Abstract:
A building structure having a high efficiency solar control system is provided. The building structure may have a window defined by a sheet of glass and a film mounted to its exterior side. The film may reflect solar radiation in the near and mid infrared ranges yet allow high transmission of light in the visible range such that the occupants of the building structure may view his/her surroundings through the window. The film may have a layer of silver which reflects the solar radiation in the near and mid infrared ranges. Since the silver is susceptible to oxidation and turns the silver into a black body which absorbs the near and mid infrared radiation, the film may be designed to slow the rate of oxidation of the silver layer to an acceptable level. The silver layer may be sandwiched between the glass which does not allow oxygen to diffuse there through and reach the layer of silver and a stack of sacrificial layers having a certain thickness which slows down the rate of oxygen diffusion to an acceptable level.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Not Applicable 
       STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND 
       [0003]    The present invention relates to a building structure having a film mounted to its window for reducing solar radiation load. 
         [0004]    In warm and humid climates, direct sunlight on the building structure may cause its occupants to use the air conditioning system and/or use the air conditioning system at a higher level. Unfortunately, the air conditioning system may waste a large percentage of energy due to solar gain. By way of example and not limitation, it is believed that about 5% of the entire energy consumption in the United States is related to unwanted heat gain or loss through residential windows. High efficiency window systems have been developed such as triple or quadruple glazing window systems. Unfortunately, these systems add significant weight and cost to the window system. As a result, they have not received widespread adoption. In support thereof, these systems are believed to account for less than one percent of today&#39;s window sales. Additionally, the labor and material costs to retrofit existing homes with these high efficiency windows is believed to be excessively high (e.g., over $30,000 per home) in comparison to its energy efficiency benefits. 
         [0005]    Several factors determine the comfort level within the building structure. They include the air temperature, air speed within the building structure, humidity of the air within the building structure and the amount of thermal radiation entering the building structure such as through the window. When the air temperature is uncomfortably hot, the occupants may turn on the air conditioning system to cool down the average air temperature. In this instance, the air conditioning unit consumes energy to reduce the air temperature within the building structure. The occupants may also turn on and/or increase fan speed to increase air speed of the air circulating within the building structure. The fan consumes energy. The speed of air within the building structure increases evaporation of moisture on the skin of the occupants which cools the occupant&#39;s skin temperature. 
         [0006]    During the day, the building structure is exposed to solar radiation. A portion of the solar radiation is absorbed by the window and heated. For example, a large portion of the near infrared radiation and all of the mid infrared radiation are absorbed by the window and re-radiated into the interior of the building structure. The heated window re-radiates heat into the building structure to thereby increase the interior of the building structure&#39;s air temperature and heats up the interior of the building structure. A portion of the solar radiation is transmitted through the window and absorbed by the interior of the building structure (e.g., appliances, sofas, furniture, etc.). Upon absorption, the interior of the building structure re-radiates the absorbed energy into the air within the building structure. This further increases the air temperature within the building structure. The hot air and the hot interior of the building structure re-radiates energy generally as infrared radiation in the mid infrared range. Unfortunately, glass windows generally do not allow the mid infrared radiation to pass therethrough. As such, the mid infrared radiation is retained within the building structure and increases a temperature of the building structure above ambient temperature. 
         [0007]    A portion of the solar radiation transmitted through the window may also be absorbed by the occupant&#39;s skin. This portion of the sun&#39;s rays may cause the occupants to feel uncomfortably hot thereby encouraging use of the air conditioning system even if the air temperature is within a comfortable range. This may cause the occupant to turn on the air conditioning system and/or fan. Use of the air conditioning system and the fan both consume energy. Any reduction in the use of the air conditioning system and fan would also reduce the total amount of consumed energy. 
         [0008]    The human skin contains receptors that are sensitive to thermal radiation in the infrared range. When the occupants of the building structure are exposed to infrared radiation, the occupants may be uncomfortable even if the air temperature within the building structure is within a comfortable range. The occupants may resort to decreasing the average air temperature within the building structure and increasing the air speed of the fan system to counteract the discomfort caused by thermal radiation, both of which consume increasing amounts of energy. 
