WaterClue is reader-supported. As an Amazon Associate we earn from qualifying purchases. Amazon prices and product images are sourced live from the Amazon Product Advertising API and may not reflect current Amazon listings — confirm price and availability at Amazon before purchase. Full affiliate disclosure.

Size Calculator Best-Of
Niagara

Niagara Commercial 100-Gallon Gas Water Heater

Model NG-100
4.2/5 from 30 ratings
from Check current price
Price via Amazon
Check Price on Amazon
Free shipping with Amazon Prime · 30-day returns
Btu
500000
Venting
Atmospheric
Fuel Type
Natural Gas
Tank Type
Commercial
Energy Factor
0.83
Warranty Years
5

Niagara Commercial 100-Gallon Gas Water Heater Review

The Niagara Commercial 100-Gallon Gas Water Heater is the larger variant in Niagara's commercial gas water heater line. 100-gallon capacity for larger commercial applications.

Specs: 100 gallons stored, 199,000 BTU input, UEF 0.62, 320-gallon FHR, 5-year commercial tank warranty. Power-vent PVC venting.

The 100-gallon Niagara Commercial serves substantial commercial applications (medium restaurants, hotels, multi-family residential). About $3,300 unit, $5,800-$7,500 installed.

Right buyer: commercial application requiring 100-gallon-class gas water heater, particularly in water-conservation-focused installations.

Pros
  • Natural gas combustion — faster recovery than electric resistance at comparable tank size
  • UEF 0.83 — above federal minimum EF 0.62; solid efficiency for a non-condensing gas unit
  • Large 100-gallon reserve — comfortably serves 5+ person households in peak-use periods
  • 180-gallon first-hour rating — handles morning-rush simultaneous demand without shortfall
  • High 500K BTU input — rapid recovery for large-volume commercial-residential applications
Cons
  • 5-year warranty — below the 8–12 year average for premium models in this class
  • Atmospheric venting requires vertical B-vent — less routing flexibility than power-vent or condensing alternatives

Full Specifications

Brand
Niagara
Model Number
NG-100
Btu
500000
Venting
Atmospheric
Fuel Type
Natural Gas
Tank Type
Commercial
Energy Factor
0.83
Warranty Years
5
Capacity Gallons
100
First Hour Delivery
180

Similar Water Heaters

Rinnai

Rinnai RU199iN Sensei Tankless Water Heater

199000 Natural Gas Tankless
Check current price
4.8
View Details
Rheem

Rheem Marathon Lifetime 50-Gallon Electric Water Heater

4500 Electric Tank
Check current price
4.8
View Details
Triangle Tube

Triangle Tube Smart 80 Indirect Water Heater 80-Gallon

Indirect Indirect 0.88
Check current price
4.7
View Details