Heat Transmitting Windows – How Do They Work?

Every homeowner understands that windows are more than just aesthetic features that allow us to enjoy scenic views or let in natural light. They play a key role in the energy efficiency of a building. But how exactly do these windows work, especially when transmitting heat? Understanding the principles upon which energy-efficient windows are built is crucial if you are looking for new replacement windows for your home that will bring warmth and savings in the long run. Let’s begin!

Understanding Heat Transmitting Coefficient

At the heart of understanding heat-transmitting windows is the concept of the Heat Transmitting Coefficient, often referred to as the U-factor or U-value. This coefficient measures how well a window insulates. Specifically, it gauges the rate at which heat transfers through a window. The lower the U-factor, the better the window insulates and prevents heat transfer.

Windows are complex structures comprising various components like the frame, glazing, sash, and sill. Each of these components can influence the overall U-factor of the window. For instance, the type of glazing (single, double, or triple-pane) or the presence of special coatings can significantly impact the window’s insulating properties.

Mechanisms of Heat Transfer

Heat transfer through windows is not a singular process but a combination of several mechanisms:

  1. Thermal Radiation: Every object emits energy in the form of radiation. In windows, this radiation can either be absorbed, reflected, or transmitted, depending on the properties of the window materials.
  2. Conduction: This is the process where heat moves through a solid material. In the context of windows, it refers to how heat travels through the window’s frame and glazing.
  3. Convection: As the air heats up, it becomes less dense and rises, while cooler air sinks. This air movement can cause heat to circulate around a window, leading to heat loss or gain.
  4. Air Leakage: Gaps or cracks in windows can allow air to flow in and out, leading to heat loss in winter and heat gain in summer.

Heat, in its essence, is energy. That’s why windows that do well with preserving heat are interchangeably called energy-efficient windows. Overall, investing in windows, front doors, and patio doors is an excellent investment for homeowners because it leads to better thermal performance of the entire building. In the next section, we will explain the benefits of choosing energy-efficient housing and how, at OKNOPLAST, we combined technology with stellar design.

Benefit Description
Reduced Energy Costs Energy-efficient homes require less energy to heat in the winter and cool in the summer, leading to significant savings on energy bills. Energy-efficient windows and doors prevent heat from escaping during cold months and block excessive heat during warmer months, ensuring optimal operation of heating and cooling systems.
Enhanced Comfort Energy-efficient homes offer consistent indoor temperatures, eliminating cold drafts in the winter or excessive heat in the summer. This creates a cozy and comfortable living environment year-round.
Positive Environmental Impact By reducing the amount of energy consumed, energy-efficient homes contribute to reduced greenhouse gas emissions, leading to a smaller carbon footprint and promoting a sustainable future.
Increased Property Value Homes with energy-efficient features, especially windows and doors, often have higher market value. As energy costs rise and environmental concerns grow, homebuyers increasingly value properties, prioritizing energy efficiency.
Impact on Annual Spending The benefits of energy efficiency extend beyond monthly savings. Over the course of a year, energy-efficient windows and doors can lead to substantial savings on heating and cooling costs, positively impacting homeowners’ annual spending.

Pava window - Oknoplast

Energy Efficient Windows by OKNOPLAST

At OKNOPLAST, we consistently deliver windows that combine beauty with advanced technology. Let’s explore the thermal insulation properties of our main uPVC systems.

PIXEL: Modern Design Meets Thermal Excellence

  • Maximized Thermal Efficiency: PIXEL windows are designed to keep homes comfortable throughout the year. Their unique design, which includes a floating mullion and a reduced sash height, enhances room illumination and heating. When equipped with a triple glazing package and a Warmatec spacer bar, these windows achieve a U Factor of 0.16, showcasing their commitment to energy efficiency.
  • Brighter and Warmer Interiors: The design elements of PIXEL windows, such as the narrower floating mullion, result in a larger glazing surface. This allows up to 22% more natural light into rooms, contributing to warmth and brightness.

PAVA: A Blend of Elegance and Efficiency

    • Thermal Insulation Excellence: PAVA windows are designed with energy efficiency at the forefront. Their construction ensures high thermal insulation, making them ideal for homeowners who want to maintain a comfortable indoor temperature while reducing energy consumption.
    • Design Flexibility: PAVA windows offer homeowners a range of design options. Whether you’re looking for a classic look or a more modern aesthetic, the PAVA system has you covered. The availability of various colors and textures, including those that mimic natural wood patterns, allows homeowners to customize their windows to their exact preferences.
    • Durability and Longevity: Beyond their aesthetic appeal and insulation properties, PAVA windows are built to last. They are constructed using high-quality materials that ensure durability and longevity, making them a long-term investment for any home.
Window System U Factor Value
PIXEL 0.16 – 0.29
PAVA 0.73 W/(m²K)


PIXEL, and PAVA, come with a stamp of quality and assurance. They are certified by The National Fenestration Rating Council (NFRC), ensuring they meet stringent energy performance standards. Additionally, they have the endorsement of The Passive House Institute US (PHIUS), a testament to their superior energy efficiency. Furthermore, the Keystone Certification, which emphasizes energy efficiency, indoor environmental quality, and structural safety, is another feather in their cap, underscoring their commitment to excellence and homeowner satisfaction.

Schedule a personal consultation with one of our experts, and let us help you choose the right system for your home.

 

About the Author: Oknoplast Team

The Oknoplast Team is a group of specialists and experts from various fields. Thanks to their broad knowledge, continuously improved skills, and diverse passions, they develop intriguing and substantive articles. Our team consists of specialized copywriters supported by product engineers and technologists. Amidst the plethora of information, advice, inspiration, and current trends, the Oknoplast Team goes the extra mile to select the content that will be most valuable to you.

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