         [0009]    Conversely, during the winter months, heat is lost through the windows of the building structure. In particular, objects within the building structure are heated by the heating system, fireplace, body heat, etc. The heated objects emit infrared radiation in all directions including toward the window of the building structure. This infrared radiation may be transmitted through the window of the building structure thereby increasing the heating needs of the building structure. 
         [0010]    As such, there is a need in the art for an apparatus and method for reducing the need to use the air conditioning system and/or fan of the building structure&#39;s cooling system and reducing occupant exposure to solar infrared radiation. Additionally, there is a need in the art for an apparatus and method for retaining infrared radiation within the building structure to retain heat and reduce the load on the building structures heating system due to loss of infrared radiation. 
       BRIEF SUMMARY 
       [0011]    The present invention addresses the needs discussed above, discussed below and those that are known in the art. 
         [0012]    A building structure is provided having a high efficiency solar control system. The solar control system may comprise a glass sheet and a film mounted to its exterior side, namely, the side closer to the environment. The glass and film may define a window (e.g., bedroom window, backdoor window, etc.) of the building structure. The film may have high transmission of light in the visible range such that the occupants of the building structure may view his/her surroundings through the window. Also, the film may reflect a high percentage of light in the near infrared range and the mid infrared range back into the environment. As such, during the summer months, the solar load on the building structure is reduced by the amount of solar radiation in the near infrared range and the mid infrared range reflected back into the environment. 
         [0013]    Conversely, during the winter months, the film may be operative to reflect thermal radiation emanating from within the building structure back into the building structure to retain heat within the building structure and reduce a load on the building structure&#39;s heating system. As previously discussed, the heated objects within the building structure and the occupants emanate thermal radiation in all directions. This thermal radiation includes infrared radiation in the near, mid and far infrared ranges. This thermal radiation may be directed toward the windows of the building structure. A portion of the thermal radiation is absorbed by the glass of the window and re-radiated back into the interior of the building structure. A portion of the thermal radiation may be absorbed by the glass and re-radiated toward the film. Fortunately, the film reflects substantially all of the reradiated thermal radiation in the mid and far infrared ranges and about half in the near infrared range back to the glass which absorbs the reflected thermal radiation and re-radiates the thermal radiation back into the interior of the building structure. 
         [0014]    The film may additionally have a plurality of sacrificial layers which have a high transmission value with respect to the visible range and the near and mid infrared ranges. The topmost sacrificial layer may be removed or peeled away when it has been unacceptably degraded due to environmental elements (e.g., chips, oxidation, etc.) thereby exposing a fresh new topmost layer. Additionally, the additional sacrificial layers mitigate oxidation of a silver layer embedded within the film. In particular, the film is mounted to glass of the window. As such, one side of the film does not allow diffusion of oxygen into the film since oxygen cannot diffuse through the glass. On the other side of the film (or the silver layer(s)), a thick stack of sacrificial layers may be formed. Although oxygen may be diffused through the sacrificial layers, such diffusion of oxygen through the sacrificial layers may be slowed down by increasing the thickness of the sacrificial layers. Either or both the number of sacrificial layers may be increased or decreased as appropriate or the thickness of each of the sacrificial layers may be increased or decreased to bring the rate of oxygen diffusion to an acceptable level. The silver layer is disposed between the glass and the thick stack of sacrificial layers which protects the silver layer from oxidation. 
         [0015]    More particularly, a building structure for protecting people from an environment is disclosed. The building structure may comprise a glass window defining an interior side and an exterior side and a film attached to the exterior side of the glass window for reflecting solar infrared radiation away from the glass window to the environment and reflecting thermal radiation back into the building structure. The film may comprise an infrared reflecting layer and one or more protective layers. The infrared reflecting layer may define an interior side and an exterior side. The interior side of the infrared reflecting layer may be attached to the exterior side of the glass window. The infrared reflecting layer may have an embedded infrared reflecting core which comprises one or more layers of silver and one or more layers of dielectric for reflecting infrared radiation. The silver and dielectric layers may alternate. The one or more protective layers may be removeably attached to the exterior side of the infrared reflecting layer for mitigating oxidation of the silver layer and for providing a sacrificial top layer which can be removed when damaged due to ultraviolet light exposure or oxidation. 
