Patent Publication Number: US-2017347813-A1

Title: Thermal- And Moisture-Regulating Duvet Inserts

Description:
REFERENCE TO PRIOR APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/345,249, filed on Jun. 3, 2016 and U.S. Provisional Patent Application Ser. No. 62/450,728, filed on Jan. 26, 2017. 
    
    
     FIELD OF THE DISCLOSURE 
     The present invention relates to the field of a duvet insert for quilts, bedspreads and the like. The duvet insert provides thermal insulation and/or moisture regulation while sleeping. 
     BACKGROUND 
     A duvet insert provides the major insulation layer in a bedding sleep environment. The duvet insert is designed to regulate temperature and humidity. A more consistent temperature results in better sleep with less disruptive waking. As the temperature rises, humidity also increases. Inconsistent humidity regulation can also lead to poor sleep and more waking. 
     Current duvet inserts typically use large sewn square chambers to hold insulating duck/goose down clusters between layers of woven fabric. The larger the square chamber, the more likely the down will shift and migrate within the chamber. This leaves empty areas of no insulation, ultimately creating cold spots and poor temperature regulation while sleeping. 
     To handle down migration within duvets, it is common for the size of the sewn box to be made smaller. The smaller the box, the better at holding the insulation materials. But the smaller box tends to produce a more expensive product. Further, the additional sewing adds labor time and the stitching process may trap down between the stitching. This trapped down is compressed and does not provide proper insulation. 
     Accordingly, there is an opportunity to help users sleep better by ensuring consistent temperature and humidity regulation, calibrating insulation to known room temperature ranges, and constructing down holding chambers in a unique manner. This prevents the insulation from moving/migrating and ensuring consistent insulation across the entire duvet insert. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views, together with the detailed description below, are incorporated in and form part of the specification, and serve to further illustrate embodiments of concepts that include the claimed invention, and explain various principles and advantages of those embodiments. 
         FIG. 1  shows a duvet insert in accordance with the present invention. 
         FIG. 2  is an inset view of the duvet insert in accordance with the present invention. 
         FIG. 3  shows the use of a duvet insert in accordance with the present invention. 
         FIG. 4  shows a cross-section of a duvet insert in accordance with the present invention. 
         FIG. 5A  shows a method of inserting material in a duvet insert with sewn-through pockets in accordance with the present invention. 
         FIG. 5B  shows a method of inserting material in a duvet insert with baffle boxes in accordance with the present invention. 
         FIG. 6  shows a stitching method of a duvet insert in accordance with the present invention. 
         FIG. 7  is an exploded view of a first embodiment of a duvet insert in accordance with the present invention. 
         FIG. 8  is an exploded view of a second embodiment of a duvet insert in accordance with the present invention. 
     
    
    
     Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention. 
     The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. 
     DETAILED DESCRIPTION 
     Most people sleep in a temperature-controlled environment (the bedroom) where temperature is managed by a thermostat. In addition, human bodies thermoregulate, which is a process that maintains internal core temperature. Humans have discreet biological mechanisms that happen automatically whenever the body gets too cold or too hot. When the body&#39;s core temperate drops and the person becomes cold, blood vessels contract, extremities get cold, the body shivers the heart rate increases. These mechanisms disrupt sleep. When the body&#39;s core temperate rises and the person becomes hot, the body sweats (typically above 98.6°), the person turns and kick the covers away. These mechanisms also disrupt sleep. 
     Insulation plays an important part of finding the right temperature. If there is too little insulation, the cooler ambient temperature sucks away all the heat from under the covers. If there is too much insulation, heat gets trapped underneath the covers with no way to escape. (It should be noted that the bedding industry markets towards overly fluffy duvets. These are over-insulated and almost always sleep too hot.) This may be further aided by providing specific temperature ratings for specific products. For example, high-end sleeping bags are typically rated for a specific temperature range. 
     Maintaining proper core temperature is key to good sleep. This involves a balancing act between body temperature, ambient temperature, insulation, and material permeability. The ideal duvet creates the proper sleep envelope; providing a lightweight and adaptable layer of insulation to help the body maintain temperature and get a good night&#39;s sleep. 
     The current marketplace provides a plethora of insulation options based on pre-determined seasonal temperature variations. For example, in Europe, it is common for duvets to be sold as a system. There are different weights that may be used separately or combined together to give the user the ability to control the amount of insulation. Alternatively, some manufacturers offer a “winter duvet insert,” “spring duvet insert,” or “summer duvet insert.” Some manufacturers have their own proprietary system (L 1 , L 2 , L 3 ). Some manufacturers offer an all-season duvet insert which claim proper temperature regulation for year-round use. 
     Some companies sell a “smaller box” duvet. The smaller the box, the less chance of down migrating around and creating cold spots. Some companies sell moisture wicking bed linens that attempt to proactively manage heat and moisture. 
     Despite the claims of superior performance throughout the industry, there are no objective guidelines that justify claims of optimal performance. This leaves the consumer no choice but to “buy and then try” and hope for a satisfactory result. 
     The present invention involves calibrating duvet insulation to a specific room temperature range. Since most people sleep in temperature controlled environments (air-conditioned in summer and heated in winter), calibrating insulation to an ideal ambient sleep temperature may eliminate the guessing when purchasing a duvet. Typical bedding already consists of several layers; bottom sheet, top sheet, duvet cover, and duvet insert. Each of these layers provides measurable amounts of insulation. The disclosed bedding system (including the duvet insert) allow for users to customize insulation by just using their existing bedding. One example is the following: 
     For coldest situations: Use bottom sheet, top sheet, duvet insert and duvet cover. 
     For medium situations: Use bottom sheet, no top sheet, duvet insert and duvet cover. 
     For hot situations: Use bottom sheet and top sheet. 
     Moreover, temperature regulation for one person in a bed is different than two people in a bed. This is because some people sleep hot and others sleep cold. The customization is configurable to take this into account by forming different configurations on different sides. 
     The various choices for choosing material for a duvet are described herein. 
     Insulation. Temperature regulation is typically managed by fill type, fill power, and fill weight. There are 3 main fill types; duck down, goose down, and synthetic polyester filling. For down, fill power is a measure of how big each individual down cluster is. The larger the cluster, the greater its insulation value is per weight of material. The higher the fill power, the less weight of insulation is needed to achieve the same insulation value. Higher fill power is perceived as better insulating. 
     Duck down clusters offer the best insulation per weight. Down traps air incredibly well. Its lightweight nature allows for a comfortable drape over the body while sleeping. The down cluster is unique to waterfowl birds. It is a collected from a remarkable inner coat that helps keep them warm, buoyant, and keeps eggs warm during nesting. The cluster has no hard quills (like feathers) and has many filaments growing in all directions. Down is the best insulator per weight in the world. 
     Down clusters are blown into a duvet and form a light matrix of structural filaments and air pockets. Air gets trapped in down “puff balls” to help maintain temperature while still allowing for moisture and excess heat to pass through. 
     Down clusters are sorted by puff ball size. “Fill power” refers to how large a volume 1 oz. of puff balls will hold. The larger the cluster, the larger 1 oz. of that material will hold. “Fill weight” refers to the total amount (by weight) of down clusters blown into a duvet. Identical insulation values may be created by varying fill power and fill weight. 
