solar heat gain factor table

David, Home | Window specifications and climate data for your specific construction project are more important than the generalizations made here. Latitude: N: NE: E: SE: S: SW: W: NW: HORIZONTAL : 24 o N: 42: 37: 36: 26: 15: 95: 174: 134: 162: 25 o N: 41 . /Properties This shows that a good percentage of the gains from south windows are retained, despite losses, except in Anchorage, Alaska. Thank you for sharing your thoughts, Bob. This simple computation provides a metric to rate locations for ease of using passive solar or solar tempered winter space heating. Window Joe says to always keep it simple and follow NFRC and Energy STAR ratings that are suggested for your specific county. << 10;I#l3*O@`0wo : If not, how can I find a better alternative at a reasonable price? The challenge in selecting the appropriate SHGC is balancing out the ideal amount of incoming solar radiation in cold months (to heat your home from the sun's warmth and to lower heating bills), versus keeping solar heat out in hotter months of the year in order to save on air conditioning costs. I enjoyed the bright sunlight and warm interior temps mid-winter too. Passive solar designs typically employ large south facing windows with a high SHGC and overhangs that block sunlight in summer months and permit it to enter the window in the winter. The amount of solar gain a space experiences is a function of the total incident solar irradiance and of the ability of any intervening material to transmit or resist the radiation. Other cities in the list across the Midwest and northern central U.S. get about half the net solar heat gain of Denver. 0000021012 00000 n m 0000041586 00000 n This allows glass to block mainly short-wave infrared radiation without greatly reducing visible transmittance.[3]. 0000009701 00000 n (13) Design roof overhangs, patio or deck coverings, and landscaping to preserve unobstructed sunshine in winter, and shade west- and east-facing windows during summer months. But it would not shade the window as much as you'd like by late August, or earlier or later during the day on June 21st, as you point out. The manufacturers may have improved the materials that made up the frames or the coatings to the glass to meet demands. Great Article! The Energy STAR program provides window buying guidance on the most energy efficient windows for buyers based upon their regions: Some areas of the country are plagued with a hot, dripping summer as well as a long, cold, we winter. North windows get almost no direct sunlight, so would be less of a problem. Table 4 only looks at solar heat gains without considering losses. Even if there's only one south-facing window in the room at mid-day in winter, light will bounce off the window sill and floor and diffuse the light, especially at the other end of the room. 0000053548 00000 n 0000000016 00000 n So the cost of electricity is used to compute the value of solar heat gains in the following analysis. /CS0 8 0 R AL rates 0000043512 00000 n 0000038796 00000 n In a room, its likely you have light coming from multiple windows on different sides of the home. glazing Thanks for your comments. What about glare? Higher SGHC=0.7 could be used on south-facing glazing to increase solar gains, but still get decent heat loss performance (e.g., Cardinal LoE-180 glass with SHGC=.69, U=26). 0000053260 00000 n standard low-E and about .40 for spectrally selective low- The lower the number, the less you'll spend on cooling. The solar gain factor is a complicated series of factors multiplied together starting with the transmittance factor of the glass, and ending with all possible shading devices/methods and adjusted for local weather (cloud cover). 0000044364 00000 n endstream endobj 644 0 obj<> endobj 646 0 obj[647 0 R] endobj 647 0 obj<>>> endobj 648 0 obj<> endobj 649 0 obj<> endobj 650 0 obj<> endobj 651 0 obj<> endobj 652 0 obj<> endobj 653 0 obj<> endobj 654 0 obj<> endobj 655 0 obj<> endobj 656 0 obj<> endobj 657 0 obj<> endobj 658 0 obj<> endobj 659 0 obj<> endobj 660 0 obj<> endobj 661 0 obj<> endobj 662 0 obj<> endobj 663 0 obj<> endobj 664 0 obj<> endobj 665 0 obj<> endobj 666 0 obj<> endobj 667 0 obj<> endobj 668 0 obj<> endobj 669 0 obj<> endobj 670 0 obj<> endobj 671 0 obj<> endobj 672 0 obj<> endobj 673 0 obj<> endobj 674 0 obj<> endobj 675 0 obj<> endobj 676 0 obj<> endobj 677 0 obj<> endobj 678 0 obj<> endobj 679 0 obj<> endobj 680 0 obj<> endobj 681 0 obj<> endobj 682 0 obj<> endobj 683 0 obj<> endobj 684 0 obj<> endobj 685 0 obj<> endobj 686 0 obj<> endobj 687 0 obj<> endobj 688 0 obj<> endobj 689 0 obj<> endobj 690 0 obj<> endobj 691 0 obj<> endobj 692 0 obj<> endobj 693 0 obj<> endobj 694 0 obj<>/ProcSet[/PDF/Text]/ExtGState<>>> endobj 695 0 obj<> endobj 696 0 obj<> endobj 697 0 obj<> endobj 698 0 obj<> endobj 699 0 obj<> endobj 700 0 obj<>stream December 21st there is no shading from overhangs. 