Generally speaking, you should only need one return air vent per room in your home. However, you may need additional air vents for larger sized rooms.
Do I need a return air duct?
Yes, if your house is either hot or cold, I'll bet you have inferior or lacking return air ducts. If you live in a home that has rooms that are either too hot in hot weather or are cold in cold weather you could have a return-air duct issue. Return air ducts are necessary for just about every room.
What size HVAC ducts do I Need?
The lowest you should go is about 350 per ton when the conditions are very humid. Most return air vents are 16 by 20 inches or larger. Get free, zero-commitment quotes from pro contractors near you. Having the correct duct size installed in your home is essential for the HVAC to do its job correctly.
How many return vents do I need for my home?
Many houses, especially older homes, only have one return vent in a central location, which works for a small house (about 800 square feet). However, for consistent air pressure, HVAC professionals recommend one return air vent per room, except for the kitchen and bathrooms. But there are other things that can make this question more complicated.
What size return duct do I need for 3 ton unit?
What size return duct do I need for a 3-ton unit? A 3-ton unit uses approximately 1200 CFMs or approximately 400 CFMs per ton. The lowest you should go is about 350 per ton when the conditions are very humid. Most return air vents are 16 by 20 inches or larger. Get free, zero-commitment quotes from pro contractors near you.
Do you need a return duct in every room?
Having several return vents (ideally one in every room, but even two or three is better than just one) creates consistent air pressure. If you have one return vent, your home is fine. Keep the doors to each room open so air can properly circulate.
How do I know if I have enough return air?
If you were to put a wet finger close to the vent that is generating airflow, you should be able to tell if there is a lot of airflow or not enough airflow. This is the simplest way to tell if you are getting enough return air. If you lick your finger and put it close to the return vents, you will feel the airflow.
How many returns should I have?
Having a number of return vents (preferably one in every room, but also 2 or three is far better than just one) creates regular air pressure. If you have one return vent, your house is great. Maintain the doors to every room open so air can properly flow.
Why does my house have 2 air return vents?
Having two air return vents allows you to seasonally control which air is returning to the HVAC system. In older homes, this may not be an option. The theory is that in the Summer cooling season, you want to be circulating warmer air back through the HVAC system to be cooled.
What happens if I dont have enough return air?
If there is not enough return air available, your HVAC system will not heat or cool properly. They must be properly sized — Return air ducts must be large enough to carry a sufficient amount of expended air back to your furnace, air conditioner, or heat pump.
What happens if there is no air return in a room?
The consequences of inadequate return air pathways Some of that air will find its way under the door and through interior leaks back to the central return vent. The rest of it, though, will push through openings and leak to the outdoors and into interstitial spaces. It leaks out.
Where should return vents be located?
Return air vents are generally located near the center of the homes. Older and newer homes often have one register per floor, but homes built from 1960-1990 may have a cold return air vent in each room.
How much does it cost to install a return air duct?
A return air drop replacement will run around $300-$400, including installation. In rare cases where a second drop needs to be added, the cost can be up to twice that amount. Sometimes, one or two individual duct runs need to be modified or added, for situations like the room addition we mentioned earlier.
Should return duct be larger than supply?
Return vents are usually larger than supply vents, and they usually don't have adjustable slats to direct airflow since the air is going into the ducts instead of out. Return vents may be found on the floor, on the ceiling, or at the base of the wall like a typical supply vent.
Can I add another return air duct?
A second return duct can lower static pressure if the airflow bottleneck is on the return side. If the static is on the supply side, adding a second return will do nothing. So it's usually a good idea. Get in touch with the trusted team at Greiner to learn the best way to install this in Your home.
Should return vents be on the floor?
An air return on the floor collects much more dirt and debris such as hair and lint. For this reason wall air returns will require less frequent cleaning. Floor air returns must be clear of obstructions and heavy furniture. Transferring your air return to the wall will allow you to utilize your floor space more freely.
Should I add a return duct?
Adding one or two Return Air vents with your attic insulation upgrade may be the perfect ticket for getting those rooms comfortable and in harmony with your thermostat. Remember, (generally) every room needs a Return Air vent, except bathrooms and kitchens.
How do I check my return air duct supply?
To identify a return vent, take a piece of paper and hold it up to the vent. If the paper is drawn towards the vent, then it's a return vent. Return vents are usually larger than supply vents, and they usually don't have adjustable slats to direct airflow since the air is going into the ducts instead of out.
Does adding a return increase airflow?
Return vents bring air into your room. The larger the return vent, the more airflow you will get. What is key to understanding here is that the air pressure in the ducts is constant (or thereabout). If you increase the size of the return vent, the drop in air pressure in the ductwork will be insignificant.
How do you increase airflow return?
How to Increase Airflow to Second Floor?Keep Air Conditioner Running in Fan Mode. ... Install a Ceiling Fan. ... Increase the Size of Return Vents. ... Increase Number of Vents. ... Clear the Vents. ... Close Vents on Lower Floors. ... Go for Ductless Air Conditioning. ... Get a Zoned HVAC System.
Why is my return vent not pulling air?
Blocked air duct. The blockage usually comes over time, by a buildup of dust and debris that just accumulates until it begins choking the system. To alleviate this, perform consistent home maintenance, as well as utilize the help of a professional with professional HVAC maintenance!
Your Return Vents Are Responsible for Air Pressure
When your HVAC system blows air into your home, that changes the air pressure inside. The excess air needs somewhere to go, which area is the return vent. The return vent is normally bigger than your supply vents since it’s exactly how the air handler sucks the air right into the HVAC system.
Your Home May Not Have Sufficient Return Vents
Houses constructed prior to central air prevailed frequently have actually retrofitted HVAC systems. When contractors initially set up central air, they put in a solitary big return vent someplace central in the house. This isn’t the most effective system.
What to check after adding return air?
After adding return air, it's critical that your HVAC technician also checks the refrigerant pressure in your system. We've just made a change to the way air moves throughout your home, so we might have to tweak the refrigerant charge to ensure the system cools properly with the new ductwork.
Do dirty air filters restrict airflow?
We all know that dirty air filters restrict airflow. But really dense filters can have the same effect, even when they're brand new!
How Do You Calculate Return Air Duct Size: 3 Step Guide
Calculating the return air duct size is simple. I’ve described the entire process in a few steps for your convenience. Just follow along.
Why Do You Need Return Air Ducts?
The return air duct (RAD) moves air from the room. It takes the air inside the room and feeds it into your air-conditioning system. Basically, the purpose of the return air duct is to circulate the air in your room.
Conclusion
I’ve provided the answer about how to calculate the return air duct size. Everything you need to consider and even the formulae you’ll need is all here.
Where should HVAC return air ducts be?
"An HVAC return air duct should be in every room except a bathroom and kitchen. They should be on interior walls across the room from the supply ducts that should be washing exterior walls with conditioned air."
What is the air duct in your house?
The air ducts in your house should be designed exactly like the blood vessels in your body. Think about it. The veins and arteries supplying blood to the different parts of your body, even out to your fingers and toes, are the same size as the veins and arteries returning that blood back to your heart.
Why does my furnace need return air?
The reason for return air is simple. Your furnace is simply a recirculating pump. Instead of pumping water, it is pumping air. We need to get the air back to the pump. Furthermore, without a return air duct in each major room, the supply duct air has to "push" all of the air in the room out of the way as it makes its way towards you.
What is the purpose of a return air grill?
The intent is to wash the exterior walls with heated or cooled air. You are trying to combat the heat or cold at its source. The single giant return air grill in the floor balances the load at the furnace motor but does nothing to promote cross-ventilation in each room.
How to get the most bang for your return air buck?
If you want to really have a way to get the most bang for your return air buck, think of installing grill covers on the wall that have operating louvers. This will allow you to choke down rooms possibly on the first floor that are drawing too much air.
How to size an air conditioner?
To properly size an air conditioner, one has to perform a heat gain calculation. In other words, you must determine how fast heat is getting into your house and what things inside the house are contributing to heat gain .
Where should the air conditioner be located?
Supply air from furnaces and air conditioners should be on outside walls. The return air vent openings need to be on the opposite side of the room so the conditioned air is pulled across the room.
What is return air duct?
Return air ducts channel air from rooms back to the air handler. They’re connected to the air grilles you might find on the walls or ceilings of your hallways and larger rooms. The return ducts help maintain good air circulation, preventing hot and cold spots, and keeping your rooms from feeling stuffy. Balanced airflow prevents indoor pressure ...
What to do if your home has no return ducts?
