If your home is not heated using forced air, chances are a boiler will make sure you stay warm during cold nights. A hot water system delivers hot water through a network of pipes that run to every room in your house. The heating effect gets maximized through radiators. The most common issues with hot water heating tend to be not be major, but small problems that add up over time. Mineral deposits within the water tank, a pilot light malfunction, or an issue with a radiator itself can require professional repair. On average, you will pay between $183 and $582 for these problems. The exact amount will depend on the exact problem, as described in our boiler repair cost guide.
The most recognized standards for HVAC design are based on ASHRAE data. The most general of four volumes of the ASHRAE Handbook is Fundamentals; it includes heating and cooling calculations. Each volume of the ASHRAE Handbook is updated every four years. The design professional must consult ASHRAE data for the standards of design and care as the typical building codes provide little to no information on HVAC design practices; codes such as the UMC and IMC do include much detail on installation requirements, however. Other useful reference materials include items from SMACNA, ACGIH, and technical trade journals.
According to a 2015 government survey, 87% of the homes in the United States use air conditioning and 65% of those homes have central air conditioning. Most of the homes with central air conditioning have programmable thermostats, but approximately two-thirds of the homes with central air do not use this feature to make their homes more energy efficient.[56]
The thermocouple is a copper rod that the pilot flame heats-up. When it gets hot enough, the thermocouple signals that there is enough heat to burn the gas fuel being released into the appliance—and so it allows the gas to be released to the burners. In some cases where the pilot light won’t stay lit, the thermocouple needs to be adjusted or replaced. This is generally a job for a professional.

In the United States, HVAC engineers generally are members of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), EPA Universal CFC certified (for installation and service of CFC HVAC devices), or locally engineer certified such as a Special to Chief Boilers License issued by the state or, in some jurisdictions, the city. ASHRAE is an international technical society for all individuals and organizations interested in HVAC. The Society, organized into regions, chapters, and student branches, allows exchange of HVAC knowledge and experiences for the benefit of the field's practitioners and the public. ASHRAE provides many opportunities to participate in the development of new knowledge via, for example, research and its many technical committees. These committees typically meet twice per year at the ASHRAE Annual and Winter Meetings. A popular product show, the AHR Expo, is held in conjunction with each winter meeting. The Society has approximately 50,000 members and has headquarters in Atlanta, Georgia.
Furnaces and thermostats are not mix-and-match appliances. Using the wrong type of thermostat with a furnace will cause operating problems and can be dangerous. Although thermostats look similar, they are designed very differently. There are numerous types of heating systems and thermostat systems and they need to be coordinated for safe and proper operation. There are three types of thermostat systems used today: millivoltage, low voltage, and line voltage.​