Low NOx vs. Ultra Low NOx Commercial Water Heaters: What You Need to Know
Shopping for a commercial gas water heater is not always as simple as matching the gallon capacity and BTU input of the existing unit. Depending on where the equipment is being installed, local emissions requirements can determine which type of natural gas water heater you need.
Low NOx and Ultra Low NOx requirements are especially important when replacing commercial water heaters in states such as Texas, California, Utah, and Colorado. Choosing the wrong model can create unnecessary delays, so it is important to confirm the installation location before ordering.
Which Commercial Water Heater Should You Use?
Low NOx
Natural Gas- Texas
For a 100-gallon, 199,900 BTU commercial natural gas application in Texas, a popular option is the Rheem GN100-200 .
Shop GN100-200Ultra Low NOx
Natural Gas- California
- Utah
- Colorado
For these applications, the Rheem GNU100-200 is the Ultra Low NOx version of this popular 100-gallon commercial platform.
Shop GNU100-200Power-Vent Option
Natural Gas- Available for applications nationwide
The high-efficiency Rheem GHE100SU-200 Triton provides another option when a power-vent, high-efficiency commercial water heater is preferred.
Shop GHE100SU-200Popular Commercial Water Heater Options
The models below all serve different installation needs. Always confirm fuel type, local code requirements, venting, dimensions, BTU input, and existing system conditions before selecting a replacement.
Rheem Low NOx
A 100-gallon, 199,900 BTU natural gas commercial water heater designed for Low NOx applications, including Texas.
View GN100-200 →
Rheem Ultra Low NOx
A 100-gallon, 199,900 BTU natural gas commercial water heater for Ultra Low NOx applications in California, Utah, and Colorado.
View GNU100-200 →
Rheem Propane
For liquid propane applications, the G100-200LP provides the familiar 100-gallon Universal platform with 199,900 BTU input.
View G100-200LP →
Rheem Triton Power-Vent
The Triton GHE100SU-200 is a 100-gallon, 199,900 BTU high-efficiency commercial natural gas model with power-vent capability, leak detection, and smart monitoring.
View GHE100SU-200 →Low NOx, Ultra Low NOx, Propane, and Power-Vent at a Glance
| Model | Fuel | Capacity | Input | Best Fit |
|---|---|---|---|---|
| GN100-200 | Natural Gas | 100 Gallons | 199,900 BTU/hr | Low NOx applications, including Texas |
| GNU100-200 | Natural Gas | 100 Gallons | 199,900 BTU/hr | Ultra Low NOx applications in California, Utah, and Colorado |
| G100-200LP | Liquid Propane | 100 Gallons | 199,900 BTU/hr | Commercial propane applications |
| GHE100SU-200 | Natural Gas | 100 Gallons | 199,900 BTU/hr | High-efficiency power-vent applications |
Do Not Assume the Standard Natural Gas Model Will Work Everywhere
A standard commercial natural gas water heater may look nearly identical to its Low NOx or Ultra Low NOx counterpart, but the combustion system and emissions rating can determine whether the unit is appropriate for the installation location.
This becomes especially important for businesses with properties in multiple states. A water heater that works for one hotel, restaurant, school, or senior living facility may not meet the requirements for another property in a different jurisdiction.
Before ordering a replacement, confirm the installation address, fuel type, model being replaced, gallon capacity, BTU input, venting configuration, dimensions, and any applicable emissions requirements.
What If the Building Uses Propane?
The Low NOx and Ultra Low NOx models discussed above apply to the natural gas applications covered by this guide. For a comparable 100-gallon, 199,900 BTU liquid propane application, consider the Rheem G100-200LP .
It maintains the familiar Universal commercial platform while being configured specifically for liquid propane.
Consider the Rheem Triton for a High-Efficiency Power-Vent Replacement
Depending on the project, the Rheem GHE100SU-200 Triton can also be worth considering.
The GHE100SU-200 combines a 100-gallon tank and 199,900 BTU input with a high-efficiency design, power venting, integrated leak detection, and EcoNet smart monitoring. It can be especially useful when a facility wants to move beyond a traditional atmospheric commercial water heater.
Make Sure You Order the Right Model the First Time
If you are replacing a commercial water heater and are unsure whether you need standard, Low NOx, Ultra Low NOx, propane, or a power-vent model, Wholesale Water Heater can help review the application before the order is placed.
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