         [0016]    An adhesive layer may be disposed between the infrared reflecting layer and the glass window for adhering the film to the glass window. The infrared reflecting layer may be generally transparent to visible spectrum of light. The infrared reflecting layer may be fabricated from biaxially-oriented polyethelene terephthalate. The protective layers may be peelably adhered to one another. An exterior side of each of the protective layers may have an ultraviolet light absorbing hard coat. The adhesive may be an ultraviolet light absorbing adhesive. The one or more protective layers may be sufficiently thick to reduce the rate of oxidation of the silver layer to a level such that the film has a sufficiently useful long life. The one or more protective layers may be fabricated from biaxially-oriented polyethelene terephthalate. 
         [0017]    A method for reducing solar radiation load on a building structure or reducing a heating requirement is also disclosed. The method may comprise the steps of providing and attaching. The providing step comprises the step of providing a film for reflecting infrared radiation to an exterior of the building structure for reducing the solar radiation load or to an interior of the building structure to retain heat therewithin. The film comprises an infrared reflecting layer defining an interior side and an exterior side. The infrared reflecting layer may have an embedded infrared reflecting core which comprises one or more layers of silver and one or more layers of dielectric for reflecting infrared radiation. One or more protective layers may be removeably attached to the exterior side of the infrared reflecting layer for mitigating oxidation of the silver layer and for providing a sacrificial top layer which can be removed when damaged due to ultraviolet light exposure or oxidation. The attaching step comprises the step of attaching an interior side of the infrared reflecting layer to an exterior side of a glass window of the building structure. 
         [0018]    The attaching step may comprise the step of adhering the interior side of the infrared reflecting layer to the exterior side of the glass window. 
         [0019]    The method may further comprise the step of providing a stack of sacrificial layers removeably attached to each other such that a top most sacrificial layer may be removed and discarded when the top most protective layer is damaged due to ultraviolet light exposure or oxidation. The sacrificial layers may each be a layer of biaxially-oriented polyethelene terephthalate or similar material. The method may further comprise the step of mounting the stack of sacrificial layers to the one or more protective layers. 
         [0020]    A building structure is disclosed. The building structure may comprise a glass window defining an interior side and an exterior side and a film attached to the exterior side of the glass window for reflecting infrared radiation away from the glass window. The film may comprise an infrared reflecting core which comprises one or more layers of silver and one or more layers of dielectric for reflecting infrared radiation. The infrared reflecting core may define opposed first and second sides. The film may also comprise a first protective layers attached to the first side of the infrared reflecting layer. The first protective layer having a first thickness. The film may also comprise a second protective layer attached to the second side of the infrared reflecting layer and the glass window. The second protective layer having a second thickness. The first thickness being greater than the second thickness. The first and second protective layers provide structural support to the one or more silver layers. Also, the thicker first protective layer mitigates oxidation of the one or more silver layers caused by oxygen diffusion through the first protective layer. In the building structure, a stack of sacrificial layers may be mounted to the thicker first layer. The stack of sacrificial layers may be removeably attached to each other such that a top most sacrificial layer may be removed and discarded when the top most sacrificial layer is damaged due to ultraviolet light exposure or oxidation. The sacrificial layers may be adhered to each other. The first thickness is sufficiently thick to reduce the rate of oxidation of the silver layer to a level such that the film has a sufficiently long useful life. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which: 
           [0022]      FIG. 1  illustrates a building structure having a high efficiency solar control system; 
           [0023]      FIG. 2  is a cross-sectional view of a window of the building structure shown in  FIG. 1 ; 
           [0024]      FIG. 2A  is a cross sectional view of a prior art building structure window without an absorption film; 
           [0025]      FIG. 2B  is a cross sectional view of the prior art building structure window with an absorption film; 
