Accelerating Clean Cooling & Heating

Contact UsNewsletter
01

Why this matters

Most refrigeration runs on chemicals that warm the planet, or quietly poison it.

HFCs warm the atmosphere up to 14,000× more than CO₂. Their HFO replacements break down into TFA, a forever chemical now detectable in rain, ice, and human blood.

The answer

CO₂, ammonia, hydrocarbons. Proven for over a century. They don't warm the planet, and they don't leave a forever chemical behind.

Natural refrigerants avoid both.

02
Primary metric

A year of avoided emissions, made visible.

GHG emissions M&M Carnot avoided over the lifetime of 2025's equipment placed in the market.

M&M Carnot · 2025

504,000metric tons of CO₂e avoided.

Over the lifetime of 2025's equipment placed in the market. The comparisons that follow show what that volume actually looks like.

03
In real-world terms

What it adds up to.

67.7k
homes / year
powered for a year on the same footprint
117.5k
petrol cars off the road
for one year of driving emissions avoided
1.3B
miles not driven
distance equivalent never burned in a tank
9.0%
of Boston City's
annual emissions in 2023
04
Hidden pollutant

TFA: the forever chemical you haven't heard of.

Trifluoroacetic acid is an ultra-short-chain PFAS that forms as a breakdown product of synthetic refrigerants and accumulates in rainwater. Natural refrigerants don't break down into TFA.

Stage 1 · Emission

HFCs and HFOs leak from refrigeration systems.

Synthetic refrigerants escape over the lifetime of every system: installation, service, end-of-life. The leaks are small, but they add up across millions of installations worldwide.

Refrigerant gas leaking from cooling equipment
05

Growth

Cumulative avoided CO₂e emissions over the years.

M&M Carnot has been ATMO Approved since 2022, now 4 consecutive years of independently verified impact.

Trajectory bars appear once at least one data year is recorded.

06
Founder

In the words of the people who built it.

Our partnership with ATMOsphere aligns with our mission of advancing smart, healthy and sustainable spaces and places. ATMO fills a critical role as we work to advance natural refrigerant adoption worldwide.

Joe Duncan (National Sales Manager)
07
Voices from the field

What operators say after a year on natural refrigerants.

Ryan Ritter
President
Enns Industrial Refrigeration
Performance
How has the system performed over the past year?

M&M Carnot Refrigeration delivered a system that met the specified performance requirements and has operated reliably since commissioning.

Ryan Ritter
President
Enns Industrial Refrigeration
Quality & Reliability
How has the build quality and reliability held up?

M&M Carnot Refrigeration’s system has been very reliable to date, with smooth operation and no breakdowns or recurring issues. Overall, we have been very satisfied with its performance and dependability.

Ryan Ritter
President
Enns Industrial Refrigeration
Safety
How has safety been operating natural refrigerants?

Yes. M&M Carnot Refrigeration supplied equipment that complied with applicable safety standards, including TSSA requirements. The documentation and equipment quality supported a safe and compliant installation.

Ryan Ritter
President
Enns Industrial Refrigeration
Service
How was the level of service and technical support?

M&M Carnot Refrigeration provided strong service and responsive technical support throughout the process. They met their delivery commitments and were helpful in addressing questions and support needs as they came up.

Ryan Ritter
President
Enns Industrial Refrigeration
Satisfaction
Would you work with this company again?

We would be very likely to work with M&M Carnot Refrigeration again based on the quality of the equipment supplied, reliable performance, and the level of service and support provided throughout the project.

Ryan Ritter
President
Enns Industrial Refrigeration
Training
Did the training prepare your team to run the system?

Yes. M&M Carnot Refrigeration provided valuable training, including bringing our engineers into their office for hands on instruction. This helped our team build confidence in managing and operating CO2-based equipment

Clark Andrews
Director of Business Development
IR Pros
Performance
How has the system performed over the past year?

While the transcritical CO2 system has not been fully commissioned yet, the engineering/design process, build quality and delivery time met or exceeded our expectations.

Clark Andrews
Director of Business Development
IR Pros
Quality & Reliability
How has the build quality and reliability held up?

We have not experienced any major issues to date.

Clark Andrews
Director of Business Development
IR Pros
Safety
How has safety been operating natural refrigerants?

Yes, the system was designed to meet all required safety requirements.

Clark Andrews
Director of Business Development
IR Pros
Service
How was the level of service and technical support?

While the transcritical CO2 system is not fully commissioned, the technical support received and delivery time commitment met or exceeded our expectations.

Clark Andrews
Director of Business Development
IR Pros
Satisfaction
Would you work with this company again?

We are highly likely to work with this company again.  They are a leader in transcritical CO2 technology, deliver high quality equipment and have knowledgeable engineers and technicians.

Clark Andrews
Director of Business Development
IR Pros
Training
Did the training prepare your team to run the system?

Yes, M&M Carnot provides several training classes per year for both engineers and technicians on their natural refrigerant-based equipment.  We routinely participate in this training.

James Duffy
Sr. Manager Engineering, Transformation & Development
United States Cold Storage
Service
How was the level of service and technical support?

Technical support has been great, and deliveries have been on time with no issues.

James Duffy
Sr. Manager Engineering, Transformation & Development
United States Cold Storage
Satisfaction
Would you work with this company again?

My experience working with M&M/ JCI has always been excellent and continues to be so. We continue to work this this group and expect our relationship to stay strong in the future.

James Duffy
Sr. Manager Engineering, Transformation & Development
United States Cold Storage
Training
Did the training prepare your team to run the system?

On-site training has been provided, and additional classroom-style Transcritical CO₂ training opportunities have been offered. It is up to our team to fully take advantage of these resources.

08
The company

M&M Carnot: company profile.

M&M Carnot's vision is to drive the advancement of natural refrigeration technologies across a broad spectrum of industries — from industrial and commercial applications to recreational facilities and data centers. At the heart of this mission is a steadfast commitment to leading the transition toward systems that respect and preserve the environment, ensuring every client has access to sustainable alternatives to the synthetic refrigerants that continue to harm our planet.

M&M Carnot is specialized in high-performance, eco-friendly refrigerants — including Ammonia, Cascade Ammonia-CO₂, and Transcritical CO₂ — providing solutions that meet rigorous performance demands while aligning with global sustainability goals. Now operating as a product line of Johnson Controls, M&M Carnot carries this legacy of innovation forward.

Work with M&M Carnot

Tell us about your project. We'll route the conversation to the right team.

Get in touch

Become ATMO Approved

Does your company use natural refrigerants?

The ATMO Approved label is independently verified. Not self-declared, not marketing. If your equipment runs on CO₂, ammonia, hydrocarbons, or water, you may qualify.

Apply for the labelLearn how the process works