Heating 101

Understanding how a typical HVAC system works will empower you to make better decisions when working with your local heating contractor. You will ask better questions, and can then feel confident about decisions made for a solid and efficient system.

Home heating installations are typically made up of a gas powered furnace, or a split system design using a heat pump and fan coil. Hover over the diagram below to see definitions of the different components of an HVAC system. Below the diagram you can read in detail about the entire process:

The points below guide you through the general concepts of how a residential HVAC system works with optional indoor air quality components installed.

Gas Furnace:

Flames heat up the heat exchanger. A heat exchanger is a type of metal grid that air passes through, and it is heated by the gas powered flames.
Fan pulls air from the home. The fan in your system pulls air from the home through the return air duct. A variable speed fan is quieter, more efficient and provides a more comfortable climate.
The air is filtered. Above you can see an air cleaner positioned between the return air ducts and the main unit. Such air cleaners can have very high MERV ratings (used to rate the effectiveness of air cleaners), with the ability to filter microscopic particles and viruses out of the air.
The air is heated. The air is then pushed over the heat exchanger by the variable speed fan motor.
Humidity is added back. A heat exchanger dries out winter air even more. A whole home humidifier replenishes needed moisture for a healthier home. Restored humidity also helps the air feel warmer, thus decreasing the energy needed during the winter.
Heated air sent back into the home. The fan forces the warm air back into the home via the installed ductwork.
Air is exchanged. At the top left of the above system layout sits a ventilator. Ventilators are part of complete indoor air quality solutions as they exchange fresh outdoor air for stale indoor air. A ventilator is able to do this with minimal loss of energy, retaining the warm, humidified air your HVAC system worked hard to produce!

Heat Pump:

Heat is extracted. Even cold, outside air contains heat energy. The heat pump absorbs this energy into the refrigerant contained in the copper coil, and then sends the heated refrigerant inside.
Fan pulls air from the home. The fan in your furnace or fan coil pulls air from the home through the return air duct.
The air is filtered. As with the first method, an advanced air cleaner filters out micro scopic dust and organisms.
The air is heated. The air is then pushed through the coil system by the variable speed fan motor. The heated refrigerant warms the passing air and then is cycled back outside to repeat the process.
Mold is killed & coil efficiency kept high. In the damp interior of an indoor coil system, mold will grow which affects not only the health of your family (mold spores in the air), but the efficiency of your HVAC system. In the system example above, a UV lamp is mounted within the coils to prevent this.
Heated air sent back into the home. After leaving the indoor coils, warm air is pushed back into the home. In dry winter climates, a separate whole home humidifier can be installed to replenish the indoor air.
Air is exchanged. At the top left of the above system layout sits a ventilator. Ventilators are part of complete indoor air quality solutions as they exchange fresh outdoor air for stale indoor air. A ventilator is able to do this with minimal loss of energy, retaining the warm, humidified air your HVAC system worked hard to produce!

Hybrid System:

A hybrid system uses both a furnace and a heat pump. Heat pumps are typically more efficient when the temperature is 40° and above, while a gas furnace is more efficient as the temperature drops. Additionally, heat pumps cannot provide adequate heat in extreme cold.
A smart thermostat is used, and set locally based on the prices of fuel. Then the hybrid system intelligently switches between units for the highest energy efficiency available.

Seasonal Tips

Maintenance

Follow manufacturer's routine maintenance directions.
Have entire system checked once a year by a qualified service technician.

What Homeowners Can Do:

Check Filters

Permanent - Clean with mild detergent, per manufacturer's recommendations, every 30 to 60 days.
Replaceable - Replace every 30 to 60 days.

Windows and Doors

Keep closed when system is running.
Caulk and weatherstrip to close air gaps.
Open drapes and shades over windows facing sun.

Activities

During cooling season, don't wash/dry clothes during warmest times of day (late morning and afternoon).
When cooking, use exhaust fan only as needed.
Keep thermostat at desired setting.

If you have further questions about HVAC products for your home, simply use our dealer locator: Heating Contractor