     Shell. The duvet shell needs to be lightweight, breathable, and not too crunchy. Breathable fabrics (like lightweight cotton) perform better than synthetic fabrics for a duvet shell. Their increased permeability allows for heat and moisture to pass through into the ambient environment, preventing a hot and muggy sleep microclimate. 
     A lightweight cotton shell may be used to help the overall weight of the duvet become lighter. Cotton is a natural material that has optimal breathability and permeability performance. Using cotton allows for moisture vapor generated by the user to easily pass through the assembly and out into the ambient environment; preventing a hot and muggy sleep environment. Typical synthetic fabrics are far less breathable and tend to trap heat and moisture within the sleep environment. 
     The fabric shell often weighs more than the insulating down material inside. The lighter the total assembly, the lighter it is on the body; increasing comfort by not weighing down and compressing the insulation material. A lighter assembly also has less thermal mass for the user&#39;s body to warm up. Thus, the user is able to reach a comfortable temperature faster. 
     The permeability of the duvet shell fabric must be “down-proof” to prevent leakage of the down our of the shell. Down “proofness” may be achieved a number of ways and in particular, by decreasing the yarn diameter and increasing the woven density of the fabric. In so doing, a tighter barrier is created that prevents the down from escaping form the shell. 
     Duvet boxes. The boxes that contain the down in the duvet insert are important in regulating the performance of the duvet. The larger the box, the more room for down to move around within. When down migrates or clumps up, it leaves areas of bare fabric with no insulation. These create cold spots which could disrupt a cozy night of sleep. 
     Turning to  FIG. 1 , shown is a duvet insert  100  in accordance with the present invention. The duvet insert  100  shown herein is divided into ninety (90) rectangular channels formed by short channels  101 - 116  and long channels  121 - 125 . The long ends of the rectangular channels run along the length of the duvet insert  100  and the short ends of the rectangular channels run along the width of the duvet insert  100 . The duvet insert  100  may have any number of rectangular channels depending on the number of short channels  101 - 116  and long channels  121 - 125  in the particular duvet insert  100 . The number of rectangular channels will also depend on what bedding size the duvet insert is for, e.g., a king, queen, full or twin duvet. 
     Turning to  FIG. 2 , shown is an inset of the underside of a corner of a duvet insert  100 . Cutting across the underside corner edge  210  of the duvet insert  100  is a corner loop  220 . The corner loop  220  may be elastic or inelastic. The corner loop  220  may be repeated on all four sides of the duvet insert  100 . The corner loop  220  is designed to secure the duvet insert  100  to a duvet cover (not shown) having ties or snaps on each corner. 
     Turning to  FIG. 3 , shown is a mock-up  300  of the duvet insert  320  draped over a human  310 . The mock-up  300  shows that the long side of the channels of the duvet insert  320  are draped over the length of the human  310 , while the short side of the channels of the duvet insert  320  are draped over the width of the duvet insert  320 . The reason that the long side (rather than the short side) is draped over the length of the human body is to ensure that there is optimal distribution of down over the body. Even if the down moves along the channels, there will still be more down-filled portions covering the body. Moreover, if the channels were horizontal, the insulation could migrate to the sides and leave more cold spots over the body than if the channels were vertical. 
     Turning to  FIG. 4 , shown is a cross-section  400  of a single portion of a duvet insert having both down and wool. Shown is a cross-section of a top shell  405  and a cross-section of a bottom shell  410 . The top shell  405  and bottom shell  410  are secured by a first stitching  442  and a second stitching  444 . A cross-section of a first region  420  may be filled with down, including duck down. A cross section of a second region  410  may be filled with wool in the form of a wool batting. In between the first region  410  and second region  420  is a barrier  415  to keep the down in the first region  420  from mixing with the wool in the second region  410 . Like the top shell  405  and the bottom shell  415 , the barrier  415  is also secured by a first stitching  442  and a second stitching  444 . 
     There are two possible methods of constructing a duvet: baffle boxes or sewn-through regions. Baffle box-based duvets are a grid of square boxes with internal baffles (or gussets) that helps create a consistent thickness to the construction. They are complex and are the predominant construction of duvets. They also allow for overly puffy aesthetics. Sewn-through region duvets are much simpler. Stitching joins two layers of fabric together to create pockets (usually square) for down to be held within. In a typical duvet, if all stitching happens after filling, down is often trapped between the stitching. 
