How to Install Duct Insulation?

Minimize the duct wrap to suit, then set up

Photo 1: Cut to size

Picture 1: Minimize to dimension

Minimize the ductwork insulation to match the circumference of the duct, plus 2 in. Then peel away the foil backing and minimize off 2 in. of fiberglass.

Photo 2: Wrap the duct

Picture 2: Wrap the duct

Take away a number of duct hanger brackets and slide the insulation across the high of the duct. Overlap the 2-in. foil tab on the seam and seal with aluminum tape.

Photo 3: Secure sections with wire

Picture 3: Safe sections with wire

Relieve stress on the seam by wrapping wire across the insulation. Place two wires on every 4-ft. part.

Picture 4: Wrap spherical ducts additionally Repeat the slicing, tabbing and taping process for every spherical duct.

Uninsulated ducts that run by way of unconditioned areas can lose greater than 30 % of their heating or cooling capability. So that you’ll lower your expenses by insulating them. The Residential Constructing Code requires R-8 insulation for these ducts, however verify along with your constructing inspector for native code necessities. Earlier than you insulate, nevertheless, plug any air leaks by sealing all of the joints with caulk or tape.

Search for “duct wrap,” a fiberglass product with an outer foil vapor barrier. The foil barrier prevents condensation (and mildew) from forming on the duct.

Sadly, R-8 duct wrap might be troublesome to seek out. We checked three house facilities and located solely R-3 duct wrap. That didn’t meet our native codes, so we contacted a heating tools provide home. That firm knew precisely what we have been on the lookout for and had it in inventory.

We purchased a roll of 3-in. by 48-in.-wide by 50-ft. duct wrap for our set up. We additionally purchased a couple of rolls of UL181 aluminum duct tape to seal the insulation seams.

You’ll be dealing with fiberglass, so put on lengthy sleeves, goggles, masks and leather-based gloves. Measure the circumference of the duct, add 2 in. to the whole, and minimize the insulation to that size. Take away a 2-in. strip of fiberglass to create an overlapping flap for taping (Picture 1). To complete the job, butt the insulation edges collectively alongside the underside of the duct, overlap the 2-in. strip of foil, and safe it with aluminum tape (Picture 2). Wrap wire across the insulation to alleviate seam stress and stop the seam from separating (Picture 3).

You’ll save numerous slicing and becoming time on rectangular ducts by eradicating the hanging brackets one part at a time. Take away the screw from the joist and rotate the bracket. As soon as the insulation is in place and taped, minimize a small gap close to every bracket, rotate it again up by way of the opening and reattach it to the joist. Seal across the bracket with tape.


So, which is it? Insulate or change?

It is as much as you, however it’s typically more economical to replace the ducts. By the point you pay for supplies and labor for sealing and insulating present ducts, it is going to often shake out to a worth that is near what it prices to get new ones.

In case your contractor does issues the way in which we do, substitute additionally ends in a greater duct system that retains you extra comfy and maximizes effectivity.

With us, you get a model new duct design that’s precisely sized to your house and your HVAC system. Treasured few HVAC contractors will do that. Most are “field swappers” who simply change what you’ve with the identical precise factor. In different phrases, the system will nonetheless underperform – even after the ducts are insulated!

Within the occasion you are already replacing your HVAC system, that is a good time to additionally change your previous ducts. The brand new duct system will decrease vitality loss and, assuming it is put in by a educated firm, will provide higher high quality and luxury in comparison with no matter you have obtained now. It should additionally pair properly along with your new HVAC tools. Your present ducts, alternatively, may not.

How to decide on the thickness of ductwrap / duct board?

As we’re a UK primarily based online insulation store, we can be following the British Customary, BS5422:2009 to decide on the thickness of our ductwrap and duct boards. Completely different codes and requirements apply to completely different areas and nations, however you might be fairly assured British Requirements are amongst the very best and most rigorous on this planet.

One caveat we’ll make is that the under recommendation shouldn’t be meant to be an alternative to correct design calculations which strictly talking needs to be made by a reliable guide or constructing management. 

The under recommendation is normal in nature, while referring to BS5422 and can be utilized by the layman to assist them select the proper thickness, however all types of things come into play when choosing the thickness of duct lagging, similar to humidity, location of the ductwork, materials the ductwork is made out of and many others so skilled recommendation needs to be sought or thorough analysis needs to be carried out to will let you select the proper thicknesses required.

For the precise thicknesses required, for England & Wales, Discuss with TIMSA Information Part 6.2.5, web page 26 & BS 5422: 2009 Tables 12,13 & 14.

Beneath are snippets from Isovers personal foil faced ductwrap information sheet which you could find on our web site here.

The primary snippet exhibits you ways to decide on the suitable thickness relying on the kind of air that's being carried by way of the duct, to attain the utmost permissible warmth acquire or loss. As you may see, 50mm is the desired thickness in most cases. If the ductwork is used for each heat and chilly air, it is best to go along with the central, twin objective column which states 50mm.

Nonetheless, should you're simply seeking to stop condensation moderately than stopping warmth acquire / loss then the under desk particulars the thickness required.

