We are often asked about what the R-value is on new Garage Doors. Often building plans and specs require a particular R-value. Some of these specifications are nearly impossible to meet such as in aluminum glazed doors because aluminum and glass conduct heat and cold so well. This got me thinking about what R-value is all about and what it means in the world of Garage Doors. I looked up R-Value on Wikipedia to see how it was determined, it said: “The R-value is a measure of thermal resistance [1] used in the building and construction industry. Under uniform conditions [italics added] it is the ratio of the temperature difference across an insulator and the heat flux (heat transfer per unit area per unit time, ) through it or . The R-value being discussed is the unit thermal resistance. This is used for a unit value of any particular material. It is expressed as the thickness of the material divided by the thermal conductivity. For the thermal resistance of an entire section of material, instead of the unit resistance, divide the unit thermal resistance by the area of the material.
For example, if you have the unit thermal resistance of a wall, divide by the cross-sectional area of the depth of the wall to compute the thermal resistance. The unit thermal conductance of a material is denoted as C and is the reciprocal of the unit thermal resistance. This can also be called the unit surface conductance, commonly denoted by h.[2] The higher the number, the better the building insulation‘s effectiveness. R-value is the reciprocal of U-value.” Did you get all that? Well, I can sort of follow what they are saying but I also know there is some game playing going on when it comes to the way they measure the R-value of Garage Doors. Different Door Manufactures use different methods of measuring R-Value. This results in some inconsistancies in being able to compare “apples to apples”. One Garage Door Company recently sent us a chart showing the difference between R-values. They called it the R-Value Reality Check. So, it appears that R-values are like the percentage rating in milk.
Whole milk contains usually between 3.25% and 4.0% fat, where as 2% obviously contains 2% fat. It’s not as if whole milk is 100% fat! An R-value of 16 is not twice as good as an R-value of 8. It does not offer twice as much thermal resistance or twice the energy savings. A value of R-16 offers a 5% reduction in heat flow and a 5% improvement in energy efficiency over an R-value of 8. Should you be concerned about R-value in choosing your Garage Door? I think so but the reasons may be a little surprising. If you were living in an extremely cold climate and never intended to open your garage door it could be very significant, but the R-value of an open Door immediately becomes zero. A Door that is never opened is called a wall. A well insulated door can really be nice when the Garage is used as a workshop but there are other advantages of an insulated Garage Door. Most insulated steel and wood Garage Doors are insulated with polystyrene (styrafoam) layers.
Some improve their R-values by using high density polystyrene or HD. Some of the highest rated insulated doors are those that are ‘foam injected’ doors that use polyurethane. Polystyrene insulation is either attached to the back of steel door panels with a vinyl backing or sandwithced between layers of steel. To increase insulation you either use a higher density foam or make a thicker door. Some manufactures have even started making a three inch thick door. It looks pretty impressive but it still can’t match the R-value in a two inch thick polyurethane door. Polyurethane is like the foam insulation in a can that can be sprayed or injected to seal around doors and windows. Urethane injected doors and laminated polystyrene sandwich doors make good solid and sturdy sections and are both reasonably priced. But, then we add windows for light and style and that is the end of reasonably priced; by this I mean insulated glass is lots more expensive and a fraction of the R-value.
Even double pane glass with one half inch space between panes has an R-value slightly above 2. Unfortunately, Sectional Garage Doors can’t be installed air tight, there needs to be room for the door to slide up and down against the jambs. These little spaces let cold air draft in and negate much of the insulating that was done in door construction. Some of the drafts can be stopped with a vinyl weather seal around the door and bottom seal, or astrigal, can fill in the space along the bottom of the door depending on how level and even the floor is. We’ve now come back to why, in the moderate climate of the Northwest do we need an insulated Garage Door. If you have questions regarding any of this, please give us a call! Call today at 1-800-478-8428 or Contact Us HereSee all 9 reviewsWe are extremely satisfied with that product and have referred it to many ...The insulation kit arrived as scheduled and was securely packaged ...Great product and easy installationthis is a great product, my garage is half as hot than ...
