Engineering; Chemical Engineering; Chemical Engineering questions and answers; 400 TABLE 15 SOLAR HEAT GAIN THRU ORDINARY GLASS (Contd) Btu/(hr) (sq ft sash area) 400 East 110 102 47 90 40 NORTH LATITUDE . << At the bottom of the table, the yearly gains are totaled for south-, north-, east-, and west-facing windows. The higher the number, the more light transmitted without adding excessive amounts of heat. 0000008467 00000 n 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. U-factor (inverse of R-value), which measures the rate of heat losses through that window to the cold outdoors. Not that I watch it much (or at all) during daytime), but still :) 0000058060 00000 n /Font (8) Unobstructed west-facing windows produce heat gains mostly in the afternoon. /Width 76 0000051467 00000 n 0000028620 00000 n To remain as Energy Star products, manufacturers had to either make changes to their effected products or lose the rating altogether. 0000032660 00000 n In practice though, most g-values will range between 0.2 and 0.7, with solar control glazing having a g-value of less than 0.5. 0000054052 00000 n There is more total sunlight shining in summer (June to August in the northern hemisphere) than mid-winter (December to February). + Locations that lack significant net solar heat gain, or that require a lot of wintertime heating, score lower on this index. 0000046898 00000 n 0000039534 00000 n 0000030815 00000 n 0000010476 00000 n Heat gains from windows can contribute to overheating. Which design principles from the 1970s are worth retaining, and which should be discarded? /ColorSpace Long stretches of overcast days produce large heat losses through large windows, with minimal solar heat gains to compensate. Thermal Radiation b. Earth-Sun geometry Average daily solar heat gain per square foot of south-facing window glass in January. Solar gain compared to Denver, the city with the highest solar heat gain in the list. On the flip side that means that cold air would normally go from outdoors to indoors with metal framed windows. 0000058680 00000 n North latitude location (degrees north of the Equator). 0000053637 00000 n This energy performance rating isn't always provided. 0000045401 00000 n East- or west-facing windows produce the most heat gain from May through August. 0000029557 00000 n 0000048271 00000 n Does one use visible light transmission or some other figure? 0000046212 00000 n 0000048946 00000 n 0000026274 00000 n 0000053840 00000 n Designing south-facing roof overhangs m That makes more sense.]. (My apologies if these assumptions are printed and I overlooked them.). FIND A DEALER. One of the best I've read here. 0000014163 00000 n You might be able to find or make untreated triple pane glass units, or even try to use three layers of glass for your own site-built fixed window if you are looking for the ultimate cheap solution. This is covered in the U-Factor article, but it is worth mentioning because it also impacted the solar heat gain coefficient for the Northern Zone. Therefore, the sun is shining on your south-facing walls and windows during wintertime. Our Comment Box is provided by Countable Web Productions countable.ca, Click to Show or Hide Citations & References, Heat Exchangers for Solar Water Heating Systems, Heat-Transfer Fluids for Solar Water Heating Systems, Solar Water Heating System Maintenance and Repair, Solar Water Heating System Freeze Protection, Scaling and Corrosion in Solar Water Heating Systems, Solar Heat Gain & Windows, the facts about, HOME INSPECTION EDUCATION COURSES (Canada), HOME INSPECTION EDUCATION: HOME STUDY COURSES, Ar-Lite Panelcraft, Inc., 13030 Wayne Rd., Livonia MI 48150, 2005 ASHRAE Handbook : Fundamentals: Inch-Pound Edition (2005 ASHRAE HANDBOOK : Fundamentals : I-P Edition) (Hardcover), Thomas H. Kuehn (Contributor), R. J. Couvillion (Contributor), John W. Coleman (Contributor), Narasipur Suryanarayana (Contributor), Zahid Ayub (Contributor), Robert Parsons (Author), ISBN-10: 1931862702 or ISBN-13: 978-1931862707, 2004 ASHRAE Handbook : Heating, Ventilating, and Air-Conditioning: Systems and Equipment : Inch-Pound Edition (2004 ASHRAE Handbook : HVAC Systems and Equipment : I-P Edition) (Hardcover). Solar heat gain coefficient (SHGC) is the fraction of solar radiation admitted through a window, door, or skylight -- either transmitted directly and/or absorbed, and subsequently released