Remember to take into account any air boundaries you may have, such as with the outside or with the inside of rooms. Continue reading at HEAT LOSS R U & K VALUE CALCULATION or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX. Apologies for the delay. Thermal conductivity is conventionally defined as the rate of thermal conduction through a material per unit area per unit thickness per unit temperature differential (ΔT). AddThis use cookies for handling links to social media. Also available on Android is a free Green Dictionary of 800+ Eco & Green terms. Keeping cool in Summer and warm in Winter for free! ON Thu, 19 May 11, 2:46am probably from Australia  Reply to this comment, with a few changes the adroid app could be quite usefull. What is a Trombe Wall and how can you use one? The Council's researchers answered many critical questions that would affect the quality of the nation's housing stock. 50 materials in the list is just way too limiting. Not recommended for building insulation, may be serious fires hazard. Filled with sand and gravel aggregate [30] We consider this questionable and note that moisture content is omitted. To get the right depth of a material enter multiples of it tell you get above the required depth. ON Mon, 23 Dec 13, 5:51pm probably from United States  Reply to this comment, I was given an R-Value as 0.26 (m2K)/W for a particular material and I need to convert to U-Value which is expressed as W/m2K. ON Sun, 13 May 12, 3:41pm probably from Canada  Reply to this comment, ON Sat, 10 Nov 12, 5:27am probably from Australia  Reply to this comment, ON Fri, 7 Sep 12, 3:05am probably from Israel  Reply to this comment. This definitely needs to be fixed, as it discredits an otherwise brilliant array of tools. ON Mon, 26 Sep 11, 2:56am probably from United States  Reply to this comment, Is there a chance you would look at an app for iphone ipad? Wood siding, 1/2-inch clapboard or shiplap. The government needs to stop subsidising high-carbon heating and use the extra revenue to support low-income homes, writes Libby Peake of the Green Alliance, £2bn scheme risks becoming ‘postcode lottery’ without government action, says expert, Energy experts say record rise in new gas boilers installed shows UK going in wrong direction. Mount Vernon, WA 98273-3269 2-How can find R-Value? Installers say expanding fiberglass assists in sealing air leaks, Fiberglass panel, rigid (fiberglass "boards"). Note: appearance of your Comment below may be delayed: if your comment contains an image, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Have a nice day, placed vertically along with concrete chinking to fill in the wall plane. e.g. , optional and will not be search engine visible). The most-insulated roof structure I've built combined insulation of the space between rafters with a layer of high-R foil-faced foam board on the underside of the rafters. Varies by species, no authoritative source. It is helpful to understand R-value, K-value, and U-value as various ways of describing heat loss or gain. The Individual Gas Constant depends on the particular gas and is related to the molecular weight of the gas. The R-Value calculator is best used as follows: Work out all the different materials and surfaces that make up the wall/ceiling or surface you want to work out the R-Values and U-Values for. Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly. The actual change in rate of heat loss through the roof will be (most-likely) a lower percentage as heat loss is affected by, At HEAT LOSS R U & K VALUE CALCULATION we note that. Air Krete®, Air Krete Inc., P.O. Also you can add your own materials as required. The value is independent of temperature. Both of those factors mean that a 600% improvement in or reduction in heat loss rate by improved R-value will not be likely to give an actual 600% net improvement. Or click here if on an Android phone. Box 380, Weedsport NY 13166-0380 Keene Christopher, Principal Telephone: (315) 834- for 1/2" thickness, INSULATED VINYL SIDING as HOME INSULATION, AirKrete® Green Insulation Specifications, Dow® TUFF-R™ and Super TUFF_R™ POLYISOCYANURATE INSULATION, 10-Wall Polycarbonate Sheet, 16mm/10X E.S. In general, higher "R" means more resistance to heat loss and therefore lower heating or cooling bills for the building. If passable send me calculation. Google use cookies for serving our ads and handling visitor statistics. Enter each material or surface into the above R-Value calculator. However moving right along to viewpoint #2, Watch out: in my opinion increasing R-value to reduce the rate of heat loss in a roof is entirely and only theoretical. "The Small Homes Council (our original name) was organized in 1944 during the war at the request of the President of the University of Illinois to consider the role of the university in meeting the demand for housing in the United States. I was pulling my hair out at the erroneous calculations! When buying various insulation materials you will almost always see an "R" value quoted for the material. Nomaco Insulation, "Calculation of K Value and R-Value, Technical Bulletin TS12-0909", Nomaco Insulation, 3006 Anaconda Rd., Tarboro NC 27886, Tel: 866-876-2684, Website:, offers this helpful explanation of K values: Quoting: Steve DeBusk, writing on low-e glass vs window films at, retrieved 4/16/2014 original source: , quoting; Low-e window film U-value and emissivity values can range, depending on the type of film. Tectum: a patented cementitious wood fiber EPS-core insulating roof deck tile, plank, or panel of several thicknesses. I'll look at that and see if I can fit it in. The heat loss by