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What Is a Thermal Break in a Window or Door?


Thanks to the steep rise in energy bills, coupled with the push for eco-friendly living, improving your home's insulation has become more important than ever.

A well-insulated home is far better at trapping the heat in during winter and keeping it out during summer, meaning you don't need to run your heating or air conditioning for as long. Not only does this cut down on your energy bills, but it also shrinks your home's carbon footprint - a win for both you and the planet!

That's why most modern doors and windows are designed with energy-efficiency in mind. Aside from being manufactured from highly insulated materials like uPVC and aluminium, they incorporate another technology to increase their insulation even more: thermal breaks!

Thermal breaks help meet higher standards for insulation and reduce the overall energy consumption of your home, but what actually are they? Well, that's what we're here to explore today.

At Alimax, we manufacture high-quality, energy-efficient aluminium doors and windows for both trade and residential customers. Below, we explore what thermal breaks are, how they work, and their key benefits.

What Is a Thermal Break in a Window or Door?

Put simply, a thermal break is a design feature that helps prevent the direct transfer of heat or cold between the inside and outside portions of the frame. It's particularly important in reducing the U-value of a window or door.

What Are Thermal Breaks Made Of?

A thermal break is a non-conductive material inserted between the interior and exterior sections of the frame. This material acts as a barrier, reducing the direct conduction of temperature and helping to maintain a more stable indoor climate. Windows and doors with thermal breaks are commonly referred to as thermally broken windows or doors.

Two common types of materials used for thermal breaks are:

  • Polyurethane: Polyurethane is a versatile polymer that can be formulated to have excellent thermal insulation properties. It is often used as a thermal break material in the construction industry due to its low thermal conductivity.
  • Polyamide (Nylon): Polyamide, commonly known as nylon, is another material used for thermal breaks. It is lightweight, durable, and has good thermal insulating properties. Polyamide thermal breaks are often used in aluminium window and door frames.

The specific choice of material may depend on factors such as the application, structural requirements, and local building codes.

What Are the Benefits of Thermal Breaks?

There are plenty of reasons why thermal breaks are employed. Here are some of the key ones:

  • Thermal breaks help reduce heat transfer between the interior and exterior of a building. By interrupting the thermal bridge, they minimise the exchange of heat, which can lead to more efficient heating and cooling systems and, consequently, lower energy consumption.
  • In areas with temperature differentials, condensation can occur when warm and cold surfaces meet. Thermal breaks help prevent condensation by minimising the temperature differences across the building envelope, reducing the risk of moisture-related issues such as mould growth and material degradation.
  • Improved thermal insulation contributes to a more comfortable indoor environment. By minimising heat transfer, thermal breaks help maintain consistent temperatures within a building, reducing the need for excessive heating or cooling.
  • Thermal breaks can improve the long-term durability of building components by reducing the impact of thermal stress on materials. This can result in less expansion and contraction, leading to a longer lifespan for windows, doors, and other structures.

Trust Alimax for High-Quality, Thermally Broken Aluminium Doors and Windows

Alimax are Dorset and Hampshire's number one suppliers of thermally efficient aluminium windows and doors. Thanks to our years of expertise, we're able to offer:

  • A-rated energy performance with market-leading U-values to reduce bills
  • Custom-designed frames guaranteed to fit each property flawlessly
  • Advanced weatherproofing and security to protect homes
  • Lead times starting from just 10 days
  • Fully assembled windows and doors up to 7 x 3 m for easy installation

When you need stunning, energy-efficient aluminium windows and doors to impress your customers, Alimax delivers the quality you're hoping for. Get a quote online, call us on 01425 205465, or visit our Fordingbridge showroom to get started today!