as heat inside a home. AL is an I used pleated or cellular shades at night, and sometimes insulating shutters to reduce heat loss during snowy days. The solar gain is not stored near the windows to be lost at night but is captured through an open door into the main building. E Is this correct? Objects struck by sunlight absorb its visible and short-wave infrared components, increase in temperature, and then re-radiate that heat at longer infrared wavelengths. Overall, it is best to take your time, build your knowledge, and scrutinize each portion of the process and product when choosing new replacement windows. /Filter /FlateDecode 0000029981 00000 n 0000032325 00000 n SOLAR GAIN CALCULATION at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice. I understand that some passivhaus builders pour 8 inch thick concrete slabs for heat distribution from solar gains. Clear double Finally, Anchorage, Alaska, along the far northern Pacific coast, with by far the lowest solar heat gain. 0000060552 00000 n AL rates Thank you for sharing your thoughts, Bob. HUrF}WoND{_2#J$v:>-%uE">Tw[~Aq}$,N.7n@0v]Av8`o For optimum absorption of solar heat in passive solar homes using a direct gain slab (like in the photo shown), many solar home designers recommended slab floors be a dark color. Again, the northeastern coastal cities look promising for using solar heat gains for wintertime space heating. 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. 0 We don't have extensive open space, placing furniture near windows and glass doors. 0000053434 00000 n 0000000016 00000 n << 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. 0000051214 00000 n 0000057247 00000 n Tables 4 and 5 show the re-ordered lists. Note that the values in Table 6 highlighted in light blue show that south-facing windows gain less heat in June and July compared to east- or west-facing windows. Contrast between the direct sunlight and the TV screen needs to be avoided. December 21st there is no shading from overhangs. 0000059464 00000 n % 0000027129 00000 n . 0000037011 00000 n 0000036017 00000 n cooling season. Passive Solar Buildings. 0000021721 00000 n F Other factors like style, finish, hardware, and function can also play a big part in the curb appeal and aesthetics of your home. This is a particular concern in hot, tropical climates such as southern Florida, Georgia, Texas and other states in that experience extreme heat. Apologies for the delay. What Is Solar Heat Gain Coefficient? 2279 0 obj <>stream OR. 0000059089 00000 n The list of 22 northern U.S. cities can be re-ordered by the two indices for the ease of heating by solar gains and the value of solar heating. The NFRC (National Fenestration Council) describes Solar Heat Gain Coefficient (SHGC) as: Solar Heat Gain Coefficient(SHGC) measures how well a {\displaystyle E(\lambda )} Its no accident that Cape style homes appeared in winter-dominated climate up north; and southern plantation style homes with big windows, big overhangs and wide porches in the cooling dominated climate of the southern US. Technical Report: Solar Heat Gain Through Fenestration Systems Containing Shading: Procedures for Estimating Performance from Minimal Data Title: Solar Heat Gain Through Fenestration Systems Containing Shading: Procedures for Estimating Performance from Minimal Data Full Record Other RelatedResearch Abstract I'm old enough to remember the passive solar homes of the 1970s and 1980s. Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia. My great aunt used to live with family in Oregon, but had to live elsewhere during the overcast winters there. 0000041454 00000 n This information in an aid in choosing the best direction and size of windows facing different directions. %PDF-1.6 . 154 0 obj <>/Filter/FlateDecode/ID[<7A4022D89D0845C14B1934A88527FBA7><3CC1F5B57CF1284BA9D476A461DF3FBB>]/Index[143 23]/Info 142 0 R/Length 76/Prev 918310/Root 144 0 R/Size 166/Type/XRef/W[1 3 1]>>stream Even during winter afternoons, additional space heating may not be needed by the afternoon. ) 0000027305 00000 n /MediaBox [0.0 0.0 612.0 792.0] 0000025712 00000 n The lower the SHGC, the less solar heat it transmits and the greater its shading ability. 0000029882 00000 n 0000045996 00000 n SHGCs range from approximately 0.70 for single clear glass to 0.31 for low emissivity glass (toned or coated glass). 