I would hope this article would lead people to consider quantifying solar gains for any type of home, not just solar-oriented designs. Will be adding solar panels on our large south facing roof when our city, state and utility stop punishing those with a solar tax who have. 0000038260 00000 n 0000022435 00000 n The value of the shading coefficient ranges from 0 to 1. 0000048108 00000 n AL$/RB!)z&S7NOauE,|?q GQFSnD{.gTbPZsAFl rwxLCC C-bJD[F;#lTM5Xn"[. 0000011938 00000 n Solar Heat Gain through Glass Internal Heat Gains from People, Lights, and Equipment ASHRAE Zones for Solar Cooling Load (SCL) Factors for Glass are based on: Floor Level and Room Location Single Story Building (Table 8.8-A) Top Floor (Table 8.8-B) First / Ground Floor (Table 8.8-C) Middle Floor (Table 8.8-D) Interior Rooms (Table 8.8-E) The primary metric in opaque components is the Solar Reflectance Index which accounts for both solar reflectance (albedo) and emittance of a surface. number between 0 and 1. The sun rises in the east, goes overhead, then sets in the west, with little sunlight directly striking a south-facing wall or window. include it on their labels. << I saw that a lot: first, the designer included too much south-facing glazing; then the homeowners installed interior shades to cut down on the glare. 0000024478 00000 n /Annots 26 0 R 0000011477 00000 n 0000061092 00000 n 0000026274 00000 n My great aunt used to live with family in Oregon, but had to live elsewhere during the overcast winters there. 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. Watch out: other very important factors need to be considered in arriving at an accurate picture of solar heat gain through windows. 0000053347 00000 n Heating Degree Days vary year-to-year, so other HDD numbers may be found. The lack of joints in vinyl windows increases their energy efficiency and reduces their solar heat gain coefficient because there are not any joints for heat to travel through. Low-E Type . 0000037304 00000 n This is a very basic question I confess not knowing the answer to. Thank you for sharing your thoughts, Bob. 0000056381 00000 n 0000039839 00000 n 0000008386 00000 n About | MIT Press, 1992. Having lots of sunlight entering the home in the winter is a way to elevate mood when many folks find it hard to be outside like when it's warm. Many had problems with glare. (8) Unobstructed west-facing windows produce heat gains mostly in the afternoon. 0000021486 00000 n Passive solar design is a key element of creating resilient homes, Cold-climate glazing is surprisingly hard to find. The question-and-answer article above, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss. Your home and the Colorado passive solar house I designed and built seem quite similar in construction. [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). 0000060083 00000 n Cost of electricity varies over time as well. lL)Cg4xo` =[3lhb$qrCcUT?iFgqH10L9e:Q` 8 We also provide an ARTICLE INDEX for this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need. 0000008689 00000 n 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. 0000008467 00000 n This is quite significant in the design of roofs since dark roofing materials can often be as much as 50 C hotter than the surrounding air temperature, leading to large thermal stresses as well as heat transfer to interior space.[5]. The amount of solar heat gain from windows varies tremendously. 0000019574 00000 n Fortunately, Energy STAR pulled back a bit, which means windows could remain a bit more affordable. It comes down to three ways windows are improved with the use of glass technology, coatings and gases: Review in-depth information on energy efficient glass for your window replacements. This article explores the viability of passive solar and solar-tempered space heating in northern U.S. regions and metro areas. Thirty-five years ago, I designed and built a classic passive solar home in Colorado. Blocking solar heat gain is particularly important during the summer cooling season. 0000010861 00000 n 0000018332 00000 n hb```g`` ,@Q ?>K kwlsEGyGG#h`@ %X 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). -- The highest sun angle (for the northern hemisphere) is around June 21st, when the sun is nearly overhead at noon, just a little toward the southern horizon. 0000039433 00000 n Designing south-facing roof overhangs The larger the net solar gains, and the smaller the winter heating needed, the better the score on the index. YZR$%s)Gp9y} X<~ea We have about 2' overhangs on all south facing windows and doors which work well in this latitude. The list of 22 northern U.S. cities can be re-ordered by the two indices for the ease of heating by solar gains and the value of solar heating. However, in contrast to the shading coefficient, the total solar gain is calculated on a wavelength-by-wavelength basis where the directly Climate zone temperatures are important, as are available solar heat gains and utility prices. 0000042317 00000 n 0000024716 00000 n ( 0000020608 00000 n Clear double E a9` zY ZOy 7!K?e. 0000021997 00000 n h)u^Si!vr:(q;}xH)\@|&u$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{=.! (15) Consider less costly minisplit heat pumps or even simpler resistance or radiant heating in energy-efficient high performance homes, which have a much lower heating load. Cardinal glass makes LoE-180 for passive solar applications. hb``` , b-0.X)![)?OXjL ~E-AzMVk+u9:MX@qKpDa%E={d C=H:]JxrWur{. 0000009701 00000 n Column 8 shows (with red negative numbers) the average January daily heat loss per square foot of glass (assuming glazing is rated R-5 or U=0.2, with window coverings adding some insulation during nighttime hours to attain U=0.15). /TT7 16 0 R 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. 