The average cost to repair ductwork in a crawl space is $900 and ranges between $450 and $2,400. Overall costs depend on the level of damage, accessibility, and hours required.
The average cost to repair ductwork in crawl space is $900, though most homeowners pay between $450 and $2,400. If there are leaks or decomposing ductwork, you could be heating your house in the summer or losing all your heat in the winter without knowing it. However, repairing the ducts in your crawl space will seal your HVAC system and ensure efficiency. Learn about all the cost factors of repairing your crawl space’s ductwork.
While the largest cost factor is the type of repair required, the cost of working under a house or in the attic is something not many want to do. Because of this, you’re going to pay more than you would for the same work done on exposed ductwork.
Whether it’s a minor leak or fully replacing a section of ductwork, the type of repair will impact your cost.
| Repair Type | Average Cost |
|---|---|
| Simple leak repair with tape | $150–$300 |
| Swapping a section of ductwork | $500–$3,200 |
| Mold removal and cleaning | $300–$900 |
| Adding or replacing insulation | $300–$1,700 |
| Securing loose ducts | $300–$900 |
| Removing obstructions | $100–$1,000 |
Ironically, duct tape doesn’t really work on ducts. Because the adhesive melts at high temperatures, you’ll want to use special tape for fixing minor leaks. Mastic works as well; just make sure it’s specifically for ducts, as it needs to be both resistant to high temperatures and safe to breathe. While checking for air duct leaks can cost $150 to $450, it’s less expensive to fix it—especially if you DIY.
A full air duct replacement costs $3,500 on average, but you likely won’t need to take it that far. Most ducts, whether they are made from fiberglass or sheet metal, can be cut and replaced with newer sections. This fix is only really suitable though if a section of ductwork was damaged beyond repair. Otherwise, you may need to replace every duct.
Air duct cleaning should be done at least once every three to five years. If mold or other harmful biological growth is noticed during an inspection, you’ll need to clean it. On average, air duct cleaning costs around $400, but the price is worth the clean air and peace of mind. While some repairs can be DIY, mold removal is better left to the pros.
Insulating ducts in a crawl space is no easy feat. While you can try wrapping your ductwork, it needs to be in good condition, and you better be ready to be uncomfortable for long stretches of time. The insulation itself costs around $100 per 25 linear feet, but the real cost is the time required to insulate your duct sufficiently.
Sometimes you don’t need to replace your air ducts—you just need to tighten them down. Any rattling or banging noises coming from your crawl space could mean your ductwork is loose. Consider crawling into the space and locking everything down or hiring a pro to handle the work at a cost of $40 to $80 per hour.
Removing obstructions in your ducts can either be quite cost-efficient or, in some cases, pretty expensive. If the obstruction is large enough, you’re better off removing the section and replacing it. If no materials are required, expect to pay the hourly rate above.
While the largest factor is the type of repair required, the size of your ductwork matters too—especially if you plan on replacing large sections. While each repair has a different cost basis, you can see below how the length of the ductwork impacts the total project cost. Due to the wide range of materials and labor time required, the average estimated cost is about $275 per 10 linear feet.
| Ductwork Length in Linear Feet | Average Cost |
|---|---|
| 4 | $90–$120 |
| 8 | $180–$230 |
| 12 | $300–$360 |
| 20 | $3580–$600 |
| 40 | $900–$1,20 |
| 70 | $1,800–$2,400 |
| 100 | $2,500–$3,800 |
General labor will cost between $40 and $80 per hour. Hopefully, you don’t require specialized equipment or professionals with certain licenses—such is the case with mold contamination—as those hourly rates can be between $50 and $120 or more. For repairs, you’ll likely be quoted in hours. For larger jobs, expect a more detailed cost breakdown.
There are a few instances where you should consider replacing your ductwork. Mold issues, pest infestations, and severe damage are all costly and complicated fixes. While they may cost 75% more than a repair, they are often the better choice.
That being said, you can do many minor repairs yourself. Taping or sealing an obvious duct rip can be satisfying and cost-effective. You can wrap your ductwork in installation, provided you can get to it. A general rule is to hire a local ductwork professional if the ducts are contaminated or if the job takes too much time or requires more than 10 minutes of research.
You may consider DIY ductwork repair in a crawl space. However, there are some drawbacks to going it alone. Safety complications could arise due to unknown contaminants, and there’s also the potential for costly or dangerous mistakes.
When you hire a duct pro, you’re paying for licensing and years of expertise. Professionals are extremely efficient compared to DIYers, and while their hourly rates might be high, they can work much faster than most homeowners. The key is to get a range of quotes from different contractors and hire someone you trust.
There are a few ways you can lower costs when repairing ductwork in a crawl space:
Handle simple repairs yourself.
Hire professionals outside of busy seasons, like deep winter or high summer.
Shop around—the best deals might not be at the closest store.
Sign up for blanket discount codes from home improvement stores.
You should insulate ducts in a crawl space if you live in a colder climate or you run your air conditioning for most of the year. Insulating ducts doesn't take too much time or investment and can make a big difference on your electricity bill. While this is more difficult in a crawl space, if any ductwork is being done either you or a professional will be down there anyway. A bonus benefit is since they will be putting off less hot or cold air they'll be less attractive to any unwanted pests in the home.
Ductwork sweats for the same reason you might find beading on your windows or why cold drinks drip in the heat—temperature difference. When you see your ductwork and you notice sweating, that's a sure sign that your system is not operating anywhere close to peak efficiency. The best way to keep ductwork from sweating is to wrap it in inadequate insulation.
One of the most common but overlooked symptoms of damaged ductwork is a spike in your utilities bill or an inability to heat or cool the house as you previously could. When ductwork is damaged, it tends to bleed air, and the result is you're paying to cool or heat your crawl space instead of your house. For handy DIYers, you might be able to find the damage by going into your crawl space, but for those unable to, you should pay a professional for an air duct inspection.
Ductwork should be replaced when it's more than 20% damaged or after around 10 years. There are so many factors at play that it's hard to give an exact time as a house using the system in a harsh environment will need repairing much more than someone who just flips on air conditioning three or four times a year. The only real way to know is to hire a professional to assess your entire system.
If your ductwork is damaged you need to repair it, and if it's damaged enough to require replacing it's absolutely worth it. Replacing ductwork will positively affect your electricity bill by making your system more efficient and damage ductwork can actually be a health hazard in certain circumstances. While a minor duct seal is easy enough, more serious problems need to be addressed by a professional.
