This duct insulation guide discusses the reasons, materials and HVAC ductwork insulation costs. The average duct insulation cost will be between $0.95 and $2.00 per sq.ft. installed, the cost will vary depending on a few factors which are discussed below, however r-values have the biggest impact and unsurprisingly insulation with r-values of r-3.5 are the cheaper, up to r-8.0 for the most costly.
| HVAC Ductwork Insulation Costs | |||
| Basic | Average | High | |
| Expect to Pay | $0.95 – $1.37 per sq.ft. | $1.45 – $1.85 per sq.ft. | $1.50 – $2.00 per sq.ft. |
| Insulation Type | Fiberglass | Mineral Wool (Foil or Non-Foil Faced) / Fiberglass | Mineral Wool (Foil Faced) |
| Value | R-3.5 / R.6.0 | R.6.0 | R-8.0 |
| Ease of Access | Easy | Medium | Hard |
| DIY or Pro | DIY / Pro | Pro | Pro |
| Note: Prices above include supply of insulation and labor / tools for installation.
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Most duct insulation is a two-piece product. The insulation is fiberglass made from spinning molten glass or stone wool made from spinning molten slag. The insulation is then faced with an aluminum heat and moisture barrier. Unfaced duct insulation is also available.
Duct insulation is also known in the industry as HVAC insulation since it contributes to the efficiency of the HVAC (Heating, Ventilation, Air Conditioning) system.
The material is produced in the form of a blanket for wrapping round and rectangular ducts to prevent heat loss or gain through the sheet metal and seams. Duct insulation is a cost-effective way to reduce heating and cooling bills and control humidity in your home throughout the year.
Reasons to Insulate the Duct Work
Energy experts from the US Department of Energy state that about 20% of the treated (heated or cooled) air that moves through ducts in your home is “lost due to leaks, holes, and poorly connected ducts.” That’s a significant waste or energy and money. Adding insulation to ducts will make them much more efficient when heating or cooling your home.
A second reason to consider insulating your ducts is the control of humidity levels in your home. If you have a humidifier on your furnace to keep humidity levels at a comfortably high level when heating, faced duct insulation will ensure that the moisture finds its way to the living spaces of your home rather than being lost through those leaks, holes and seams.
When using central air conditioning, it is important that uncomfortably humid air reach the indoor coil where the moisture can be condensed and drained away. You’ll feel more comfortable at a higher temperature when the air is relatively dry, and this means you can set your thermostat higher.
A final reason to consider duct wrap is that it prevents condensation from forming on ducts when air conditioned air is moving through them. This will prevent dripping from the ducts into living space.
Some of the duct work insulation products on the market meet federal requirements for tax credits for the installation of energy efficient building materials. Check with the manufacturer or your insulation contractor for details on which products are part of the tax credit program.
Recommended Insulation Levels for Ducts
The basic recommendation from insulation contractors is that you should add one to three inches of insulation to your ductwork. Here are the relative values:
- 1 inch of insulation: R-value of 1.9
- 1.5 inches of insulation: R-value of 3.5
- 2.5 inches of insulation: R-value of 6.0
- 3 inches of insulation: R-value of 8.0
The more extreme climate in which you live – very hot summers or bitterly cold winters – the more insulation you should consider adding for cost-effective energy efficiency in your home. Get estimates from several insulation contractors in your area to determine the best choice for your home at the most competitive prices.
In addition, the longer you plan to live in your current home, the more insulation it makes sense to add. The long-term benefits of adding more insulation are outstanding.
Types of Insulation Used in Duct Work
The most common type of duct work insulation is the foil-faced wrap. The facing acts as a moisture barrier to help control indoor humidity n all seasons. The insulation used most often is fiberglass or mineral wool, also known as rock wool. Like fiberglass, mineral/rock wool is produced from spun molten material, in this case molten slag.
The insulating value of duct insulation ranges from R-1.9 to R-8.0.
Duct Work Insulation Costs and Comparisons
This duct insulation cost, or HVAC insulation cost, will help you anticipate the cost of the project before you contact insulation contractors in your area.
Table 1: Prices shown for Duct Insulation, divided down into Material per Sq. Foot and Labor per Sq. Foot:
| Insulation Rating | Material per Sq. Foot | Labor per Sq. Foot |
| R-3.5 | $0.33 to $0.55 | $0.60 to $0.72 |
| R-6.0 | $0.80 to $1.10 | $0.65 to $0.75 |
| R-8.0 | $.085 to $1.20 | $0.65 to $0.80 |
Factors Affecting Duct Insulation Costs
The prices above are reasonably accurate based upon current HVAC ductwork insulation costs, however from job to job there will always be a small number of factors which are likely to affect the cost of the project. These include:
- Length of the Ductwork – Ductwork insulation is calculated in sq. ft., therefore the longer the ductwork the more insulation is going to be require for the job. This will consequently be affected by the insulation rating, which as already discussed in the tables above, will be cheaper for R-3.5 and more costly for R-8.0.
- Thickness of Ductwork Insulation – The thickness of the ductwork will affect the cost as you will need to add more insulation in order to achieve the desired thickness. As quoted above there are specifically recommended insulation levels which depend upon the R value of the ductwork insulation you’re using. However, it really goes without saying that 1 inch thickness of ductwork insulation will be cheaper than 3 inches of ductwork insulation.
- Supplementary Materials – For every 1,000 square feet of insulation installed, expect supplementary materials and supplies to cost $25 to $40.
- Pro or DIY Pro or DIY – Expect to pay an additional $0.60 – $0.80 per sq. ft. of material installed, so for a 200 sq.ft. project this would see labor costs put an additional $120-$160 for that project. Ductwork insulation isn’t difficult, but if you’re not used to doing it, then you will need to take your time as it can be a fiddly job which will also need you to be accurate about how many inches of insulation you add. For small projects we recommend DIY if you feel confident, however for larger projects we always recommend a pro.
For the best prices on the project for your home, get written estimates from at least three contractors who know that they are competing for the job.