0000010168 00000 n Passive solar heat gains are more valuable in areas with higher costs for electricity or other heating fuels, or with occupants who are less affluent, or architects, owners, or builders more concerned with sustainable building. [4] Though the shading coefficient is still mentioned in manufacturer product literature and some industry computer software,[6] it is no longer mentioned as an option in industry-specific texts[2] or model building codes. 0000052240 00000 n Calculating solar gains by hand is a laborious, imperfect process. 0000011323 00000 n The winter climates in these cities differ not just in temperature ranges, but also in the amount of winter sunlight. 0000040500 00000 n 0000030709 00000 n 0000018860 00000 n I found it both interesting and very useful. In a room, its likely you have light coming from multiple windows on different sides of the home. 0000040162 00000 n I think these recommendations are a mistake, as that high contrast of dark floor and white ceiling and walls adds to the perception of glare. 0000047288 00000 n That makes more sense.]. 0000026490 00000 n << 0000031405 00000 n 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. 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. The "solar input" in the 3M Sungain film brochure, also known as the solar heat gain coefficient, is the solar transmittance modified to account for re-radiated heat. Glare would not be the reason shades were drawn at that hour for south-facing windows in any home, unless someone needs a dark interior, like trying to sleep late. 0000038900 00000 n 0000014495 00000 n Apologies for the delay. 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. Thank you so much for sharing 0000011785 00000 n 0000030815 00000 n hbbd```b``A$cXDDr@3N,IF@L@s&00Lg`` 0000016860 00000 n Even if it is not possible to build a classic passive solar home in other climates, solar gains can be used for substantial solar-tempered wintertime home heating. [3] The transmittance of each component is calculated in a similar manner to the shading coefficient. Motions of the Sun Simulator The SHGC is the measurement of how much radiant heat, or heat produced by the sun, comes in through a window. You bring up an important point. 0000060198 00000 n Kinda like today, 11 degrees, very sunny and pleasant indoors, with a high-pressure system in control. 0000057378 00000 n Solar heat gain coefficients are expressed as decimals from 0.00 to 1.00. 0000038796 00000 n Solar Heat Gain Coefficient (SHGC) Worksheet -For Non-HERS Registered Projects (Page 3 of 3) TABLE 110.6-B DEFAULT SOLAR HEAT GAIN COEFFICIENT (SHGC) FRAME TYPE PRODUCT GLAZING FENESTRATION PRODUCT SHGC . Also for example, if I am to have brunch/lunch during daytime, where do I put dining table? So if you have your heart set on high-solar-gain glazing, you should keep looking. Rather than looking for a window with a high U-factor, you should be looking for a window with low U-factor. Additionally, the homeowner may choose to augment solar heat coming in the windows with exterior awnings or interior window blinds or curtains. 0000055107 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. 0000033229 00000 n This may help break up the glare. << 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. sketchup 0000036867 00000 n IMHO the typical USA under-insulated home with oversized fossil fuel heating and AC is the failed design in need of our greatest attention. 0000030384 00000 n 0000055784 00000 n 0000032810 00000 n 0000038693 00000 n NFRC U-factor ratings, however, represent the entire window performance, including frame and spacer material. 0000031213 00000 n Other internet data sources may include somewhat different data, but the patterns of data would lead to similar conclusions. In January, south-facing windows always account for more solar gain than east + west + north combined. Argon filled would be affordable and add about R-1. Contrast between the direct sunlight and the TV screen needs to be avoided. Use our Energy Star climate zone tool to look up the specific combinations of u factor and solar heat gain coefficient for the county you live in. So I don't think glare around the dining table on the opposite side of the room would be much of a problem. (10) Calculate solar heat gains when designing, and compare to heat losses. If you were to draw a Dec 21st shading line for the top of the window, then draw a shading line for June 21st from the bottom of the window, the point of intersection could be used to set the lowest, farthest out point of the roof overhang. 0000025712 00000 n 0000027028 00000 n The basement windows look out only on the east and south sides of the home where they barely see the light of day. The larger the net solar gains, the larger the amount of winter heating needed, and the higher the price of electricity, the better the score on the index. 0000019823 00000 n 0000042551 00000 n 0000011554 00000 n 2023 The Taunton Press, Inc. All rights reserved. To maximize wintertime interior daylighting and solar heat gains, south windows should be larger in size or in number than windows facing other directions. Terms | You will not receive a notification when a response to your question has been posted. Too much south-facing glazing can make a home very uncomfortable and unpleasant in February and March. 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. This label displays AL in U.S. units. Fy(@k ,dKa`C]Ll*EWXhS While you may like having free heat in the winter, it might be too much of a good thing in the summer months if you live in a climate zone with extreme seasons. 0000011092 00000 n 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). They have been prepared in exactly the same way as the tables in the ASHRAE Handbook of Fundamentals (1967), but are for the latitudes of particular relevance in Canada and for . Totally agree. how glass is used in the house design. Meanwhile, the solar heat gain through east- and west-facing windows is more intense due to the greater amount of solar radiation around June (for the northern hemisphere).

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