Energy-efficient exterior doors. How do you choose a door that will help reduce heat loss?

Energy efficiency is no longer a choice, but a necessity. In 2010, the European Parliament issued a directive stipulating that building permits are to be issued only for homes that meet high energy-efficiency standards and are also powered by renewable energy sources.

The changes were implemented gradually. The latest regulations took effect in early 2021 and brought building standards closer to passive house standards. This means that energy efficiency is now a priority in the design and construction of homes. And one of the key factors influencing this is high-quality, energy-efficient exterior doors.

Energy-efficient doors with low thermal transmittance

Energy-efficient exterior doors are those characterized by low heat transfer, and thus a high level of thermal insulation. This property is described by the heat transfer coefficient, denoted by the symbol U or Ud. It takes on different values for various parts of the house. The specific U-values for individual components of an energy-efficient building are as follows:

• maximum U-value for foundations = 0.15 W/m²K,
• maximum U-value for the basement ceiling = 0.30 W/m²K,
• maximum U-value for exterior walls = 0.25 W/m²K,
• maximum U-value for the roof = 0.2 W/m²K,
• maximum U-value for skylights = 1.3 W/m²K,
• maximum U-value for windows in exterior walls = 1.1 W/m²K,
• maximum U-value for doors = 1.3 W/m²K.

These discrepancies stem, among other things, from differences in the distribution of heat loss across the various components of the house. They are also related to the different functions of these components and the materials from which they are constructed (it is obvious that a window does not have the same thermal insulation properties as a wall).

Most heat escapes through the roof—as much as 25 to 30 percent. Slightly less, 20–25 percent, escapes through the walls and corners of the house. “From below”—through the basement and foundation—about 15 percent of thermal energy escapes. Doors and windows, on the other hand, are collectively responsible for about 20 percent of heat loss.

The lower the U-value, the warmer the house

High-quality doors should have a thermal transmittance below 1.3 W/m². This is the case with the models offered by BARAŃSKI. The U-value for our “warmest” design is only 0.7 W/m²K! These specifications significantly reduce heat loss from rooms, ensure comfort for residents during the fall and winter, and help lower heating costs.

Energy-efficient THERMO WOOD doors minimize heat loss

By comparison—for standard exterior doors, it is generally accepted that the U-value should not exceed 1.5 W/m²K, while doors with a U-value as low as 1.3 W/m²K are already considered to have good thermal insulation. Insulated exterior doors made of wood and wood-based materials have a U-value ranging from 0.9 to 1.3 W/m²K. Lower U-values indicate a very high-quality construction.

It is worth noting that some manufacturers use labeling that may confuse less attentive customers. They include U-values for individual door components in their product descriptions, rather than for the entire assembly. However, what matters most to the customer is the thermal transmittance of the complete door (the entire door leaf and frame)—and this is the primary factor they should consider when choosing a specific model.

Energy-Efficient and Burglar-Resistant Doors in One

Another issue of interest to many customers is the ability to combine energy-efficient and burglar-resistant features in a single design. BARAŃSKI offers such solutions by incorporating RC2 burglar-resistant packages even in doors with low thermal transmittance. Thanks to this, residents can enjoy both the comfort of a comfortable temperature and a peaceful night’s sleep with a sense of security.

>>See also: Which exterior doors should you choose for your home?

THERMAL TRANSMITTANCE OF BARAŃSKI EXTERIOR DOORS

1. STANDARD rebated
   U – 1.1 W/m²K
   Leaf thickness – 78 mm
   Insulation panel – 42 mm
2. THERMO WOOD rebated
   U – 0.85 W/m²K
   Door leaf thickness – 78 mm
   Insulation panel – 60 mm
3. THERMO WOOD non-rebated
   U – 0.7 W/m²K
   Door leaf thickness – 90 mm
   Insulation panel – 72 mm