conduction to the building exterior is not a fixed rate. Then the app calculates the resulting u-value and adds it all together. Simple HTML is supported i.e etc. Applies to Asphalt/asbestos floor tiles, linoleum, vinyl, rubber floor tiles, per inch. Are you a human? Clothing insulation, not used in buildings, Formaldehyde outgassing concerns, especially new, possibly, 1/16" (0.175")to 3/32" (0.093") thick vinyl siding, hollow-backed, U-value and emissivity values vary depending on the type of film, with emissivity values from 0.07 to 0.81 - DeBusk. The Universal and Individual Gas Constants are known from the Ideal Gas Law. Windspeed/Pressure (Pa) induced on building facades, on wind experienced on a day or via an average. how to convert US value R30 to Europe W/m2 K ? Cookies are only used in the browser to improve user experience. Click to Show or Hide Citations & References,; 2.1 lbs/sq.ft. The inverse of conductivity is resistivity (or R per unit thickness). So you can actually calculate "U" for your specific roof, but with the warnings I gave that this is still only theoretical since the true heat loss or gain is affected by air leaks and other factors. Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications! ON Fri, 26 Apr 13, 9:45am probably from United Kingdom  Reply to this comment. This can be really helpful when understanding the average overall pressure that might be affecting a building in a particular area by using weather bureau data. Trying entering .088 for the U value. We cannot calculate the R-value of a wall assembly until we know the complete list of all of the components that comprise the wall, and their individual dimensions and also the actual wall construction and dimensions including where there are air spaces. Mathematically, "R" is simply the reciprocal of the two measures discussed in more detail below: U - the measure of heat transfer (the ability of a substance to conduct heat) discussed above and also at "U", K - the coefficient of heat transmission discussed at "K", Heat transfer rates through a roof (or walls or floors) are usually calculated and expressed in U-Values - detailed at U-VALUE, U-value measures the ability to transfer heat, an inverse condition, to heat movement resistance, or in other words, or U-value measures the ability of a substance to allow the transfer of heat. Work out all the different materials and surfaces that make up the wall/ceiling or surface you want to work out the R-Values and U-Values for. We need to add up all of the wall components (and of course we're ignoring any effects of air leakage), If your wood siding is plywood you can see R-values in the table above. 1 (888)-977-POLY [888-977-7659] ON Wed, 14 Feb 18, 5:43pm probably from United States  Reply to this comment, Valid Email (not published but required see T&C's), Tick to be notified when someone replies to your comment, URL (i.e. Eco Guy: where is the switch? The DOE in turn cited these sources, ASHRAE, 1997 ASHRAE Handbook: Fundamentals, p. 24-4, 22-5, DOE, Insulation Fact Sheet, Jan. 1988, p. 6, Journal of Thermal Insulation, 1987, p. 81-95, ORNL, Science and Technology for a Sustainable Energy Future, Mar. For example, to those R-values I would add the value of air spaces in the construction but I would deduct for those same air spaces if they are not sealed and protected from in-wall-cavity convection currents that can actually pump heat between the hot and cold side of such a wall. In the imperial system the most common units for the individual gas constant are ft lb/slug oR. Or see INSULATION R-VALUES & PROPERTIES FAQs - questions & answers posted originally at this page. ON Mon, 2 Apr 12, 11:47pm probably from United States  Reply to this comment. Dear Mr/Madam, The Individual Gas Constant depends on the particular gas and is related to the molecular weight of the gas. Fourier's Law gives us the rate of heat loss through conduction: U = thermal conductance, BTU / (ft2) (Fº)(hr), ΔT = temperature difference (T1 -T2), Fº. INSULATION R-VALUES & PROPERTIES at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice. If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. What kinds of construction and production techniques worked well and which did not? This calculator is now available as a fully featured Android app, work out R-Values on the move and share - search for R Value Calculator on the Android Market. In the SI system the most common units are J/kg K. Unit conversion: 1 J/kg K = 5.97994 ft lb/slug °R… Thanks Fernando, ON Mon, 20 Jan 14, 11:04am probably from United Kingdom  Reply to this comment. WHAT IS THE R VALUE THROUGH A 2 X 4 WOOD STUD AT THE 3 1/2 INCH ? Here's the values from Wiki: The conversion between SI and US units of R-value is 1 h•ft²•°F/Btu = 0.176110 K•m²/W, or 1 K•m²/W = 5.678263 h•ft²•°F/Btu, ON Mon, 6 Feb 12, 11:32am probably from United Kingdom  Reply to this comment. ON Mon, 22 Jan 18, 1:41pm probably from Afghanistan  Reply to this comment. There is an imperial and metric switch you can use for this. Beaver Board and Upson Board: History and Conservation of Early Wallboard, Shelby Weaver, We don't save this data. Doesn't work! The value is independent of temperature. energy efficiency, sustainable development, passive solar, insulation, buildings. If I'm really list the materials used in the wall or roof, tell me what the thermal conductivity is, let me enter the thickness. What's in your wall? 28, No. How did people use different kinds of spaces in their homes? The R-Value calculator is best used as follows: Remember, the values calculated here should be taken as a rough guide, as certain materials (i.e.