There is no complete house without windows. Windows allow natural light to enter inside the rooms and help to keep the house properly ventilated. Windows will also enable the people occupying the house to enjoy better views of their external environment. As a result, if your house has enough windows, it will never feel stuffy or gloomy. Windows can make your home more energy efficient by allowing natural light into the home while retaining warm air inside the house. Also, windows can increase the visual effect and appeal of your home.

However, the materials used in making window frames are not the same. A window can offer durability, maintenance reduction, energy-efficiency, and insulating value depending on its material. That is why; whether you are installing new windows or replacing existing ones, it is important to be better informed about different window frame materials if you want the outcome of your project to be successful and to meet your requirements.

Any window material you choose should provide numerous benefits. It should be able to upgrade the interior and exterior of your house. Also, it should make the cleaning of your home easier.

What is the best material for windows?

Most people who want to install or replace their windows often think only of the window style or glass type. They often forget that the material used in designing the window is important also. That is why; you need to explore the different window materials available and their benefits. Also, you should consider their installation, maintenance, cost and many other things.

Most of the available windows in the market are made from Wood, PVC, Aluminum, and Vinyl materials. The materials with the highest quality are often expensive and have higher chances of weather-stripping. Moreover, they can prevent air from passing through from the sashes. Almost every window material can prevent wind when the weather condition is comfortable. However, if the temperature happens to drop below the freezing point, most of their weather-stripping can stiffen, shrink, or become brittle. As a result, they are likely to crack. That is why the best window material should be the one that can hold its own and offer high-performance even at 0 degrees Fahrenheit temperature.  

However, for you to get the best material for windows, there are certain factors you should look out for. Such factors like;

R-value

This factor measures the capacity of the window to prevent the transfer of heat. R-value can determine how the window retains a comfortable temperature inside and how it can keep the uncomfortable temperatures outside the house from entering. It is, therefore, better for a window material to have higher R-value.

U-value

The window material’s U-value otherwise known as U-factor is greatly the opposite of the R-value. What it determines is the heat transfer tendency. That is why; it is better for a window material to have lower U-value.

Solar Heat Gain

This particular factor is also regarded as SHGC {solar, heat, gain coefficient}. Its function is to determine how windows can heat the room as the sun shines. During cold weathers, solar gain is perfect for a window material. But during the summer, it can increase your air-conditioning costs. If the number of solar gains is high in the material, the heat gain will also be greater.

Wind Resistance

Window resistance otherwise known as air leakage can be determined by CFM {cubic feet per minute}. It usually comes in two numbers which are 70 degrees Fahrenheit and 0 degrees Fahrenheit respectively. It is great for the seal if the numbers are lower.

For this article, we are considering PVC, Vynil, Wooden, or Aluminum Windows. Each of them comes in diverse colors, sizes, and shape options. Moreover, some of these materials offer better thermal resistance than the other ones. Also, they have their pros and cons which you should consider before choosing the appropriate one for your project. They are as follows;    

PVC Windows

PVC windows are among the popular options available today. Moreover, it is resistant to weather and impact. Unlike wooden windows, you do not need to stain or paint PVC windows.

Pros:

• They are recyclable
• PVC windows only require low maintenance. As a result, homeowners can save money and time.
• Since PVC windows do not change shape or warp, you may not need to replace it.

Cons:

• You have to get the best quality of PVC to get that aesthetic appeal of aluminum or wood.
• If you are unfortunate to get poor quality PVC, it can discolor or become brittle.

Vynil Windows

Vinyl windows consist UV-resistant Polyvinyl Chloride and are high-performance and affordable. They can accommodate many other applications. They offer high moisture resistance, almost maintenance free, and do not require painting. The best part is that you can insulate vinyl windows to enhance energy efficiency. Moreover, technology upgrades have increased its manufacturing processes. Thus, it enables vinyl windows to overcome its poor reputation of being substandard.

Pros:

• It is the most affordable window among all the other materials
• They can be insulated with foam or kept hollow which makes it energy efficient.
• Vinyl windows retain its beauty for years and do not need maintenance.
• It is UV-resistant and non-corroding.
• Water and air infiltration are prevented due to the welded seams of vinyl. The welded seams also promote its durability.
• The vinyl that has high-quality titanium dioxide is more resistant to heat.
• There are also various color options to choose from than the standard tan and white.

Cons:

• You cannot stain or paint the interior to suit the décor. If you do, it is likely to peel away and need reapplication in the long run.
• There are so many sub-standard vinyl products available, and if you are not careful, you may end up with one. Thus, you are reducing its insulation value and durability.
• Vinyl windows most times have no room for customization and as a result, may not suit traditional architectural designs.
• They are likely to warp as time goes on and can even damage during its installation.
• Changes in seasonal temperature can induce vinyl windows to contract and expand. As a result, the glass seals may break and cause moisture and air infiltration.

Wooden Windows

Wooden material is the favorite of most homeowners who are installing or replacing their windows. Moreover, for eons ago, wooden materials have been the choice for construction. No doubt, it is as a result of its complete energy efficiency, its architectural matching ability, and warm appearance.

Pros:

• You can fabricate a wooden material into numerous sizes and shapes.
• Woods are natural resources and environmentally sustainable
• It provides maximum insulation value, which is cold transfer and low heat.
• Wooden windows are highly durable and strong. In short, it becomes stronger over time.
• You can stain or paint wooden window to your suit your specific exterior décor.
• Due to its warmth and natural beauty, wooden windows can provide you with a greater return on your investment.

Cons:

• The price is a bit on the high side than the other materials
• It is high maintenance. You need to clean, caulk, stain, paint, and sand it regularly.
• Wooden windows are prone to insect infestation, rotting, mildew, and molding due to weather conditions.

