Home heating systems are designed to increase the temperature inside a house by tapping thermal energy from a fuel source, then transferring it to living spaces. There are several types of systems used to provide heat in residential homes, and each broad type has more specific variations. Some HVAC systems share components with the home’s cooling equipment, some work independently, and some provide both heating and cooling.
No matter what HVAC system is installed, the purpose of all heating appliances is to use some type of fuel to warm the interior of a home. Heating systems can use a variety of fuel sources, including natural gas, propane, fuel oil, biofuel (such as wood), solar, and electricity. Some homes have more than one heating system: For example, some additions or finished basements are heated by different systems than the rest of the house.
Here, learn about seven different types of heating systems plus the pros and cons of each to help you decide which option is best for your home.
Forced Air Heating/Cooling Systems
By far the most common HVAC system in modern North American homes, the forced air system uses a furnace with a blower fan that delivers warmed air to the various rooms of the home through a network of ducts. Forced air systems are very quick at adjusting the temperature of a room, and because air conditioning systems can share the same blower and ductwork, this is an efficient overall HVAC System.
Installing a new forced air HVAC system typically costs between $5,000 and $10,000.1 This is based on the square footage of your home, and larger houses will require stronger units that may increase costs. These systems can last up to 25 years before needing replacement units.
Fuel sources: The furnaces that power forced air systems can be fueled by natural gas, liquid propane (LP), fuel oil, or electricity.
Distribution: Air that is warmed by the furnace’s burner or the heating element is distributed through a network of ducts to heating registers in individual rooms. Another system of ducts returns the air back to the furnace through cold-air returns.
Gravity Air Furnace Systems
A precursor to forced air systems, gravity air furnaces also distribute air through a system of metal ducts—but rather than forcing the air via a blower, gravity air systems operate by the simple physics of warm air rising and cool air sinking. However, the temperature adjustments are slow because the systems operate by simple convection currents.
A gravity air furnace in a basement heats the air, which then rises into the various rooms through ducts. Cool air returns to the furnace via a system of cold-air return ducts. The so-called “octopus” furnaces found in many older homes are gravity air furnaces.
Gravity air systems are no longer installed, and the cost of maintaining them should be minimal. In many older homes, they continue to perform effectively.
Fuel source: Gravity air furnaces can be fueled by natural gas, liquid propane (LP), or fuel oil. They are seldom fueled by electricity since these systems are older and electricity was rarely used in their era.
Distribution: Conditioned air is circulated through a network of metal ducts.
In-Floor Radiant Heating Systems
Modern in-floor radiant heating involves plastic water tubing, which is installed inside concrete slab floors or attached to the top or bottom of wood floors. It is quiet and generally energy-efficient. It tends to heat slower and takes longer to adjust than forced air heat, but its heat is more consistent. While maintenance can be difficult to reach the hidden pipes, in-floor radiant heating units should last for several decades.
Radiant heating is different from forced air heat in that it heats objects and materials, such as furniture and flooring, rather than just the air. Most whole-home radiant systems distribute heat via hot water heated in a boiler or hot water heater. However, boiler-based systems cannot be combined with air conditioning.
There are also in-floor systems that use electrical wiring installed under flooring materials, typically ceramic or stone tile. These are less energy-efficient than hot water systems and are typically used only in small rooms such as bathrooms. They primarily heat the floor in such a way as to keep your feet warm, but not so much the room itself. Installing radiant floor heating typically costs between $1,800 and $6,000, while costs gradually decrease as more square footage is added.1
Fuel sources: Hot water tubing systems are usually heated by a central boiler, which can be fueled by natural gas, liquid propane (LP), or electricity. Hot water also can be provided by solar hot water systems, which are commonly used to supplement fuel-based systems.
Distribution: In-floor systems are usually distributed by hot water flowing through plastic tubing.
Traditional Boiler and Radiator Systems
Traditional boiler and radiator systems include a central boiler that circulates steam or hot water through pipes to radiator units positioned strategically around the house. Older homes and apartment buildings in North America often are heated with these systems. The classic radiator—a cast-iron upright unit usually positioned near windows—is often called a steam radiator, although this term is sometimes inaccurate.
In reality, there are two types of systems used with these older radiators. True steam boilers actually do circulate gaseous steam through pipes to individual radiators, which then condenses back to water and flows back to the boiler for reheating. Modern radiator systems circulate hot water to radiators via electric pumps. In older steam boilers, hot water releases its heat at the radiator, and the cooled water returns to the boiler for more heating. Hot water radiator systems are very common in Europe. Expect to replace boilers and radiators about every 10 to 15 years, which typically costs between $3,700 and $8,200.1
Fuel sources: Boiler/radiator systems can be fueled by natural gas, liquid propane, fuel oil, or electricity. Original boilers may even have been fueled by coal.
