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.

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.

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.

Ouellet is the manufacturer of heating and ventilation equipment for institutional, commercial, industrial and residential applications; electric heating equipment to include unit heaters, ceiling heaters, cabinet heaters, baseboard, bath ventilation, Heating Cable, Self-Regulating Cable etc.

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.

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.

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.

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

Payne offers residential HVAC products available over the counter at Totaline Sales Centers nationwide. Products include split system air conditioners and heat pumps, gas furnaces, evaporator and fan coils, ductless split systems and packaged products.

Peak Heating & Cooling Inc. specializes in the repair and replacement of the heating and cooling systems for the home or business. Peak Heating & Cooling Inc. will send only the best technician to fix the plumbing problem, air conditioner repair and, gas or propane (LP) furnace and heater repair as well as the air conditioner installation, furnace, boiler replacement, and tankless hot water heaters installation.

PemTech offers world-class quality and unparalleled customer service with a wide range of industrial gas detection systems. The company's industrial gas detectors and wireless gas sensors are equipped to handle a variety of toxic and combustible gases. Their detectors specifically designed to monitor Hydrogen Sulfide (H2S), Carbon Dioxide (CO2), Methane (CH4), and various combustible and toxic gases.

Pennco's hydronic heating products, designed for residential and commercial buildings, have earned a reputation for exceptional value, high performance and dependability. Built with high quality components and standards, Pennco gas and oil-fired boilers are manufactured by the company's dedicated workforce in the U.S.A. to ensure that customers get the very best in home heating comfort.

Peoples Heating and Cooling has been a household name in the Shelbyville and the Greater Indianapolis area. With thousands of customers who rely on them for their home and business heating and cooling needs, Peoples Heating and Cooling provides prompt, professional, and friendly service all at an affordable price.

Perdido Heating and Air Conditioning cater to all air conditioning and heating needs. They service and repair their customers with excellence. They do sales, service, and installation and make sure their customers feel good at home or business. They also provide estimates on new installations.

Perfect Temp Heating and Cooling is one of the best HVAC contractors in Minneapolis, MN, USA. At Perfect Temp, their commitment is to provide customers with the best possible service experience goes beyond just honoring a warranty or showing up when called upon.

PFE Corp. offers complete sales and service for all brands, makes, and models of residential and commercial HVAC equipment. Whether one needs an upgrade, a full system replacement, or routine maintenance, they handle it all.

Phelps Heating & Cooling, heating and cooling isn’t only their job, it’s their passion. They strive to provide the best HVAC service in Hodgenville. They’ll offer the support whether it’s putting in an up-to-date HVAC system or repairing and inspecting current equipment.

Philco provides heating and cooling products for residential and light commercial industries. They provide Air conditioners, gas furnaces, heat pumps, air handlers, air cleaners.

Pickrel Brothers is one of the Midwest's providers of pipe, valves, fittings, plumbing, heating and industrial supplies. They also provide boilers and hydronic equipment, heating and cooling coils, unit heaters, water softners, plumbing fixtures and much more.

PJM Air Conditioning specializes in Air conditioning breakdown repairs, Air conditioning service and Air conditioning maintenance of commercial and residential premises. Their goal is to not only meet the expectations of our clients but to exceed them whilst also maintaining long term and cost effective solutions to any of the air conditioning needs.

Plumhouse manufactures central heating chemicals, radiator controls, fire valves, pumps, central heating controls, thermostats, motorized valves and more.

Plumbing Medic is ready to help with any type of heating and air conditioning job in Gilbert. They’re also able to offer comprehensive plumbing services throughout Maricopa County.

Polidoro USA Inc. develops innovative custom solutions designed to save energy by exploiting many years of experience in the sector and by co-designing with their customers. Their products range from premix Metal-fiber or steel gas burners., tubular burners atmospheric or semi-premix, multi-blade burners, pilots.

Since 2001, Powell Heating & Cooling has been the premier provider of heating and air services in Tippecanoe County. With over 30 years of combined experience, their team is dedicated to delivering exceptional service and unparalleled expertise. As a family and locally owned business, they pride themselves on their commitment to the community, offering reliable and prompt solutions for all HVAC needs.

Power Flame is an innovative and forward thinking manufacturer of gas, oil, combination gas/oil, low NOx burners, and combustion control systems designed for commercial, industrial, and process applications

Precision Heating & Air Conditioning distributes air conditioners, boilers, ductless systems, evaporator coils, fan coils, gas furnaces, geothermal heat pumps, heat pumps, oil furnaces and more.

As Temecula Valley’s most dependable and professional HVAC contractor, ProFlo Air Conditioning, Heating & Plumbing strive to keep their reputation in tact. They hold themselves and their work to the highest standard. Their technicians are constantly improving their skill set by frequently completing required training by their heating and air conditioning appliance suppliers.

Propous is one of the largest independent suppliers of gas and oil burner’s spare parts, valves, air heaters, and HVAC products. The success of the company can be attributed to its efficiency, reliability, technical knowledge and an understanding of the customer’s requirements.

Since 2019, ProThermal Heating and Cooling has served as the trusted HVAC contractor in Tulsa, OK, and nearby areas. Each technician on their team maintains certification and professional licenses. They consistently go above and beyond customer expectations, and they stand behind their work.