2 0 obj 0000052561 00000 n Low-emissivity coating is another more recently developed option that offers greater specificity in the wavelengths reflected and re-emitted. 0000044969 00000 n available solar energy falling on the window. When placed in the path of admitted sunlight, high thermal mass features such as concrete slabs or trombe walls store large amounts of solar radiation during the day and release it slowly into the space throughout the night. So I don't think glare around the dining table on the opposite side of the room would be much of a problem. Conversely, if your are trying to keep your home cool in a hot climate, adding the intensity of the sun's warmth could create a suffocating situation, particularly if the energy is trapped inside by an incorrect u factor. The lower the rating, the less solar heat is transmitted through the glass, and the greater its shading ability. _________________________________________________________________________. 0000039534 00000 n (12) Consider different glazing for windows facing different directions. 0000030116 00000 n Passive solar heat gain almost eliminated the need for space heating on the main floor. /Parent 25 0 R 0000048946 00000 n For more information about SHGC and windows, see. /Font ( So I'd recommend designing overhangs for minimal shading mid-winter, and not worry so much about summer (for winter-dominated northern climates). West-facing windows gain that heat in the afternoon, usually during the hottest time of the day, making west-facing windows particularly undesirable unless well shaded. I will quantify solar heating potential by looking at climate data for 22 large cities across the northern U.S. 0 0000021997 00000 n 0000027129 00000 n 0000041454 00000 n Only one image can be added per comment but you can post as many comments, and therefore images, as you like. 0000051944 00000 n Excellent Resource! SHGC is expressed as a number between 0 and 1. The NFRC (National Fenestration Council) describes Solar Heat Gain Coefficient (SHGC) as: Solar Heat Gain Coefficient(SHGC) measures how well a 0000040713 00000 n In January, south-facing windows always account for more solar gain than east + west + north combined. We find the coldest days are very clear and let in a lot of light and heat contrary to what some say about passive solar in this area. 0000032660 00000 n To maximize wintertime interior daylighting and solar heat gains, south windows should be larger in size or in number than windows facing other directions. 0000042040 00000 n East-facing windows can be more useful on winter mornings to warm up a cold house, but are quickly overtaken by warming from south-facing windows. 0000034200 00000 n , - Jeff Pendl, Enervision, Cincinnati OH. ( But if you really don't want to move your TV and have glare issues, besides curtains or shades, you could use other ways to block light from reflecting off your TV screen or creating too much glare competing with the TV in your viewing direction. For east- and west-facing windows, overhangs are not particularly effective in preventing unwanted heat gain. 0000054516 00000 n Though transparent building materials such as glass allow visible light to pass through almost unimpeded, once that light is converted to long-wave infrared radiation by materials indoors, it is unable to escape back through the window since glass is opaque to those longer wavelengths. ( n Sitemap | From what I've read, slab depth beyond 4" thick doesn't get you much additional heat storage or dampening of temperature fluctuations in direct gain passive solar designs. Accompanying text is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss. The first six columns list the same 22 U.S. cities and other previously displayed data, which are helpful in determining the value and ease of using solar heat gains for space heating. Light-to-solar gain (LSG)is the ratio between the VT and SHGC. 0000058060 00000 n I think glare would be a bigger problem if you were sitting in direct sunlight, not at the other end of the room. ) For double glazed windows SHGC is more often in the range of 0.42 - 0.55. CCPA | (4) South-facing windows can provide about fifteen times as much light and solar heat gain in winter as north-facing windows. 0000052997 00000 n 2023 The Taunton Press, Inc. All rights reserved. /TT6 17 0 R 0000023337 00000 n There are a couple of ways that glass can maintain the indoor temperatures to keep you comfortable indoors. Though the original proposed changes to U-Factor and SHGC to Energy STAR would have cut the market share by 50% due to vastly increased costs of manufacturing that would have been passed on to the consumer. 