       FIGS. 5A and 6  show a method of filling a duvet insert using sewn-through regions with down in a manner to limit trapped down in the stitching. Turning to  FIG. 5A , shown is a first step of a method  500  of filling down into a partially-completed duvet insert  520 . The partially-completed duvet insert  520  comprises a series of sewn-through channels after the stitching has been done along the long side but before the stitching has been done along the short side. As shown in the inset, to accomplish the filling of down, blowers  501 ,  502 ,  503 ,  504  push the down  505 ,  506 ,  507 ,  508  into the channels  509 ,  510 ,  511 ,  512 . Turning to  FIG. 6 , shown is a second step of a method  600  of filling the now-completely stitched duvet  606 . The completion is caused by the stitching  601 ,  602 ,  603 ,  604 ,  605  across the short side of the duvet insert  606 . 
     Thus, all of the vertical stitching is done first, which is followed by filling the vertical channels of the duvet cover, which is then followed by the horizontal stitching. This minimizes the trapped down and maximizes the insulation. 
     More specifically, creating a duvet insert—the duvet insert having a top portion with a top portion left long side, a top portion right long side, a top portion front short side, a top portion rear short side, and the duvet insert having a bottom portion with a bottom portion left long side, a bottom portion right long side, a bottom portion front short side, a bottom portion rear short side—may occur in several steps. 
     First, the duvet insert may be formed by stitching the edge of the top portion left long side with the bottom portion left long side to create a left-edge stitch and by stitching the edge of the top portion right long side with the bottom portion right long side to create a right-edge stitch. 
     The next step is stitching a plurality of long-side stiches running from the top portion front short side and the bottom portion front short side to the top portion rear short side and the bottom portion rear short side, the plurality of long-side stitches being substantially parallel with the left-edge stitch and the right-edge stitch, so as to create a plurality of long-side contiguous channels within the duvet insert. 
     The next step is inserting insulating material into the plurality of long-side contiguous channels 
     The next step is stitching the edge of the top portion front short side with the bottom portion front short side to create a front-edge stitch and stitching the edge of the top portion rear short side with the bottom portion rear short side to create a rear-edge stitch. 
     The next step is stitching a plurality of short-side stiches running from the top portion left long side and the bottom portion left long side to the top portion right long side and the bottom portion right long side, the plurality of short-side stitches being substantially parallel with the front-edge stitch and the rear-edge stitch, so as to create a plurality of substantially rectangular pockets within the duvet insert. 
     In the duvet insert, the number of the plurality of short-side stiches may be less than the number of the plurality of long-side stitches. 
     The preceding steps may occur in a different order. 
       FIG. 5B  shows an alternative method of filling a duvet insert via baffle boxes. Baffle box duvets are a grid of square boxes with internal baffles (or gussets) that helps create consistent thickness to the construction.  FIG. 5B  shows a filling method  550  of filling baffles with a tube. Specifically, baffles  551 ,  552 ,  553  are attached to each other and have baffle doors  556 ,  557 ,  558  to allow access between them. To fill the baffles, a tube  554  is inserted into the baffle doors  556 ,  557 ,  558  and down  555  is blown into the first baffle  551 . The tube  554  is then pulled through the first door  556  and down is blown into the second baffle  552 . The tube  554  is then pulled through the second door  557  and down is blown into the third baffle  553 . The tube  554  is then withdrawn from the third door  558 . 
     Also shown in  FIG. 5B  is are filled baffle boxes  590  that result from the filling method  550 . Shown are three filled baffle boxes  559 ,  560 ,  561  with doors between them  563 ,  565 ,  567 . Down  562 ,  564 ,  566  is now resident within each of the baffle boxes  559 ,  560 ,  561 . Baffle doors my leak because they are held shut by the pressure of the filled down. Down can move between boxes fairly easily. 
     Although three baffle boxes are shown in  FIG. 5B , any number of baffle boxes may be used. 
     In the industry, it is believed that a duvet insert with baffle boxes provides better performance than a duvet insert with sewn-through regions. The theory is that there is less heat leakage in baffle boxes than sewn-through regions. Several experiments were conducted to verify this hypothesis. 
     Experiment 1 
     A duvet insert mockup was constructed by combining 4 portions of other duvet inserts and stitching them together to form one duvet insert with 4 regions: 
     1. Top Left Region: duvet insert with large baffle box construction (large baffle box region). 
     2. Bottom Left Region: duvet insert with small baffle box construction (small baffle box region). 
     3. Top Right Region: duvet insert with large sewn-through construction (large sewn-through region). 
     4. Bottom Right Region: duvet insert with small sewn-through construction (large sewn-through region). 
     The duvet insert mockup was placed over a fitted sheet and an electric blanket. For the sewn-through regions (large and small), temperature measurements were made on the seams of the sewn-through regions and in the center of the sewn-through regions. For the baffle box regions (large and small), temperature tests were made on the seams of the baffle boxes and in the center of the baffle boxes. Testing took place without a top sheet. The temperature for each region without a top sheet was measured and the results are in Table 1. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Variance without a top sheet. 
               
