Heating, air conditioning, and refrigeration mechanics and installers—often referred to as HVACR technicians—work on heating, ventilation, cooling, and refrigeration systems that control the air quality in many types of buildings.

Heating, air conditioning, and refrigeration mechanics and installers typically do the following:

Heating and air conditioning systems control the temperature, humidity, and overall air quality in homes, businesses, and other buildings. By providing a climate controlled environment, refrigeration systems make it possible to store and transport food, medicine, and other perishable items.

Although trained to do all three, HVACR technicians sometimes work strictly with heating, air conditioning, or refrigeration systems. They also may specialize in certain types of HVACR equipment, such as water-based heating systems, solar panels, or commercial refrigeration.

Depending on the task, HVACR technicians use many different tools. For example, they often use screwdrivers, wrenches, pipe cutters and other basic handtools when installing systems. To test or install complex system components, technicians may use more sophisticated tools, such as carbon monoxide testers, voltmeters, combustion analyzers, and acetylene torches.

When working on air conditioning and refrigeration systems, technicians must follow government regulations regarding the conservation, recovery, and recycling of refrigerants. This often entails proper handling and disposal of fluids.  

Some HVACR technicians sell service contracts to their clients, providing regular maintenance of heating and cooling systems.

Other craft workers sometimes help install or repair cooling and heating systems. For example, on a large air conditioning installation job, especially one in which workers are covered by union contracts, ductwork might be done by sheet metal workers and duct installers, or electrical work by electricians. In addition, home appliance repairers usually service window air conditioners and household refrigerators. For more information on these occupations, see the profiles on sheet metal workers, electricians, or home appliance repairers.

Plumbers, pipefitters, and steamfitters install and repair pipes that carry water, steam, air, or other liquids or gases to and in businesses, homes, and factories.

Plumbers, pipefitters, and steamfitters typically do the following:

Although plumbers, pipefitters, and steamfitters are three distinct specialties, their duties are often similar. For example, they all install pipes and fittings that carry water, steam, air, or other liquids or gases. They connect pipes, determine the necessary materials for a job, and perform pressure tests to ensure a pipe system is airtight and watertight.

Plumbers, pipefitters, and steamfitters install, maintain, and repair many different types of pipe systems. Some of these systems carry water, dispose of waste, supply gas to ovens, or heat and cool buildings. Other systems, such as those in power plants, carry the steam that powers huge turbines. Pipes also are used in manufacturing plants to move acids, gases, and waste byproducts through the production process.

Master plumbers on construction jobs may be involved with developing blueprints that show where all the pipes and fixtures will go. Their input helps ensure that a structure’s plumbing meets building codes, stays within budget, and works well with the location of other features, such as electric wires.

Plumbers and fitters may use many different materials and construction techniques, depending on the type of project. Residential water systems, for example, use copper, steel, and plastic pipe that one or two plumbers can install. Power-plant water systems, by contrast, are made of large steel pipes that usually take a crew of pipefitters to install. Some workers install stainless steel pipes on dairy farms and in factories, mainly to prevent contamination.

Plumbers and fitters sometimes cut holes in walls, ceilings, and floors. With some pipe systems, workers may hang steel supports from ceiling joists to hold the pipe in place. Because pipes are seldom manufactured to the exact size or length, plumbers and fitters measure and then cut and bend lengths of pipe as needed. Their tools include saws, pipe cutters, and pipe-bending machines.

They then connect the pipes, using methods that vary by type of pipe. For example, copper pipe is joined with solder, but steel pipe is often screwed together.

In addition to installation and repair work, journey- and master-level plumbers, pipefitters, and steamfitters often direct apprentices and helpers.

Following are examples of occupational specialties:

Plumbers install and repair water, drainage, and gas pipes in homes, businesses, and factories. They install and repair large water lines, such as those that supply water to buildings, and smaller ones, including ones that supply water to refrigerators. Plumbers also install plumbing fixtures—bathtubs, showers, sinks, and toilets—and appliances such as dishwashers, garbage disposals, and water heaters. They also fix plumbing problems. For example, when a pipe is clogged or leaking, plumbers remove the clog or replace the pipe. Some plumbers maintain septic systems, the large, underground holding tanks that collect waste from houses not connected to a city or county's sewer system.

Pipefitters install and maintain pipes that carry chemicals, acids, and gases. These pipes are mostly in manufacturing, commercial, and industrial settings. They often install and repair pipe systems in power plants, as well as heating and cooling systems in large office buildings. Some pipefitters specialize: