In the world of HVAC, heating comes in two varieties: radiant heat and forced-air.
Forced-air, also known as central HVAC has dominated the country for a few decades now. You might know them as furnaces, heat pumps and ductless mini-splits. Conversely, radiant heat is used in boilers and radiant heating systems.
Because we understand that our customers save more money when they understand how they use energy, we have gathered some basic information on the different types of home heating systems so that homeowners can educate themselves about the kind of heating system they have and how it works.
Basics
Forced Air
These systems use a blower or fan to pull air into the system where it is heated and circulated throughout the home. Most forced-air systems use natural gas to produce a flame to heat the air, which is then distributed throughout your home via ductwork. Forced air systems use ducts to transport and blow heated or cooled air into a space.
Forced air systems can integrate both heating and cooling in one mechanism and are a very common form of heating and cooling in residential and especially commercial buildings. Buildings with central heat and existing duct systems often use forced air.
Radiant Heat
Radiant heating systems supply heat directly to surfaces in the home—wall, floor, or ceiling panels. Generally, electricity, hot water, or air make direct contact with the system’s surface and infrared radiation delivers the heat to the air and occupants of the room to warm up the space.
These systems rely on the use of heat to move air through convection. That is, heated air rises and is replaced by cooler air, which is heated and rises. Since these systems work passively, they tend to heat rooms slowly. Also, because radiant systems use contact to transfer heat, they do not disrupt allergens in the home the way forced air can. However, most are inexpensive to buy, install and maintain.
Types of Forced Air (Central HVAC)
Forced air systems use a furnace or heat pump to heat the air and then disperse it through the house via duct work and in-room vents. Once the temperature is set at the thermostat, cold air from the home is pulled onto the system where it passes through the air filter, removing allergens like pollen and dust. It then blows the air through the air handler where it is warmed via the furnace’s heat source and spread to the home through the ducts via the blower motor. If a heat pump is your primary source for heat, it will immediately begin pulling heat out of the air at the outdoor unit, pass it through the refrigerant lines going into your home, and then through the air handler and into your ducts.
- Electric Resistance Heating is energy efficient because all the electricity is converted to heat. And since the heating elements in an electric furnace are in direct contact with the air, the air heats up very quickly. This makes them very efficient but expensive to operate during extended cold weather.
- Natural Gas/Propane Systems is the most common furnace is a forced-air central heating system that uses a natural gas burner to heat air. Cool air is drawn into the system, moved into a heat exchanger where it is warmed by the gas burner and then circulated by a blower or fan through the home s ductwork.
- Heat Pumps include both air condensers that are installed outside and geothermal condensers that are buried underground or in nearby water. Both use R-410A refrigerant that is also used in air conditioning, but the process runs in reverse so that instead of warm air being expelled outside as waste heat, it is blown inside to supply heat.
- Ductless Heat Pump/AC Systems are forced air systems that do not use ductwork. Sometimes called “split systems”, the interior air handling and heat exchanging unit is directly connected to through the exterior wall to the outside unit. Due to their small size and the fact that they do not use ductwork, split systems like these are best suited for heating and cooling small areas.
Types of Radiant Systems
“Radiant heat” is the phenomenon of heat transfer via electromagnetic waves. In other words, it is the same kind of heat you feel coming from a campfire or from a cup of hot coffee. Radiant heating systems use a set of tubes or cables to generate radiant heat, either with electricity or heated water. On the other hand, boilers also take advantage of radiant heat through the use of metal radiators.
Radiant heat can be more efficient than forced air systems with duct loss problems, and some people with allergies prefer it because the lack of air circulation does not stir up allergens. However, because these systems circulate water as either steam or liquid, radiator systems can be prone to problems such as blockages and leaks.
- Passive Solar is the most environmentally-friendly and least expensive to operate since the sun’s heat is stored in the thermal mass of the home. The sun’s heat radiates and warms the space. However, your home needs to be very well air sealed and insulated. Your home will also need to have adequate southern exposure to allow enough sunshine to enter the windows and warm the home.
- Boiler-Based Systems include radiant floor heat that uses hot water, radiators that use steam or hot water, and also some hydronic (liquid-based) baseboard systems. In these systems, a central boiler heats the water to steam, or it uses hot water and pumps it through pipes throughout the home to radiators or coils of tubing embedded in walls or flooring.
