OpenTherm is a non-manufacturer-dependent system of communication between modulating HVAC appliances and room thermostats. It consists of a communication protocol and an interface specification. The OpenTherm communication protocol is primarily designed to control modulating heating appliances. The protocol is available to members of the OpenTherm Association only.

Optergy provides effective tools to help manage the building’s comfort conditions and improve tenant retention. By optimizing comfort conditions (temperature, humidity, and ventilation) they can ensure the tenants are happy and more productive.

Optima Heating and Air Conditioning has provided Melbourne homes and businesses with heating and cooling solutions for more than 30 years. Their extensive industry experience and strong supplier partnerships allow them to provide affordable heating, cooling, and ventilation solutions across residential and commercial projects.

Optimum Energy’s patented software and engineering expertise has helped customers reduce energy use in heating and cooling systems, the largest consumer of energy in buildings, by up to 50%. Their solutions combine technologically advanced HVAC optimization software with powerful cloud-based data analytics and world-class engineering support.

Family owned by Dave and Kathy Ignasiak, Orchard Hill Mechanical offers 25+ years of experience as a full featured residential, commercial, agricultural, and industrial mechanical contractor.

The history of the ORION dry pump started in Japan with the oil-free rotary vane vacuum pump. Thanks to its reduced noise and longer life, the dry pump has been indispensable in automation and labor-saving applications, playing an active and wide-ranging role for every kind of industry

Orell Filtration is based in Stalybridge and supplies Dust Extraction Equipment, Bulk Bags, Air Filters, Filtration Products, Filter Fabrics, Filter Sleeve Bags, Multipockets, and much more.

Over 25 years ago, Victor Orzech began an HVAC company out of a basement workshop in his home. The years have brought many changes, but one thing remains the same: a commitment to the highest level of service and installation in the HVAC industry.

As a full service Air Conditioning, Heating and Ventilation company, OSBORN AC and Heat has been delivering high standard HVAC services.

Osborn HVAC is a full service Sugar Land AC Company servicing both residential and commercial Air Conditioning, Heating and Refrigeration equipment. OSBORN HVAC has provided quality AC Repair, HVAC maintenance and AC installation throughout the Houston and surrounding area since 2009. Located in Sugar Land, Tx, they continue to service a growing community of satisfied customers who depend upon us for quality service.

Oventrop is one of the European manufacturers of valves and controls for the Building Services Industry. The company is an expert partner to stockists, consultants, contractors, and industry. Oventrop offers its partners a long-term beneficial relationship.

Over represents what every innovative company must be: Over and Above. Following this concept, it is set to establish a global standard for energy management and indoor air quality to make cities healthier, smarter, and more efficient. Over aim to be a pivotal resource with a collective effort to combat environmental issues mainly climate change and achieve energy efficiency within the UN Sustainable Development Goals.

Owen AC Services specialize in providing HVAC services, as well as air quality services. They work with air conditioners, providing installations, repairs, and maintenance, as well as heaters. They work with folks throughout Houston and the surrounding area, and they strive to ensure that home is comfortable, and its air remains fresh and healthy.

Owens Companies brings over six decades of experience to each building they service. They are the leading fully integrated, single-source mechanical contractor in the Twin Cities. Twenty-four hours per day, seven days per week, Owens is here for home or business.

OxiCool, Inc. is a Pennsylvania based company that develops air conditioning technologies which are widely in use in commercial and military spaces. The company is dedicated to developing environmentally friendly cooling technologies that have low operating and maintenance costs.

Oxygen8 is changing the way buildings provide healthy, comfortable and energy efficient spaces for occupants. They provide 100% fresh, filtered air and smart technology for maximum comfort and value.

P & R Heating provides a wide range of installation and servicing such as mechanical installation, plant room renewals, heating installation (large and small scale), hot and cold water storage and distribution, plant control installations, gas and oil servicing and maintenance, periodic test and inspection, emergency lighting and much more.

PED Associates Inc. is a manufacturers’ representative company serving HVAC/R, appliance parts, wholesale distributor, OEM’s and exporters.

Pace Heating and Air - Albany service all makes and models of furnaces and air conditioners. And they proudly offer the full line of Carrier heating and cooling equipment, as well as hearth products from HEAT-N-GLO.

Pacific Air Conditioning & Sheet Metal, LLC is Maui's leading Air conditioning repair contractor. They pride themselves on offering the best quality possible to service both commercial and residential air conditioning for customers alike; they will continuously strive to exceed all of expectations. The main goal of the company is to create a lasting impression on all its customers. They believe that the way in which they treat their customers.

Pacific Coast Heating and Air has been serving the San Fernando Valley Santa Clarita and Ventura County area since 1995. They are dedicated to meeting their customer’s heating and air conditioning repair needs. Their focus on customer service can be seen in the positive reviews the company has received over the years.

Pacific NW Reps, LLC is a progressive manufacturers representative firm in the Pacific Northwest representing HVACR manufacturers in Alaska, Arizona, Idaho, Montana, Nevada, New Mexico, Oregon, Washington, Utah & Western Canada.

Pacifica Home Services Ltd. provide a wide range of HVAC and home improvement services in the region of Houghton Le Spring, in Sunderland, in the United Kingdom.

Pack HVAC services has been customer's solution for heating and cooling issues in the Baton Rouge area for over 15 years! Their licensed and bonded team repairs, installs, and services all major brands of HVAC systems including heat pumps, furnaces, air conditioners, thermostats, air handlers, and high efficiency units.

Packerland Heating & Cooling provides heating and cooling services and is based out of the USA.

Palatine Heating & Cooling Company offers quality service in Palatine and the surrounding suburbs. They provide installation, repairs and maintenance services.

When it comes to heating & cooling for home or office, Palatine Unique Indoor Comfort provides expert HVAC installation & repair services in Palatine & nearby areas of the US state of Illinois.

Pallardy Heating & Air Conditioning is dedicated to providing the best possible solution for home or business. One can count on them to provide you with a system and solution that fits one's unique needs.

Pamlico Air, Inc. is a family owned business. They have been in operation since 1990. From the first day in business, their goal has been to provide first rate service with top-quality products.

Panasonic is a manufacturer of versatile heating and cooling solutions including single-split systems, multi-split systems, ECOi VRF-systems, controls and accessories.