0000040713 00000 n The U-Factor measures how well the window in-sulates. So the cost of electricity is used to compute the value of solar heat gains in the following analysis. The overall shading coefficient is thus given by the ratio: S Solar Heat Gain Coefficient, or SHGC, is the amount of solar radiation, or heat, that passes through windows into the home In other words, SHGC tells you how well the windows block the sun's heat from coming inside An SHGC closer to 0 means that little solar heat is let in An SHGC closer to 1 means more solar heat is let in The cost of electricity, natural gas, or other heating fuels can impact the use of passive solar heat gains for wintertime space heating. 0000019489 00000 n 0000037750 00000 n 0000007296 00000 n For more information, see All About Glazing Options. The most important factors are budget and energy efficiency. One shading method is to have roof overhangs stick out above the south-facing walls enough that they cast shade on south-facing windows in late August. Denver, with the highest average solar heat gain in January. 0000022215 00000 n Overhangs, shading and sizing of west-facing and east-facing windows is most important to prevent summertime overheating! 10;I#l3*O@`0wo : 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). We pull tight insulating shades over the windows in the evening to reduce heat loss. That would provide ideal sun shading for those dates at solar noon. F All you need to do is look for the ratings that indicate a good fit for your climate. The NFRC label can be found on all ENERGY STAR qualified window, door, and skylight products, but ENERGY STAR bases its qualification only on U-factor and solar heat gain coefficient ratings, which are described below. 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. 0000054894 00000 n Balcomb, J.Douglas, editor. ( 0000059744 00000 n 0000008765 00000 n 0000052473 00000 n 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. 0000010322 00000 n 0000035147 00000 n 0000010245 00000 n 0000057599 00000 n The home is a three story house, with a basement comprising the bottom floor. For some locations, the heat is more pronounced and longer in duration than the short months of frigid temperatures with little snow. Many more cities in the U.S., Canada, Europe, and elsewhere could be added to this list to compute comparative solar heating ease and value. The shading coefficient (SC) is a measure of the radiative thermal performance of a glass unit (panel or window) in a building. Choosing a window frame material that does a fine job of insulating against thermal (heat) transference is one way to reduce the solar heat gain coefficient. Windows, doors, skylights can gain and lose heat through: These properties can be measured and rated according to the following energy performance characteristics: NFRC labels on window units give ratings for U-factor, SHGC, visible light transmittance (VT), and (optionally) air leakage (AL) and condensation resistance (CR) ratings. However, I did have problems with too much solar heat gain from west-facing windows during hot summer days. Currently, there's plenty of software and consultants to perform calculations, or do it yourself with spreadsheets. 0000052997 00000 n 2252 0 obj <>/Filter/FlateDecode/ID[<83C04542AF040F4C833A7DC507AC7EE9><9975C82B1E27C340964B5370330FFFE6>]/Index[2225 55]/Info 2224 0 R/Length 124/Prev 708226/Root 2226 0 R/Size 2280/Type/XRef/W[1 3 1]>>stream /Length 2106 Robert Kids in school and adults at work have been shown to have better moods and do complex work better with sunlight entering the room. 0000010707 00000 n . 0000039839 00000 n /Properties I have 35 year old home-made fixed glass windows on the south side of my house that need to be replaced. Appendix D, Degree Day and Design Temperatures. 