Works great, howeverFive StarsFive StarsGet fast answers from reviewers See all 3 answered questions What do customers buy after viewing this item?Best SellingM-D Building Products 50100 10-feet Single Door Garage Door Threshold Kit217Top RatedGarage Door Insulation Kit- DIY---- R-9 Complete Garage Insulation Kit9Lowest PriceReflectix ST16025 Staple Tab Insulation 16 Inch x 25 ft Roll97Need customer service? Image 1 of 4 Is R-8.6 per inch even possible? The advertised R-value for Clopay’s model 9200 garage door strains credulity. If you’re shopping for a garage door, the door’s energy performance may not matter — especially if you don’t heat your garage. However, there are a few reasons why you might be looking for a well-insulated, draft-free garage door: So, how do you tell a high-performance garage door from a lemon? “We sell high doors!” Many garage-door manufacturers advertise the R-values of their doors: Should I Insulate My Garage Door?
Garage Door Openers Are Always On How to Heat a Garage A Stupid — and Illegal — Way to Air Condition Your Garage Unfortunately, these advertised R-values are almost meaningless. Advertised R-values are inaccurate, irrelevant — or both To determine the thermal performance of a garage door, you need to know two things: The R-values that are trumpeted by garage-door manufacturers are measured at the center of one of the door panels. No manufacturer, as far as I can determine, reports the R-value of the entire door assembly (including the panel edges, the seams between panels, and the perimeter of the door) in their promotional materials. Moreover, manufacturers’ reported R-values tell us nothing about air leakage. Most garage-door manufacturers are reluctant to share actual laboratory reports showing the results of R-value testing. When I asked Mike Willstead, a technical representative for Raynor, if I could see a copy of Raynor’s test results, he suggested I send him an e-mail.
He later e-mailed his response: “I apologize if I misled you. I was informed that this is proprietary information that will not be disclosed.” The window industry does a much better job More than a decade ago, responsible window manufacturers realized that the reputation of their industry was being damaged by misleading R-value and U-factor claims. (U-factor is the inverse of R-value; in other words, U=1/R and R=1/U). To address these problems, industry leaders developed a method for testing and reporting whole-window U-factors. The U-factor reported on an NFRC label accurately describes the U-factor of the entire window, including the sash frame and the window frame — not just the center-of-glass U-factor. When it comes to accurate reporting of U-factors or R-values, however, the garage door industry is years behind the window industry. There’s nothing to prevent garage-door manufacturers from using the NFRC testing and labeling protocol — a protocol that yields a more honest and useful result than the center-of-panel numbers trumpeted by garage-door marketers.
Alternatively, garage-door manufacturers could use the voluntary consensus standard (ANSIAmerican National Standards Institute. National nonprofit membership organization that coordinates development of national consensus standards. Accreditation by ANSI signifies that the procedures used meet the Institute’s essential requirements for openness, balance, consensus, and due process. /DASMA 105) for reporting whole-door U-factors adopted by the Door and Access System Manufacturers Association (DASMA). A technical data sheet (DASMA TDS #163) describes this testing protocol, dubbed the “tested installed door” protocol by DASMA. “For marketing purposes, the garage door people get a measurement on the center of panel,” said David Yarbrough, a research engineer and insulation expert at R&D Services in Cookeville, Tennessee. “The overall R-value of the entire door might be quite a bit less — in extreme cases, it may be half — of the R-value of the center of the panel.
