The Quest for a Highly Efficient Home
One thing that most barndominium owners are concerned about is energy efficiency. It can make your home more comfortable, keeping it cool in hot weather and warm in cold weather, and it can make a huge difference in your energy bills for a lifetime. A big part of energy efficiency is dependent on the insulation installed in your barndo. But how should you decide which insulation to use to meet your goal?
When you understand how different insulation products work, it will be easier to pick the products that are best for your situation. It starts with the basic knowledge that there are three forms of heat transfer. Therefore, the insulation or combination of insulations being installed must address, prevent or control all three forms of heat transfer.
How Insulation Works
There are many ways to insulate a building. There are three forms of heat transfer, and there are options for each.
The first form of heat transfer is conduction. The transfer of heat energy through matter like concrete, wood, vinyl, metal, etc. One important thing to remember is that metal conducts approximately 300 times faster than wood. An insulation that works as a thermal break placed between conductive materials helps prevent heat transfer and thermal bridging and is highly recommended when possible.
The second form of heat transfer is convection which is heat transfer in a gas or liquid by movement of warmed air. This can vary from 25% up to 40% of the problem to control or address for a solution. The variables are windows, big or small doors openings or any air leaks in the structure. An insulation that provides an air-vapor barrier is best.
The third form of heat energy transfer is through radiation or infrared rays, not just from the sun, but also radiant heaters or fire in fireplaces, etc. This is one of the most predominant forms of heat energy transfer and for many years the most ignored or neglected. Currently there are many insulation combinations or methods to meet the goal of controlling all three forms of heat transfer.
Reflective Insulation
Most reflective insulation products are an air – vapor barrier and radiant blocker. All reflective products will enhance the performance of all cavity-fill porous insulations like fiberglass, cellulose or rockwool. Reflective laminates improve performance on all foam products. When laminated on both sides of foam panels or sheets it helps keep the inside temperature in – and the outside temperature out. Continuous insulation foam sheets or panels also provide a thermal break on the structural frame.
How do you pick the right reflective product and get the best performance or value? The basic rule of thumb is, the lower the emissivity, which is less heat absorption, the higher the reflectivity.
R-Value codes are the measure of how well insulation restricts the flow of heat through it, but you should know that standards and codes are based on lab tests, not real world tests, which can make a difference. When you are setting your goals to have an energy efficient Barndo, try to address or prevent all three forms of heat transfer, thermal bridging and dew point. This can be achieved with multiple products or just a few products and still be very cost productive. This will be one of your bigger decisions regarding your home, so do your due diligence and find what best meets your goals for a lifetime payback on utilities and less chance for future regret.
Other Considerations and Benefits
Some key points to consider are what climate zone you are in and what materials are being used on your barndo. Materials used, whether concrete or brick, pre-engineered steel, wood, shingle or metal roof are all variables.
Since radiant heat is one of the predominant forms of heat transfer, and you want to reduce the gain or loss of heat, radiant barrier products should always be used in any climate zone. However, the requirements for insulation will be different dependent on the temperatures where your home site is. Requirements to maintain inside temperatures in a climate that varies between 70℉to 100℉ versus a climate that encompasses -30℉to 70℉to maintain inside temperatures. In the north you will need to combine a reflective insulation with a thermal resistant product like cellulose or foam.
Testing has proven reflective products are a great choice for stand-alone use for some situations, and they significantly increase performance of porous cavity fill insulations like fiberglass, cellulose rockwool and even foam thermal insulation products.
Reflective insulation products have many benefits beside the main purposes of insulation: keeping the home’s interior comfortable and the heating and cooling bills down. These benefits include ease of installation. It is comparatively low cost, lightweight, safe to install without masks or gloves, and it can serve as a vapor barrier. Most have a Class A fire rating.
Remember to always follow local codes when required, and talk to your contractor about your efficiency goals for your barndo. You may use multiple beneficial insulation products or one product, but be sure to control all three forms of heat transfer for your home.
Types of reflective Insulation
• The first example is Innovative Energy’s TUFF STUFF radiant barrier designed with two layers of high-strength polyethylene bubble film, giving it superior puncture-resistance and the ability to withstand 500psi. This product is used to insulate cement flooring.
• Reflective radiant barrier product is MWI’s Infinity Shield® won’t compress, collapse, or disintegrate and multiple applications.
• Double reflective radiant barrier product is quite versatile, such as This option features foil on each side of the heavy gauge polyethylene bubbles to improve performance. rFoil®’s 2200 Reflective Insulation is an example, and it works well for roofs, attics, walls, and even duct insulation.
• A Single reflective foil example is Reflectix Single Reflective product with an approximate 96% reflectivity layer of foil with two layers of heavy gauge polyethylene bubbles.
• Foil Scrim – This insulation is created with foil and a fabric or fiberglass woven piece for greater rigidity.
• Foil Foam-The lamination of reflective foil on foam provides radiant resistance. The foam core provides thermal resistance and thermal break. The combination provides both air and moisture barriers.
• Foil Fiberglass- The foil provides reflectivity and is joined by the thermal performance of fiberglass core for added thermal resistance.
• Thermal 3H+ – This insulation product is EPS/expanded polystyrene laminated on both sides with Mylar-like reflective metalized plastic or with a tough double woven white on one side and reflective on the other.
Things You Should Know
Regardless of the reflective insulation you choose, all seams should be securely taped to ensure effective performance. There are many tapes on the market specifically formulated to work with foil or any reflective product to create a strong, airtight seam.
Remember that most reflective product applications require an air space between the reflective product and metal, wood, or any other material. Read the instructions that come with the reflective product. Some reflective products should be draped over purlins, attached to the inside of the purlins, or stapled to posts.
Now to get back to the initial question we posed: Will reflective insulation improve your barndo’s efficiency? The answer is Yes!
Resources: Innovative Energy, MWI Components, rFoil, Thermal Building Concepts, Reflectix, Fi-Foil,
Structural Insulated Panel Association