- Radiant Floor Heat makes use of the floor’s thermal mass. Hot water tubing is arranged in loops on the floor and then surrounded with poured concrete or a sandwich of tile and plywood. With this method, the floor will stay warm longer and radiate the heat longer, which keeps the room warm longer and more evenly.
Cost and Maintenance of Forced Air vs Radiant Heat
- Cost
Forced Air: One advantage forced air systems have is the initial cost. Forced air systems will initially cost about 50% less than a radiant system heating the same space, but much of the efficiency can be lost due to poor installation. Although forced air systems will require more maintenance than a radiant system, the components are generally accessible. This is in contrast to radiant heat flooring systems, which tend to require much more demolition to repair.
Radiant Heat: The cost associated with installing radiant heating depends on the same factors as any home improvement project, which are the size, location, and function. The type of system you use, where it is going, and the problem it solves can change the project cost dramatically. The type of radiant heat system used will usually depend on the cost and how big the project will be. For instance, installing any version will be easier if the room(s) is already under renovation. Therefore, consideration should be given to the scope of the project to keep costs under control.
- Warmth
Forced Air: Forced air systems do a much better job of eliminating cold spots often associated with space heaters and radiators. Because the air is constantly moving, fresh air is brought in from outdoors and circulated around the home evenly. However, forced air systems depend greatly on how well they are designed, so care should be taken to hire a reputable contractor.
Radiant Heat: A typical room using radiant floor heating will use about the same, or up to 15% less energy than a similar forced air system. Radiant floor heating systems are very efficient to operate, and heat the room evenly. As opposed to the traditional space heater or radiator, there are no cold spots, nor a need to increase ventilation because an area has become too warm.
- Air Quality
Forced Air: In contrast to radiant systems, all HVAC systems will have at least one air filter that captures airborne contaminants. The return then recirculates the air back into the system. For families with allergies, hepa filters can also be added.
Radiant Heat: Since radiant heating systems use pumps to move water instead of fans or blowers to push air, the system does not circulate viruses, allergens, or odors throughout the indoor space.
- Installation
Forced Air: Forced air systems can usually be installed in just a day or two. Because the mechanical components of a forced air system must be accessible by building code, repairs and maintenance are also simple to accomplish. Technicians in the field must be licensed as well, since these systems can involve the use of freon.
Radiant Heat: Radiant systems are typically embedded in a flowable underlayment prior to installation of the finished floor. While underlayments formulated with portland and/or calcium aluminate underlayments may be suitable for radiant installations over concrete, their need to be well bonded to a sound substrate can lead to costly failures with radiant systems.
Pros
Forced Air:
- Fast to Heat: Forced-air heating is much faster compared to radiant heating. It can also be felt more intensely, but that does not always mean it is effective or thorough.
- More Efficient Electric Heaters: Heat pumps are the most efficient on the market and capable of outperforming electric in-floor radiant heating systems.
- Easier Installation: Even the most difficult forced-air system has an easier installation than a boiler or radiant heating system.
Radiant Heat:
- Comfortable, Even Heating: Since radiant heat does not rely on the flow of air, it does a better job of evenly heating spaces.
- Better Air Quality: The lack of airflow means that contaminants and allergens are not disturbed.
- Less Maintenance: Thanks to less moving parts, radiant heating systems tend to need less maintenance.
Cons
Forced Air:
- Prone to Uneven Heating: Air does not always distribute evenly through a room, leaving some rooms feeling a bit colder than the rest.
- Indoor Air Quality Reduced: Since air is blowing through the room, dust and allergens can circulate.
- Noisier: As forced-air heaters go through their cycles, you can expect to hear the constant sound of rushing air.
Radiant Heat:
- Installation Can Be Expensive: Radiant heating systems need to be installed under the floors or in the walls. With an existing house, this will require significant remodeling. Boiler installation is also more complex.
- Slower to Heat: Radiant heating is able to heat more evenly but it takes longer for it to heat a room thoroughly.
- Radiators: When using radiant heat through a boiler, a large, metal radiators or baseboard heater will need to be installed in every room.
Give Us a Call
Knowing your options for heating your house is your first step to staying comfortable with efficiency and less expense.
If your system needs repair or inspection, call Aire-Tech on 951-926-1002. You can also visit our Contact page and complete the contact form.