0000025712 00000 n Wall CLTD selection. (14) Exploit sustainable solar heating to lower the buildings heat load, utility bills, and supplementary space heating systems. I don't ever remember using shades to reduce glare or overheating during the winter. on the climate, summer and winter fuels costs, and If the TV were on the same wall, next to a south window around noontime mid-winter, the light from the window would be likely be much brighter than your TV or computer screen. In Table 2, it was noted that north-facing windows are always a net BTU loss, since heat losses exceed the meager solar heat gains for all 22 cities. 0000046682 00000 n AL is an Locations that lack significant net solar heat gain, or that require a lot of wintertime heating, score lower on this index. 0000040500 00000 n My great aunt used to live with family in Oregon, but had to live elsewhere during the overcast winters there. Just that insulated door is shut at night and the porch is then isolated from the main heated building. I'm not so sure about small windows of a dark passive house that is currently expensive to build, even if you can find someone who can do the work right, but the very low energy use is great. Light through windows isn't all direct sunlight. 0000009545 00000 n 0000054894 00000 n startxref The overall shading coefficient is thus given by the ratio: S Avoiding south-facing windows because in rare cases people created window walls without considering the solar gain or glare impact would be a mistake. ( The lower the SHGC, the better If you divide by 0.87 (the coefficient for 1/8-inch clear glass), you get the shading coefficient you need to calculate solar heat gain. Solar Heat Gain Coefficient (SHGC) measures how well a product blocks heat from the sun. 0000010013 00000 n This Solar Gain Index uses south window glazing net BTUs of heat per day per square foot of glazing, and divides by the Heating Degree Days for that location. 0000053840 00000 n Reflections of the window or objects in direct sunlight (that are behind you) could be visible on your TV or computer screen as reflections on the screen. June 21st, only sees direct sun in the early hours of the morning, and the window son the north-west side of the house in the late evening. Passive solar heating is a design strategy that attempts to maximize the amount of solar gain in a building when additional heating is desired. A product with a high SHGC rating is more effective at collecting solar heat during the winter. /TT0 23 0 R /CS2 6 0 R Do Not Sell My Information |, 2022 Window Joe Replacement Windows All Rights Reserved, Energy STAR, from the U.S. Department of Energy, (NFRC) is an independent organization that tests windows and doors, The Top Factors To Consider When Buying New House Windows, What Is The Average Cost To Replace Windows 2022 Edition, What Does A Quality Home Window Replacement Look Like, Vinyl Vs Aluminum Windows Which Is Better, 6 Quick Questions To Ask Your Window Replacement Company, 4 Real Life Reasons Why You Need New Windows Now, Window Replacement 101 Should You Replace All Windows At Once. Motions of the Sun Simulator Also for example, if I am to have brunch/lunch during daytime, where do I put dining table? %%EOF For south-facing windows, designing overhangs to maximize mid-winter solar gains yet reduce summertime solar gains is useful, but more of a detail than a major contribution to passive solar heat gain management. h)u^Si!vr:(q;}xH)\@|&u$y?Cm_Sk5a4iiARd(q-tc:Ng^*,,eH%Gk(SX~w X%l0As6_L t 5i f5=P8E UUn vmSfoB`F(a\N`! w]T,&hX#XXJ Xo7Jj%I:hL$^B;4DC{=.! A product with a higher VT transmits more visible light. 0000023982 00000 n Unfortunately, whatever shading is caused by these roof overhangs also causes just as much shading on April 21st (two months before June 21st) as two months after (August 21st). The standard method for calculating the SHGC also uses a more realistic wavelength-by-wavelength method, rather than just providing a coefficient for a single wavelength like the shading coefficient does. As well, 3 years ago, having been so pleased with the shutter effect, I built a "low mass, super insulated south facing solar porch. 