Fiberglass doors are superior insulators and are suited for many climates — hot or cold, wet or dry. Unlike steel doors in wet climates, they are not susceptible to rust. Unlike steel, fiberglass does not transfer heat, which makes it a better choice for areas with greater seasonal fluctuations in temperature.
Steel can be an excellent option if you have security concerns. Since it's a heavy, tough material, steel entry doors are very difficult to break down. Fiberglass doors are still a pretty secure choice, but they're far more lightweight than steel and are easier to manipulate.
And steel can get hot when exposed to sunlight and high temperatures, which makes it a little less efficient than fiberglass. Verdict: While both steel and fiberglass are energy-efficient options, fiberglass outperforms steel in this area, making it a favorite door replacement option for many homeowners.
Wooden Doors
Being naturally insulating, they are excellent at retaining heat inside. For interior or external doors, a solid wood door is an excellent option for helping to keep your home warm.
Fiberglass and insulated steel exterior doors offer the best energy efficiency ratings because they're manufactured with interior cores designed to reduce energy transfer.
Steel and fiberglass front doors require the least amount of maintenance. They're made from durable materials that resist dents and scratches, with a long-lasting finish. Wood front doors require a bit more maintenance if you choose a wood exterior.
Fiberglass doors are versatile and heavy-duty. They offer nearly three times as much insulation as solid wood or wood core doors for a much higher R-value or insulation effectiveness.
Fiberglass. Fiberglass wins for the choice of the most insulative exterior door choice. While they fill a fiberglass door with foam much like a steel door, its low maintenance feature makes it superior to steel.
Fiberglass doors come with foam insulation that, combined with their durability, makes them more energy efficient than wood doors. This insulation helps to keep hot air from escaping the home in the winter, as well as preventing drafts.
A fiberglass front door is your best bet for peak energy efficiency. Fiberglass doors have an exceptionally insulating polyurethane foam core that provides a high R-value. The R-value is a standard measure of insulation effectiveness; higher numbers mean better insulation.
Steel Door Disadvantages
Denting and Rusting – While steel doors cannot warp they can be dented if hit by something, and if the paint on the door gets chipped off at the dent then rusting can develop with the metal being exposed to the moisture in the air.
Drawbacks of Fiberglass Exterior Doors
The disadvantages of fiberglass doors include: Price – While not as costly as some types of wood, fiberglass is one of the more expensive options on the market. Sizing – The material is difficult to trim, so it's not well-suited for exterior doors that aren't standard sizes.
The main price difference between steel and fiberglass doors is not in the door cost itself but in the cost of painting the door. A steel door comes factory painted white and does not have to be painted unless you want a different colour.
Fiberglass and steel doors both perform well in terms of energy efficiency. One of the biggest advantages of fiberglass doors is the cost savings they provide, thanks to their energy efficiency. Fiberglass doesn't expand and contract like some materials, thus providing excellent insulation throughout seasonal changes.
Steel provides the best long-term value in the door and frame industry. It lasts longer, requires the fewest repairs, and is sturdier than other products. Steel's natural strength also outperforms other materials in security, fire rating, sound reduction, vandal resistance, sanitation, and more.
Thanks to the insulating foam inside, a fiberglass door is typically about R-6, compared with R-2 for wood. Keep in mind, however, that adding windows—even ones with low-e glass—significantly lowers the advantage.
The R-values of most steel and fiberglass-clad entry doors range from R-5 to R-6, excluding a window. For example, a 1-1/2 inch (3.81 cm) thick door without a window offers more than five times the insulating value of a solid wood door of the same size.
You can choose from different skins and designs on the fiberglass door to create a custom look. Another plus to choosing a fiberglass door for full sun exposure is that this type of material is the best at climate control. It can withstand the California heat and keep your home cooler than other door types.
Steel exterior doors
Steel may seem like a bad option because it conducts temperature very well, however, a high-density insulating core and quality construction makes them exceptionally warm. In fact, many energy efficient doors are steel doors.
Most commercial steel doors are not insulated. A Polystyrene Core provides insulation to many steel doors. A Polyurethane Core inside steel doors offers superior insulation. Doors with a Vertically Stiffened Core have sound deadening fiberglass insulation.
Fiberglass doors are strong and durable, but they're not as fire-resistant as steel doors. They can also be damaged by ultraviolet light. Steel doors are the strongest type of door, and they're also fire-resistant. They're the best option for security and durability.
Fiberglass exterior doors are among the strongest on the market. They're also some of the most energy-efficient. Fiberglass is a poor conductor of heat, making it energy-efficient on its own, but when insulation is added, it's hard to beat.
Timber doors are naturally insulating and will always be the first choice for listed buildings and homes located in conservation areas, and multi-chambered uPVC doors will always be the first port-of-call for affordable energy efficient replacement doors.
Unlike steel, fiberglass does not transfer heat, which makes it a better choice for areas with greater seasonal fluctuations in temperature. Both materials are significantly more resilient than wood. Over time, wood withers and becomes susceptible to weather damage, whereas both steel and fiberglass doors hold up well.