azmater.com Vacuum insulated glass provides superior thermal insulation and reduces heat transfer significantly compared to low emissivity glass in skylight applications. Low emissivity glass primarily minimizes infrared radiation while still allowing some heat loss, making vacuum insulated glass more energy-efficient for temperature control.
Table of Comparison
| Feature | Vacuum Insulated Glass (VIG) | Low Emissivity Glass (Low-E) |
|---|---|---|
| Insulation Performance (U-Value) | 0.4 - 0.6 W/m2K (Superior thermal insulation) | 1.0 - 1.5 W/m2K (Good thermal insulation) |
| Solar Heat Gain Coefficient (SHGC) | 0.25 - 0.35 (Reduces heat transfer) | 0.2 - 0.4 (Optimizes solar control) |
| Thickness | 6 - 8 mm (Thin profile for skylights) | >= 4 mm (Standard thickness) |
| Weight | Lightweight due to vacuum layer | Heavier due to multiple coatings |
| Durability | Highly durable, resistant to thermal stress | Durable, slight risk of coating degradation over time |
| Cost | Higher upfront cost | Moderate cost |
| Ideal Use | Energy-efficient skylights requiring maximum insulation | Skylights with focus on solar control and UV protection |
Introduction to Skylight Glazing Options
Skylight glazing options primarily include vacuum insulated glass (VIG) and low emissivity (Low-E) glass, each designed to enhance energy efficiency and comfort. Vacuum insulated glass offers superior thermal insulation by eliminating heat transfer through a vacuum layer, significantly reducing energy loss. Low-E glass features a microscopically thin coating that reflects infrared energy, maintaining indoor temperature while maximizing natural light transmission.
What is Vacuum Insulated Glass?
Vacuum insulated glass (VIG) consists of two glass panes separated by a narrow vacuum space to eliminate conductive and convective heat transfer, providing superior thermal insulation compared to low emissivity (Low-E) glass. This advanced glazing technology minimizes heat loss and solar heat gain, making it highly effective for skylights in both residential and commercial buildings. VIG's vacuum layer enhances energy efficiency and reduces condensation, offering better performance in maintaining indoor comfort and lowering energy costs than conventional Low-E glass.
What is Low Emissivity (Low-E) Glass?
Low Emissivity (Low-E) glass is coated with a microscopically thin, transparent layer that reflects infrared energy while allowing visible light to pass through, enhancing thermal insulation in skylights. Unlike vacuum insulated glass, which relies on a vacuum layer to minimize heat transfer, Low-E glass reduces heat loss by controlling radiant heat flow, improving energy efficiency and comfort. This technology significantly reduces UV rays and solar heat gain, making Low-E glass ideal for maintaining temperature balance in skylight applications.
Thermal Performance Comparison
Vacuum insulated glass (VIG) offers superior thermal performance for skylights by creating an almost complete vacuum between panes, significantly reducing heat transfer and enhancing energy efficiency. Low emissivity (Low-E) glass improves thermal insulation by reflecting infrared radiation while allowing visible light, but it still relies on a gas-filled gap, resulting in higher U-values compared to VIG. In comparative studies, VIG typically achieves U-values as low as 0.3 W/m2K, outperforming Low-E glass systems which usually range from 1.0 to 2.0 W/m2K, making VIG the preferred choice for maximizing thermal insulation in skylight applications.
Energy Efficiency Benefits
Vacuum insulated glass provides superior thermal insulation by eliminating conductive and convective heat transfer, significantly reducing heat loss compared to low emissivity glass, which primarily minimizes radiant heat transfer through a reflective coating. Skylights fitted with vacuum insulated glass achieve higher energy efficiency by maintaining indoor temperature stability, leading to lower heating and cooling costs. Although low emissivity glass enhances energy performance by reflecting infrared radiation, vacuum insulated glass offers a more comprehensive solution for energy savings in skylight applications.
Daylight Transmission and Visual Comfort
Vacuum insulated glass (VIG) offers superior thermal insulation with high daylight transmission, allowing abundant natural light while minimizing heat loss, enhancing visual comfort in skylights. Low emissivity (Low-E) glass reduces infrared heat transfer by reflecting radiant heat, but may slightly reduce visible light transmission compared to VIG, potentially affecting daylight quality and visual comfort. For skylights prioritizing maximum daylight transmission and balanced thermal performance, VIG provides better visual comfort due to clearer views and less glare than Low-E glass.
Durability and Lifespan of Each Glass Type
Vacuum insulated glass (VIG) offers superior durability with its robust construction that resists moisture ingress and maintains a stable vacuum, ensuring a lifespan often exceeding 25 years without significant performance degradation. Low emissivity (Low-E) glass features a thin metallic coating that enhances energy efficiency but can be more susceptible to coating wear and environmental damage over time, typically lasting around 15 to 20 years under normal conditions. For skylight applications, VIG's extended longevity and resistance to thermal stress make it a more durable choice compared to Low-E glass, which may require more frequent maintenance or replacement to sustain optimal performance.
Cost Analysis and Return on Investment
Vacuum insulated glass (VIG) for skylights offers superior thermal performance with R-values often exceeding 10, reducing heating and cooling costs significantly, but comes with higher upfront costs typically 3 to 5 times that of low emissivity (Low-E) glass. Low-E glass, costing less initially, provides moderate energy savings by reflecting infrared radiation, which results in a faster return on investment for budget-conscious projects. When evaluating total cost of ownership, VIG can yield greater long-term savings and increased property value despite its premium price, whereas Low-E glass balances affordability and efficiency with quicker payback periods.
Installation Considerations for Skylights
Vacuum insulated glass (VIG) for skylights requires precise framing and sealing techniques to maintain the vacuum seal and ensure thermal performance, demanding expert installation to avoid compromising insulation. Low emissivity (Low-E) glass is easier to install using standard skylight frames, but special attention to orientation and spacing within the frame is necessary to maximize energy efficiency. Proper installation of both types must consider load-bearing capacity and weatherproofing to prevent air and moisture infiltration, which can impact skylight durability and performance.
Choosing the Best Glass for Your Skylight
Vacuum insulated glass (VIG) offers superior thermal insulation by creating a vacuum layer that minimizes heat transfer, making it ideal for skylights in extreme climates. Low emissivity (Low-E) glass features a microscopically thin coating that reflects infrared heat, improving energy efficiency while allowing natural light to pass through. Selecting the best glass for your skylight depends on factors like climate, energy savings goals, and budget, with VIG providing the highest insulation and Low-E glass balancing cost and performance.
Infographic: Vacuum insulated glass vs Low emissivity glass for Skylight