           [0026]      FIG. 3  is an enlarged view of the window shown in  FIG. 2 ; 
           [0027]      FIG. 4  illustrates an alternate embodiment of the film shown in  FIG. 3 ; and 
           [0028]      FIG. 5  illustrates thermal radiation emanating from within a building structure being absorbed by a glass window and being reflected back into an interior of the building structure by a film having an infrared reflecting core. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    Referring now to  FIG. 1 , a building structure  10  having a window  12  is shown. The window  12  protects the occupants from environmental elements (e.g., wind, rain, etc.) yet allows the occupants to view the surroundings from within a room  14  of the building structure  10 . As shown in  FIG. 2 , the window  12  may have a film  16  attached to an exterior side  18  of a glass  20 . The film  16  may be generally optically transparent in the visible wavelengths and generally reflect radiation in the non-visible or infrared wavelengths. The sun&#39;s rays transmit solar radiation both in the visible light range and also in the infrared range. A majority of the radiation in the infrared range may be reflected back to the exterior  11  of the room  14  or the building structure  10  by the film  16 . A small portion of the energy may be transmitted into the room  14  through the glass  20  of the window and a small portion is absorbed by the glass  20 , converted into heat and re-radiated into the interior  13  of the room  14 . Beneficially, the film  16  reduces the amount of solar radiation in the near and mid infrared ranges from entering into the room  14  or the building structure  10  by reflecting a large percentage back to the environment. As such, the amount of solar radiation introduced into the air of the room  14  or building structure  10 , absorbed into the interior of the room  14  and contacting the occupant&#39;s skin is reduced. This lowers the average air temperature within the room  14  or the building structure  10 . This also reduces discomfort of the occupants due to exposure to infrared radiation when the occupant is in the line of sight of the sun. Beneficially, the film  16  increases the occupant&#39;s comfort with respect to temperature. 
         [0030]    Conversely, during colder months, it is desirable to retain heat within the building structure  10 . The objects and occupants within the building structure emanate thermal radiation in all directions including toward the windows. This thermal radiation is reflected by the film  16  back into the building structure. 
         [0031]    As will be discussed further herein, the film  16  is mounted to an exterior of the glass  20  of a window  12  of a building structure  10  to reduce solar radiation load during the summer months and retain heat within the building structure  10  during the winter months. 
         [0032]    Referring now to  FIG. 2 , solar radiation may be divided into the visible range  38 , near infrared range  40 , and the mid-infrared range  42 . For each of these ranges  38 ,  40 ,  42 , a portion of the solar radiation is transmitted through the film  16  and a portion of the solar radiation is reflected back to the exterior  11  of the room  14  or the building structure  10  as shown by arrows  44 ,  46   a, b.  In the visible range  38 , a large percentage (i.e., more than 50%, but preferably about 70% or more) of the light is transmitted through the film  16 . In contrast, in the near infrared range  40  or the mid infrared range  42 , a large percentage (i.e., more than 50% but preferably about 80% or more) of the light is reflected back to the exterior  11  of the room  14  or building structure  10 . Since the film  16  is mounted to the exterior of the glass  20 , less of the near infrared radiation  40  and the mid infrared radiation  42  reaches the glass  20  compared to the prior art as shown by comparing  FIG. 2  with  FIGS. 2A and 2B .  FIG. 2A  illustrates untreated glass  20 .  FIG. 2B  illustrates glass  20  with a commonly used absorption film  55  mounted to the interior or inside of the glass  20 . In  FIG. 2B , the reflected mid infrared radiation may be absorbed by the glass  20 . In certain cases, the heat from the absorbed radiation may detrimentally affect (e.g., break) the glass  20 . The lengths of the lines  54   a, b  and  50   a  which generally indicates magnitude of transmission and radiation is longer in  FIGS. 2A and 2B  compared to  FIG. 2 . As shown, the glass  20  is heated to a lesser extent and the amount of near and mid IR radiation  40  transmitted through the glass  20  is less with use of the film  16  mounted to the exterior of the glass  20  such that the heat load on the building structure  10  and occupant exposure to near infrared radiation  40  is reduced. This promotes less or no use of the air conditioning system and/or fan. 