            
           
           
               
               
               
               
            
               
                 Type of duvet 
                 Temperature at 
                 Temperature at 
                   
               
               
                 insert 
                 the center (° F.) 
                 the seam (° F.) 
                 Variance (° F.) 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 Small sewn- 
                 76.4 
                 81.9 
                 5.5 
               
               
                 through 
               
               
                 Large sewn- 
                 74.6 
                 80.4 
                 5.8 
               
               
                 through 
               
               
                 Small baffle box 
                 76.4 
                 78.8 
                 2.4 
               
               
                 Large baffle box 
                 76.3 
                 77.3 
                 1.0 
               
               
                   
               
            
           
         
       
     
     The differences in baffle boxes temperature for the center and seam (2.4 and 1.0) are less than the differences in the sewn-through temperature for the center and seam (5.8 and 5.5). This demonstrates that baffle boxes may retain heat in a duvet better than sewn-through region when no top sheet is used. 
     Experiment 2 
     The duvet insert mockup used in Experiment 1 was placed over a fitted sheet and an electric blanket and a top sheet was added on top. For the sewn-through regions (large only), temperature measurements were made on the seams of the sewn-through regions and in the center of the sewn-through regions. For the baffle boxes (large only), temperature tests were made on the seams of the baffle boxes and in the center of the baffle boxes. The temperate for each region with a top sheet was measured and the results are in Table 2. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Variance with a top sheet. 
               
            
           
           
               
               
               
               
            
               
                 Type of duvet 
                 Temperature at 
                 Temperature at 
                   
               
               
                 insert 
                 the center (° F.) 
                 the seam (° F.) 
                 Difference (° F.) 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 Large baffle box 
                 77.2 
                 77.8 
                 0.6 
               
               
                 Large sewn- 
                 76.0 
                 77.1 
                 1.1 
               
               
                 through 
               
               
                   
               
            
           
         
       
     
