What size return air ducts do I Need?
Therefore, your return air duct and grill size will be 24 by 24 inches.) Always place return ducts as far away from the supply air vents as possible. Julie Boleware has been writing since 1997.
How many cold air return vents do I Need?
That’s quite easy to understand. If you have a house with 7 rooms, you need 7 cold air return vents. If you have a house with 12 rooms, you need 12 return vents. Example: How strong should air come out of vents for a 200 sq ft room?
How do I know what size air conditioner I Need?
Look for the data tag on the outside of your condenser (outside unit) to determine the size of your air conditioner (example: 3 ton). Decide if you'll be using round or rectangular duct. Calculate the return duct size based on the air conditioner's size and the type of duct you are using.
What is the standard size of a heat Return Vent?
A typical supply vent is 4 by 10 to 12 inches and a typical return vent is 16 by 20 inches or larger. Houses often have two or more return collecting points, each with a filter, which join before re-entering the heating unit. Two-story houses will have one return downstairs and another upstairs.
How Many Cold Return Air Vents Do I Need?
How much pressure does a cold air return vent have?
How many CFM can a 16x20 vent handle?
How many vents are needed for a 100,000 BTU furnace?
Why do furnaces need cold air return vents?
How many CFM does a 60,000 BTU furnace produce?
Why are furnace vents installed low on the wall?
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How many CFM should a 9 return grill handle?
All else being equal, the 9 return grills should be good for somewhere in the vicinity of 2200 CFM. I hedge that a little because the specific grill determines how many CFM it can handle. I think I see two PVC pipes, one for exhaust and one for combustion air intake. Is that truly the case? If there's only one pipe, then combustion air is the issue. But if there are two pipes, I'd suspect the furnace blower is pulling some air through leaks in the return air ducts. I'd be concerned about the water heater venting properly if it's in the same combustion zone as the furnace.
Why is my basement feeling bad?
The reason (many times) you're feeling a negative in the basement is because of the RA duct leakage. This could be due to the fact that there are not enough RA upstairs.
How many cfm does a 9 RA grille give?
Anyway, the 9 RA grilles will give you around 1,350-1,575 cfm. It all depends on the size of the openings that were cut. I saw a condo addition where the contractor used a 3" hole hog (1 hole per 14"x6" grille)!!!!!!!!
What happens if the furnace doesn't get the air back through the grilles?
If the furnace can't get the air back thru the grilles, it'll get it from the basement.
How many grills are there in the RA?
The RA grilles are 14"x6". There are a total of 9 (4 on first floor and 5 on the second floor).
How many tons is a 13 SEER?
It is a 3 ton 13 SEER (Amana ASC13).
Does a furnace return cold air to the basement?
The furnace supplies heat to all floors and the basement living space. However the basement does not have any cold air returns. What I find odd is that there seems to be a negative pressure in the basement when the furnace is on.
How many BTUs are in a heating return?
A label or manual for the unit will give the maximum output in cubic feet per minute. The basic standard is 100 cubic feet per minute representing 6,000 BTUs. Ducts are calculated in multiples of this standard, with adjustments for friction; air flows most efficiently through metal and through round ducts. The BTU capacity of the unit and its airflow will determine how large a return system must be to collect that air.
How does a furnace return system work?
An insufficient return system or one too large will reduce the efficiency of the heating and increase energy bills. A return system also filters air, to cleanse it of dust and debris before it goes back through the furnace.
What is the purpose of a return vent?
The purpose of the return vents is to return the air from the house to the heating or cooling unit, to be recirculated. Those elements must be balanced for an efficient, effective system. Advertisement.
How big is a typical return vent?
There usually are fewer return vents, but they are much larger. A typical supply vent is 4 by 10 to 12 inches and a typical return vent is 16 by 20 inches or larger. Houses often have two or more return collecting points, each with a filter, which join before re-entering the heating unit.
Where are return entries placed?
Return entries are usually placed in hallways or other central locations, in areas where cold air flows naturally. They are called cold air returns, although they also return "used" air in combined heating and cooling systems.
Who is Bob Haring?
Bob Haring. Bob Haring has been a news writer and editor for more than 50 years, mostly with the Associated Press and then as executive editor of the Tulsa, Okla. "World.". Since retiring he has written freelance stories and a weekly computer security column. Haring holds a Bachelor of Journalism from the University of Missouri.
Why is it important to properly install an air conditioner?
Properly sizing and installing your air conditioning system are important in making sure your air conditioner operates efficiently, according to the U.S. Department of Energy. One thing to remember is that you must have enough supply vents (vents blowing air out) and return vents (vent sucking warm air back in the air conditioner). Also, improper duct installation will impact your air conditioner's efficiency and your electric bill.
How to calculate return air duct?
For round duct: Diameter of duct x 3.14 = return air duct in square inches
Who is Julie Boleware?
Julie Boleware has been writing since 1997. She has been published on the Internet Public Library and various websites. Boleware's interests are in arts and entertainment and business. She holds a Bachelor of Arts in communications from Cameron University and a Master of Library and Information Science from Florida State University.
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.
Do Old Homes Have it Backwards?
Do you have a house that is approximately 80 years old? If so, your supply ducts may be on inside walls. You may have a single giant return air grill on the floor or at the bottom of a staircase. This is all wrong.
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 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.
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 happens if you live in a house that is too hot?
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.
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 Many Cold Return Air Vents Do I Need?
A house may have anywhere from 1 to 10 cold air vents. Here are two ways how you can calculate how many return air vents you need:
How much pressure does a cold air return vent have?
Even floor cold return air vents (the place where pressure is the highest due to cold air going down), we don’t get that kind of pressure. At most, you will get anywhere from 10% to 30% of that; that’s 150 CFM to 450 CFM per standard vent. The assumed average is about 300 CFM. There is a large range of CFM’s a standard-sized cold air return can let through, however.
How many CFM can a 16x20 vent handle?
It includes the cold return air duct grille. If you consult the duct CFM sizing chart, you can quickly figure out that a 16×20 inch can handle about 1,500 CFM airflow.
How many vents are needed for a 100,000 BTU furnace?
7 standard-sized vents with each providing 300 CFM will allow for a 2,100 CFM airflow. That means that a 100,000 BTU furnace requires 7 standard-sized cold air return vents (with cold air return grilles, of course).
Why do furnaces need cold air return vents?
That’s because we have to at least match the quantity of hot air furnace produces. To keep ‘breathing’, furnace cold air return vents have to supply enough air to the furnace. If we miscalculate how many return vents to install, the furnace will get insufficient airflow and it will start ‘suffocating’; operating at lower than 100% capacity.
How many CFM does a 60,000 BTU furnace produce?
That means that a 60,000 BTU furnace produces 1,200 CFM airflow. Similarly, 80,000 BTU furnace produces 1,600 CFM airflow and 100,000 BTU furnace produces 2,000 CFM airflow. You get the gist.
Why are furnace vents installed low on the wall?
Air return vents are necessary for the ‘inhale’ process. They are located on the walls or floors; they are installed low on the wall because cold air has a higher density and it accumulates near the floor.