0000029773 00000 n Taking account of heat losses from the windows produces much more extreme results favoring south-facing glazing. The shading coefficient depends on the radiation properties of the window assembly. The cost-effectiveness of solar heating varies among regions as well. 0000042133 00000 n -- Seasonally, the coldest temps of winter, and the hottest temps of summer, lag the sun's seasonal changes in path and intensity. In this example, of the window is covered with the venetian blind and is not; therefore, the solar heat gain factor equals of the overall factor + of the glass factor. include it on their labels. The product 0000034200 00000 n 0000037411 00000 n Tile floors over wood doesn't provide much thermal mass (about 1/2" vs. 4" slab), but more than wood floors. The SHGC is the measurement of how much radiant heat, or heat produced by the sun, comes in through a window. Window Joe says to always keep it simple and follow NFRC and Energy STAR ratings that are suggested for your specific county. For example, If my living/dining/kitchen open space is taking up the whole south facing side of the house, where do I put the TV? 0000028760 00000 n 0000036698 00000 n Fixed Clear . Cost of electricity varies over time as well. 0000012792 00000 n 0000051730 00000 n %PDF-1.6 % 0.83 0.73 0.73 . Only one image can be added per comment but you can post as many comments, and therefore images, as you like. The warmer HDD numbers are highlighted in tan, and colder are highlighted in ice blue. =J04pajo/7iv}F1&04 kkAVF/n0 0000040918 00000 n 0000042040 00000 n Note: appearance of your Comment below may be delayed: if your comment contains an image, photograph, 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. Using window shades is not a defect of passive solar or other types of homes. 0000059373 00000 n 0000055107 00000 n If the TV itself is not in or adjacent to direct sunlight, and at a 90 degree angle to the window receiving direct sunlight, it should be okay. 0000040500 00000 n How to calculate solar gain for a building: This article discusses the method for calculating solar heat gain through windows. 0000021224 00000 n How do you optimize this shading in a more so sophisticated way that the common arc diagram? Kinda like today, 11 degrees, very sunny and pleasant indoors, with a high-pressure system in control. 0000044168 00000 n Solar gain can also be transferred to the building by indirect or isolated solar gain systems. 0000030489 00000 n 0000058589 00000 n Simple 2x6 with exterior 1" aluminium skinned polyiso foam, south facing rear with larger windows and doors, few windows on other walls. SHGC also decreases with the number of glass panes used in a window. {\displaystyle T=\int \limits _{350\ nm}^{3500\ nm}T(\lambda )E(\lambda )d\lambda }, Here When architects (yes I've done it for clients) draw diagrams showing the solar exposure of south-facing windows, they often decide on the depth of overhangs for shading based on the angle of the sun at noon in both summer and winter. 0000045710 00000 n 0000060982 00000 n Because of this, the most common metrics for quantifying solar gain are used as a standard way of reporting the thermal properties of window assemblies. 0000027405 00000 n This label displays AL in U.S. units. These cities are geographically dispersed, with more cities located in the northeast and Great Lakes regions. startxref For a classic direct-gain passive solar design with a south-facing window wall paired with thermal mass, the answer seems to be no or not easily. Five cloudy days in a row is not unusual for New England, for example. /StructParents 1 Unlike the upstairs, the first floor has a tiled, concrete floor (with large amounts of thermal mass) to absorb heat to radiate later, stabilizing interior temperature fluctuations. Annual heating degree days (HDD), an index of the amount of heating needed each winter season. Modeling thermal mass performance seems difficult or approximate. To perform an approximate conversion from SC to SHGC, multiply the SC value by 0.87. Solar Heat Gain Coefficient, or SHGC, is the amount of solar radiation, or heat, that passes through windows into the home, In other words, SHGC tells you how well the windows block the sun's heat from coming inside, A window with a climate correct SHGC can be like a free heat source in cold climates and it can also lower AC costs in hot climates, Pay up to 50% LESS for energy costs by purchasing replacement windows that meet stringent Energy STAR ratings, The direction the windows face in relation to the sun, The amount of shade your home gets each day, The basement windows got a higher SHGC to allow in warmth, The living room got a middle of the road SHGC, The sunroom got a higher SHGC because of the sheer number of windows it has, The westward facing bedroom windows got an SHGC closer to 1 to prevent it from heating up in the afternoon hours, Blocking out cold temperatures in winter months, Allowing in more of the sun's thermal radiation (heat), U Factor