RENSHADE – SUMMER AND WINTER BENEFITS Aug 2011
Please view http://www.concertinafoilbatts.com/renshade.htm
RENSHADE is designed for use on internal surfaces of windows and under transparent roofing or skylights.
RENSHADE with airspaces stops approximately 85% of all incoming radiation. This is by either 97%
reflection outwards as well as 3% low re-radiation/emission inwards, allowing for holes constituting
11% of the surface area.
It is not essential for a clear airspace to exist between the glass and the RENSHADE – the inward surface
always functions independently because it always has a clear airspace facing into the room. The ideal
minimum width airspace for vertical foil surfaces is 20mm.
RENSHADE can be made into Holland Blinds but we do not organize this, rather we sell the base material
alone to the blind manufacturers who deal direct with customers. Perfectly functioning chain driven blinds
are on display at our showroom in Cheltenham - and they really work well. Blinds are the ultimate
application because the view and amount of light can be controlled.
RENSHADE is paper-based double-sided foil laminate, not a flexible fabric and will have a potentially
long life as blinds so long as handling is minimized.
99% of sales to date have been for direct velcro application to inside of glazing.
Results: greatly reduced incoming summer heat, no glare, view is maintained and significantly reduced
cooling costs. RENSHADE is not an external use sun shield. It is ideal for protected use applications,
namely fixed (by velcro) against inside glazing, under skylights and stapled beneath transparent roofing.
One of the best RENSHADE velcro applications is when combined with slim-line venetian blinds producing
attractive optical variations throughout the day while the RENSHADE is largely hidden and obscured.
A successful result was achieved at Brunswick South-west Primary School(Melbourne) in Nov 2003 with
RENSHADE fixed directly to inside of windows (4.5m high ceilings) with velcro, which was commented in
the Community Power News write-up Spring 2004. Air-conditioning as well as external blinds were cost
prohibitive and so RENSHADE blinds were first considered but we advised this would be unsuitable
long term as damage would readily happen in a school environment.
In this school application RENSHADE fixed to glass will remain permanently in place for all of the year,
and wintertime would let less light in but electric lighting remains on regardless in institutional buildings –
winter or summer. RENSHADE fixed to glass will very easily be the cheapest option for residential,
commercial or institutional buildings and the summer benefit is quite literally enormous.
The news articles http://www.concertinafoilbatts.com/press.htm provide further background to why incoming
radiation must be identified and stopped. Aluminium insulations such as RENSHADE,
CONCERTINA FOIL BATTS and conventional roll foils do this. For comfort in hot climates, these foil
insulation products combined with natural ventilation and air movement by ceiling fans will often be
sufficient with the avoidance of expensive refrigerative air-conditioning. The key step is to remove the
sources of incoming radiation.
RENSHADE testimonial letters and data files can be viewed: http://www.concertinafoilbatts.com/renshade.htm
RENSHADE - WINTER HEAT RETENTION
RENSHADE will have an impact in keeping in winter heat. We predict that if the RENSHADE was left in
place for the duration of winter, then heavy drapes would not be needed for either summer or winter - and
then a lightweight blind, curtain or drape may be sufficient, eg venetian or vertical tilting blinds, sheer fabric.
We expect what is happening with winter heat is that there is an 11% surface area of holes and each hole
is 2mm wide. It might just be that convected heat cannot make sufficient contact to the cold glass. If some
type of blind exists, then a reflective airspace has been formed which will have thermal resistance.
Aluminium backed drapes (which still exist on the market and are very expensive) also create greater
thermal value than if there was no aluminium present. Trapped airspaces create insulation. Still airspaces
are more effective than ones with air movement, and still reflective aluminium airspaces have greater
Vertical foil airspaces are known to have approximately the same thermal resistance
HEAT FLOW IN(summer) or HEAT FLOW OUT(winter). So if the RENSHADE works in summer, then it
must also be working in winter. But the RENSHADE was invented so as to be in place for the duration of
summer and in many cases removed in winter. However, if made into Holland Blinds and combined with
well fitting drapes, logically there will be aluminium foil airspaces on either side of the RENSHADE with
more thermal value than if it were just RENSHADE stuck to the glass with velcro with one airspace - but an
airspace against the glass is not essential.
It is a complicated technical subject, but the existence of the RENSHADE foil will enhance thermal resistance
of the window, with or without an additional drape or curtain, in either summer or winter.