Installing Jumper Ducts to Make Bedrooms More Comfortable

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Published 2012-05-07
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Climate control and comfort in a home depends on much more than the size, power and efficiency of the heating and cooling system. It depends on proper insulation, air sealing and, above all, it depends on the air duct's distribution and adequate balance between return and supply ducts.

Larry Janesky, founder of Dr. Energy Saver, was recently in Central Florida helping a homeowner with a high cooling bills, and uneven temperatures around the house.

The bedrooms in his house had only supply ducts. The only return ducts were located in the common areas. Using state-of-the-art equipment, Larry demonstrates how the lack of return ducts in this home's bedrooms was increasing the positive pressure in the rooms above acceptable levels, consistently pushing air out of the house, and causing unconditioned, hot and humid air from the outside to be sucked into the common areas of the house. The differences in pressure made the air conditioner work harder, without ever making the whole house comfortable.

When homeowners experience similar problems, they tend to mistakenly believe that they need a bigger, and more powerful heating and cooling system. This is why it is a good idea to call in an energy conservation specialist, before you commit to buying an HVAC upgrade.

In this case, for example, just by adding a return duct to each bedroom, Dr. Energy Saver experts brought the pressure levels in the rooms down to normal. The temperatures are now even around the house, comfort has improved and the old air conditioner now works more efficiently.

If you want to save money, energy and make your home more comfortable, call a Dr. Energy Saver dealer in your area!

All Comments (21)
  • Phil Davis
    Great explanation Larry. I've been in the sheet metal industry for more than 30 years and after seeing my share of shady contractors I always appreciate it when someone such as yourself shows the right way to do something. I agree 100% in regards to adding individual returns to each room and dampering both return and supply air runs. Great video!
  • Boneyfreak
    Good job.
    This is such a common situation. Every home I've ever tested has this situation. New, old, add-ons and unfortunately also homes with newly installed/replaced systems. 99% of Homeowners will drive 2-5 extra miles to save 4 cents on gas but don't understand they're paying 25% more a year in heating and cooling their homes, living with nasty air drafts, hot/cold spots and auto opening and suck slamming doors because of this and other issues with their HVAC system.
    Then you have the goobs that cut an inch off the bottom of the doors or install a bypass right above the doors or even through the door itself and this eliminates any audible privacy in that room.
    Depending upon the room load(s)you can often properly air balance existing or install dampers and balance the system. I've actually run into situations of gross over supply with 2/3 supply registers in a room area then often I replaced a supply grill with a 1 or 2 way register to get mixing and made the furthest supply run a return duct.
  • teakettle
    Been watching HVAC videos all day and that bit about the imbalanced air pressure is genius. Thats the most valuable tip I've heard yet.
  • Brian G C
    As an HVAC professional who is a Building Performance Analyst, I can tell you that jumper ducts are a very expensive solution to a simple problem. The overlooked, and very obvious problem is that the jumper ducts are always routed through the attic. Every attic is a solar heat collector, a solar oven. The heat in the attic will heat the jumper ducts (regardless of R rating) and will passively heat the home. I have carefully measured the heat gain during the summer and found that a 4˚F gain is a minimum and often I measure an 8˚F gain. All day long, the heat enters the home via convection air circulation when the A/C is off and by forced air when the A/C is on.
    As the A/C air enters the room, the equal amount of air is forced through the jumper ducts and is passively hearted by the attic. That hotter than room temperature air is now spreading through the main hallway and gives a false hot reading to the thermostat and that hot air is drawn into the return duct. The result is the return air is now a few degrees warmer from the jumper ducts, which means the supply air is also a few degrees warmer. Our forefathers knew this 200 years ago. Many homes built 150 years ago had transfer air openings above the doorway of each room. That feature in a home was discontinued when central forced air heat and cooling became more common in new home construction.
  • A Merlin
    I wonder how effective it would be if you could plan an upper and lower return vent in a room, one to be closed/blocked and the other open, swapping on a seasonal basis.
  • Coder1024
    Fantastic video. I was about to add an air duct to a finished room in my basement and didn't account for return air ducting. Thank god I found this video before I started drywalling my ceiling!
  • Coroa
    With homes without properly placed return vents, simply removing/cutting off about 1/2" to 1" from the bottom of the door for each "problem" room (so there's more space between the bottom of the door and wood floor/carpet) should be enough. Example, for a 32" wide door you would have an extra 16 to 32 square inches of space/ventilation to work with. It's also a lot quicker (and cheaper) than cutting a hole in the ceiling of each room to install a jumper duct.

