Why You Need Low NOx HVAC Equipment

Why You Need Low NOx HVAC Equipment

Explaining Low NOx

Due to state EPA regulations, an increasing number of U.S. residents are in need of heating HVAC equipment designated as low NOx or ultra low NOx. In addition, HVAC retailers and installers cannot sell products to consumers in certain states unless the equipment is within specific requirements.

As environmental restrictions increase with each passing year, homeowners around the country are left wondering: "Just what exactly is low NOx and where do I find low NOx HVAC products?"


Browse Low NOx Equipment



What is Low Nox?

NOx is an abbreviation used to describe Nitrogen Oxides, a family of reactive and toxic greenhouse gases. When fuel is burned at high heat, whether it's in the engines of automobiles or in the heat exchanger of your furnace, boiler, or water heater, nitrogen oxide gases are emitted.



Is NOx harmful?

Yes. Given the significant impact on the environment from the brownish gas, the EPA has put forth regulations to help limit exposure to one of the most prevalent forms of NOx called nitrogen dioxide, or NO2. According to the EPA, nitrogen oxides are "chief causes of concern" because NOx contributes to:

  • ground-level ozone
  • respiratory problems
  • acid rain and smog
  • low water quality
  • toxic chemicals
  • global warming

This is why it's so important to use the proper venting when installing new heating equipment.


Learn More: How to Pick Venting


How Heating Equipment Reduces NOx

Gas Furnace BurnerPreventing global warming and lung damage aren't the only advantages of low NOx appliances. Using a two-step combustion process-first the fuel and air is premixed, then the mixture burns on a lower flame-NOx emissions are reduced while improving heating efficiency.

High-efficiency heating appliances use premixed fuel burners that achieve an optimal blend of oxygen and fuel prior to combustion, resulting in a cleaner burn without wasting fuel.


Emissions Regulations

If you live in California, any heating equipment you buy will need to conform to local EPA standards as set forth by the South Coast Air Quality Management District. Texas and Utah also have low NOx standards. The standards may change depending on the size and type of heating appliance and where you live. Check out the Low NOx requirements California map below.

Low NOx requirements California map
Basically, there are two categories in which you'll need to purchase your equipment: Low NOx and Ultra-Low NOx. These designations involve a complicated calculation that involves:

  1. The capacity and size of the equipment
  2. The output of energy (expressed in joules) per unit of NO2 emitted (expressed in nanograms or 1-billionth of a gram). 

Low NOx vs Ultra-Low NOx

The difference between Low NOx and Ultra-Low NOx is determined by local EPA standards and based on the type of heating equipment.


For example, It's not uncommon to see an Ultra-Low NOx water heater that emits less than 10 nanograms of NO2 per joule of heat output (10 ng/J). Other equipment like furnaces may allow for higher emissions of NO2 depending on the size.


How Do I Find Low NOx Equipment?

Goodman Low NOx FurnaceAt eComfort, we are constantly updating our products and website to reflect the ever-changing regulations to make shopping for new HVAC products simple.

Even if you do not live in a state that requires it, a low NOx appliance is still a great choice for those concerned about the environment. In fact, many will find that today's newer, high-efficiency appliances are labeled as "Low NOx".

Browse Low and Ultra-Low NOx Products by Category:

Not Sure What You Need?

If you need to replace a heating appliance but are not sure exactly what type or size you need, our HVAC experts are here to help!


Contact Us


Ken, the eComfort Product Expert
Product Expert
Was this article helpful?