Solstice® yf: What’s Keeping Your Vehicle's Air Conditioner Cool

Solstice® yf: What’s Keeping Your Vehicle's Air Conditioner Cool

The hydrofluoroolefin (HFO) refrigerant that has transformed the global automobile industry for the past decade.

It’s the hottest day of the summer season. The air is humid, and everything feels sticky. You run to your car or heavy-duty truck and blast your air conditioner to the highest setting and glorious cold air comes out – pure bliss.

How’s that possible? You have the refrigerant in your vehicle to thank for that and chances are it may be the hydrofluoroolefin (HFO) refrigerant, Solstice yf® (R-1234yf).


What is a Refrigerant?

A refrigerant is a gas that’s used for refrigeration purposes. It flows through an air conditioning system and enables the cooling of a space. In your case, it cools the air that your car’s air conditioner produces.

Refrigerants can be used for automobile air conditioning applications in light-duty, medium-duty, heavy-duty and off-road vehicles. Additionally, depending on the formulation, it can also be used for applications such as industrial and cold storage refrigeration, commercial and supermarket refrigeration, organic ranking cycle (ORC) systems and even ice rinks.

The most commonly used mobile air conditioner (MAC) refrigerant over the past decade has been Honeywell's Solstice® yf (R-1234yf), a hydrofluoroolefin (HFO) refrigerant.

Since its development a decade ago, Solstice® yf (R-1234yf) has become the alternative to refrigerants with high global warming potential (GWP) such as R-134a.

The Evolution of Refrigerants

What makes an HFO a better option?

To understand why an HFO refrigerant is a better option, let’s quickly look at some of its usage history.

Decades before the wide adoption of Solstice® yf (R-1234yf), the automobile industry first used a refrigerant called CFC-12. Most industries relied heavily on the use of chlorofluorocarbon refrigerants (CFCs) before the 1980’s.

CFCs were eventually found to cause extremely high levels of ozone depletion and as a result were banned by many governments in the 1990’s. After CFCs came the hydrofluorocarbon, HFC-134a (R-134a).

This material was effective at cooling cars and was globally adopted by every carmaker on the planet. The problem with HFC-134a is that it contributes to global warming.

When governments started focusing on reducing global warming, HFC-134a (R-134a) quickly became a target for phase out. Continuously evolving government regulations have added more pressure on automobile manufacturers to find alternatives to HFC-134a with less global warming potential. That's where Solstice® yf (R-1234yf) comes in.

The Impact of Solstice® yf

To respond to the needs of the automobile industry, Honeywell invented and patented a hydrofluoroolefin (HFO-1234yf) that could be used as a near drop-in replacement for the hydrofluorocarbon refrigerant, HFC-134a (R-134a).

In the last decade, Solstice® yf (R-1234yf) has become the leading refrigerant for original equipment manufacturers (OEMs) and aftermarket automobile air conditioners.

What makes it a better alternative? Solstice yf (R-1234yf) performs nearly the same as previous refrigerant generations (HFC-134a), but also has the following improved characteristics:

  • Ultra-low global warming potential
  • Meets current government regulations demanding the transition to lower GWP solutions
    • Complies with the EU’s low GWP requirement
    • Qualifies for U.S. Environmental Protection Agency (US EPA) greenhouse gas (GHG) tailpipe credits under the Corporate Average Fuel Economy (CAFE) Standard

The global adoption of not only Solstice® yf (R-1234yf), but also the rest of the Solstice® portfolio has helped avoid the potential release of the equivalent of more than 326 million metric tons of carbon dioxide into the atmosphere, equal to the carbon emissions from nearly 70 million gasoline-powered passenger vehicles per year.1

A decade later we continue our efforts to help the automobile service industry through new developments. The latest has been the addition of ultraviolet (UV) dye to our Solstice® yf (R-1234yf) refrigerant that’s now available at all participating NAPA Auto Parts stores within the United States.

Solstice yf (R-1234yf) with UV dye incorporated is a ready-now solution that will enable the automotive service industry to quickly identify and repair leaks, shortening servicing time, reducing technician cost, eliminating call-backs and ultimately increasing customer satisfaction.

Honeywell is committed to continue helping automakers worldwide meet global regulatory requirements for ultra-low GWP automobile air conditioning with Solstice® yf (R-1234yf).

Learn more on Solstice® yf's (R-1234yf) technical aspects.

Contact us to speak to our experts and learn how our Solstice® portfolio can help you with your emission goals and needs.


1 Calculations are based on actual sales of Solstice products (in lbs) from Jan 2010 through Dec 2022, and utilize the EPA GHG equivalency calculator for conversion.