Thinking of purchasing a new skylight for your home but not sure which type of skylight to choose? You have come to the right place! This skylight buyers guide will discuss and cover common questions like, what is a skylight, what types of skylights are there, how to plan a skylight’s location, what are the various glazing options, which are the most energy efficient, and more.
Installing a skylight in your home can completely change the overall character of a room by increasing the natural light potential, as well as making the room feel more spacious/open. In addition to changing the aesthetic of a room, a skylight can also help you save some money. In many cases, they will reduce the need to use electric lights, can deliver warmth in the winter and cooling in the summer, as well as minimize the need for fuel-based heating and air conditioning. On winter days, the sun will be able to shine through the skylight to help warm interior surfaces. Then during the summer, a ventilating skylight can help promote air circulation by releasing the rising warm air. The real trick to making these benefits possible is to make sure that you choose the right materials and features, as well as install the skylight in the optimal place in your home.
Types of Skylights
The first aspect to think about are the different types of skylight options that are available to you. Skylights are commonly plastic or glass and can be either fixed or operable. They also come in several different styles and sizes. They can have insulated glazing, UV-blocking capabilities, louvers, shades, and more. As previously mentioned, determining the right materials, the proper size, and the appropriate features to meet your needs is critically important. Below are a few resources to help you dial in the particular qualities that you want in your new skylight:
- Operable Skylights & Roof Window Types
- Skylight Installation
- Popular Skylight Blinds & Shades
- Tubular & Flexible Skylights
We always recommend consulting a roofing expert to help determine the best skylight options for your home.
Planning a Skylight
It is important to keep in mind that a skylight will only work in a room that is directly below the roof or is below an unfinished attic space. If you choose to install a skylight in a room that has an attic above it, you will need to build a light shaft through the attic to the roof. Furthermore, the shape of a light shaft will help determine the spread of the natural light beam.
- A shaft that’s flared on all four sides will cast light over the widest area.
- A perpendicular shaft with more vertical sides will focus the light straight down.
- A shaft flared only on one or two sides will send more light in the direction of the flared sides.
When planning your skylight installation, be sure to consider the sun’s natural path. South/West-facing skylights often capture the most direct sun, while North/East facing skylights may not gather any direct sunlight at all. Note that a skylight receiving direct sunlight can potentially become a heat trap in the summer unless it includes blinds or shades. On the other hand, a skylight placed in a bedroom can offer an amazing nighttime view of the stars but, if it doesn’t have some form of daylight shade, it will come with a bright awakening at daybreak.
The sizing and placement of a roof window calls for careful planning. Roof window manufacturers often have charts that list recommendations based on the slope of the roof. It is also important to note that a skylight intended to provide a view should be kept clean, so ease of maintenance becomes a big factor in choosing the best location and the type of skylight for your home.
Lastly, be sure that the skylight you intend to install will meet local building codes for load, wind resistance, and other related factors. Building permits are required for installation in most regions.
Glass vs Plastic Skylights
Both glass and plastic skylights come in single, double, and even triple glazing. Several manufacturers also make both glass and plastic. When choosing between the two, weight is a big factor. A 4×4 plastic skylight weighs around 65 pounds, while a 4×4 glass skylight weighs about 120 pounds.
Plastic skylights are commonly double-glazed with two plastic panes separated by an air space. As a rule of thumb, plastic skylights come molded in flat, round, bubble, pyramid, ridge-shaped, dormer, and barrel-shaped profiles, and they are usually only available in standard sizes. Plastic glazing is most often chosen in situations where light weight, durability, and price are important considerations.
Glass is generally the preferred choice for skylights given most believe it has a more elegant appearance than plastic. Glass also offers a clear view, doesn’t scratch easy, and can be ordered in a wide variety of custom sizes and types. However, the more features and customization you want, the more expensive the glazing will be.
Below is some additional information about common choices:
- Tempered, double-insulated glass:
- This is the minimum standard for most quality products – tempered for safety with two layers of glass with an air space in-between for energy efficiency.
- Tempered, double-insulated glass w/ low-emissivity coatings:
- With this glass, the outer pane is tempered, and the inner pane has an invisible low-e coating that helps hold heat in during the winter, reduces heat during the summer, and blocks ultraviolet rays – which can bleach fabrics and damage furniture and floors.
- Tempered, double-insulated glass w/ low-e coatings and an argon gas filling between panes:
- This glass is the same as the above but has a greater insulating value. Some companies even offer low-e, argon-filled glass as their standard glaze, while other manufacturers sell this as a premium option.
- Tempered, low-e, argon-filled glass w/ bronze tint:
- This features the same qualities as the above two options but is designed to reduce solar heat.
- Tempered-over-laminated, low-e, argon-filled glass:
- This was designed to eliminate the danger of interior glass breakage in areas that require laminated glass. Available with or without a bronze tint, this glaze blocks nearly all UV rays. It’s a sensible glazing for regions where the sun’s heat buildup is a problem, such as on south- and west-facing roofs in hot climates.
Most skylight manufacturers test and measure their products for heat loss, heat gain, and blockage of ultraviolet rays – measurements are expressed numerically. The following terms will be helpful to know as you shop for your new skylight:
- U-Value: Measures the rate of heat flow (from either side) through a skylight. This measurement does not include solar heat gain. The lower the U-value, the better the product resists heat flow.
- R-Value: Measures a material’s insulation value – the resistance a material has to heat flow. The higher the R-value, the better it insulates. Skylights with the best R-values have low-e insulating glass with argon gas between the panes – these yield about twice the insulating value of standard dual-glazed panes.
- Shading Coefficient: Measures solar heat gain through glass. A low shading coefficient means low solar heat gain.
- UV Blockage: The value approximated by glazing manufacturers, expressed as a percentage of ultraviolet rays blocked by the glazing.
- Visible Light Transmittance (VLT): Measurement used by manufacturers to rate the percentage of visible light a skylight transmits. When homeowners want a lot of natural light, they generally choose a high VLT value. Tinted glazing, which blocks glare by letting in less light, has lower VLT ratings.