When most people think about heating and air systems they intend to either thank about the system itself or the supply vents. The supply vents would be the vents that blow air into the home. Even though your filter is located in-line with the return duct it is one that is oftentimes forgotten about. Of course, it could be forgotten about during the installation because without the return duct the system just wouldn’t heat and cool the home properly.
In fact, there are a number of homes out there right now with hot and cold spots of inadequate heating and cooling due to the lack of return ducts or bad return duct placement. This is why it is pertinent to understand everything you possibly can about return ducts before attempting to install one.
What Exactly Is A Return Ducts Function?
Even though return ducts are responsible for housing the filter people just don’t understand their true function and what they have to bring to the overall duct system. A return duct is the part of the system that carries the air back to the furnace or air handler where it will then be circulated back out through the supply vents. That’s right, your heating and air system is nothing more than a big circulation unit. Without the return duct, the air in the home would not be able to properly circulate. This would not only cause your energy bills to rise, but it will cause your entire system to not function at full efficiency. Since the return duct is basically applying negative pressure to the system it is the one that houses the filter.
The theory behind this is so that the air can be filtered before it is recirculated back the entire system. Now, this does not necessarily mean that you need a return in every room. Yes, some systems are designed to work this way, but most modern duct systems will just usually have one or two returns accounting for the entire system. And, these systems are more than effective.
Where Are The Best Places To Put Return Ducts
You are probably thinking since the purpose of a return duct is to suck the air back into the system they should be located right across from the supply vents. This is somewhat true and somewhat not true. Yes, this would be an effective setup, but it doesn’t necessarily have to be done this way.
Installing a return duct in each room where there is a supply vent would be more than feasible but isn’t always the best case. In fact, when installing return ducts it is always advisable to avoid putting them in bathrooms or kitchen. This would just simply cause the heating and air system to circulate cooking odors and moisture throughout the system. This would be a recipe for disaster and bad smells.
When it comes to two-story homes things can get a bit more complex, but the general rule of thumb is to install the return as close as possible to the thermostat. This is the general rule of thumb because it will allow the thermostat to monitor and record the temperature that is being circulated back through the system. In addition to this, the thermostat is usually installed in a centralized location.
Centralizing the thermostat and return duct will mean that you draw circulation and temperature readings from every part of the home. Unfortunately, this might not be an ideal setup for all home design. In these cases, it might be entirely necessary to install returns in each room of the home except for the bathrooms and kitchen.
Balancing The Return Air
If you really want to get the most out of your duct system, you should consider installing dampers on both the supply and return vents. This is something that can be done after the initial installation as long as you can access the ducts, which will usually be located in the crawlspace, attic, or basement.
Sometimes you can even use the grill cover to cut down and open airflow, but the whole process will be more efficient with dampers. Installing these dampers will allow you to choke down rooms that are located to close to the return duct. These rooms will be pulling the most air and taking away suction power from the rest of the system. Choking down the ducts that are located on the first floor or closely to the return duct will allow you to allocate more air to the ducts that don’t have as much suction power.
Best Possible Locations
If you make a careful not you will probably notice right away that most of your supply ducts are either installed by the windows or doors. This is because this is where most heat enters the home. The ducts are installed strategically in these locations to help battle this heat loss or heat gain. And, this is just one of the reasons that the return ducts need to be installed directly across from the supply vents.
When installed in this fashion it will allow the system to suck the air throughout the entire room. Of course, this setup will only be applicable for individuals that are installed returns in every room of the home. If you are going with just one or two return vents you will want to install the return vent in a centralized location as possible.
Another thing to consider is the physical location of the supply ducts. Are they installed in the floor, wall, or ceiling? If the supply ducts are in the ceiling or high up on the wall, you will want to install the return ducts or grills as low as possible. This once again will go back to the old theory of pulling the air across the entire room.
The Size Of Your Return Ducts
Not only does the location of your return ducts make a major difference, but the size does as well. Sizing your return ducts usually depends on the size of your ducts as well as the size of your HVAC system. In most cases, if you are installing ducts in each room where there is a supply, you will want to go with the same size as your supply vents.
If you are installing just one or two return vents, you will want to go with a 12-inch return for 2-ton units and lower. 14- inch for 3 and up. 16-inch should be suitable for 4 ton systems, whereas 5 might require 18-inch returns.
Always Keep Those Ducts Clean
You can see just how important the return ducts are to the overall operation of the system. You also learned that return ducts aren’t supposed to be installed in bathrooms and kitchens because they will just circulate the odors and moisture from the rooms throughout the duct system. This is just another reason as to why duct cleaning is important. A dirty return duct will just cause the system to circulate dust and debris throughout the home over and over again.