         [0033]    For that portion of the solar radiation transmitted through the film  16 , a portion is transmitted through the glass  20  in the visible range as shown by arrow  48 . The remainder is absorbed into the glass  20  thereby heating the glass  20  and reradiated as thermal radiation into the interior  13  of the room  14  or building structure as shown by arrows  52 ,  54   a, b.  Generally for residential glass, all of mid infrared radiation  42  is absorbed by the glass  20  and reradiated into the interior  13  of the room  14  or building structure as shown by arrow  54   b.  However, it is contemplated that other glass compositions may be employed for building structures such that a portion of the mid infrared radiation  42  may be transmitted through the glass  20 . The film  16  has a high percentage (i.e., more than 50% but preferably about 70% or more) of transmission  48  of the solar radiation in the visible range  38  and a high percentage (i.e., more than 50% but preferably 80% or more) of reflection  46   a, b  in the near-infrared range  40  and the mid-infrared range  42 . The film  16  also reflects a portion of the solar radiation in the far infrared range (not shown in  FIG. 2 ). 
         [0034]    Referring now to  FIG. 3 , an enlarged cross-sectional view of film  16  and glass  20  is shown. The film  16  may have an infrared reflecting layer  22  with an embedded infrared reflecting core  24 . The infrared reflecting core  24  may comprise one or more silver layers  26  and one or more dielectric layers  28 . The silver layer  26  and the dielectric layer  28  may alternate such that the infrared reflecting core  24  may comprise a layer of dielectric  28 , a layer of silver  26 , a layer of dielectric  28 , a layer of silver  26 , a layer of dielectric  28  all stacked upon each other. Preferably, the dielectric layers  28  are the outermost layers of the embedded infrared reflecting core  24 . At a minimum, one silver layer  26  is disposed between two layers of dielectric  28 . The silver layers  26  and dielectric layers  28  may have a thickness measured in nanometers. The silver layer  26  may be generally transparent in the visible range and reflect a high percentage of infrared radiation especially in the near infrared range  40  and the mid infrared range  42 . The number and thickness of silver layers  26  and the number and thickness of dielectric layers  28  may be adjusted to tune the amount or percentage of infrared radiation being reflected by the infrared reflecting core  24 . 
         [0035]    The infrared reflecting core  24  may be sandwiched between two layers  30  of material having high transmission (i.e., greater than 50% but preferably about 90% or more) both in the visible range and the near and mid infrared ranges. By way of example and not limitation, the layer  30  may be biaxially-oriented polyethelene terephthalate (hereinafter “BoPET”) mylar. BoPET is the preferred material since it is dimensionally stable (i.e., not elastic), has a high transmission in the visible and near and mid infrared ranges, low scatter and low cost. The dimensional stability of the BoPET layer  30  provides support for the silver layer  26 . Otherwise, the silver layer  26  may crack or become damaged upon stretching of the layer  30 . Additionally, the infrared reflecting layer  22  is useful for reflecting a high percentage (i.e., more than 50% but preferably about 70% or more) of solar thermal radiation in the near and mid infrared ranges  40 ,  42  and allowing light in the visible range  38  to be transmitted through the BoPET layers  30  and the infrared reflecting core  24 . 
         [0036]    One of the characteristics of the silver layer  26  is that upon exposure to oxygen, the silver oxidizes as a black material. In the oxidation process, the silver is converted from a material that reflects heat in the near to mid infrared ranges  40 ,  42  to a black body that absorbs heat in the near to mid infrared ranges  40 ,  42 . Instead of reflecting a majority of the heat in the near and mid infrared ranges  40 ,  42 , the silver layer  26  now absorbs radiation in both the visible range  38  and the near and mid infrared ranges  40 ,  42 . Detrimentally, the silver layer  26  absorbs and re-radiates such energy into the building structure  10 . Additionally, one of the characteristics of the BoPET layer  30  is that oxygen diffuses through the BoPET layer  30  such that oxygen ultimately reaches the silver layer  26  and oxidizes the same  26 . To prevent or reduce the rate of oxidation of the silver layers  26  to an acceptable rate, additional layers  30   a - d  may be stacked on the infrared reflecting layer  22 . Any number of layers  30   a - n  may be stacked on the infrared reflecting layer  22 . The amount of oxygen diffused through the layers  30   a - n  and  30  is a function of a distance  32  from the silver layer  26  and the exterior side  34  of the topmost layer  30 . The amount of oxygen reaching the silver layer  26  from an exterior side (i.e., from outside the building structure  10 ) is reduced since the oxygen must travel a greater distance through the layers  30   a - n  and  30 . On the interior side, the film  16  is mounted to the glass  20  which protects the silver layer(s)  26  from oxidation. Oxygen does not pass through the glass  20 . 
