This project is continued from Part 2.
The Speedi-Boot™ air vent is fastened by nailing the feet of the telescoping arms to the wood joists with the pre-installed nails (you can also use screws). This is where the Speedi-Boot really shines compared to a raw vent boot where I’d have to measure, saw and mount 2″x4″ blocks to build a box frame.
Remember, the Speedi-Boot can be mounted perpendicular (as shown) or parallel (turned 90 degrees) to the joists by removing the telescoping arms and reinstalling on the other side as illustrated in Part 1 of this project.
Mounting the Speedi-Boot Air Vent
Installation Tip: Lightly press and hold the Speedi-Boot against the drywall for a snug fit while nailing the feet.
Flexible Air Duct Installation
Push back the fiberglass outer jacket to expose the coiled-wire inner core of the air duct. Slide the inner core over the Speedi-Boot as shown.
Slide the Air Duct Inner Core over the Speedi-Boot Air Vent
Secure the duct to the Speedi-Boot with metal foil HVAC tape. Smooth out all wrinkles for an air tight seal.
Seal the Flexible Duct to the Speedi-Boot with Metal Foil Tape
Slide the insulated outer jacket over the neck of the Speedi-Boot and secure with a zip-tie. Trim off the excess tail of the zip tie.
Secure the Insulated Jacket to the Speedi-Boot with a Zip Tie
Lay the flexible air duct as straight as possible and cover the Speedi-Boot with insulation.
Speedi-Boot Air Vent and Flexible Air Duct
Take care to provide a generous radius on all bends in the flexible air duct to avoid kinks that would restrict the air flow.
Rigid Air Duct Trunk Line Take-Off
The new air vent branch line will be connected to the rigid air duct trunk. I strongly recommend against splicing into an existing supply branch line if at all possible, i.e. making a wye or tee connection, because this can result in insufficient air flow for comfort. However, if you’re installing a return air vent, then splicing into an existing branch line is OK.
Place the starting collar in the center of the rigid duct and trace a circle to cut the mounting hole.
Trace for Starting Collar Take-Off on Trunk Air Duct
Cut the starting collar hole with a utility knife.
Cut for the Starting Collar in the Rigid Air Duct
The starting collar is installed with the mounting fingers inside the air duct.
Insert the Starting Collar – Fingers Down
Reach inside the starting collar and bend the fingers outward 90 degrees to secure it the rigid air duct.
Spread the Mounting Fingers to Secure the Starting Collar
The starting collar is sealed to the rigid air duct with metal foil tape.
Seal the Starting Collar with Metal Foil Tape
Use only minimum length plus an extra 2 feet of flexible air duct needed to span the distance from the air vent to the starting collar. Cut the outer- an inner jackets with a utility knife or scissors, then cut the spring wire on the inner jacket with wire snips. My pocket Leatherman has wire snips at the base of the pliers tool. Fasten and seal the inner duct with metal foil tape.
Fasten the Air Duct Inner Core to the Starting Collar
The air duct installation is completed with a zip tie.
Zip Tie the Flexible Air Duct to the Starting Collar
Here’s the new flexible air duct branch line:
New Air Duct Branch Line
The attic work is now complete.
Air Register Installation
I’m ready to install the air register on the new Speedi-Boot vent. Speedi-Boots have dust covers to keep out spray paint, dirt and debris. The dust cover is especially helpful for floor installations to keep out dirt during while remodeling or adding a new room.
Speedi-Boot Air Vent Ceiling Installation
Remove the dust cover:
Remove the Speedi-Boot Dust Cover
Speedi-Grille™ Ceiling/Wall Air Register
The Speedi-Grille register is a high quality product that snaps into the vent boot, holding itself in place until permanently fastened with the included screws.
Speedi-Grille™ Ceiling/Wall Air Register
The secret to Speedi-Grille are the two sheet metal spring tabs that run the length of the register. Just press the Speedi-Grille into the Speedi-Boot and it snaps into place until the mounting screws are installed. I really liked this feature because I’m always dropping screws while trying to hold a standard grille in place.
Speedi-Grille™ Spring Tabs for Snap-in Installation
Speedi-Grille installation is a snap (pun intended). Now I’ve got two free hands to install the mounting screws.