of 0.28 and SHGC of greater than or equal to 0.32, U Factor of 0.29 and SHGC of greater than or equal to 0.37, U Factor of 0.30 and SHGC of greater than or equal to 0.42, Keeping homes comfortable in more moderate weather, Finding balance in letting heat in and keeping cold air out, U Factor of less than or equal to 0.30 and an SHGC or less than 0.40, Keeping more heat out in the summer to lower air conditioning costs, Letting some heat in during winter months, U Factor of less than or equal to 0.30 and an SHGC of 0.25, Keeping heat out in the spring and summer to lower air conditioning costs, Lowering energy bills by keeping heat out most of the year, U Factor of less than or equal to 0.40 and an SHGC less than or equal to 0.25. "T" is the transmissivity of the glass, "A" is its absorptivity, and "N" is the fraction of absorbed energy that is re-emitted into the space. What about glare? >> 0000052109 00000 n This is a different figure from visible transmittance (VT) of light, also defined by the NFRC as follows: Visible Transmittance(VT) measures how much light comes through a product. 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. >> [For those unfamiliar with the terminology 0000060317 00000 n Unfortunately in the US, most windows sold are low SHGC. -- Buildings are considered "solar tempered" if they provide enough wintertime solar heat gain to keep the building's interior warm during sunny days. 0000008386 00000 n You might have to order windows, rather than just the sealed double or triple-pane IGUs. Only their (1) net south-facing glazing heat gains; (2) winter heating degree days; and (3) cost of electricity, would be needed to create a more comprehensive list. 0000038260 00000 n We want to keep our solar heat, not lose it back through the same window that brought it in. 0000010784 00000 n http://www.vitrowindowglass.com/lowe_glass/sungate_500.aspx. (4) South-facing windows can provide about fifteen times as much light and solar heat gain in winter as north-facing windows. 0000054516 00000 n Thermal mass may be used to even out the fluctuations during the day, and to some extent between days. 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. 0000009311 00000 n E a9` zY ZOy 7!K?e. ) Very helpful. Solar heat gain (SHG) describes the way radiation from the sun is turned into heat. 2 (b)] /a; + a~ ` g=r+URI h +Ra;I (5) where T is the total transmittivity; UR is the overall heat loss coefficient of the window; aj, aare, respectively, the absorptivities of the inner and outer glasses; R is the heat resistance of the glazing; and ho is 0000046325 00000 n 0.80 0.70 0.70 . 0000039433 00000 n I think that the key design criteria for passive solar involves locating and sizing windows, thermal mass, and doing sufficient insulating and air-sealing so that only solar heat gain can provide most of the home's wintertime space heating, yet avoid summertime overheating. 0000041109 00000 n /TrimBox [0.0 0.0 612.0 792.0] Source: Text Bob Fegan 12/2008; Table on BTU per person heat gain from www.engineeringtoolbox.com 9/2005; diagram . Fy(@k ,dKa`C]Ll*EWXhS Excellent Resource! 0000020469 00000 n _________________________________________________________________________. 0000060771 00000 n 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). 0000020109 00000 n The other two factors related toSolar Heat Gain Coefficient when choosing replacement windows are: Window Joe went to look at a home recently that required different solar heat gain coefficients based on the two factors above. In this article, Window Joe guides you to thefactors to consider then determining the best SHGC for your window replacement project. trailer Is It Easier To Clean Replacement Windows? My goal was to build an energy-efficient home using materials that cost no more in total than typical home construction. This won't delete the articles you've saved, just the list. What exactly does that give you? 0000035419 00000 n However, many northern U.S. locations can experience uncomfortably hot summers as well as cold winters. . 0000009857 00000 n 0000059651 00000 n 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). 