0000038900 00000 n In climate-responsive design for cold and mixed climates, windows are typically sized and positioned in order to provide solar heat gains during the heating season. The lower the SHGC, the better a product is at blocking unwanted heat gain. We don't seem to have an issue with glare. ) We have about 2' overhangs on all south facing windows and doors which work well in this latitude. [I notice that after I wrote this response, you edited your comment, changing "high U-value" to "low U-value." Vinyl windows are generally made of one continuous piece. The home show in the photo used ceramic floor tile which varied in color but overall was a coffee color. Go . Depending on how many changes a manufacturer had to make, it could have greatly impacted the retail price of your window replacement installation. In June, the sun is closer to overhead at noon, so south windows have far less solar heat gain. The maximum allowable fenestration U-factors in Table R402.1.2 (for the prescriptive compliance path) for climates zones 3 through 8 have been reduced from the values in the 2015 edition. {\displaystyle T=\int \limits _{350\ nm}^{3500\ nm}T(\lambda )E(\lambda )d\lambda }, Here /XObject HUPTekzreUXT ey""E + efw# >XimcQLTs}w#HT^bo$kuYPU:)l {ewGJc'8qq`VHK'O]Hy&$z]=16FlN.S-$&uQ/:w However, a few strategically placed deciduous trees and i have all but eliminated my summertime window solar exposure. >> (9) Design for the local climate, considering winter temperatures (heating degree days and winter design temperatures), cloudiness (or average percent of available sunlight in January), and costs of electricity (or fuel for heating). 0000029050 00000 n 0000009311 00000 n Thank you Bob for sharing this very thorough article! 0000009077 00000 n [8], A conversion from SC to SHGC is not necessarily straightforward, as they each take into account different heat transfer mechanisms and paths (window assembly vs. glass-only). In the hotter summer season, solar heat gain through windows is usually undesirable. Note that the photo at the top of the page shows a passive solar house from 1982. Note that this article doesn't promote classic passive solar design, even though a well-designed passive solar home works great in dry cold winter climates (but not in climates with overcast winters). The other climate zones underwent more stringent Energy Star qualifications that took effect on January 1, 2015. 0000020109 00000 n 0000059957 00000 n ) 0000007296 00000 n The U-factor, Solar Heat Gain Coefficient (SHGC), Visible Light Transmit-tance (VT), and air leakage rate for all manufactured fenestra-tion products shall be determined by a laboratory accredited by a nationally recognized accreditation organization, such as the National Fenestration Rating Council. 0000023760 00000 n The complete source for building, designing, and remodeling green homes. Simply choose your state and then your county below and we will display the combinations of u factor and SHGC as recommended by Energy STAR and the National Fenestration Rating Council. Glass Color . 0000052109 00000 n 0000011092 00000 n But it might be a good compromise. The following four cities are along the north central and western U.S. (Minneapolis; Salt Lake City; Bismarck, N.D.; and Billings, Montana) . The primary metric in opaque components is the Solar Reflectance Index which accounts for both solar reflectance (albedo) and emittance of a surface. The south-facing window advantage ranges from at least 140% (Indianapolis) and 144% (Denver), to the most extreme 179% (Seattle) and 338% (far-north Anchorage, Alaska). Note that east- and west-facing glazing provide an equal amount of solar heat gain, but east gains mostly in the morning, and west mostly in the afternoon. Columns 3-6 lists the daily amount of solar heat gain in January, per square foot of glass, for windows facing south, east, west, and north (and the total of all four), respectively. 8 , fgMPW'J[2JM2~&e@l3-9wDWj2bXec&X.!X095 0000055259 00000 n m MIT Press, 1992. Columns 1-3 lists the same city data, in the same order, as Table 1. 0000057117 00000 n It is important to note that the standard SHGC is calculated only for an angle of incidence normal to the window. It quantifies how some US climates (and not others) can use solar heat gain for space heating, or reduce utility bills cost-effectively, by designing to manage solar heat gain. 0000046898 00000 n It is defined as the ratio of solar radiation at a given wavelength and angle of incidence passing through a glass unit to the radiation that would pass through a reference window of frameless 3 millimetres (0.12in) Clear Float Glass. Solar heat gain coefficient or SHGC primarily reflects the percentage of solar radiation or sunlight admitted through a door, skylight, or a window, either directly or absorbed, only to release a fraction of heat inside the house to keep it warm. Reflectivity can be modified through the application of reflective metal oxides to the surface of the glass. 