GB2058897A

GB2058897A - Window insulation

Info

Publication number: GB2058897A
Application number: GB8030002A
Authority: GB
Original assignee: Maclean P G; Maclean R G
Current assignee: Maclean P G; Maclean R G
Priority date: 1979-09-17
Filing date: 1980-09-17
Publication date: 1981-04-15
Also published as: GB2058897B

Abstract

An insulation means for a window has a flexible translucent plastics layer of a thickness greater than 0.127 mm and preferably about 0.254 mm. The flexible layer is secured to the top rail of a window frame by a first fastening means which may be a top bar screwed to the frame or a roller mechanism. The rest of the layer is releasably secured to the frame by a filamentous hook and/or loop strip for attachment to the frame, and a filamentous hook and/or loop strip secured to the periphery of the layer so that the two strips may cooperate together. Preferably, in order to provide optimum insulation the width of the strip on the frame is about 15 mm wide and the width of the strip on the flexible layer is about 10 mm wide. <IMAGE>

Description

SPECIFICATION Window insulation This invention relates to the insulation of windows.

With the increasing expense of heating industrial and domestic premises, energy-saving is becoming much more important than previously. One form of energy-saving is preventing heat loss through windows and many types of double-glazing incorporating sealed units or secondary windows have been proposed and are in current use. However, conventional double-glazed units are extremely expensive and, on present estimates, are unlikely to pay for themselves in heat-saving terms much within twenty years. As such, particularly in industrial and commercial premises, window insulation for heat-saving is rare. A cheaper double-glazed structure was proposed in U.K. Patent Specification No.

944994, however, such an arrangement would not be suitable for larger industrial applications and we have found that in order to provide optimum insulation certain conditions should be met.

According to the present invention insulation means for a window comprises a flexible translucent layer dimensioned to cover the window and overlap an adjoining surface, first fastening means at an upper edge of the layer for permanently securing the layer to the adjoining surface and second fastening means about the periphery of the layer so that the rest of the layer may be releasably secured to the adjoining surface so as to seal about the window.

Preferably the first fastening means comprises a top bar secured to the layer and including a plurality of screw fasteners whereby the bar may be screwed into the surrounding frame.

The second fastening means may comprise a filamentous hook and/or loop strip for attachment to the frame, and a filamentous hook and/or loop strip secured to the periphery of the flexible layer so that in use the two strips cooperate together to releasably secure the layer to the window frame.

The invention also includes an insulated window unit comprising a window frame having top, bottom and side rails, a window mounted in the frame, a flexible translucent layer dimensioned to cover the window and overlap the frame and secured at the top of the window frame by a first fastening means, second fastening means in the form of filamentous hook and/or loop material secured down each side rail and along the bottom rail of the frame, and filamentous hook and/or loop material secured along the side and bottom edges of the flexible layer, the filamentous material on the frame and on the flexible layer being cooperable to secure the layer to the frame and seal about the window.The first fastening means takes the weight of the insulation means and may be a top bar secured to the layer and screwed into the top rail of the frame or alternatively the layer may be secured to the roller of a roller mechanism secured to the top rail of the window.

Preferably the filamentous material down the sides of the frame is secured to a batten providing the desired spacing between the window and the layer and also accommodating any window catches that may be provided.

The upper ends of the side battens are preferably tapered so as to ensure engagement of the layer with the filamentous material on the frame when the flexible layer is manipulated from below.

In order to store the flexible layer during non-use the layer may be rolled up and secured at the top of the frame by means of tie straps secured to the frame or by means of the roller mechanism.

This invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a plan view of a window and frame incorporating a first embodiment of insulation in accordance with the present invention; Figure 2 is a side view on arrow A in Figure 1; Figure 2a is an enlarged view of the upper fixing means; Figure 3 is a plan view of a window and frame incorporating a second embodiment of insulation in accordance with the present invention; and Figure 4 is a side view on arrow B in figure 3.

In the drawings a window 1 is mounted in a frame having top and bottom rails 2 and 3 and side rails 4. The window 1 is mounted in the frame on hinges (not shown) and is openable by means of a catch diagrammatically indicated 5. In order to insulate the window both with respect to heat loss from within and, less importantly, noise, the window is covered by a flexible transparent layer 6.

The layer 6 is secured to the top rail 2 of the window frame by means of a first fastening means in the form of a bar 7, suitably of PERSPEX (Registered Trade Mark); the bar 7 being secured to the frame by screw-fasteners 8. The layer 6 is designed to cover the window 1 and overlap the adjoining frame and, in the illustrated case, is of rectangular form. The bottom of the layer 6 is secured to the underside of a second pear-shaped bar 9, also suitably of PERSPEX material.

