U-Values indicate the amount of heat lost through glass. The lower the value the better, because it means less heat is being lost. Typical glass ranges begin around 6.0 with a single pane of glass and reaches amounts around .25 with LowE coatings, insulated glass, stainless steel spacers, and argon filled. LowE: Allows the sun’s rays to pass through the glass, while reducing the amount of heat or cooling that is lost from the interior.
A helpful article to understanding U-values can be found here.
Laminated glass is typically used on all conservatory roofs. Most building codes require glass above 12′ from finished floor to be laminated. When laminated glass is broken, it cracks and holds in place, as opposed to shattering. This is the same type of glass that is used in car windshields. The composition includes two pieces of glass which are bonded together with a PVB adhesive. Typically the laminated glass is used in conjunction with an airspace and tempered glass on the exterior for added strength.
Commonly called safety glass. This glazing is used in the walls of conservatories as it is the most durable type of glass. Household windows and doors also use tempered glass, making it the most commonly used on construction projects. The glass will withstand bumps and should the glass break, it does so into small pieces, without sharp edges.
Easy clean glass is becoming more popular in the United States. This specialty glass is aimed at reducing the time and frequency that glass requires cleaning. Pores, while not visible to the naked eye, actually capture dirt. Easy clean glass features a coating that fills these pores, to minimize dirt retention. As it rains the glass is cleaned.
Easy Clean glass is affordable, however, multiple coatings may need to be placed on a glass unit. You can place an easy clean coating and LowE coating on the glass, even if the unit is tempered or laminated.
For a detailed description of easy clean glass click here.
This glass type is used when the conservatory needs to be shaded from intense direct sunlight. A coating is applied to clear glass, which blocks the sun and causes a soft blue tint. “LowE” 340 insulated glass has a U-value of 0.25, an R-value of 4.0, a visible light transmittance of 39%, and a solar heat gain coefficient of 0.18.
LoE 272 provides a very slight green tint and assists in regulating the conservatory’s temperature, keeping it cool in the summer and warm in the winter. This is the most commonly used LowE glass. The insulated double pane version has a U-value of 0.25, an R-value of 4, a visible light transmittance of 71%, and a solar heat gain coefficient of 0.27.
LoE 366 provides the best insulation values. It helps retain the conservatory’s heat in the winter and blocks the heat in the summer. LoE 366 blocks 95% of the sun’s harmful UV rays, which will help preserve the color and composition of furnishings, draperies, and wall treatments. This insulated double pane product has a U-value of 0.24, an R-value of 4.13, a visible light transmittance of 71%, and a solar heat gain coefficient of 0.27.
LoE i89 is used in conjunction with other LowE coatings to provide better energy performance. It is ideal for higher altitudes and colder climates. A double pane LoE i89 unit delivers better thermal performance than a clear triple pane unit when combined with LoE 366. An insulated pane with i89, when combined with LoE 366, has a U-value of 0.20, a visible light transmittance of 63%, and a solar heat gain coefficient of 0.27.
While it provides spectacular views to the outdoors, a full glass conservatory may also be cause for privacy concerns. There are several options to combat these issues. One option is to use a textured glass like English Reeded or Rain. This allows natural light to still enter the room but vision is obstructed. Another option is Solera glass, which is white in color and offers thermal properties that reduce glare and achieve up to an R-20 depending upon glass selection. The glass is always a solid white and completely blocks vision from inside out and vice versa.
Historically accurate conservatories often featured leaded glass or stained glass windows with leaded grids.
In the past, lead was melted and formed into a grid pattern, then individual pieces of glass were poured into the grid. Today, faux grid designs are still used on traditional, historically accurate conservatories. Modern leaded windows use a lead grid applied to the surface of the glass; virtually any pattern can be created.
Pattern glass is created by a process called acid etching, which adds a pattern to the glass making it appear frosted or fogged. Available patterns include: Pattern 62, Rain, Single Chip, and English Reeded.
|Leaded Glass||Pattern 62||Rain||Single Chip||English Reeded|
Electrochromic (ECM) Glass
Electrochromic Glass is an energy efficient glazing selection which utilizes advanced technology. Through the use of building management systems, the glass can be tinted to provide glare and heat control while offering unobstructed views of your surroundings.
There are several manufacturers of “tintable” glass. Many of them are able to provide several predetermined tint levels
which can be automatic or manual. For electrochromic glass, zones can be created by grouping windows together for simultaneous tinting.
Pleotint offers a thermochromic glass called Suntuitive as another “tinting” glass option. This type of glass tints without the use of electricity and lightens and darkens automatically based on the ambient temperature of the glass’s surface increased by sunlight. Suntuitive provides clear views, saves energy, and reduces interior glare without the use of additional wiring or electricity.