Distribution: Heat is produced by steam or hot water circulating through metal pipes to radiators shaped to facilitate the transfer of thermal energy.
Hot Water Baseboard Radiator
Another more modern form of radiant heat is a hot water baseboard system, also known as a hydronic system, which also use a centralized boiler to heat water that circulates through a system of water pipes. This water flows to low-profile baseboard heating units that radiate the heat from the water out into the room via thin metal fins surrounding the water pipe, typically made of carbon steel. This is essentially just an updated, evolved version of the old upright radiator systems. Hot water baseboard heaters can last for several decades, and typically cost between $450 and $1,200 to install new or replace old units.1
Fuel Sources: Boilers for hydronic systems can be fueled by natural gas, liquid propane (LP), fuel oil, or electricity. They can also be aided by solar heating systems.
Distribution: Hot water is heated by a boiler and piped to “fin-tube” baseboard units mounted along walls. The fins increase the surface area of heat dissipation for efficiency. Heat is distributed by natural convection: Heated air rises from the baseboard unit, while cold air falls toward the unit for heating.
Heat Pump Heating Systems
The newest home heating (and cooling) technology is the heat pump, which uses a system similar to air conditioners to extract heat from the air and deliver it to the home via an indoor air handler. Standard home systems are air-source heat pumps that draw heat from the outdoor air. There are also ground-source, or geothermal, heat pumps that pull heat from deep in the ground as well as water-source heat pumps that rely on a pond or lake for heat.
A popular type of air-source heat pump is the mini-split, or ductless, system. This has a relatively small outdoor compressor unit and one or more indoor air handlers that are easy to add to room additions or remote areas of a home. Many heat pump systems are reversible and can be switched to air conditioning mode in the summer. Heat pumps can be energy efficient, but they are suitable only for relatively mild climates; they are less effective in very hot and very cold weather. These systems usually last 15 years or more and cost about $4,200 to $7,300 to replace.1
Fuel sources: Heat pumps are usually powered by electricity, although natural gas models are also available.
Distribution: Heat (and cooling) are provided by wall-mounted units that blow air across evaporator coils made from copper or aluminum, which are linked to an outdoor pump that extracts or absorbs heat from the outdoors.
Electric Resistance Heating Systems
Electric resistance systems like baseboard heaters are a popular option for supplemental heating in finished basements, home offices, and seasonal rooms like three-season porches and sunrooms. These heaters are not commonly used for primary home heating systems, mostly due to the high cost of electricity.
Like in-floor radiant heat, radiant electric heaters warm the objects in the room rather than just the air. Electric heaters are easy and inexpensive to install, typically costing between $450 and $1,200, and they require no ductwork, pumps, air handlers, or other distribution equipment.1 The units are inexpensive, have no moving parts, and require virtually no maintenance.
There are two main types of baseboard heaters: convection (traditional) and hydronic. Convection is a metal rod with fins that, as electricity is applied, the rod and fins heat and give warmth to the room. Hydronic is a metal tube filled with a liquid that is heated when electricity is applied and holds the heat longer, but it takes longer to heat up and is 3-4 times more expensive than convection units.
In addition to conventional baseboard heaters, there are electric radiant heaters that heat with radiation. These typically are installed near the ceiling and are directed toward the room occupants, providing more focused heat than you get with baseboard units. Radiant heaters also are more energy efficient than baseboard units.
Fuel sources: Electric resistance systems are plugged into the home’s electrical circuits, using the home’s main electricity which may be powered by coal.
Distribution: Baseboard heaters use natural convection to circulate heat throughout the room. Wall-mounted heaters and many specialty heaters (like toe kick heaters) usually have internal fans that blow out heated air.
Choosing a Home Heating System
When choosing a new heating system for your home, it’s important to weigh the pros and cons of each option and determine what type of heater suits your needs. For example, in-floor radiant heating is a great option for those living in warmer climates that don’t need to heat their home in freezing temperatures for several months straight. In colder regions, forced air heating or radiators can provide more consistent and comfortable temperatures through the winter.
Additionally, the cost of replacing an outdated system may not be worth it when modern, more energy-efficient options can be installed. In most cases, it’s best to contact a professional HVAC technician to help you begin the process of updating your home’s heating system based on its size, layout, and your regional climate.
Source: The Spruce