     Here, the differences in baffle boxes from center to seam (0.6° F.) are functionally equivalent to the differences in the sewn-through regions from center to seam (1.1° F.). The 0.5° F. difference is negligible in real-world situations. This demonstrates that any advantages that baffle boxes have in retaining heat in a duvet better than sewn-through region becomes essentially irrelevant when a top sheet is used. Thus, a tentative conclusion was reached that the temperature variances between baffle box and sewn-through regions are negligible for indoor climate controlled environments. 
     Experiment 3 
     To confirm the foregoing, a certified lab was retained using a temperate controlled guarded hot plate device. 
     Methodology: The insulation value of the fabrics was measured using the constant temperature method specified in ASTM D 1518, Standard Test Method for Thermal Resistance of Batting Systems Using a Hot Plate (option #1) (ASTM, 2015). This method uses a box hood to produce still air conditions. There was no air velocity over the plate and sample. 
     Apparatus: A Dynatech hot plate apparatus Model TCB-TX was used in an environmental chamber. The plate measurement section was a 25.4×25.4 cm (10×10 in.) square surrounded by a guard section which increased the total size of the plate to a 50.8×50.8 cm (20×20 in.) square. The function of the guard heater was to eliminate lateral heat flow to or from the main heater. A second bucking heater located beneath the main heater eliminated the heat flow in the axial direction away from the test sample. These two heaters thereby forced all of the heat generated in the main heater to flow in the direction of the test sample. The side of the test sample away from the heater plate assembly was exposed to still air conditions inside a fabric box hood. The heater controllers and readout instrumentation for the various sensors in the apparatus were located in a separate cabinet outside the environmental chamber. The hot plate also included a data acquisition and control system which is interfaced to a computer. 
     Procedures for Measuring Thermal Resistance (Insulation): One 50.8×50.8 cm (20×20 in.) square specimen was prepared for each type of fabric/duck down/fabric system. The construction varied among the specimen types. 
     The specimen types were the following: 
     1. Sewn-thru region with stitching on center without fabric cover. 
     2. Sewn-thru region with box on center without fabric cover. 
     3. Baffle-box with stitching on center without fabric cover. 
     4. Baffle-box with box on center without fabric cover. 
     5. Sewn-thru region with stitching on center with fabric cover. 
     6. Baffle-box with stitching on center with fabric cover. 
     The samples were stored on a shelf inside the environmental chamber to “condition.” The samples were randomized for testing for each replication of the test method. 
     The air temperature in the chamber was 2° C. (35° F.). The air layer resistance (bare plate value) was 0.085 m 2 ° ·C./Watt. The relative humidity was not controlled at a specific level, but it was stable between 30-70% as specified in the standard. The plate temperature was maintained at 35° C. (95° F.). Each fabric system was placed on the horizontal, flat plate so that the code number was visible on the top. Then it was covered by the box hood. When the temperatures were within their tolerance limits and the system had reached steady-state (defined as a less than 1% change in R t , insulation value), data were collected every 30 seconds for 30 minutes. The data collected included plate surface temperature (T s ), air temperature (T a ), air dew point temperature (T dp ), and current and voltage to the test section. Four air temperature sensors hanging 508 mm (20 in.) above the center of the plate were averaged to determine the mean air temperature. Power (H) to the test section was determined from the voltage and current readings. Three replications of the test were conducted on each fabric type and on the bare plate. 
     First, the total resistance to dry heat transfer (R t )—or insulation value—for the fabric system including the air film resistance was calculated. Data from three replications of the dry hot plate tests were averaged to determine the mean R t  for each fabric system and for the bare plate. 
     The thermal resistance (insulation) values for the fabric systems are given in Table 3. The higher the dry resistance value, the higher the insulation provided by the fabric system. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 3 
               
             
            
               
                   
                   
               
               
                   
                 Total Insulation 
                   
               
            
           
           
               
               
               
            
               
                   
                 R t   
                   
               
               
                   
                 (m 2  · ° C./Watt) 
                 I t  (clo) 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Sewn-thru with 
                 0.696 
                 4.489 
               
               
                   
                 stitching on center 
               
               
                   
                 without fabric 
               
               
                   
                 cover 
               
               
                   
                 Sewn-thru with 
                 0.823 
                 5.308 
               
               
                   
                 box on center 
               
               
                   
                 without fabric 
               
               
                   
                 cover 
               
               
                   
                 Baffle-box with 
                 0.772 
                 4.979 
               
               
                   
                 stitching on center 
               
               
                   
                 without fabric 
               
               
                   
                 cover 
               
               
                   
                 Baffle-box with 
                 0.787 
                 5.076 
               
               
                   
                 box on center 
               
               
                   
                 without fabric 
               
               
                   
                 cover 
               
               
                   
                 Sewn-thru with 
                 0.864 
                 5.573 
               
               
                   
                 stitching on 
               
               
                   
                 center in pillow 
               
               
                   
                 case 
               
               
                   