If you find your home has insufficient return ducts, ask a heating and cooling technician about adding more. In some cases, additional ducts can be installed in the wall cavities and connected with the main return duct. Depending on the construction of your home, however, your technician may opt for other methods. Door undercuts and transfer grilles can also help ensure sufficient return airflow.
Why do return air ducts matter?
Return air ducts play a significant role in your home’s energy efficiency. Why Return Ducts Matter. Your duct system has two types of ducts: supply and return. The supply ducts channel conditioned air from the air handler out to the air registers in your rooms. That is, they supply your rooms with warm or cool air.
Does every room in a house have a return air grill?
Optimizing Your Return Ducts. Ideally, every room except the kitchen and bath should have its own return air grille. At the very least, each level of the house should have one.
Can door undercuts help with return airflow?
Depending on the construction of your home, however, your technician may opt for other methods. Door undercuts and transfer grilles can also help ensure sufficient return airflow. Maintenance matters, too. Make sure your return grilles aren’t blocked by drapes, furniture or other items that could interfere with airflow.
What happens if you don't have a return duct?
If supply air doesn’t have a way to return to return ducts, it will leak out of the house through cracks and openings in the home’s outer envelope. In the winter, this means you’re losing heat energy to the outside, and rooms won’t stay warm for long.
Why is it important to have return air ducts?
It’s important that roughly the same amount of air moves through supply ducts as return ducts, in order to maintain neutral air pressure in rooms.
Can you be forgiven for not knowing about your air duct system?
A person can be forgiven for not knowing much about their home’s air duct system. It plays a vital role in the home’s forced-air heating and cooling system, performing its job quietly and without much attention.
Do you need a return vent in every room?
For this reason, it’s important that house construction doesn’t scrimp on return vents and ducts. Ideally, there should be a return register or vent in every room where a supply register is located. If that’s not possible, there should be easy airflow between rooms, via such strategies as air pass-through grilles in doors or jumper ducts in ...
Why do you need to match duct size?
Your duct sizing must match perfectly with the sizing of your heating or cooling unit in order to ensure that the correct amount of air is distributed around the home. Choosing ducts that are oversized will cause your air handler to have more area to cover.
What is the next important unit to know when determining duct sizing?
The next important unit to know when determining duct sizing is the friction loss rate. This will ultimately help your contractor establish the static pressure of your unit, another measurement that affects air flow.
Why Is Duct Size So Important?
There are many different options available for duct sizing and these are meant to correspond with the different size heating or cooling systems so that the correct amount of air is circulated around your home.
How to calculate friction loss?
Your contractor will utilize a duct size calculator to factor in all of these measurements, multiply by 100, and divide by the total length of your ductwork.
Why is it important to have a duct size?
Having the correct duct size installed in your home is essential for it to do it’s job correctly. If your ducts are too small, or too large, you will allow the air to escape, and it will end up costing more in your heating or cooling bill. This is because the heat or air is escaping, and not making it to the rooms of your home, so you keep it running.
Why is my ductwork so noisy?
Ductwork that is too small for your heating or cooling system will cause a surge in static pressure. This means that your ducts will be noisier than normal and have to work harder to service your home. To adequately heat or cool your home, your system will need to run longer, costing you more money on your bills.
What is the most important thing to consider when it comes to heating and cooling?
Duct sizing is by far the most important aspect to consider when it comes to your heating and cooling systems. Improperly sized ducts can result in unnecessary wear and tear, place too much pressure on your units and end up costing you more money on your energy bills.
How Do You Calculate Return Air Duct Size: 3 Step Guide
Why Do You Need Return Air Ducts?
- The return air duct (RAD) moves air from the room. It takes the air inside the room and feeds it into your air-conditioning system. Basically, the purpose of the return air duct is to circulate the air in your room. Now, why is that done?
FAQs
- Question: Is going under the required size okay? Answer: No. If you lower your duct size, your airflow will be restricted. There will be greater resistance within the duct. This resistance will result in higher noise. It will also cause greater power consumption. Question: Can a duct be too large? Answer: Yes. There is such a thing as a duct that is too large. A duct significantly larger than th…
Conclusion
- I’ve provided the answer about how to calculate the return air duct size. Everything you need to consider and even the formulae you’ll need is all here. All you gotta do is follow along. Just remember, it is okay to go a little above the recommended size not under. Well, I hope I’ve helped you figure out what size return air duct you need. Goodbye!