0000014397 00000 n [10] For dynamic fenestration or operable shading, each possible state can be described by a different SHGC. 0000060771 00000 n In direct solar gain systems, the composition and coating of the building glazing can also be manipulated to increase the greenhouse effect by optimizing their radiation properties, while their size, position, and shading can be used to optimize solar gain. 0000051339 00000 n 0000042224 00000 n This site is protected by reCAPTCHA and the Google, What's Really Behind the Gas Stove Debate, Common Method of Sewer Repair Poses Health Risks, Appendix D, Degree Day and Design Temperatures, https://www.greenbuildingadvisor.com/homes/passive-solar-home-1980s, http://www.cardinalcorp.com/products/coated-glass/loe-180-glass/, http://www.vitrowindowglass.com/lowe_glass/sungate_500.aspx, Reassessing Passive Solar Design Principles, A Proposed Solution to the Embodied Carbon Problem, A Look at State Premiers New Heat Pump Water Heater, Indoor Air Quality and Building Diagnostics. Does The New Glass In Windows Need Any Special Care? 0000034107 00000 n Yet, the living room and the sun room, get a little bit more but welcome heat, while the bedrooms on the top floor facing west get a wallop in the afternoon. Solar Heat Gain Factors (SHGFs) for selected latitudes of the Northern Hemisphere Source: Handbook of Fundamentals American Society of Heating, Refrigeration and Air-Conditioning (ASHRAE) Use: Select latitude (16o-64oN) month of year (January-December) and orientation of exposure (North, East, South, West or intermediate orientation). /C2_0 15 0 R 0000034811 00000 n The winter climates in these cities differ not just in temperature ranges, but also in the amount of winter sunlight. 0000010861 00000 n Solar transmittance is used to compare different types of glass. 0000026490 00000 n /Type /Page 0000025994 00000 n Heat gains from windows can contribute to overheating. 0000011477 00000 n 0000045185 00000 n 0000050182 00000 n Thank you so much for sharing this with us. For more information, see All About Glazing Options. 5. You wouldn't be able to see the TV well, and would experience glare from the window. I see lots of examples where people try things without "doing the math" beforehand. ) 0000034462 00000 n Such devices can reduce the shading coefficient by blocking portions of the glazing with opaque or translucent material, thus reducing the overall transmissivity. This Solar Value Index uses south window glazing net BTUs of heat per day per square foot of glazing, and multiplies by the Heating Degree Days and by the price of electricity. The higher the VT, the higher the Simple 2x6 with exterior 1" aluminium skinned polyiso foam, south facing rear with larger windows and doors, few windows on other walls. At the bottom of the table, the yearly gains are totaled for south-, north-, east-, and west-facing windows. Solar Heat Gain Coefficient measures how well a product can resist unwanted heat gain, which is especially important during summer cooling season. Last edited on 13 February 2023, at 00:16, Learn how and when to remove this template message, https://en.wikipedia.org/w/index.php?title=Solar_gain&oldid=1139027242, This page was last edited on 13 February 2023, at 00:16. Therefore, the sun is shining on your south-facing walls and windows during wintertime. >> However, many northern U.S. locations can experience uncomfortably hot summers as well as cold winters. Buffalo, Pittsburgh, and cities in the Pacific Northwest do not do as well as most other cities. 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. potential for daylighting. The U-Factor measures how well the window in-sulates. 0000011169 00000 n be adjusted for thermal lag and time delay. 1996 Ashrae Handbook Heating, Ventilating, and Air-Conditioning Systems and Equipment: Inch-Pound Edition (Hardcover), ISBN-10: 1883413346 or ISBN-13: 978-1883413347 , Principles of Heating, Ventilating, And Air Conditioning: A textbook with Design Data Based on 2005 AShrae Handbook - Fundamentals (Hardcover), Harry J., Jr. Sauer (Author), Ronald H. Howell, ISBN-10: 1931862923 or ISBN-13: 978-1931862929, 1993 ASHRAE Handbook Fundamentals (Hardcover), ISBN-10: 0910110964 or ISBN-13: 978-0910110969, Colloidal Materials, Inc., PO Box 696, Andover MA 01810, Pennwalt Corp., King of Prussia, PA 19406, The Passive Solar Design and Construction Handbook, Steven Winter Associates (Author), Michael J. Crosbie (Editor), Wiley & Sons, ISBN 978-047118382 or 0471183083, www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=12850 is the base U.S. DOE website for these articles, Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the. 0000041841 00000 n 0000060426 00000 n 0000059464 00000 n [3], The g-value (sometimes also called a Solar Factor or Total Solar Energy Transmittance) is the coefficient commonly used in Europe to measure the solar energy transmittance of windows. b +{roFw@Qv.Pb=Z"3>!06&rhS8EnVw\/bw +rt|bSL6),W=^O *cAL^u'MH} ^D;p.'*{6OQYbS2tAD2)T=z 0!"Tl,|Am5q/Up+XwNM7}!