Speedi-Grille™ Air Register Snap-In Installation
The Speedi-Grille air register is attached with two screws that fit into the register pilot holes on the Speedi-Boot. The screws clamp the register and Speedi-Boot together, compressing the foam rubber gasket of the mud ring to the drywall for an air-tight seal. Compare this to a raw vent boot that leaks air into the attic.
Speedi-Grille™ Air Register Installation
Standard Air Register Option
Standard air registers also work fine with Speedi-Boot, just install the normal way with a screw- or socket driver.
Attach the Air Register to the Speedi-Boot Vent
The Speedi-Boot is huge improvement in air vent installation speed, fit, finish, and quality.
Thanks for reading,
Bob Jackson
Copyright © 2013 HandymanHowTo.com Reproduction strictly prohibited.
Hi,
I’m currently going to try and do this project myself to my own room because it becomes like a sauna in there sometimes. I have a question though. Since you know so much about this I was wondering if there is any how to on Return Air Vents that you could make or recommend. While I do feel that this WOULD improve the air cooling in my room I still thing that one of the biggest problems I will have will be that there isn’t enough circulation in my room either way. The Main (and ONLY) return air vent is downstairs in the middle of the living area. Nothing upstairs. Meaning a return air vent in each room upstairs could really improve the airflow even. So what recommendations can you make on that?
Return air vents are installed more or less the same way as supply air vents. You could do one of several things:
1) Shorten the door so there’s a 1″ clearance between the carpet/floor and door bottom for the return air to escape.
2) If your building codes allow, use the wall cavity between the 2×4 studs and sheet rock as a return airway. You’ll have cut a 1 foot high access panel in the drywall at floor level to cut through the 2×4 sole plate and subfloor to complete the air return to the 1st floor and so on to the basement, or where ever you can tie into the main air return duct work. Not easy and not the best method due to leakage between adjoining studs, but you won’t waste any floor space when the job is complete. Be sure to choose a vertical cavity where there’s no electrical outlets, light switches, etc.
3) Look around the attic for an existing utility cavity between the walls down to the basement. If so, you could install a ceiling return vent and flexible duct.
4) Build an 8″ square column in an inside corner of the room to conceal a 6″ flexible air duct. You only need to frame in two sides and cover it with drywall to hold the new flexible air duct. The finished product will look like a square post in the corner as often seen in commercial office buildings where a support column is located. You’ll need to plan carefully and evaluate your floor plan above & below the room to confirm you can reach the main air return duct. If you’re lucky, the 1st floor room will also have a corner at the same position as upstairs to continue the framing, drywall and duct work. You’ll have to cut holes in the floor and ceiling of course, so plan very carefully.
5) Consider a window air conditioner unit. Not pretty but it may be your best option.
Just about anything can be accomplished with creativity, planning, time and skill.
Thanks for this I’m going to try and install another vent in the master bedroom. I’m wondering why you choose 4″ materials instead of 5 or 6. Like the 4″ duct.
I installed a 4″ duct because it doubled the A/C vent capacity of this average size room over the existing 4″ duct, and there was less risk of unbalancing (i.e. starving) another room by using a smaller duct. The air flow can be balanced (or regulated) by the partially closing the louvers with a larger diameter duct, but there’s an increased tendency for noise from whooshing or whistling air.
The duct working currently being used in my attic seems big at least 6 or 7″. I’m not sure if I should try and match that size or go smaller since it’s just an additional vent to a room. What do you think?
How much play room is there between the register and the boot? I want to install this in a drop ceiling where the tiles will hang about 2 inches below the joist. Do you think this would work?
You’ll want to mount the Speedi-Boot to the metal stringers as shown in this project: “How to Install an Air Duct in a Suspended Drywall Ceiling” because the boot face must seal against the back of the ceiling tile to prevent air leakage.
Thank you,Bob. I am finally encouraged to add a vent in my son’s bedroom. It is on top of the garage and is hot like hell. I already insulated the garage door and doubled the insulation in the attic. It helped, but didn’t solve the problem, as we live in South Florida and the summer easily reaches the high nineties, sometimes goes over 100F. I am also planning to move an existing vent in another bedroom, which is located over the bed, to another spot on the same room. I want to use the same duct with a new speediboot. I looked at it but it looks like it will be very difficult to uninstall the old “raw” boot. It was installed when the house was built 5 years ago, using some kind of metal frame between the joist and the drywall. How can I properly seal this boot and keep it quiet there? I will leave the grill there as well.
