You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
FIELD OF THE INVENTION 
     This invention relates to portable toilet accessories. 
     Portable toilets are used extensively on construction sites and for special events such as parties, etc. 
     One problem with portable toilets is that they can become very cold to use during the winter and the contents of the holding tank freezes in the cold weather. A heater can be supplied with the portable toilet but, due to the usual construction of the toilet, the heat readily escapes therefrom. The portable toilet is usually manufactured with a front wall, including a door, a rear wall, two opposite side walls, a top and a floor for standing on. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided an insulating cover for a portable toilet. 
     In one arrangement the cover comprises a front panel of insulating material cut to the size and shape of the front wall of the portable toilet; a rear panel of insulating material cut to the size and shape of the rear wall of the portable toilet; a plurality of side panels of insulating material each cut to the size and shape of a respective side of the portable toilet; and a roof panel of insulating material cut to the size and shape of a top of the portable toilet. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which: 
     FIG. 1 is a front view of a front insulating panel according to one embodiment of the invention; 
     FIG. 2 is a view of a rear insulating panel; 
     FIG. 3 is a view of a side insulating panel; 
     FIG. 4 is a view of a roof panel; 
     FIG. 5 is a view of the open bottom of the portable toilet cover; 
     FIG. 6 is a cross-sectional view of part of a panel to show the construction thereof; and 
     FIG. 7 is a perspective view of a second embodiment of the invention. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIG. 1, the front panel  2  is of approximately rectangular shape when viewed from the front with a rounded top  4 . A door opening  6  is cut in the front panel  2 . 
     All the panels in FIGS. 1 to  4  are constructed of bonded polyester insulation material  8  (FIG.  6 ). 
     All the panels in FIGS. 1 to  4  are constructed of bonded polyester insulation material  8  (FIG. 6) covered with polyethylene material  10  attached to both surfaces with adhesive. The polyethylene material  10  consists of high-density polyethylene tapes coated with low-density polyethylene on both sides of the tapes. This material contains U.V. inhibitors and is well suited for outdoor applications. 
     The door opening  6  (FIG. 1) is cut and trimmed with pieces of the polyethylene  10 . A gender cardholder  12 , as well as a nameplate  14 , is sewn to the front panel  2 . 
     A door handle hole  16 , or door pull hole, is cut and sewn in place as shown in FIG.  1 . The lower edge of the panel  2  is trimmed and two tie loops  20  are installed. Snap fasteners  18  are installed to attach portions of the front panel  2  to the door  5  and frame  7  of the portable toilet  38  (FIG.  7 ). 
     The two side panels  22 , as shown in FIG. 3, are cut and sandwiched with glue and insulation (sandwich combination FIG. 6) as was the front panel  2 . A window frame is cut and sewn whilst a clear, 30 mil. U.V. resistant PVC window  24  is sewn in place. If the particular model of portable toilet to be covered does not have windows or vents this step is omitted. The lower edge of panel  22  is trimmed. 
     The rear panel  26  of FIG. 2 is cut from the insulated combination (FIG. 6) and constructed as described above. The lower edge of the panel  26  is trimmed and three tie loops  28  (see FIG. 5) are installed at the rear. 
     The roof panel  30  (FIG. 4) is cut and Constructed with the insulated combination (FIG. 6) as described above. A vent hole  32  is located in position and a circular pattern sewn but not cut out. The customer will cut this out for ventilation if required. 
     During assembly of the portable toilet cover, the roof panel  30  and side panels  22  are attached by sewing them together. The front panel  2  and rear panel  26  are then sewn to the side panels  22  and the roof panel  30 . 
     A rope attachment  34  is threaded through the loops  20  and  28  as shown in FIG. 5 to attach the cover to the portable toilet. 
     In FIG. 7 a second embodiment of the invention is illustrated. This comprises an insulating quilted cover  36  for fitting around and over the portable toilet  38  with appropriate openings and flaps. A quilted, or other cover, could also be used in combination with the panels of FIGS. 1 to  4 . 
     It will be appreciated that the fastening of the door  6  (FIG. 1) can be by any mechanical means, such as the snaps  18  in FIG. 1, VELCRO* (hook and loop), ¼ turn buttons, lift the dot fasteners, snap lock buttons (TENAX*) etc. All these are two (2), three (3), or four (4) part holding mechanisms. They can be glued, riveted or screwed to the door frame and the door. 
     * Trademark  
     In addition to the insulated cover, high-density Styrofoam* may be placed below the portable toilet floor. This material, typically two inches thick, is cut to size depending on the model of the portable toilet. 
     The rope  34  (FIG. 5) on the bottom of the portable toilet cover has two uses. First, for securing the insulated cover itself to the portable toilet. The second use for the rope  34  is to secure the high-density Styrofoam* insulation as described above. 
     From the above it will be seen that the described embodiments enable a portable toilet to maintain warmth even during winter months. The structure of the existing toilet, in use, forms the contour of the cover. It is placed over the toilet hut and is snapped to the existing door and frame. Tie loops located on the lower edge of the front and rear panels are fastened to each other under the portable toilet, securing the cover in place. The insulated covers provide a way for contractors to meet existing regulations, such as in Canada, Section 29.1(1) of the Ontario Occupational Health and Safety Act and regulations, requiring the units to be adequately heated. 
     It will be readily apparent to a person skilled in the art that a number of variations and modifications can be made without departing from the true spirit of the invention which will now be pointed out in the appended claims. 
     *Trademark

Summary:
An insulating cover for a portable toilet as used on construction sites and for outdoor events is described. In one arrangement insulating panels are fastened around the portable toilet to reduce the escape of heat therefrom.