In last week’s post, we talked about the performance considerations that homeowners and home builders must make when choosing between insulated flexible duct options. When it comes to the choice between products, cost is often the other major factor that you may be considering. Whether you’re trying to optimize the heating and cooling system in your own home or working to meet the needs of your clients as a home builder, it is important to ensure that the duct you choose falls within your short-term and long-term budget. There are two main factors that affect the prices of insulated flexible ducts: diameter and R-value. Read on to learn more about the direct (and indirect) costs (and savings) associated with each.
The Impacts of Duct Diameter and R-Value on Cost
In general, the lengths of insulated flexible ducts are standardized around 25 feet, regardless of their diameter. That way, you always have the option of cutting the duct to whatever length you need. As duct diameter increases, so does the amount of insulation in a 25-foot-long duct, which explains the simultaneous increase in price. When you think about buying a duct with a larger diameter, you also have to consider the cost of the supports that you will need to prevent the duct from sagging when you install it. Ideally, you want to prevent the duct from sagging by more than about two-and-a-half inches, so with large-diameter ducts, you should plan to us a support every four feet.
As you consider the upfront costs of ducts, the other key factor is the R-value. The R-value indicates the effectiveness of the insulation, with a higher R-value associated with higher effectiveness. Insulated flexible ducts can range between R4 and R8, and the price increases for higher R-values. At the same time, choosing a duct with a higher R-value may save you money in the long run–especially if you live in a cold area–since ducts with higher R-values are more effective for trapping heat and can therefore help lower your energy bills.
The Relationship between R-Value and Duct Diameters: Ratings vs. True R-Values
When you’re thinking about energy savings, it is also important to acknowledge the interplay between R-value and duct diameter. A duct with a 6-inch diameter and a duct with a 14-inch diameter may both be rated R6, but the true R-value — that is, the true effectiveness of the insulation for retaining heat — is higher for the 14-inch duct, simply because the larger amount of material makes it harder for heat to escape. That means that R-value ratings are can only truly be compared for ducts of the same diameter. Therefore, the discrepancy between R-value ratings and true R-values is another factor that you should keep in mind as you weigh the short-term and long-term financial costs of different insulated flexible duct options.
At National Air Warehouse, you can find competitively priced insulated flexible ducts with R6 and R8 ratings, ranging in diameter from 4 inches to 20 inches. Contact us today for more help finding the right one for your project!