/;yy6Q@=vjI~}krN>+e_CC-ccB: p7B . Average January temperature (F), the coldest month of the year. , 0000039839 00000 n An interesting result: It turns out that when these cities are ordered by average solar heat gain, they happen to be ordered somewhat by geographic areas: This geographic ordering is illustrated in the map in Figure 1. Cost of electricity varies over time as well. The lower the U-factor, the more energy-efficient the window, door, or skylight. ( Since I built that passive solar house back in the 1980's, there were no low-e windows available. endobj The lower the The glass on the TV or computer screen can also be highly reflective smooth glass for best visual screen performance, or can be less reflective glass for less interference with reflections on the screen. Here, is the wavelength of radiation and is the angle of incidence. 0000033432 00000 n This is a very basic question I confess not knowing the answer to. Many had problems with glare. Watch out: other very important factors need to be considered in arriving at an accurate picture of solar heat gain through windows. 0000057247 00000 n While the U-Factor can take any value, in general for windows it ranges from 0.20 to 1.20. You can use the energy performance ratings of windows, doors, and skylights to understand their potential for gaining and losing heat, as well as bringing sunlight into your home. 0000032457 00000 n /BleedBox [0.0 0.0 612.0 792.0] A Contrarian View of Passive Solar Design, GBA Prime Sneak Peek: Reassessing Passive Solar Design Principles. -- The lowest sun angle at noon is around Dec 21st,, when the sun is low on the southern horizon, even at noon. The intense summer sun on the east side of the building in the morning, and the west in the hot afternoon, is greater than the sunlight striking the south side. 0000010245 00000 n Like most things, you can have too much of a good thing. 0000019823 00000 n 0000033945 00000 n Glazing with lower U-factors (higher R-values) for north- and west-facing windows tend to have lower SHGC. Average percent of sunlight shining in January (opposite of cloudiness). Same for east or west-facing windows, early or late in the day, respectively. (The result also is divided by 10 million so that numbers are transformed into the single digit range.). 0000029981 00000 n 0000022435 00000 n The most important factors are budget and energy efficiency. 36" overhangs, 9' walls. The tables and charts that follow provide solar radiation data in units of Btu / ft 2 / day for five surfaces: a horizontal (Figure 12.5) window and a vertical window . But solar transmittance does not include the solar heat that the glass absorbs and re-radiates into the building, so alone it is not accurate enough for calculating total solar gains through windows. >> The trapped heat thus causes solar gain via a phenomenon known as the greenhouse effect. This quantity includes both energy that is transmitted directly through the glass as well as energy that is absorbed by the glass and frame and re-radiated into the space, and is given by the following equation:[4], F Gases are added between the layers of glazing to further increase insulation, the gases are heavier than air, making it less likely air will penetrate the glazing. (My apologies if these assumptions are printed and I overlooked them.). 0000039733 00000 n So overhangs tend to keep the house cooler in the Spring as well as late summer. Too much south-facing glazing can make a home very uncomfortable and unpleasant in February and March. Next seven cities are all located in the northeast, along the Atlantic coast (Providence; Hartford; Boston; Portland, Maine; New York City; Philadelphia; and Concord, N.H.). The ability of glazing in a window, door, or skylight to transmit sunlight into a home can be measured and rated according to the following energy performance characteristics: Review the state fact sheets or use the window selection tool for new construction or existing homes from the Efficient Windows Collaborative to determine the desired performance ratings for your climate. Their net solar heat gain is only about a quarter of Denvers. U-Factor * SHGC (Solar Heat Gain Coefficient) * Product Type * Frame Material * Air Fill Type * Impact Resistance * Series . Is it possible to determine an appropriate period of shading for summertime sun that also allows peak wintertime solar gain? 0000026777 00000 n Before choosing window locations, sizes and performance characteristics, we need to examine solar heat gains throughout the year, not just January. 0000035512 00000 n 0000011400 00000 n %3Qd Vw9k\1W7CL9tqM=~u5b&XfmFk!$"4c?9%fb|$N}0R16f]oqnDxo[hot;3Nq_fO-jldHA '*bIgdyfs[B[Z+^:E 9)Uii;/J PH( 6.u. w This is a particular concern in hot, tropical climates such as southern Florida, Georgia, Texas and other states in that experience extreme heat.

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