Retrofit Double Glazing v's Replacement Windows: The Window Frame Factor
We all want to live in a warmer, drier, healthier home. Upgrading to high-performing double glazing will do a tremendous job at increasing home comfort, but it's important that we understand the effect the window frame has on the performance of our windows too!
retroGLAZE® Timber and Aluminium Retrofit Double Glazing, and Replacement Windows and Door solutions each provide distinct advantages, influencing the effectiveness of double glazing in different ways.
But before we look at the strengths and weaknesses of these window solutions, lets first understand how heat moves through our window frames.
The movement of heat
Heat moves through window frames by conduction. Conduction is one of the three main methods of heat transfer, the other two being convection and radiation. Conduction occurs when the flow of heat passes through a material, bouncing from one molecule to another, even though the material may be still.
How does conduction work?
Temperature Gradient: Conduction typically occurs where there is a difference in temperature between two adjoining regions of a material.
Heat naturally flows from the hotter area to the cooler area.
Molecular Interaction: The molecules on the warmer side have more kinetic energy and vibrate more vigorously. They then collide with the nearby cooler, less energetic molecules on the other side.
Energy Transfer: During these collisions, energy is transferred from the more energetic molecules to the less energetic ones. .
This process moves heat from the warmer side to the cooler side until there is no temperature difference, achieving thermal equilibrium
Materials' Role: The rate at which heat is conducted depends significantly on the nature of the material.
Some materials, like metals, are excellent conductors of heat because their molecular structure allows for easy transfer of energy between atoms.
Other materials, such as timber, are poor conductors (good insulators) because their molecular structure reduces the flow of heat.
Ok so now we understand how heat moves through a material, lets look at our frame types.
Timber window frames
Timber frames are celebrated for their inherent natural beauty, enhancing any architectural style with a warm, classic feel. retroGLAZE® Timber Retrofit Double Glazing allows homeowners to increase the warmth and dryness of their home, whilst retaining the classic character and feel.
Functionally, wood is a poor conductor so as we just learnt that means it’s an excellent insulator, making it a top choice for energy efficiency in New Zealand homes.
Benefits of retaining your timber window frames
Natural Insulator: Wood's low thermal conductivity means it minimizes heat passage, helping stabilize indoor temperatures.
'Retro-Glaze'able: Most timber frames can be easily machined to allow for double glazing to be installed where single glazing once sat.
Durable and long lasting: When maintained correctly, timber windows are proven to stand the test of time. 30 year old windows are still retroGLAZE®able.
Customizable: Timber's versatility allows it to be painted or stained to match existing décor, a significant advantage in replacement scenarios.
Eco-Friendly: As a renewable resource, sustainably sourced timber is environmentally beneficial and biodegradable at the end of its life.
Timber unfortunately has a bad reputation due to poorly maintained windows that have become warped and bowed, with gaps letting cold air into the home.
But don’t throw the timber out with the single glazing!
retroGLAZE® Timber Retrofit Double Glazing allows your timber windows to be rejuvenated and given a new lease on life.
Opening windows can be straightened or replaced, and quality high performing draught seals can be added, preventing air getting through any remaining gaps into your cosy, warm home.
Old, cracked putty is removed and new timber beads are installed giving a tidy, weathertight seal around your windows.
Aluminium window frames
Known for their and modern look and minimal maintenance requirements, aluminium frames fit well into contemporary renovation projects. Since the 1970’s good, robust frames have been installed into New Zealand homes, providing a different look than traditional timber windows and giving homes a more modern feel.
retroGLAZE® Aluminium Retrofit Double Glazing gives your joinery a fresh new look with flat beads replacing the existing sloped beads. These flat face beads are in keeping with the joinery in a new home build.
Benefits of retaining your aluminium window frames
Style: When retrofitted, joinery looks similar to that of a new home build with flat faced beads replacing old sloping beads.
Durability: Aluminium withstands warping, cracking, and corrosion, ideal for harsh climates
Maintenance: Demands minimal upkeep.
Strength: The structural robustness of aluminium allows for large glass panes with minimal frame support meaning you can bring those expansive views inside your home and maximize natural light.
Not all aluminium is retrofittable, especially joinery older than the 1970’s due to the robustness of the aluminium and the platform available inside the frame for the glass to sit. As with all external facings, fading occurs and can sometimes be very evident. With timber all that’s needed is a coat of paint, but with aluminium, specialist applications are required to bring the colour back, if able.
Aluminium is a good heat conductor, which means it has poor thermal performance. Heat flows easily from the inside to the outside of the window frame to reach thermal equilibrium. As the frame on the inside of your home gets colder, the air around it also gets colder until it reaches dew point and condensation forms of your frame.
Not only that, but the cold frame will impact the temperature at the edge of the double glazing, increasing the chance of the double glazing having condensation form around its edges
Thermally Broken Aluminium window frames
Thermally broken (thermally enhanced) frames significantly improve the insulating properties of standard aluminium frames. Thermally enhanced frames have a thermal separation between the inside and the outside of the frame, designed to interrupt the thermal pathway or flow of heat. This separation greatly reduces heat transfer and is similar to the performance of timber.
Benefits of replacing existing windows with thermally enhanced window frames
Durability and Maintenance: Aluminium withstands warping, cracking, and corrosion, ideal for harsh climates, and demands minimal upkeep.
Strength: The structural robustness of aluminium allows for large glass panes with minimal frame support meaning you can bring those expansive views inside your home and maximize natural light.
Insulator: Similar insulation performance to timber windows.
Adaptability: When you change to Replacement Windows and Doors you change the whole layout of your windows to increase ventilation or to open up the view.
retroGLAZE<sup>®</sup> Full Replacement Windows and Doors allow for the existing window frames to be entirely removed and new, thermally enhanced windows and doors to be installed. Not only will your home be warmer and drier, but you can also change the colour of your frames and the layout of your windows and doors.
But maybe you don’t want to completely lose the character of your home? retroGLAZE<sup>®</sup> Insert Windows allow you to retain the timber reveals, architraves, and sills of your existing windows. A thermally enhanced insert is fitted into the existing timber giving your windows a modern look whilst retaining their classic charm.
Choosing the right solution for your home takes more than choosing the right double glazing. Understanding the benefits and the concerns with your existing frames will help you ensure your window and door frames also pull their weight when it comes to keeping your home warmer, drier and healthier.