So you’re going to abandon an existing vent & vent boot so you can reroute the ductwork to a new vent, and want to seal off the abandoned vent.
You can seal off the abandoned vent boot after disconnecting the ductwork by cutting a piece of fiberglass insulation about 2″ larger than the vent boot. Insert the insulation into the vent boot with the paper side facing the room, just like a picture inside a frame. Tape/seal the edges of insulation paper face to the inside of the vent boot with metal foil HVAC tape. Reinstall the air register to cover up the hole. This will insulate and seal the abandoned vent boot.
Yes, Bob. You understood my layman language into what I wanted and gave me the best answer, very fast. I’ll do it this weekend. You are the one. Thank you again.
Wow! I was reviewing your instructions and had to stop and say thank you for the 110% clarity. This seems so feasible for even a simple housewife such as myself. (My husband specializes in sports stats and kindness but nothing handymanish.)
I will try this rather than purchase a portable ac unit!
Thanks again, Bob!
Hey…what do you know about damaged wood floors? Hee hee, if your ever in Orlando, please stop by.
TiaZhan
Thanks for the excellent tutorial! I was able to follow it and install a vent pretty easily. I ran in to two problems I thought I’d share. First, the nails that come with the Speedi-Boot bent up too easily when I was hammering them into the ceiling joists and I was unable to get them all the way in. Next time I’ll use different nails. Second – Home Depot doesn’t sell the Speedi-Grille for some reason so i bought a standard one. The screws that came with the standard grille were too big for the pilot holes in the Speedi-Boot. Fortunately I had a couple of screws that fit. I went with the 6 x 10 vent.
Thanks again for this tutorial.
Hi Bob
Great site, I’m really enjoying reading all of your “real world” tutorials. Question about this one though… how do you know if your AC unit has enough capacity to handle another new vent? That is, could adding another vent somehow compromise the system? Or would the only risk be slightly lower AC pressure in all the other rooms serviced by that unit?
I’m pleased you found my site helpful.
> how do you know if your AC unit has enough capacity to handle another new vent?
The Air Conditioning Sizing Chart is a good reference to check if your AC system is properly sized for your home. A properly sized AC system should have sufficient capacity (i.e. tonnage or BTUs) to support a couple of new vents, as there’s so many variations in floor plans between homes of comparable total square footage, window area and quality of insulation. At the opposite end of the spectrum, adding more vents won’t make up for a undersized system that struggles to keep house cool.
For example, a co-worker says his AC system is undersized and won’t cool the house below 80 degrees F when the weather is in the mid 90′s; the home inspector noted the system was “barely” sufficient when he bought the house – but it was mild weather and he didn’t realize the impact until the summer heat was on. By comparison, the two 3 ton units on my home can drive the temperature down to the high 60′s in the same summer conditions – if I’m willing to pay the huge electric bill!
> … could adding another vent somehow compromise the system?
It could if the new branch line were taken off another branch line. This is why I ran the new branch line(s) from the main trunk ductwork. One or two new branch lines from the trunk shouldn’t be a problem, but a half-dozen new branch lines could be. For example, suppose your finishing a full basement and need to install new ductwork; supporting that much new living space may require either a larger or a new dedicated compressor and air handler. In my projects, the total living space hasn’t changed.
> Or would the only risk be slightly lower AC pressure in all the other rooms serviced by that unit?
The air flow to the other rooms could be reduced and needs to be re-balanced by adjusting the louvered vents to equalize the air flow so all rooms are comfortable.
Thanks for asking!
Planning on adding a vent to a newly converted screen room to sunroom. Although there is a vent neaby in an adjacent area you seem to shy away from splicing into it to add the line. You recommend cutting into the main line…..BUT….my main line is flex duct. there is no rigid box or plenum to cut into. So how do I add a line cutting into the main flex using speedi products?
Cut the main flex duct in two where you want to take off the branch line for the sun room and install a Tee Wye. Pull the insulated main duct and branch duct lines up tight on the Tee Wye to cover and insulate the metal Tee Wye. You will need cut a circular pattern in the side of the main flex line so it will fit properly and cover the exposed metal. AmericanHVACparts.com can custom make a fitting to your dimensions if a standard part is not in the catalog. (Disclaimer: I have no experience with AmericanHVACparts.com.) A local HVAC supply house may stock the same Tee Wye.
Thanks for reading!
Bob,
Thanks for all the great advice.