                 Baffle-box with 
                 0.914 
                 5.895 
               
               
                   
                 stitching on center 
               
               
                   
                 in pillow case 
               
               
                   
                   
               
            
           
         
       
     
     The general conclusions from the data comparisons were: 
     The constructions where the stitching was in the center of the plate (i.e., over the thermocouple), had slightly lower insulation values than similar constructions with the puffy thick box part in the center of the sample. 
     The baffle box construction provided more insulation than the sewn-thru region construction—particularly when each specimen was tested alone. 
     The use of a fabric cover on both sides of the specimens added insulation primarily because the thin fabric trapped still air between the top surface of the comforter specimen and the fabric (i.e., tenting effect). This minimized the differences between the types of constructions. 
     Thus, these experiments demonstrate that there is little difference between sewn-through regions and baffle box constriction in real-world conditions, i.e., when the duvet insert is used with a top sheet or the equivalent. 
     The duvet insert of the present invention may have two embodiments. The first embodiment includes down only. The second embodiment includes down and wool. The third embodiment includes down and wool in a different construction. 
     Shown in  FIG. 7  is an exploded view of the first embodiment, which is a down duvet  700  with the stitching forming the narrow channels (not shown). A top cotton shell  705  and a bottom cotton shell  720  have a piped edge  715  along all four sides. Within the top cotton shell  705  and the bottom cotton shell  720  is the duck down layer  710 . Four corner loops  725  (three are shown) are attached to the underside of the bottom cotton shell  720 . As shown in  FIG. 2 , the corner loops are designed to secure the duvet insert to a duvet cover having ties or snaps on each corner. A legal label  730  is also attached to the bottom cotton shell  720 . 
     The down-only embodiment may consist of an outer shell, piping and corner loop fabric consisting of 100% Cotton and having a 370 thread count (200×170) and a percale weave with 86 grams per square meter and 100″ roll width. 
     The details of the duck down itself may be as follows: Minimum 75% white duck down clusters (no more 3% dark clusters) and having a 600 Fill Power: +/−10% (by volume). 
     The Thread/Stitching for the shell may comprise white, 100% polyester thread with double-Needle Stitched Edge at 10 stitches per inch and Single Needle Channel Stitching having 9 stitches per inch. 
     The shell closing may be white, 100% polyester thread with poly core/poly wrap, T35 for closing duvet, T60 for cross stitching and 12 stitches per inch. 
     The piping cord may consist of 100% cotton, braided, white with a 0.125″ diameter (3 mm). 
     Shown in  FIG. 8  is an exploded view of the second embodiment, which is a wool and down duvet  800  with the stitching forming the narrow channels (not shown). A top cotton shell  805  and a bottom cotton shell  830  have a piped edge  825  along all four sides. Within the top cotton shell  805  and the bottom cotton shell  830  is the duck down layer  810 , a barrier layer  815  and a wool batting layer  820 . Four corner loops  835  (three are shown) are attached to the underside of the bottom cotton shell  830 . As shown in  FIG. 2 , the corner loops are designed to secure the duvet insert to a duvet cover having ties or snaps on each corner. A legal label  840  is also attached to the bottom cotton shell  830 . 
     Wool is a natural material that can absorb up to ⅓ of its weight in moisture vapor. Wool also has natural insulating, odor control, and anti-microbial properties. Thus, integrating a layer or prescribed area of wool inside the duvet construction offers increased humidity and temperature regulation. Other materials that are capable of moisture wicking may be used as well, such as cotton, linen, bamboo, rayon, silk and the like. 
     In the duck down and wool embodiment, the outer shell, piping &amp; corner loop fabric may consist of 100% Cotton having a 370 thread count (200×170), percale weave, 90 grams per square meter and 100″ roll width. 
     The outer shell top may be white. The outer shell bottom may be gray. 
     The shell top, piping, and corner straps may all be from the same dye lot 
     The wool batting may consist of 85% Merino Wool and 15% Low Melt Polyester, with tolerances of +/−5%. It may weigh 100 g/sq. meter +/−10 grams and have approximately ½″ (12 mm) thickness +/−10%. 
     The wool fiber diameter may be 30 micron+/−1 micron, be shrink-resist treated and having 100″ roll width. 
     The piping cord may be 100% cotton, braided, white and 0.125″ diameter (3 mm). 