Typically talking, condensation prevention on ductwork can often be achieved with simply 25mm thickness, that's if the air throughout the duct doesn't drop to under 10 levels which typically wouldn’t occur on conditioned air. 

Nonetheless that is definitely attainable with exterior air throughout frosty and snowy circumstances, which is being sucked in through the contemporary air ductwork, which might then require both 40mm or 50mm. 

Steps for Insulating HVAC Ductwork

  1. Verify the velocity of the blower motor on the furnace. If needed, change the wires to cut back the blower to its lowest velocity.
  2. Press a steady strip of foil tape to all longitudinal seams alongside straight runs of duct.
  3. Use a paintbrush to use duct mastic to the joints the place an elbow connects to a duct.
  4. Use a utility knife to chop foil-faced fiberglass insulation to the correct dimension.
  5. Wrap the insulation across the duct, after which pinch the seam closed. Safe the insulation with brief strips of foil tape.
  6. Apply an extended strip of foil tape alongside the seam within the insulation. Repeat to insulate the remaining ducts.
  7. To put in preformed duct insulation, begin by disconnecting an elbow to reveal the top of the duct.
  8. Snap a plastic cap onto the duct finish, then slip the preformed insulation over the duct.
  9. Gently pull the insulation over your entire size of duct.

Insulating your ducts

Including insulation to your ducts is not so simple as getting some duct wrap and taping it collectively. Okay, some individuals and contractors do insulate their ducts this manner. And technically, the ducts are insulated afterward.

However should you go this route, you are forgetting one thing tremendous vital: duct leaks.

Duct leaks are the scourge of vitality effectivity and indoor air high quality. Gaps, cracks, holes, rusted out corners… When air leaks by way of your ducts, it brings contaminants into your indoor air and reduces the effectivity of your HVAC system. By not addressing duct leaks, you are actually polluting your clear, filtered, conditioned air with soiled, unfiltered, unconditioned air!

Keep in mind, a number of your ductwork is both in your crawlspace or your attic. Do you actually need to be respiratory the air from these areas 24/7?

Anyway, the purpose of all that is to spotlight the truth that you have to seal the leaks earlier than you insulate the ducts.

Insulation blocks the motion of warmth, however it will probably’t stop air leaks. Soiled air will nonetheless enter your ductwork by way of the leaks, even after you add insulation. If you happen to determine to insulate your previous ducts, simply be sure to or your contractor follows this order of operations:

  1. Seal the leaks with mastic or mastic tape (we comply with a extremely exact “seal and take a look at” protocol that identifies all leaky areas and ends in 4% duct leakage or less).
  2. Wrap fiberglass duct insulation across the ducts and tape the seams collectively.

In fact, you may also think about…

Attainable Dangers Related With Ductwork and Fiberglass

Nothing on this planet of HVAC is risk-free. The excellent news is which you could have it safely put in by knowledgeable. If you happen to’re nervous about what may occur when ductwork touches fiberglass, you’re in the suitable place.

Right here’s a listing of attainable dangers which may happen if ductwork touches fiberglass insulation:

  • If there are leaks alongside the ductwork, condensation can buildup. Condensation and different sources of moisture trigger mildew and mildew to develop on fiberglass insulation. It’s a well being hazard that may additionally wreak havoc on the insulation and ductwork.
  • As talked about above, free fiberglass batts could cause respiratory points. Fiberglass batts are designed to remain compacted all through the set up course of, however that doesn’t stop sloppy work from ruining them.
  • If the ductwork is porous or cracked, it may pull fiberglass fibers by way of. This downside would end in small shards of fiberglass unfold all through your property, which has apparent unfavorable negative effects. Though it’s extremely uncommon, nothing beats an excellent quaint inspection.

So, above all else, your first step is guaranteeing that the ductwork is air-sealed.

As an FYI – In line with the Engineering Toolbox, fiberglass has a warmth threshold that’s effectively over 500°F or 260°C.

Whatare the advantages of getting ducted hvac techniques?

Correctly put in and maintained ductwork has three principal advantages: 

For starters, by supplying uniform temperature all through the constructing, they preserve a good, comfy temperature for its inhabitants, while eliminating cold and hot patches all through.

Secondly, it filters out mud particles and different indoor air pollution, making the indoor air cleaner and brisker. Particular filters may even filter out germs and viruses, together with coronaviruses.

Thirdly it’s rather more efficient at heating or cooling a room rapidly and evenly than say radiators or cut up air conditioners. Infact, except there are cut up air conditioners in every room which is much less environment friendly, then there isn’t a higher solution to cool a constructing than utilizing ductwork.

Ductwork might be hidden in ceilings and partitions additionally, whereas cut up air conditioners and radiators can’t, that means extra dwelling area and fewer ugly wanting home equipment on present.

The picture under is of an enormous workplace constructing's community of provide and extract insulated ductwork, earlier than it was hid by a dangling ceiling grid. 

Required Instruments for this Challenge

Have the mandatory instruments for this DIY undertaking lined up earlier than you begin—you’ll save time and frustration.

  • Caulk gun
  • Cordless drill
  • Mud masks
  • Knee pads
  • Lineman’s pliers
  • Security glasses
  • Tape measure
  • Utility knife
You’ll additionally want a hassle gentle and leather-based gloves