Question: I am finishing my basement into a large “L” shaped room (approx 12ft W x 35ft L), a bathroom (5ft W x 13ft L) and a back room (12ft x 12ft). I was planning on adding a 6″ register in the 12×12 room, a 4″ register in the bathroom, and 2 – 6″ registers opposite each other in the “L” shaped room approx 20ft apart. Does this sound about right? Also what size return would you recommend, 8″ or 12″? Thanks
The total square footage of new air conditioned space per your room dimensions is 629 square feet. The first step is to verify your AC system can handle the extra square footage with this sizing chart: Air Conditioning Square Footage Range by Climate Zone. AC 4 Life also offers professional Ductwork Design Service to take the guesswork out of a complex issue.
To figure the proper duct sizes yourself, use the Residential Air Duct Sizer and Velocity Calculator. You’ll want to size the supply and return air ducts to stay under the maximum air flow velocities in the table shown on the top right part of the Ductulator screen.
The big question for using the Duct Sizer calculator is: “How many Cubic Feet per Minute (CFM) do you need for a room of a certain square footage?” This depends greatly on where you live (climate zone), how well the home is insulated, what’s in the room that generates heat such as refrigerators, computers, lights, etc., and how many people will be in the room. See the Simplified HVAC System Design presentation by the University of Florida Environmental Technology Dept. For residential systems, start with 1 CFM per square foot of floor space.
1 CFM per square foot of floor space seems to be the rule of thumb used by contractors:
“Of the 79 contractors providing a CFM per square foot estimate, 42 of them (53.2%) use 1.0 CFM/square foot — although with a great deal of variability within the group. A value of 0.8 CFM/square foot was the second most popular response (10.1%), and a value of 1.5 CFM/square foot was the next most popular response (8.9%). The mean was 1.04 CFM/square foot.”
Reference: How Contractors Really Size Air Conditioning Systems by the University of Central Florida.
So, back to the large L-shaped 12ft W x 35ft L room is 420 square feet of floor space. At 1 CFM/Sq.Ft, this suggests you need 420 CFM of ventilation.
Assuming two supply ducts in the large long L shaped room to distribute the air flow, 210 CFM per duct is needed for a total of 420 CFM. Enter 210 CFM into the Ductalator Airflow Supply field and 420 for Return value and press the Calculate button. The result is 8.68 inch diameter for the two (2) flexible ducts and 11.24 inch diameter a single return duct. Rounding up, the calculator calls it in rounded figures 9″ supply and 12″ return flex duct.
As a sanity check, I examined the HVAC supply ducts in the larger rooms of my home. A room similar in size yours has two 4×14 inch floor registers supplied by two 8 inch flex ducts with a single 16×8 inch return grill.
Bob,
Wow, thanks for the awesome info and resources! In your room similar in size to mine, with the two 4×14 inch floor registers supplied by two 8 inch flex ducts, what size duct does your single 16×8 inch return grill have? 12 or 10 inch?
The 16×8 inch return grill uses the 2×4 stud wall cavity for a return to a vent boot in the subfloor that connects to an 8 inch flex return to the rigid trunk line.
Bob,
Thanks for advice. I notice in your article you say to avoid branching off an existing line, rather use the main. One my third floor, I have a 10 inch elbow off the unit going to 10 inch flex to a tee with reducers to two 8 inch flex to registers. I would like to finish off some additional space on this floor which will require two new registers. I could splice off this 10 inch flex after the controller before the existing tee, and not have to deal with another controller. But if I did this this would lead to a line with three tees in it (would need to tee again to go to each register). I assume this is not a good idea? Rather add a new line with another controller and just run both to same thermostat?
-Dave
> Rather add a new line with another controller and just run both to same thermostat?
That is the best approach to ensure adequate airflow.
Bob,
Great tutorial, very clear!
Would the Speedi-Boot/Grille work in a ceiling with 3/4″ shiplap behind (above) the drywall? The drywall is 1/2″, so a total thickness of 1 1/4″ give or take. Will the grille be able to be attached properly given the additional thickness of the ceiling? I’ll have to order through the mail so I can’t go check in person.
Thanks!
If you find that the included grille mounting screws are too short for the thickness of the ceiling, then buy a set of #8 x 2 inch long white hex head sheet metal screws. Your local hardware store may only have zinc (shiny finish) #8 x 2 in screws. If so, spray paint the screw heads white before installing to match the grille.