

The lineup

  • ERN-301 — 75-gallon, 300 MBH
  • ERN-501 — 100-gallon, 500 MBH (volume light-commercial pick)
  • ERN-650 — 100-gallon, 650 MBH
  • ERN-852 — 100-gallon, 850 MBH (high-recovery, large laundries / car washes / industrial)

Key features

  • Atmospheric venting via B-vent chimney — simpler install than condensing PVC
  • 81% thermal efficiency — meets minimum federal commercial standards
  • 5-year tank warranty; 1-year parts
  • Glass-lined commercial tank with magnesium anode
  • Honeywell or White-Rodgers gas valve
  • Hot surface igniter with electronic ignition

EnergyRite vs ARMOR — when to choose which

EnergyRite (Atmospheric)ARMOR (Condensing)
Thermal efficiency81%95%
VentingB-vent chimneyPVC sidewall
Upfront cost$3,900-7,500$7,500-11,000
Annual gas cost (similar duty)+15-18% higher than ARMORBaseline
Code compliance (commercial)Meets federal minimumRequired where IECC stringent
Best whenExisting chimney; lower duty cycle; budget priorityNo chimney; high duty cycle; code requires

Sizing for the application

ApplicationTypical EnergyRite
Small restaurant (40-60 seats)ERN-301 (300 MBH)
Medium restaurant / hotel limited serviceERN-501 (500 MBH)
Large restaurant / multi-family 20-30 unitsERN-650 (650 MBH)
Laundry / car wash / industrialERN-852 (850 MBH)

Engineering sizing required for any commercial application — engaging a mechanical engineer or commercial plumbing contractor is standard practice.

Install requirements

  • B-vent chimney sized to BTU input (6"-10" diameter depending on size)
  • Commercial-grade gas line, often 1.25"+ on ERN-501 and larger
  • Combustion air supply — 50 cubic feet per 1,000 BTU input
  • Commercial drain access
  • T&P relief discharge to safe location per IBC
  • Mechanical room per IBC/IFC requirements

Maintenance

Annual contractor service includes: burner inspection and cleaning, gas pressure verification, anode rod inspection (replace every 3-5 years), T&P test, flush sediment. Commercial use deposits sediment 3-5x faster than residential.

Warranty

  • 5-year tank (commercial application)
  • 1-year parts
  • 1-year labor

Bottom line

EnergyRite is the budget commercial gas pick — atmospheric venting, established platform, 5-year warranty. ERN-501 is the volume light-commercial choice. Step up to ARMOR (95% condensing) only if IECC code, utility rebate, or duty cycle justifies the upfront premium.