Disposed along the sides and bottom of the layer 6, confronting the window frame, is a continuous strip 10 of filamentous hook and/or loop material, suitably VELCRO material (Registered Trade Mark) of at least 5 mm width and preferably 10 mm. The strip 10 is secured to the layer 6 by flame-proof adhesive and stitching (not shown). In order to engage with the window frame a corresponding strip 1 1 (figure 2) of filamentous hook and/or loop material, suitably VELCRO, is secured to the window frame and arranged to as to be engageably with the strip 10. The strip 1 1 may be the same as strip 10 but is preferably wider in order to aid location, preferably the strip 1 1 is of 15 mm width.

As seen from figure 2 the strip 1 is preferably secured to the top of side battens 12 which space the layer 6 from the window 1 to give the desired spacing and also to accommodate the catch 5. The side battens 12, at least at their upper ends, may be tapered (not shown) so as to ensure engagement of the strips 10 and 1 1 when manipulated by a user from below. The side battens 12 are secured to the frame by adhesive and pins (not shown).

Secured to the top rail 2 of the frame by the bar 7 are three short VELCRO straps 13 which may be used to secure the layer 6 when not in use as will be explained in more detail below.

As seen clearly from figures 2 and 2a the layer 6 passes completely around the top and bottom bars 7 and 9 and is secured by stitching. The top bar 7 is secured to the frame by the screw fasteners 8 which also serve to retain straps 13 as well as having a head portion 14 which provides a clip location for fixing studs 1 5 on the end of each strap 13.

In addition, in order to permit partial ventilation, opposed VELCRO strip portions 16 are provided on the outside of the layer 6 so that the layer may be retained in an intermediate position.

Figures 3 and 4 illustrate an alternative embodiment which is really only suitable for smaller windows. The main difference lies in the first fastening means and therefore, for simplicity, the other corresponding parts are given the same references. In this embodiment the first fastening means for securing the layer to the top rail 2 of the frame comprises a roller mechanism 1 7. The roller mechanism 17 is of conventional construction and comprises a spring biassed lockable roller 18 to which the layer 6 is attached either by stitching and adhesive or by spring clips, orty double-sided adhesive tape. The roller 18 is supported in end fixing members 19 which are secured to the adjacent frame by screw fasteners.

In use, particularly in winter or cold conditions, the insulation layer 6 is positioned as shown.

However, should some ventilation be desired then, because the layer 6 is flexible, either the bar 9 can be moved upwardly and secured by cooperating VELCRO strips at a position spaced from the bottom of the window thus leaving a ventilation gap in the first embodiment or the roller of the second embodiment operated to partially retract the layer. When not required the layer 6 is either simply rolled up on the bar 9 and the rolled layer secured at the top of the window by means of the VELCRO straps 1 3 or the roller operated to completely retract the layer.

Although the layer 6 is preferably transparent it may be tinted or arranged only to let light through rather than being see-through. Also, although it is preferred to use filamentous hook and/or loop material, other fastening means may be provided to seal about the sides of the layer e.g.: slide fasteners.

As explained above in order to achieve optimum insulation properties we have found that it is preferable that the insulation layer and VELCRO strips have certain dimensions i.e.: that the VELCRO strips be greater than 5 mm in width and also that the plastics material from which the layer is made be greater than 0.127 mm and preferably about 0.254 mm.

For example by experiment we have made a heat loss comparison between conventional singleglazing and double-glazing and our insulation means constructed in accordance with the embodiment of figures 1 and 2 having a layer thickness of 0.254 mm, a 6 mm airspace, a VELCRO strip width on the frame of 15 mm and a VELCRO strip width on the layer of 10 mm. The results of our experiment were as follows: The accepted manner of calculating the heat loss through any structure is by use of the following formula: Heat Loss = U.A.AT.

where, heat loss is expressed in watts A is the area of the material being considered AT is the temperature difference across the material being considered in C 'U' is an empirical figure determined experimentally and is expressed in watts/m20C.

1 R where R = the resistance to heat flow of each component of the structure.

The latter is commonly know as the 'U' value. The 'U' value gives a direct indication of the heat loss through a structure. Comparison of 'U' values for differing structures gives an assessment of their relative heat losses.

If the 'U' value of a composite structure is required, it can be determined by adding the factors for the various components of the structure to obtain an overall 'U' value.