         [0037]    Alternatively, it is contemplated that the thickness  33  of the BoPET layer  30  in the infrared reflecting layer  22  may be increased (see  FIG. 4 ) to slow down the rate of oxidation of the silver layers  26  to an acceptable level. Additionally, an additional stack of BoPET layers  30   a - n  may be adhered to the BoPET layer  30  on the exterior side, as shown in  FIG. 4 . The stack of BoPET layers  30   a - n  may be removably adhered to each other such that the topmost BoPET layer  30   a - n  may be used as a sacrificial top layer as discussed herein. 
         [0038]    Referring back to  FIG. 3 , during use, the exterior side  34  of the topmost layer  30   d  is exposed to environmental elements such as rain (containing chemicals), rocks, dirt, ultraviolet light, etc. As such, the exterior side  34  of the topmost layer  30   d  may experience physical degradation (e.g., chips, oxidation, etc.). It may be difficult to see through the film  16  due to the degradation of the topmost layer  30   d.  Beneficially, each of the layers  30   a - d  may be removed (e.g., peeled away) from each other and also from the infrared reflecting layer  22 . The then topmost layer behaves as a sacrificial layer which is removed when it has been unacceptably degraded by the environmental elements. To this end, the layer  30   d  may be peelably adhered to layer  30   c,  layer  30   c  may be peelably adhered to layer  30   d,  layer  30   d  may be peelably adhered to layer  30   a  and layer  30   a  may be peelably adhered to the infrared reflecting layer  22 . A tab or other means of removing the topmost layer  30   d  may be provided such that the topmost layer  30   d  may be peeled off of the adjacent lower layer  30   c  when the topmost layer  30   d  is unacceptably degraded. Upon further use, the new top layer  30   c  experiences physical degradation. When the then topmost layer  30   c  is degraded to an unacceptable level, the topmost layer  30   c  is now peeled away from the top layer  30   b.  The process is repeated for layers  30   b  and  30   a.  As the topmost layers  30   d, c, b, a  are peeled away, the rate of oxidation of the silver layer  26  increases. As such, the number of layers  30   a - n  may be increased or decreased based on the required useful life of the film  16 . To extend the useful life of the film  16 , additional layers  30   a - n  are stacked upon each other to increase the distance  32 . Conversely, to decrease the useful life of the film  16 , fewer layers  30   a - n  are stacked upon each other to decrease the distance  32 . When the silver layer  26  is unacceptably oxidized, the entire film  16  is removed from the glass  20  and a new film  16  is mounted to the exterior surface  36  of the glass  20 . 
         [0039]    Each of the BoPET layers  30   a - d  and  30  may define an exterior side  34 . An ultraviolet light absorbing hard coat may be coated onto the exterior side  34  of the BoPET layers  30   a - d  and  30  to slow the damaging effects of ultraviolet light on the BoPET layer  30 . Additionally, the adhesive for attaching the BoPET layers  30   a - d  to each other as well as the adhesive for adhering the BoPET layer  30   a  to the infrared reflecting layer  22  may be an ultraviolet light absorbing adhesive to further slow the damage of ultraviolet light exposure. Such adhesives may continuously cover most if not all of the BoPET layer  30   a - d  and the infrared reflecting layer  22 . 
