A Greener Air Conditioner?

HFC Alternatives Post Kigali Amendment

When the Kigali amendment to the Montreal Protocol passed in October, it set a timeline for the United States and Europe to phase out hydrofluorocarbons (HFC’s) by 2019 due to their high global warming potential (GWP). So what will todays HFC’s be replaced with and what alternatives are available today?

“Due to different thermodynamic and safety properties of the alternatives, there is no “one size fits all” solution. The suitability of a certain alternative must be considered separately for each category of product and equipment and in some cases also taking into account the level of ambient temperature at the location where the product and equipment is being used,” according to the European Commission on Climate Action‘s report on F-Gas alternatives. (HFC’s are considered F-gases also known as fluorinated gases).

What to do if you are building new or remodeling:

  • SNAP – This is the United States Environmental Protection Agencies list of approved alternatives. This list still includes HFC’s. Use this list when talking to your contractor or HVAC professional if you’re in the United States. Make sure to ask your contractor how your choice will effect your energy consumption. You need to weigh your HVAC or refrigeration choice against its energy efficiency.
  • Cool Technologies – “This website includes a sampling of companies using natural alternatives in a variety of applications. It was created to demonstrate there is already a wide array of safe and commercially proven technologies available to meet nearly all those human needs formerly met by fluorinated refrigerants,” according to Cool Technologies, a Greenpeace and Environmental Investigation Agency (EIA) website.
  • Energy Star – Review the Energy Star rated HVAC systems and refrigerators. Most of these will still use HFC’s for now, but they should require less energy to run and are considered best in class.
  • European Commission on Climate Action –  The European Commission offers a guide to buying climate-friendly alternatives to HFCs and HCFCs in Europe.

 What to do with the AC and refrigerator that you currently own:

  • Heat and Cool Efficiently – Energy Star has a list of what you should do to keep your current system running efficiently.
  • Recycle or dispose of it properly once it’s no longer running efficiently. “To reduce energy demand, ozone depletion, and global climate impacts, it is critical that older units be permanently removed from the energy grid and properly disposed of so that environmentally-harmful refrigerants and foam blowing agents are captured and recycled or destroyed,” according to the EPA.

The Next Generation Of HFC’s

Hydrofluoroolefins (HFO’s)

  • Hydrofluoroolefins (HFO’s) are being marketed by Honeywell and Dupont as the fourth generation refrigerant that will be used instead of HFC’s.
  • “Honeywell developed Hydrofluoroolefins (HFOs) that have an ultra low GWP and are non-ozone-depleting. Today these HFOs are available for mobile air conditioning, refrigeration, aerosol applications, insulating and one-component foams. Soon, new HFOs will be available to serve the high performance thermal insulation and solvent segments,” according to Honeywell.

Natural Refrigerants

Ammonia, carbon dioxide, hydrocarbons, air and water are considered natural refrigerants and are outlined in ASHREA’s position document on Refrigerants and their Responsible Use.

“Some of the natural refrigerants have been used in the market place for many decades although at varying degrees of application. Although environmentally superior favorable, natural refrigerants are not free of other concerns, such as corrosion, toxicity, high pressures, flammability, or in some cases lower operating efficiencies,”according to ASHREA.


“If a lower global warming potential (GWP) refrigerant is less efficient than the fluid which it replaces, any direct global warming benefit may be offset by increased energy consumption. ASHRAE’s position is that the selection of refrigerants and their operating systems be based on a holistic analysis of multiple criteria,” according to ASHREA.

“Overall, the opportunity exists for a significant percentage of current HFC use to transition to NIK [Not In Kind/Non-HFC/HFO] alternatives during the anticipated Montreal Protocol phasedown of HFCs,” according to the Center For Climate and Energy Solutions.

“By providing a broader range of alternatives, NIK alternatives provide market and price competition to patent-controlled next generation HFOs, and in some cases offer greater energy efficiency. In addition, NIK alternatives can help Article 5 Parties leapfrog from HCFCs to low-GWP alternatives. Efforts are underway but will require several more years to address changes in codes and standards to ensure a wider range of more flammable alternatives can be used safely,” according to the C2ES.

“Chemically, HFOs are a form of HFCs, but due to the negative connotations that HFCs have acquired, this new class of chemicals is being marketed under a different name. While HFOs have lower GWPs than the earlier generation of HFCs they continue to pose dangers to the environment,” according to Greenpeace.


“HFO’s do not provide long term, sustainable solutions. Natural substances are available and technically and economically feasible in almost all cooling applications: domestic and commercial refrigeration and air-conditioning, mobile air-conditioning, industrial processes, insulation foam blowing,” according to Greenpeace.

“As Article 5 Parties consider replacing high-GWP technologies, there is a desirability (and very real potential) to leapfrog from HCFCs to low-GWP alternatives—avoiding a shift first from HCFCs to high-GWP HFCs and at a later date from HFCs to a low- or zero-GWP alternative,” according to the Center For Climate and Energy Solutions.

Kigali Amendment Details

The Kigali amendment to the Montreal Protocol sets the dates for phasing out hydrofluorocarbons (HFCs) which are used in air conditioners, refrigerators, building insulation, fire extinguishing systems and aerosols. HFC’s contribute to global warming and were originally developed as an alternative to chlorofluorocarbon’s (CFC’s)  which deplete the ozone layer. CFC’s were phased out as part of the original Montreal Protocol.

“Following seven years of negotiations, the 197 Montreal Protocol parties reached a compromise, under which developed countries will start to phase down HFCs by 2019. Developing countries will follow with a freeze of HFCs consumption levels in 2024, with some countries freezing consumption in 2028,” according to United Nations Environment Programme (UNEP).

“HFCs are the fastest growing climate pollutants, and they pack hundreds to thousands of times the climate-warming punch of carbon dioxide, pound for pound. Scientists estimate that HFCs could add up to 0.5° Celsius to global temperatures by century’s end if their growth is not checked,” according to the NRDC.



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My name is Rebecca. I was born in Sweden, where nature is a guiding force. I was raised in Silicon Valley where innovation rules. My true north is a place where both values merge. I have two high energy kids and a mutt named Sadie. I’m married to my best friend, who I met when I was 17. We juggle life, work, love, and friends in the San Jose, California suburbs. It's fun. I’m trying to answer one question: "How can I live the life I love, sustainably?"

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