When you are lying on the couch and feel the refreshing air blowing from the air vent, do you ever consider the complex network of ductwork circulating air throughout your home? While you interact with your thermostat, vents, air conditioners and furnaces, air ducts are concealed behind walls, attics and floors. This carefully designed system provides comfort and protection to your household. Learning more about the vital role air ducts occupy in heating and cooling your home broadens your understanding and appreciation of your HVAC system.
HVAC systems maintain a consistent temperature and control the air pressure within your home. Most HVAC systems consist of an air conditioner, furnace, thermostat, air ducts and vents. Considering your home as a human body, the thermostat is the brain. Modern thermostats monitor and control the temperature within your home. When the thermostat activates the HVAC system, the air handler, or heart of the system, engages. Air circulates from the air handler typically within the furnace into the air ducts. Like arteries from the heart, air ducts move freshly treated air throughout your home. As the fresh air enters each room, return vents draw stale air from the room, and like veins, return the air back to the air conditioner or furnace.
The duct system within your home includes supply ducts, return ducts and all the vents between. Proper air circulation maintains even warmth in the cool months and steady air conditioning during the summer. A well-designed and properly maintained ductwork improves indoor air quality, creates ideal air pressure inside every room and optimizes energy efficiency. Alternatively, damaged air ducts, clogged systems and blocked vents may impact the comfort of your home and even shorten the life of furnaces and air conditioners.
What Do Air Ducts Do?
As illustrated above, there are two types of air ducts – supply ducts and return ducts. Depending on your home design, supply vents appear on the floors, walls and ceilings in every room of your home. A supply vent varies in size but most feature louvers to adjust the airflow. All are easy to identify because you can feel air moving through them when your HVAC system is running. These ducts deliver freshly treated air from your air handler into your home.
The second type of air duct is return air ducts. As your HVAC system blows air into your home, excess air moves out to maintain consistent air pressure. Return vents are often larger than supply vents and do not have louvers. Stale air is drawn through these vents and returned to the furnace.
How Air Ducts Impact Heating and Cooling
The primary objective of all HVAC systems is to provide even comfort throughout your home. There are many factors that determine the location of air ducts. Most new home designs incorporate HVAC as a primary element. Older homes that predate contemporary designs and especially homes with retrofitted HVAC systems may deviate from the optimal design. There are general rules to where air ducts should be installed and located within any home.
Proper Air Flow
Straight line design delivers the most air at the fastest rate. Wandering ductwork with multiple turns slows airflow and strains furnaces and air conditioners. Air ducts are most effective when air is moved directly from the furnace to vents with as few turns as possible. Specially designed ducts are used to efficiently control airflow when turns are necessary.
Insulation Improves Efficiency
Air ducts use the insulation within your home to maintain air temperature. A poorly designed one that is exposed loses energy moving from the furnace into the rooms of your home. If your home has cold spots and warm spots, the ductwork may be at fault.
Exterior Walls Are Coldest
Vents typically appear on exterior walls. Larger rooms and rooms with exterior walls often require multiple supply vents. Delivering enough air to match the square footage of a room is key to an effective system.
Hot Air Rises, Cold Air Falls
Some designs include vents near the floor and ceiling to allow for seasonal adjustments. Upper registers are open in the summer and closed in the winter. Likewise, lower registers are closed in summer and open in the winter.
Clean Vents Matter
Air ducts should be cleaned to maintain the interior air quality within your home. A small amount of household dust is expected to collect in the duct system but excessive amounts of dust, debris and other contaminants should be removed. Professional duct cleaning removes and reduces these issues.
Furthermore, ducts need to be dry. Any indication of moisture should be addressed immediately. Airborne debris like allergens and mold spores can impact the health of your household. Air ducts that have been in contact with floors, damaged by vermin or compromised by water damage should be evaluated by a professional HVAC contractor.
Number of Air Ducts
There are numerous factors that determine the number of air ducts within each room and your entire home. The number of stories within a home, square footage, type of room and other conditions inform the design. Air vents are installed into every room to supply air. Larger rooms and walls with multiple exterior walls require multiple supply vents.
How many return vents depends on the size of your home. Return vents may appear in every room except for bathrooms and kitchens. Many homes use fewer return vents or even a single return vent for each floor of the home. Air return vents assist with efficiency and air pressure inside your home so clear airflow is important.
The area around vents should be clear of obstacles like furniture. Blocking a return air vent with a couch or covering a supply vent with a rug wastes energy and can impact how your system functions.
When to Contact an HVAC Contractor
Issues with your heating system or cooling system are difficult to solve on your own. Insufficient airflow, higher energy costs, hot and cold spots and other performance issues may be solved quickly by highly trained, experienced HVAC contractors.
Thiele Heating and Cooling helps homeowners evaluate, repair and calibrate HVAC systems. Well-maintained furnaces and air conditioners are ineffective when ductwork is damaged, clogged or otherwise compromised. If you suspect your home could benefit from a full evaluation of your system, contact our team.