Ductwork Insulation for Air Distribution

Your home is equipped with an air distribution system that helps create a comfortable living environment. Most systems use a network of air ducts, pipes, vents and registers to deliver heated or cooled air. By sealing air leaks and using duct insulation, homeowners can improve the energy efficiency of their homes and save money on heating bills. You can find ductwork insulation and accessories at local home improvement stores, or you can consult an HVAC professional to give your home a complete energy evaluation.

Conditioned Spaces vs. Unconditioned Spaces

The air distribution system in your home brings heated and/or cooled air to all conditioned areas of your home. A conditioned room is one in which you control the environment or temperature. The air that moves through ducts located in conditioned spaces probably isn’t that much different than the air outside the ducts — maybe just a few degrees.

It makes good sense energy-wise for heating and cooling systems and their related ducts to be in conditioned spaces. Ducts can be placed in drop ceilings, between walls and in unused corners of the room. HVAC systems may be installed in a conditioned basement or utility room.

However, many times, especially in older homes or those without basements, the HVAC equipment is stored in an unconditioned garage or attic. There may be a significant temperature difference between the air inside and outside the nearby ductwork when that happens. Because HVAC ducts are often manufactured from sheets of aluminum or galvanized steel, they conduct thermal energy easily. If these ducts aren’t properly sealed and insulated, they can cause a loss of energy dollars every month.

What About Condensation?

When the surrounding air meets a colder object, water molecules condense and start accumulating on the surface, whether it’s a glass of iced tea on a hot day or an air conditioning duct in your attic. Over time excess condensation can lead to moisture problems in the home, including mold and mildew. AC duct insulation can help prevent condensation problems.

How to Minimize Energy Loss From Your HVAC System

Sealing Ductwork Keeps Air Contained

ENERGY STAR® estimates that 20% to 30% of the conditioned air in a duct leaks into the surrounding space. Therefore, airtight ducts not only help you save money on heating and cooling costs but make your rooms more comfortable. Sealing air ducts can be a DIY project, at least for the ducts you have access to, or you can consult a professional.

• If you’re going to be self-sealing ducts, use mastic (duct) sealant or metal (foil) tape — not duct tape. Pay special attention to the register vents, corners and any damaged or bent ducts.
• By hiring an HVAC contractor, you get an experienced professional who can seal the ducts, evaluate your system’s airflow, and repair any damaged areas.

Duct Insulation Prevents Thermal Energy Transfer

Most homeowners are familiar with fiberglass insulation used between studs and floor joists. They have also seen or used XPS foam board, which frequently covers the exterior of walls and is also used inside the home. But they may be unaware of the range of insulation products available for HVAC ductwork. You can do air duct insulation as a DIY project, or if the scope of the project is outside your comfort zone, contact a professional.

Insulated Flexible Duct

If your project involves adding new ducts or replacing old ones, you may choose to use flexible ductwork, making it easy to bypass obstacles and go through awkward openings. Look for flexible ducts that are wrapped in Owens Corning’s PINK Ecotouch®. You’ll find various R-values ranging from 4.2 to 13 depending on the product’s thickness. In addition to its thermal performance, the insulated flexible duct also helps reduce the noise of air movement.

Fiberglass Duct Board

Contractors may choose to use fiberglass duct boards during a new home install or retrofit. Owens Corning’s QuietR® duct boards offer several advantages over regular sheet metal ducts, including:

• Resistance to bacterial and fungal growth
• Tighter seal
• Enhanced acoustic control — say good-bye to the popping and squeaking noises associated with metal ducts
• Thermal resistance in R-values from 4.3 to 8.7

Duct Wrap

One of the easiest ways to insulate your ductwork is by simply wrapping your current ductwork in an insulating fabric. Owens Corning SOFTR® Duct Wrap has installed R-values from 4.2 to 8.3 to help decrease thermal energy transfer and heat loss. The foil facing mimics the look sheet metal ducts and can be wiped down for cleaning. The wrap also helps control condensation, a common problem with AC ducts.

Loose Fill Fiberglass

If your HVAC ductwork travels through an unconditioned attic, you can use loose fill insulation in the surrounding space. Not only will this take care of any exposed ductwork, but it can help increase your home’s overall energy efficiency by ensuring heated or cooled air isn’t lost into the attic. Poorly insulated attics can make your home feel too cold in the winter and extra toasty in the summer. They are also a primary factor in ice dam formation during the winter months.

By blowing in loose fill insulation to the correct depth, you can make sure to reach the recommended R-value for your region. The Department of Energy lists R-values for different areas of the home based on temperature zones. For instance, if you live in Ohio (Zone 5), the minimum R-value for an uninsulated attic is R49. On the other hand, Florida residents (Zone 2) can get by with a minimum of R30. The R-value refers to an insulation product’s ability to resist heat transfer.

Most home improvement stores will let you rent a machine like the Atticat® by Owens Corning to blow in loose fill insulation when you purchase a minimum number of bags.

Other Ways to Save

Once your ductwork is sealed and insulated, take a moment to assess the rest of your house. Do you have air leaks and uninsulated walls or floors? The best thing about insulation is its constant return on investment, as month after month of energy savings continues to add up. Find out more about ways to use fiberglass batts and XPS foam board to improve your home’s energy footprint at Owens Corning — the insulation specialists.