0000010168 00000 n Overglazing, underinsulating, oversized HVAC and using stock home plans without site analysis, seem commonplace. [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. endstream endobj startxref /Thumb 2 0 R 0000050694 00000 n by A Bhatia Cited by 44 - Thermal Transmittance or Heat Transfer Coefficient (U-factor) - is the rate In determining the heating load, credit for solar heat gain or internal heat . We have no relationship with advertisers, products, or services discussed at this website. Columns 1-3 lists the same city data, in the same order, as Table 1. , ) "Do the math!". I have not been able to find glass at local Vermont suppliers with both low U values and high SHGC. Thanks for the kind words - and thanks for the explanation. 0000011554 00000 n A {\displaystyle F(\lambda ,\theta )=T(\lambda ,\theta )+N*A(\lambda ,\theta )}. Motions of the Sun Simulator 0000023549 00000 n AL, the better a product is at keeping air out. 0000060083 00000 n They fit the climate. Average percent of sunlight shining in January (opposite of cloudiness). ( available solar energy falling on the window. (If interested, see interior photos in this GBA article: 0000058978 00000 n E [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). Just that insulated door is shut at night and the porch is then isolated from the main heated building. The reason Energy STAR, from the U.S. Department of Energy, designates four climate zones is to help make it easier for homeowners to know which new house windows will work in their climate. 0000018740 00000 n What Are The Top Factors To Consider In New Windows? The lower the number, the less you'll spend on cooling. Solar gain(also known as solar heat gainor passive solar gain) is the increase in thermal energy of a space, object or structure as it absorbs incident solar radiation. 0000041586 00000 n 0000031934 00000 n 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. 0000018030 00000 n On a traditional southern plantation style home with porches and monster roof overhangs, you could design a south-facing overhang that would completely shade south-facing windows in June, yet not shade much of the top of the window during winter. 0000040295 00000 n The higher its solar transmittance or solar heat gain coefficient, the better a glazing is for solar heating use. Map. Note that the photo at the top of the page shows a passive solar house from 1982. In addition to glass properties, shading devices integrated into the window assembly are also included in the SC calculation. At the bottom, Anchorage is the only city that has average net heat losses through south-facing windows. 0000039633 00000 n 0000021012 00000 n /Type /Page Is there anything else other than minding where you put your furniture? 0000023641 00000 n hb``` , b-0.X)![)?OXjL ~E-AzMVk+u9:MX@qKpDa%E={d C=H:]JxrWur{. Glazing in conditioned spaces has a solar heat gain coefficient of less than or equal to 0.40, or has an overhang with a projection factor equal to or greater than 0.30. 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). 0000056639 00000 n /TT1 22 0 R << 0000031802 00000 n If your climate zone experiences many cold days, the sun's warmth, also referred to as the sun's radiation, is welcome because it allows the heat from the sun into your home. In Table 6, note that light from west or east facing windows in summer, is about the same as south-facing windows mid-winter. Energy Star Zone . -- "Passive solar" requires sunlight to shine on thermal mass (e.g., concrete slab floors, masonry walls, large containers of water) so that most of the solar heat gain is stored in the thermal mass, to avoid overheating the interior air during the day. 0000010013 00000 n 0000049884 00000 n is the incident solar spectral irradiance. Our energy use for the area is almost off the chart lower than other homes mainly due to passive solar design at not much/or no higher cost than conventional. 0000042224 00000 n 0000060198 00000 n Passive solar heating is a design strategy that attempts to maximize the amount of solar gain in a building when additional heating is desired. Locations needing a lot of heating, that have high electricity prices, and that have good net solar gains, get higher scores. 0000041718 00000 n AL$/RB!)z&S7NOauE,|?q GQFSnD{.gTbPZsAFl rwxLCC C-bJD[F;#lTM5Xn"[. North windows are a great example, since with the exception of dawn and sunset around June, there's no direct light through north-facing windows. 0000060426 00000 n High SHGC glazing 0000011477 00000 n If you live in a hotter climate zone, an SHGC closer to 0 to block the heat is more appropriate. 0000030287 00000 n