What is Central Heating?
Central Heating systems warm the inside of buildings or parts of buildings, with the heat usually originating from one point and spreading to multiple rooms and hallways. When Central Heating systems are used in conjunction with other temperature control systems, the entire system is sometimes referred to as a HVAC system. Central Heating is generally used in cooler climates; most modern buildings – including hotels, malls, office buildings, and other commercial spaces – have their own central heat. However, many times a single central heating system can be used to warm many buildings at once.
Central Heating systems are not homogeneous: the installation process is largely informed by the installer’s heating needs and requirements. Furthermore, the way the heating is controlled and monitored needs to be optimized building by building – a well programmed Central Heating system can adjust heat and monitor itself without human input. Again, how complex this system is depends on homeowner and building owner’s heating desires. “District heating” is an extension of central heating wherein a collection of houses or buildings are heated from a central location usually manned by a public utility. The heat source in these cases is usually steam from central boiler rooms.
History of Central Heating
Although modern central heating methods were developed in the last few centuries, the concept started long before with the ancient Greeks. Their temples were warmed with heat from fires that were circulated using flues. Ancient Romans continued this practice, using furnaces to heat air around a room that would lead to the entire room gradually warming. These techniques were lost with the collapse of Roman civilization.
In 1793, a British engineer named William Strutt designed a furnace based off of a design by English writer John Evelyn developed almost a hundred years before. Using an underground passage, air outside of the structure was heated in Strutt’s design. With the help of another engineer, Charles Sylvester, Strutt constructed a heating system for a local hospital that not only heated the air but also cleaned it.
In the 18th century, a Scottish inventor by the name of James Watt built the first working central boiler system. Using pipes, steam was placed under pressure and distributed through the building. Hot water heating systems didn’t proliferate until the 1830s, when buildings such as factories and churches began to adopt them.
In the late 1850s, Russian inventor Franz San Galli developed the radiator, which quickly spread across most of Europe and the United States. Radiators were doubly useful in the fact they could not only heat rooms but also provide hot water.
After World War II, central heating systems started to become commonplace in American households. They used boilers to generate heat, spreading the heat into hallways and rooms through radiators. Electric heating was introduced soon after, proving to be a cost effective and comfortable method of heating the home.
How does Central Heating work?
Most central heating systems work by warming cool air. A simplification of their processes:
- Heat is generated in the burner of the furnace by burning natural gas or propane.
- The heat generated by the furnace transfers its heat through a heat exchanger, which becomes extremely hot.
- Air from ducts in the home is blown against the recently heated heat exchanger, which warms the air.
- The blower on the furnace blows the heated air back into the home’s ductwork, which filters the air throughout the home, providing heat to each room.
What’s the difference between Central Heating and Direct Heating?
Boilers, heat pumps, and furnaces are all classified as central heating systems. This is because they generate heat in some central location within your home and ductwork or radiators are used to disseminate that heat throughout the home.
Direct heat is generally more supplemental, like a space heater. The benefit of using direct heating systems is that they can be installed much more easily than central heating systems and, if needed, are also more easy to upgrade. However, they can be expensive, especially if the whole house is heated using direct heat.
What are the types of Central Heating?
Furnaces
Furnaces force hot air throughout your home using ductwork. Furnaces can use electricity, propane, or oil to heat the air, but usually use natural gas.
Gas furnaces are especially popular as the system they used to distribute air can be used in hotter months by air conditioning units.
Boiler
Boilers are an alternative heating system that heat water instead of air and send it through pipes to heat the home. This can allow the homeowner to target areas of the home that require more heating or cooling. They are more expensive to install and maintain than boilers or heat pumps.
Boilers and furnaces are examples of central heating systems.
Heat Pump
Despite their name, heat pumps are used to heat and cool the home. Electricity and refrigerant are used to transfer heat rather than generating the heat itself. Because of this, heat pumps are very efficient. However, they work best in moderate climates and can struggle to heat at very low temperatures.