Not everyone approves of this kind of marketing. It’s been a hot debate in recent years.” In fact, the percentage turns out to be much less than half. Actual R-values are one-third the advertised values Although it’s hard to obtain actual test results that report the whole-door U-factors of “tested installed doors,” I managed to obtain one report on a garage door from Clopay, and another on a garage door from Overhead Door. Clopay provided test results for their model 3720 five-panel garage door. According to Mischel Schonberg, Clopay’s public relations manager, the door is insulated with 2 inches of polyurethane foam. Schonberg wrote, “This model is the commercial version of our residential model 9200 and has the same construction.” While Clopay advertises that the 9200 door is R-17.2 — presumably, a claim based on a center-of-panel measurement — the test report for the installed door shows R-6.14. While Overhead Door advertises that their model 494/495 Thermacore door has an R-value of 17.5 — a claim that, like competitors’ claims, is presumably based on a center-of-panel measurement — the test report for the installed door shows a U-factor of 0.16, equivalent to R-6.25.
Based on the only two test reports that I was able to track down, it seems logical to conclude that the R-value of a garage door is about one-third of the R-value claimed in a manufacturer’s brochure. All over the map Mike Thoman, the director of thermal testing and simulation at Architectural Testing Incorporated, a Pennsylvania laboratory, has tested many garage doors. “The assembly R-values are not going to be nearly as good as the R-value of the material would indicate,” Thoman told me recently. “When you compare the assembly R-value to the material R-value, the percentages are all over the map. The percentage is a function of how the joints in the panels are made, and whether any attempt was made to provide for thermal breaks at panel edges — a lot of different things. Some products have a lot of insulation in the panel but have everything else wrong. We’ve also seen doors that do everything right. There’s really a wide, wide range.” Are the reported R-values even accurate?
There’s another potential problem with the R-values reported by garage-door manufacturers: even if one accepts the fact that the advertised R-values represent center-of-panel values rather than whole-door values, the numbers are still higher than most insulation experts believe are possible. Several manufacturers report that their polyurethane-insulated door panels have R-values between R-8.6 and R-9.0 per inch — values that are highly unlikely if not technically impossible, even for the center of a door panel. “The R-value of polyurethane decreases with age,” said Yarbrough. “When it is absolutely fresh you might get R-7.5 per inch, but a realistic aged R-value would be lower — perhaps about R-6.5 per inch would be on the high end. I’m not sure I can explain these reported test results. I have seen labs make mistakes before. I think it’s an error.” One garage-door distributor who doubts the accuracy of manufacturer’s R-value claims is Bill Feder, the president of Door Services Incorporated of Portland, Maine.
On his own initiative, Feder sent a garage-door panel (Overhead Door model 194) to Yarbrough’s lab, R&D Services. The ASTMAmerican Society for Testing and Materials. Not-for-profit international standards organization that provides a forum for the development and publication of voluntary technical standards for materials, products, systems, and services. Originally the American Society for Testing and Materials. C518 test conducted by Yarbrough came up with a value of only R-7.83 for the 1 3/8-inch-thick panel. Yet Overhead Door advertises that the door is R-12.76 — or R-9.28 per inch. “If anyone calls me about a door, I tell them about my R-value challenge,” Feder told me. “I will give anyone a check for $250 if they can bring in a document that shows that a 1 3/8-inch-thick garage door has an R-value of 12. They can’t do it.” Unfortunately, Feder’s admirable challenge has not yet shamed the garage-door industry into correcting the numerous exaggerations in their product specifications.
What about air leakage? If the day ever comes when garage-door manufacturers follow the path blazed by their more honest brothers and sisters in the window industry — that is, if they ever decide to report whole-door U-factors or whole-door R-values — an important piece of the door-rating puzzle will still be missing. The reason: when it comes to the thermal performance of garage doors, air leakage matters much more than R-value. “Garage doors are so leaky that they are difficult to test,” Thoman said. “Their leaks exceed the capabilities of the available testing apparatus.” When he needed to buy a garage door for his own house, Thoman ignored advertised R-values. “I find it almost offensive that garage-door manufacturers even publish the R-value of the insulation material,” Thoman told me. “I hate it when I see that, because it’s not a representation of the door’s performance. Air leakage is a much more important issue than the R-value of the door.”