     The duck down may have the following properties: 1) a minimum 90% white duck down clusters (no more 3% dark clusters); 2) 750 fill power white duck down: +/−10% (by volume). 
     The barrier fabric may consist of 100% polyester, 35 grams per square meter. 
     The Thread/Stitching for the shell may comprise white, 100% polyester thread with double-Needle Stitched Edge at 10 stitches per inch and Single Needle Channel Stitching having 9 stitches per inch. 
     The shell closing may be white, 100% polyester thread with poly core/poly wrap, T35 for closing duvet, T60 for cross stitching and 12 stitches per inch. 
     A third embodiment presents an alternative version of the down-only duvet with a separate wool layer In this third embodiment, the wool batting layer  820  is not placed within the top cotton shell  805  and a bottom cotton shell  830 . Instead the wool batting layer  820  is secured to the bottom or top of the down duvet  700  so that it is a separate layer. The securing may take place by using snaps. 
     Thus, the present invention provides the following significant benefits: 
     Sewing the majority of the stitched lines prior to filling with insulation traps less down and leads to greater insulation. If all stitching happens otherwise after filling, down is often trapped between the stitching. 
     The rectangular shaped boxes contain down better than traditional square boxes and are oriented to work and drape of a sleeping body, while preventing cold spots. 
     Calibrating the insulation value to a known room temperature/humidity levels. This will take the majority of confusion around knowing whether the duvet will be warm enough. 
     It is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein. Reference to a singular item, includes the possibility that there is a plurality of the same items present. More specifically, as used herein and in the appended claims, the singular forms “a,” “an,” “said,” and “the” include plural referents unless specifically stated otherwise. In other words, use of the articles allow for “at least one” of the subject item in the description above as well as the to be appended claims. It is further noted that the appended claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation. 
     Without the use of such exclusive terminology, the term “comprising” in the to be appended claims shall allow for the inclusion of any additional element irrespective of whether a given number of elements are enumerated in the to be appended claim, or the addition of a feature could be regarded as transforming the nature of an element set forth in the to be appended claims. Except as specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining to be appended claim validity. 
     The breadth of the present invention is not to be limited to the examples provided and/or the subject specification, but rather only by the scope of the to be appended claim language. Use of the term “invention” herein is not intended to limit the scope of the appended claims in any manner. Rather it should be recognized that the “invention” includes the many variations explicitly or implicitly described herein, including those variations that would be obvious to one of ordinary skill in the art upon reading the present specification. Further, it is not intended that any section of this specification (e.g., the Summary, Detailed Description, Abstract, Field of the Invention, etc.) be accorded special significance in describing the invention relative to another or the to be appended claims. All references cited are incorporated by reference in their entirety. Although the foregoing invention has been described in detail for purposes of clarity of understanding, it is contemplated that certain modifications may be practiced within the scope of the to be appended claims. 
     In the foregoing specification, specific embodiments have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present teachings. 
     The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued. 
     Moreover, in this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” “has”, “having,” “includes”, “including,” “contains”, “containing” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, has, includes, contains a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a”, “has . . . a”, “includes . . . a”, “contains . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises, has, includes, contains the element. The terms “a” and “an” are defined as one or more unless explicitly stated otherwise herein. The terms “substantially”, “essentially”, “approximately”, “about” or any other version thereof, are defined as being close to as understood by one of ordinary skill in the art. The term “coupled” as used herein is defined as connected, although not necessarily directly and not necessarily mechanically. A device or structure that is “configured” in a certain way is configured in at least that way, but may also be configured in ways that are not listed. 
     The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.