'U' values and factors for components are all listed in the C.l.B.S. standard reference books (Chartered Institution of Building Services). These values are accepted as being the design figures for consulting Engineers practising in this country.

From the C.l.B.S. guide book we can find directly the following figures: typical 'U' value for single-glazing 5.6 W/M20C typical 'U' value for double-glazing consisting of a sealed unit of 6 mm glass, 6 mm air space and 6 mm glass 3.4 W/M2 In order to calculate the 'U' value of the insulation means of the present invention it is built up as follows: outside surface resistance R = 0.55 M20C/W 1 mm glass resistance R=O.O038 M20C/W air space resistance R = 0.09 M20C/W insulating material resistance R = 0.0086 M20C/W inside surface resistance R=0.123 M2 C/W I:R = .2804 = 3.57 W/M20C say =3.6 W/M20C Thus, the respective 'U' values can now be compared as follows: : single glass 5.6 W/M20C double-glazing 6 mm glass + 6 mm gap + 6 mm glass 3.4 W/M20C single glass + insulating means in accordance with the invention. 3.6 W/M20C Compared to single-glazing the insulating means will save 35.7% of the heat loss. Double-glazing compared to single-glazing will save 39% of the heat loss and therefore single-glazing plus the insulating means of the present invention is 91.5% as efficient as double, sealed glazing.

Although the invention has been particularly described with reference to an existing window in the case of rebated windows, or small windows it may be that an extra frame will be required to provide the necessary supporting surface.

Claims

1. An insulation means for a window comprising a flexible translucent layer dimensioned to cover the window and overlap an adjoining surface, first fastening means at an upper edge of the layer for permanently securing the layer to the adjoining surface, and second fastening means about the periphery of the layer so that the rest of the layer may be releasably secured to the adjoining surface so as to seal about the-window.

2. An insulation means according to claim 1 wherein the first fastening means comprises an elongate bar secured to the layer and including a plurality of screw fasteners whereby the bar may be secured to the adjoining surface.

3. An insulation means according to claim 1 wherein the first fastening means comprises a roller mechanism adapted to be secured to the adjoining surface and having a roller to which the layer is secured.

4. Insulation means according to claim 1 wherein the fastening means comprises a filamentous hook and/or loop strip for attachment to the frame, and a filamentous hook and/or loop strip secured to the periphery of the flexible layer so that in use the two strips cooperate together to secure the layer to the window frame.

5. Insulation means according to claim 4 wherein the width of the strips of filamentous hook and/or loop material is at least 5 mm.

6. Insulation means according to any one of the preceding claims wherein the layer is plastics material having a thickness of at least 0.127 mm.

7. An insulated window unit comprising a window frame having top, bottom and side rails, a window mounted in the frame, a flexible translucent layer dimensioned to cover the window and overlap the frame and secured at the top rail of the window frame by a first fastening means, and second fastening means comprising filamentous hook and/or loop material secured down each side rail and along the bottom rail of the frame, and filamentous hook and/or loop material secured along the side and bottom edges of the flexible layer, the filamentous material on the frame and on the flexible layer being cooperable to secure the layer to the frame and seal about the window.

8. An insulated window unit according to claim 7 wherein the thickness of the layer is at least 0.127 mm and the width of the filamentous hook and/or loop material on the layer and on the frame is at least 5 mm.

9. An insulated window unit according to claim 7 wherein the thickness of the layer is 0.254 mm, the width of the filamentous hook and/or loop material on the frame is 1 5 mm. and the width of the filamentous hook and/or loop material on the layer is 10 mm.

10. An insulated window unit according to any of claims 7 to 9 wherein the filamentous material down the sides of the frame is secured to a batten providing the desired spacing between the window and the layer and also accommodating any window catches that may be provided.

11. An insulated window unit according to claim 10 wherein the upper ends of the side battens are tapered so as to ensure engagement of the layer with the filamentous material on the frame when the flexible layer is manipulated from below.

12. An insulated window unit according to any one of claims 7 to 1 1 wherein first fastening means comprises an elongate bar secured to the flexible layer and fixed to the frame by screw fasteners, the flexible layer, during non-use being rolled up and secure to the top of the frame by means of the tie straps secured between the frame and the elongate bar.

13. An insulated window unit according to any one of claims 7 to 1 1 wherein the first fastening means comprises a roller mechanism secured to the frame, the flexible layer, during non-use, being rolled up and secured at the top of the frame by the roller mechanism.

14. An insulation means for a window substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.