WHY USE HEAT MIRROR™
HIGH-PERFORMANCE GLAZING IN
SLOPED GLAZING & SKYLIGHTS?

The purpose of a skylight is to add natural daylight and enhance the aesthetics of the interior of a building.

1. Heat Mirror provides the  highest  daylight  to  solar  control  ratio of any product on the market. Heat Mirror has seven shading products that can control heat gain without the use of dark or reflective glass.  These products are so effective, that tinted glass is combined with them mainly to reduce glare, as Heat Mirror with clear glass, will dramatically control heat gain.
   
   
2. Minimum deterioration of insulation value between vertical and sloped applications.  When insulating glass is tilted, it becomes a solar collector.  The U-value then deteriorates because of increased convection within the air space.  Since the Heat Mirror technology creates two small air spaces instead of one large one, this convection loop is short circuited; and the U-value remains close to that of the vertical glass (see following pages).
   
   
3. On new construction, the use of Heat Mirror should enable the Mechanical Engineer to downsize the mechanical HVAC system thus offsetting the cost of using energy-efficient glass. Some utility companies also offer up-front rebates that off-set cost of the glass.
   
   
4. Lower the cost for energy used to heat and cool the building. Due to the use of Heat Mirror total performance glass, owners should realize significant savings in energy costs..
   
   
5. Since Heat Mirror provides a high level of natural daylight while providing a stable climate under the skylights, plant growth is promoted.  This is significant whether specimen plants are used for botanical gardens or merely to provide a pleasant atmosphere within the building.
   
   
6. The use of Heat Mirror results in a significant reduction or total elimination of harmful interior condensation.  Since Heat Mirror provides outstanding winter insulation, a much higher level of humidity can be tolerated within the building before condensation forms.
   
   
7. All Heat Mirror architectural products block more harmful ultraviolet than any other similar products on the market.  It is a significant factor in reducing the rate of fading and controlling damage due to ultraviolet radiation.
   
   
8. Heat Mirror glazing is compatible with all commercial skylight systems.  Heat Mirror is basically double insulating glass with a suspended, coated film in the middle.  The standard polyurethane-sealed units are used in four-sided capture window systems.  If the job is to be butt or structurally glazed, this fact must be noted on the specification in order that the proper silicone sealant will be used in fabrication.
   
   
9. When  a  monolithic glazing system is required and/or when a good U-value/R-value is not critical, the use of Southwall's California Series® laminated product would be appropriate.

Conventional Insulated Glass - VERTICAL GLAZING Thermal convection in vertical insulated units forms a long, slow loop as warm air rises along the interior lite. Due to the long thermal loop, convective heat transfer is not a major determinate of vertical unit performance. Therefore, vertical units attain higher R-values using radiation (Heat Mirror or Low-e coating) or conduction (inert gas or increased unit thickness) barriers to heat transfer.

Conventional Insulated Glass - SLOPED GLAZING Warm air rising within a sloped glass unit quickly hits the colder outer lite, creating a thermal short circuit of I" or less. These numerous, small, rapid thermal currents cause convection to become the dominate heat transfer force within the sloped unit. Radiation and conduction heat barriers become ineffective in sloped conditions, causing gas-filled low-e units to lose most of their insulating capabilities in skylight applications.

SLOPED HEAT MIRROR™ Insulated Glass Heat Mirror units contain a convection barrier midway within the unit designed to block thermal convection currents. This allows Heat Mirror insulated glass units to attain the highest insulation R-values - even when used in demanding skylight applications. (Heat Mirror units also contain radiation and conduction barriers, however these are relatively inconsequential for skylight applications due to the same limitations that affect gas-filled low-e units.)

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