Types of Heating Systems

Steam, hot water, forced warm air, and electric heating systems all function in the same basic way. Each system is equipped with a control, a heat producer, a heat exchanger, and a heat distributor.

• The control, called a thermostat, signals a need for heat.
• The signal turns on the heat producer, usually an oil or gas burner or an electric heating element.
• The heat warms the transfer medium (air, water, or steam) in the heat exchanger.
• If the heat exchanger heats air, it is a furnace.
• If the heat exchanger heats water or produces steam, it is a boiler.
• The transfer medium moves by gravity or is forced through ducts (warm air) or pipes (water or steam) to the heat distributors located in the living areas.
• The heat distributors in a forced warm-air system are registers.
• The heat distributors in a hot water or steam system are convectors or radiators. In a hot water radiant heating system, the water moves through tubing concealed in the ceiling, walls, or floor.
• Return ducts or pipes carry the medium back to the heat exchanger.
• When the temperature reaches the level set on the thermostat, the thermostat automatically shuts down the system.

Electric Boilers and Furnaces

In an electric boiler or furnace, the heating elements are immersed directly in the transfer medium, either water or air. Maintenance of such a system is similar to that required for a gas or oil-fired boiler or furnace; problems with the electric heating elements are best left to a professional.

Duct Heaters

Designed for installations in the ducts of an existing forced warm-air hearing, duct heaters can be turned on at the same time as the blower or can be operated by a separate thermostat located in an area requiring supplemental heat. The heaters must be controlled so they don’t turn on unless the blower is running.

Baseboard Heaters

These heaters require no pipes or ducts. They connect directly to the electrical system in the house. A good choice for a room addition or a hard-to-heat area, a baseboard heater has its own thermostat and safety thermal cutoff switch.

• Some baseboard heaters use resistance coils that glow red-hot.
• Others have a resistance wire that heats a ceramic tube.
• Still others have the heating element immersed in a sealed tube. Fins that radiate heat into the room surround the tubes.

Most baseboard heaters are very reliable. If you do have a problem, you’ll have to call in an electrician.

Wall and Ceiling Heaters

Suitable for bathrooms and other small areas, these resistance-heated units are mounted in a wall or ceiling and are wired directly into the electrical system. Clean the heater occasionally. Replace a defective one.

Radiant Heating Panels

These may be electrically heated glass panels mounted in walls or ceilings or special gypsum board panels embedded with electric resistance wires and installed in place of regular gypsum board. Both kinds are wired into the electrical system and are controlled by a thermostat. Once installed, they provide trouble-free service for years.

Steam Heat

A hallmark of many older homes, steam heat begins in a boiler fueled by gas, oil, or electricity. The boiler turns water into steam, which rises through pipes to radiators or convectors. There the steam gives up its heat and condenses into water, which returns to the boiler.

Hot Water Heat

In a hot water heating system, water heating in a boiler travels through a network of pipes to the heat distributors (usually convectors or radiators) where the heat is given off. The cooled water then returns to the boiler through the return pipe.

• In older homes, the movement of water is governed by gravity. Warmer, lighter water rises and takes the place of heavier, cooler water.
• The more modern hydronic systems employ a circulating pump to move the water under pressure. A thermostat governs the operation of the pump as well as the burner.
• An expansion tank, usually mounted above the boiler, contains air and water. The air acts as a cushion to maintain heated water at the proper pressure.