So how much space does an air return vent need to work properly? Home Inspection Insider explains that an air return vent needs 6-12 inches of space in front of it, and recommends that you do not put large, bulky furniture like couches and bookshelves in front of an air return vent.
General Guidelines
Generally speaking, HVAC professionals will tell you that there should be at least one foot of clearance on each side of the unit – however, there may be some manufacturers who recommend a longer distance, such as two feet on each side.
The air now has to re-pressurize to regain its turbulent flow so it can continue to push its way down the duct. It requires about 24′ or two feet to do this. This is the 'Two-Foot Rule?. Ideally, you should allow at least 24′ between takeoffs and at the end of any duct run.
1. Openings shall not be located less than 10 feet (3048 mm) measured in any direction from an open combustion chamber or draft hood of another appliance located in the same room or space. 2. Return air shall not be taken from a hazardous or insanitary location or a refrigeration room as defined in this code.
There are lots of things to consider, such as the size of the space, lighting, colors and your return air vent. Yes, that's right, your return air vent. If you want to keep your heating and cooling system working properly, there should be a 6- to 12-inch clearance around each vent.
So how much space does an air return vent need to work properly? Home Inspection Insider explains that an air return vent needs 6-12 inches of space in front of it, and recommends that you do not put large, bulky furniture like couches and bookshelves in front of an air return vent.
Insufficient return air can lead to higher energy bills. When your HVAC system doesn't receive enough return air, it must work harder to maintain the desired temperature, increasing energy consumption. Homeowners might notice a spike in utility costs without a corresponding increase in usage.
They are usually located in central, larger rooms to more efficiently pull air from the home and into the system. Return air vents are often located on a wall, rather than the floor or ceiling. Air return vents play a critical role in balancing the air in your home.
Return air shall not be taken from a closet, bathroom, toilet room, kitchen, garage, mechanical room, boiler room, furnace room or unconditioned attic.
Up High: having an air return higher up on a wall will be better at sucking in hot air that rises. Making it more efficient at transferring this hot air back into your system to repeat the cooling cycle. Down Low: if you have your air return lower on your wall it will function better as a cold air return.
Simply put, it means you should never set your thermostat for a temperature more than 20 degrees cooler than the outside air. Why not? Most air conditioning systems can only handle a 20-degree difference between the outside and inside air temperatures.
When setting up a ventilation system we typically figure a 7% loss in CFM for every 25 ft. when using flexible ducting (a 3% loss if using metal duct pipe). You should also factor a 3% loss for every 90 degree bend in your ductwork.
Returns placed within 4' of a supply will not suck supply air over to it, due to a return having little large scale effect on air movement in a room. This is said with the understanding that the supply air is not being thrown toward the return, as might be possible with poorly aimed three-way supply registers.
If the return duct is too small or there are an inadequate number of return grilles, your HVAC system won't be able to return enough air to recirculate into the system. Again, it's like if you were breathing in through a straw while jogging.
Today, it is recommended to have one or multiple air vents in each room of your home or business to optimize air flow and reduce the cost of energy spent on cooling your home or office. So, what are air vents and how do they help your HVAC system run better?
Return air openings for heating, ventilation and air-conditioning systems shall comply with all of the following: Openings shall not be located less than 10 feet (3048 mm) measured in any direction from an open combustion chamber or draft hood of another appliance located in the same room or space.
The building codes do not allow “active” returns to be installed in closets.
While it's best practice to install a thermostat near a return air vent, so that the thermostat senses a homogenous mixture of air sucked from various areas of the home, it's a mistake to have the thermostat located near a supply air vent, where hot or cold air blowing on it can change its reading.
What room should return air ducts not be installed? Return air ducts should generally not be installed in rooms with high humidity or areas prone to moisture accumulation, such as bathrooms or kitchens.
Return vents are usually larger than heat registers and can generally be found close to the ground or in the floor in older homes or on a wall close to a ceiling in newer homes. You will not feel air being blown out of these vents, as they are used to force out the cool air in the room to be reheated by the furnace.
While return vents don't always require filters, adding them provides additional filtration, improving indoor air quality and keeping dirt and debris out of your system. However, there are pros and cons to consider.
Cavities (or interstitial spaces) within walls are also sometimes used as supply- or return-air pathways.
If there's not enough return air, your living room can be 10℉+ warmer or cooler than, for example, the bedrooms. Not enough return air in summer can cause rooms close to the central unit to be cooler and those farther from it to be warmer. In winter, rooms farther from the furnace can be too cool.
Due in large part to the short cycling issues mentioned above, components on an oversized heating and/or air conditioning systems are more likely to fail sooner than those on a properly sized system. As a result, you may end up having to replace your HVAC system sooner than expected.