    The main problem with ceiling jumper ducts, is when it's cold outside. A ceiling jumper duct would allow the heat from the furnace (that is used to keep that particular room warm) to simply exit out of the room and eventually out through the roof vents (when the furnace is running), and cold from the attic to easily enter into each room (when the furnace is off). Not a good thing if your city/state gets cold during the winter season. It would also increase the yearly costs of heating your home.

    In Canada and Europe, home builders are staring to put return vents at both the top and bottom (on the wall) of rooms/living spaces. Doing so allows for better and more efficient return air flow adjustments during the summer and winter months. Example, during winter/cold months, the top vent would be closed (bottom vent open) to help keep warm air in the room (remember, warm air rises).... and during summer months, the top vent would be opened (bottom vent closed) to help keep the room cooler in the summer.

    If the home you live in has a wall mounted vent (top or bottom), you might be able to add the opposite vent as well (as long as the wall cavity doesn't have a horizontal block of wood in that space), thus allowing you to adjust return airflow to help make your home more efficient during the summer and winter seasons.
  • Daniel Stewart
    Hey Doc, and thanks for the video. I'm in south Florida. The only home I saw w return ducts in rooms was in SC. Now I understand the return ducts in the attic; but how did you attach the 3 new return ducts to the return plenum under the unit in the video? Did you go down the inside of a wall and go through the side of the plenum under the unit where it draws the air from?
  • Mon Sheriff
    What's more probable? The air in the room going through the walls (drywall) or the air going under the door, out of the room and to the return. Insulate your house and make sure your ext. doors and windows are sealed.
  • Ron Walsh
    Had these installed in my Florida home, and it made a world of difference.
  • PressurePerfect
    Great info! I live on the bottom floor of a three story condo complex. I don't have an attic to run return ducts to the air handler. The only return duct for my whole condo is at the air handler itself and my bedroom is as far as you can get from the handler. Now I know why it's always more comfortable when I keep my door open at night but sometimes I can't because of privacy reasons. Any suggestions?
  • Sherrill Woods
    All I can do is share my experience. We upgraded our system and added a game room. We had plenty of return (conditioned air) but the room was 2-3 degrees warmer. We added a "jumper duct" and the room runs about 1 degree cooler than the main room in house. Small cost for amazing result. We did the same in the two bedrooms on West side of house with similar results. Main concern of our AC guy was keeping the supply and return air volume balanced to the HVAC system.
  • ArticWolf24
    Thank you for this video. It really did teach me a lot, now its time to redesign my furnace ducting. This video was very informative.
  • Ivan Vojt
    It would seem you need to keep your return ducts as far away from your conditioned air ducts as possible. Also if you have an older home and generally the conditioned air duct isn't installed in the center of a window or between a set of windows you would be advised to move the conditioned air duct if possible. Yes you run into the issue with filling a hole and whatever texture is on the ceiling.

    You can also use an adjustable return air vent (with the room door closed) and measure the temperature of the room and restrict the return air flow to achieve the best lower air temp.
  • I have seen some homes, especially in Florida, with vent grates added to the door towards the bottom. Serves as a pass through for when the door is shut. Not ideal but a simple solution. Or as someone else said, cut an inch off of the bottom of the door. Probably a more private solution, but either method will serve the same purpose.
  • D S
    I lived in newly built apartments in Florida. They had vents above doors in each room. It worked great equalizing pressure between rooms.
  • AJ
    excellent video and seems like a very common problems (noise return duct I guess is an indication). Esp. this takes more of an effect when door is closed! (folks in that room have to know what this is about - or would have NO idea on noisy return duct)
  • Jonathan Schulz
    What do you think the open face surface area of those return duct registers were? I would be curious to see if you could get the same results by undercutting the doors an extra inch.
  • John Spiegel
    Thank you for this great video! Did you tie in all the jumpers to the main return, or simply bridge air from room to room or rooms to hallway?
  • Peter Ruffo
    Easily done on a Ranch house. Problem being when you install in an older home (Cape Cod) you cant always do that type of return. So you can only get returns in certain locations.