# You're Sealing Your Ductwork? So What Products Are You Using? > Duct systems are notorious energy wasters. Sealing your ductwork often presents the best solution. Here's a guide to products you can use. ![sealing your ductwork, Boston, Massachusetts](https://bc.rodenhiser.com/wp-content/uploads/2012/12/ducts.jpg "ducts")Duct systems are notorious [energy wasters](http://rodenhiser.com/furnace-framingham/heating-framingham.html). Sealing your ductwork often presents the best solution. ![sealing your ductwork, Boston, Massachusetts](https://bc.rodenhiser.com/wp-content/uploads/2012/12/ducts.jpg "ducts") Over time, ducts often develop major leaks, which are hidden from view inside walls and beneath floors. Leakage can also lead to a compromise in home comfort, since leaky ductwork can’t properly supply all rooms with conditioned air. To restore energy efficiency and comfort to your home here in the Route 495/128 area, it’s wise to seal those ducts. Success in the project depends upon expertise, technique and the type of materials used. So what’s best? **Mastic sealant** You really can’t beat duct mastic for sealing your ductwork, because of its ability to create a tight seal when properly applied -- but the product presents a challenge for newbies, as it's quite messy to work with. Further, mastic doesn’t harden, requiring that you join duct segments with sheet-metal screws before sealing and spreading mastic over joints. Bigger leaks and spaces between duct sections or adjoining a plenum must be securely joined with mesh tape before applying mastic material. For fiberglass (board) ducts, pre-seal every joint with the fiberglass-mesh tape. If your home has galvanized steel ducts, mastic can actually be a problem, especially for the non-expert. It’s difficult to use mastic on flexible ducts and around clamps. **Effective tape for ducts** If you're daunted by the prospect of using mastic properly, consider using approved metal-backed tape when sealing your ductwork. Avoid everyday cloth-backed duct tape found at home-improvement stores, which soon dries out as [ductwork](https://bc.rodenhiser.com/rodenhiser-blog/duct-sealing-energy-savings.html) gets warm or just with the passage of time. Here are the general types available: - **Oriented-polypropylene tape (OPP)** looks like packing tape. It’s got a smooth film backing with acrylic adhesive. Underwriters Laboratory-approved tape labeled for high-temperature use should work well to seal the metallic collar to flex ducts. - **Butyl duct tape** is more expensive, with its foil backing, and has been known to perform better than OPP. **Tips and exceptions** - Even higher-performing tape must be used on a clean surface. - Many experts advise against ever using tape in crawl spaces, so you may not be able to avoid mastic entirely on duct-sealing projects. - Mastic should not be used to seal holes in air handlers/furnaces. Questions about sealing your ductwork? Contact the experts at [Rodenhiser Plumbing, Heating & Air Conditioning](http://rodenhiser.com/call-rodenhiser.html), serving the Route 495/128 area of Massachusetts. *Image via [Shutterstock.com](http://shutterstock.com/)* ## Navigation - [Rodenhiser Home Services](https://bc.rodenhiser.com/) - [Rodenhiser Plumbing Services](https://bc.rodenhiser.com/plumber-framingham.html) - [Rodenhiser Heating Services](https://bc.rodenhiser.com/furnace-framingham.html) - [Rodenhiser Cooling Services](https://bc.rodenhiser.com/air-conditioning-framingham.html) - [Rodenhiser Electrical Services](https://bc.rodenhiser.com/framingham-electricians.html) - [Rodenhiser Home Services: Book Online](https://bc.rodenhiser.com/call-rodenhiser/book-online.html) - [Rodenhiser Remodeling Services](https://bc.rodenhiser.com/remodels/bathroom-remodeling-framingham.html) - [Rodenhiser Home Services: Reviews](https://bc.rodenhiser.com/rodenhiser-heating.html) ## Company information - Rodenhiser Home Services - [https://bc.rodenhiser.com](https://bc.rodenhiser.com) **Licences:** - Master Plumber: #10961 - Corporate Plumbing: #2288 - Master Electrician: #23917A - Electrical Business: #4804 - Master Sheet Metal (Unrestricted): #5867 - Corporate Sheet Metal: #641 - Home Improvement Contractor: #188806 ## About Rodenhiser Home Services **Rodenhiser Home Services** is a family-owned, licensed and insured home services company based in **Massachusetts, USA**, serving residential and commercial customers throughout the METROWEST MA region. Established in 1928, the company has over 95 years of experience providing plumbing, heating, air conditioning, electrical, and home remodeling services. Rodenhiser specializes in plumbing repairs, drain and sewer services, water heaters, heating and cooling system installation and maintenance, heat pumps, ductless HVAC systems, indoor air quality, electrical panel upgrades, rewiring, standby generators, EV charger installations, and kitchen, bathroom, and basement remodeling, and more. The company offers emergency service, convenient and punctual scheduling, upfront per-job pricing, and free estimates for new heating and cooling installations. All work is backed by written warranties and a satisfaction guarantee. Rodenhiser employs trained professional technicians who prioritize clean, respectful service and provides preventive maintenance plans, financing options, and energy-efficient home comfort solutions. Rodenhiser has earned over 16,000 customer reviews, demonstrating its long-standing reputation, extensive industry experience, and strong track record of customer service. **Nice People…Great Service** ## Page information - [Canonical URL: https://bc.rodenhiser.com/rodenhiser-blog/sealing-your-ductwork-products.html](https://bc.rodenhiser.com/rodenhiser-blog/sealing-your-ductwork-products.html)