         [0040]    A method for attaching the film  16  to the glass window  20  will now be described. Initially, the film  16  is provided. The film  16  may have a peelable protective layer on both sides to protect the silver layers  26  from oxidation and the exterior surfaces from oxidation as well as chipping prior to installation and during storage. The protective layer may be impermeable to oxygen to prevent oxidation of the exterior surfaces of the film  16  as well as oxidation of the silver layers  26 . The protective layer may also block ultraviolet light to mitigate damage to the film  16  in the event the film  16  is left out in the sun. The protective layer may be adhered to the exterior surfaces of the film  16  in a peelable fashion. Prior to mounting the film  16  to the glass  20 , the film  16  may be cut to the size of the building structure window. After the film  16  is cut to size, the protective layers may be peeled away to expose the film  16 . The exposed side of the infrared reflecting layer  22  may have a pressure sensitive adhesive that may be activated by water or other fluid. The pressure sensitive adhesive may continuously cover most if not all of the exposed side of the infrared reflecting layer  22 . The exterior side of the glass  20  may be wetted down with water or the other fluid. The cut film  16  may now be laid over the exterior side of the window  12 . Any air bubbles may be squeegeed out. The moist adhesive on the infrared reflecting layer  22  is allowed to dry such that the film  16  is mounted to the glass  20  and the film  16  cannot slip with respect to the glass  20 . 
         [0041]    The film  16  may be fabricated in the following manner. Initially, a BoPET layer  30  is provided as a roll. The BoPET layer  30  is unrolled and a layer of dielectric  28  is formed on one side of the BoPET layer  30 . The thickness of the BoPET layer  30  may be approximately two thousandths of an inch thick. The thickness of the dielectric layer  28  may be measured in nanometers. As the layer of dielectric  28  is laid on one side of the BoPET layer  30 , the BoPET layer  30  is rerolled. The BoPET layer  30  is then unrolled such that a layer of silver  26  may then be laid on top of the layer of dielectric  28 . The silver layer  26  is also measured in nanometers and is extremely thin. The BoPET layer  30  is rolled back up and unrolled a number of times until the desired number of silver and dielectric layers  26 ,  28  is attained. A second BoPET layer  30  (about 0.002 inches thick) may be laminated onto the dielectric layer  28  such that two BoPET layers  30  sandwich the alternating layers of silver  26  and dielectric  28  which form the infrared reflecting core  24 . Thereafter, additional layers of BoPET  30   a - n  (each layer being about 0.002 inches thick) may be laminated onto the infrared reflecting layer  22  to serve as a sacrificial layer and reduce the rate of oxygen diffusion. Optionally, protective layers for protecting the film  16  during storage and prior to installation may be laminated onto opposed sides of the film  16 . The thickness of the film  16  may be limited by the amount of bending required to roll the film  16  during manufacture. For thicker films  16 , it is contemplated that the film  16  may be fabricated in a sheet form process. 
         [0042]    Referring now to  FIG. 5 , thermal radiation emanates from within the building structure  10 . The source of the thermal radiation within the building structure  10  may be the occupant&#39;s body heat, a light bulb, stove, heat from objects, etc. Generally, thermal radiation emits infrared radiation in the near, mid and far infrared ranges. A portion of this radiated thermal radiation in the near, mid and far infrared ranges reaches the window  12  of the building structure  10 . A portion of the thermal radiation is absorbed by the glass  20  of the window  12 . A portion of the thermal radiation is transmitted through the glass  20  and reflected off of the film  16  back toward the interior  13  of the building structure  10 . The film  16  may be effective to reflect a majority (i.e., more than 50% preferably 90%) if not all of the mid and far infrared radiation and approximately fifty (50) % of the near infrared radiation. Additionally, the thermal radiation absorbed by the glass  20  heats the glass  20  and emits thermal radiation in the near, mid and far infrared ranges toward the exterior  11  of the building structure  10  as well as the interior  13  of the building structure  10 . For that portion of the thermal radiation transmitted toward the exterior  11  of the building structure  10 , the film  16  reflects the thermal radiation in the near, mid and far infrared ranges to direct the thermal radiation back into the interior  13  of the building structure  10 . As such, the film  16  retains the thermal radiation emanating from objects and people within the building structure  10 . 
         [0043]    The various aspects of the film  16  discussed herein was described and shown with respect to a single pane glass window  12 . However, it is contemplated that the film  16  may be used in conjunction with other types of windows  12  such as single pane windows, windows manufactured from plastic, etc. 
         [0044]    The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein, including various ways of adhering the film  16  to the glass  20 . Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments.