Commentary: Combining insulation products

How to recommend the right mix for optimal performance

Comfort and performance drive insulation upgrades. Photo source: Johns Manville

A wide variety of insulation product types, combined with changing energy code R-value requirements and varied project climate zones, make recommending the right mix of insulation products to a contractor or builder seem like a daunting task. While there is no one-size-fits-all approach, understanding different aspects of the project scope and how products can work together are key in achieving the project goals. Here are three simple tips for dealers to consider when given the opportunity to recommend a mix of insulation products.

Understand the project scope

When helping to select the insulation products right for the job, the foremost questions should be to understand the project scope including, what climate zone and code requirements is the project in? What type of structure are you working with? And, what budget are you working within? Understanding project-specific details can help determine the best-suited product types, while code and climate can dictate how much insulation is needed.

The right R-value contributes to energy efficiency, leading to lower energy bills and overall energy conservation for the building owner, as well as code compliance. For example, steel- or wood-frame assemblies can require a different mix of cavity versus continuous insulation, which can influence not only energy, but also moisture control.

Lastly, consider other project goals, like increased comfort or cost savings. For example, if a project goal is to fully optimize energy efficiency, possibly through above-code programs like the Energy Star Certified Homes Program or the Passive House Institute U.S. (PHIUS) PHIUS+ Certification Program, products that combine heat, moisture, and air control might be part of the recommendation. Asking these questions upfront will ensure the recommended product mix matches the builder’s or contractor’s goals, while staying within their budget.

Combining insulation products  

Installing new or upgrading current insulation in a project improves the thermal performance, but it’s important to understand how different products can work together. Cavity insulations such as fiberglass deliver cost-effective thermal and sound-control performance, yet require separate air-sealing. Spray foam cavity insulation provides high thermal performance, as well as excellent air-sealing and moisture control, but is more costly. Continuous insulation, such as polyiso foam sheathing, effectively addresses thermal shorts through wood or steel framing, and can be an air-barrier, yet thick foam sheathing can also complicate window and door installation. An obvious advantage of combing insulation products is that it gives builders the ability to leverage multiple materials at different cost options to find the best mix that fits within the project scope.

Another common combination is installing batts or rolls throughout the structure, and using spray foam for hard-to-reach or hard-to-manage places, such as rim joists and attic eaves.  This approach can reduce overall air leakage and enhance the building envelope, at a manageable cost.

The importance of installation

Lastly, emphasize not only the importance of a well-insulated and sealed building envelope, but that achieving optimal energy efficiency and code compliance also requires good design and a quality installation. Regardless of the products used, emphasizing attention to detail during installation is critical. Encourage the use of outside expertise for installation tips and troubleshooting.     

Combining insulation products can significantly improve the energy efficiency of a building, while also helping manage costs. There is an opportunity to recommend products that work well together, meet or exceed code requirements and fit with the building. Understanding the key aspects of the project can aid in making the right recommendation. 

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J.R. Babineau is research manager and principal building scientist for Johns Manville. 

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