Aluminum Windows

Aluminum windows are almost maintenance free, strong, light, and one of the low-cost window options available. Moreover, aluminum window installation is the easiest for traditional home builders for ages now. No doubt, its standard aluminum window sizes, durability, and strength make it a great choice.

Pros:

• Aluminum windows prices are lesser than the other materials
• You can maintain aluminum windows easily. Moreover, it comes in baked-on or anodized finishes. As a result, you do not need to repaint it.
• Aluminum windows provide narrow frames and slim profile which enables better glass space and promotes sight lines.
• It is lightweight and allows for customization to your particular fitting configuration.
• Aluminum windows are joined mechanically with corners that are warp resistant to retain its shape for a long time.

Cons:

• Its U-value is high making it a great conductor of cold and heat.
• Among the other window materials, Aluminum windows offer the least energy efficiency.
• Aluminum is susceptible to condensation and is always cold when touched.
• They are also prone to corrosion when you expose them to salt air and salt water. As a result, it can cause issues with its functioning and performance.

Differences and Similarities

The comparison of the different window materials will be classified by their;

Design

The design of window material is greatly important when you want to get the best. For instance, the interior of a wooden window usually come from Douglas fir or pine while the outside is covered with PVC, fiberglass, or extruded aluminum.

On the other hand, the material design for vinyl windows comes in various finishes. If by chance it is chipped or scratched, its exterior will still have the same look. More especially, since the entire material design is the same. Aluminum window designs are thinner thus, offering a high-end aesthetic look. No wonder most commercial buildings opt for aluminum windows.

Durability

Another important factor that you should look out for when choosing the best window material is its durability. That is the material that can last for a very long time. For example, wooden materials are easy to maintain and repair. Although they may be prone to rot, the newer wooden windows come with protection. Their exterior is covered by durable cladding or finish. While, vinyl window materials can greatly resist marring, cracking, and scratching.

Moreover, you cannot dent them easily. As for PVC windows, they can tolerate poor weather conditions. On the other hand, aluminum windows are resistant to marring, cracking, and scratching as well. However, if they are powder-coated or painted, they may become more susceptible to dents.             

Colors

The color of window material is crucial when choosing the best material option. Aluminum windows do not have many color options. It is either powder-coated or painted. You can paint vinyl window materials, but you will need a special process to get your specific color requirement. PVC windows do not require painting to get your color choice since they come in a variety of colors. On the other hand, wooden windows can be painted to your color choice. However, you will need to repaint them regularly to maintain their color.

Pitting and Fading

PVC windows do not fade easily no wonder they are recyclable. On the hand wooden windows are likely to fade especially the painted surface. Vinyl windows do not have issues with pitting and fading whereas, aluminum windows can pit. Moreover, its painted surface is likely to fade.

Thermal performance and Energy Efficiency

Wooden windows are perfect in preventing the transmission of heat or cold from outside. On the other hand, aluminum windows are known to radiate unwanted heat from outside in the rooms. Even they conduct cold likewise. That is why; they have to be protected with thermal breaks before they can become energy efficient. Thus, it makes their cost to go higher. PVC, on the other hand, is resistant to impact or any weather change. As a result, its thermal performance is okay. Also, it is energy efficient. Vinyl windows also function better regarding thermal performance and energy efficiency.  

Condensation

Condensation is easily noticed on wooden windows. Moreover, it is easy for vapor pressure to push moisture through wooden windows. Vinyl and PVC are less likely to create condensation. Whereas, aluminum can create condensation and other related issues.

Thermal Breaks

Thermal breaks are vital for aluminum and vinyl window materials since it reduces heat transfers from outside to the inside. Also, it combats the issues of condensation and maximizes energy efficiency. Whereas; wooden windows are non-conductive materials and do not need thermal breaks.

Maintenance

Regarding maintenance, PVC windows only require little or no maintenance while wooden windows need regular maintenance. On the other hand, both aluminum and vinyl window materials do not need maintenance at all.

How much does it cost to replace aluminum, PVC, Vinyl, and Wooden Windows?

When you want to replace your PVC, Aluminum, Vinyl, or Wooden windows, it is important to secure bids from many well-known contractors. At least, you should compare the prices from three different contractors. This is because; their prices are likely to vary from one contractor to another. Moreover, if you are not careful, you may succumb to the high-pressure tactics of their sales representatives.

However, after our research, we can boldly say that aluminum window prices are more on the high side. That is if you go for high-quality and energy efficiency. Vinyl and PVC, on the other hand, provides better value yet, they are not expensive. Wooden windows cost more than all the rest of them may be due to its beauty.  

Conclusion

Before choosing the best option among these window materials, you should consider their cost, efficiency, look, warranty, etc. You should also ask yourself what you require from a window material when embarking on aluminum window installation or any of the others. Furthermore, each of these materials has their particular place in the market. Therefore, if you install them appropriately, they can provide you with efficiency and lifetime service.  

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Almost 60% of the world’s electricity is used by residential and commercial buildings, making it a rapidly increasing and a pressing matter of concern. It’s due to the global climate changes and an increase in costs and energy consumption requirements that the need for energy efficiency and energy efficient buildings is being emphasized.  70% of South Africa’s buildings were designed and built when electricity prices were economical, but the constant price hikes are making it not only hard to maintain a livelihood but also depleting the energy resources at a very rapid rate. Thus, the increasing burden on the South African national electricity grid forced the government to make amends and introduce The South African National Standard – SANS 10400 – XA and the SANS 204 to regulate energy use and encourage energy efficiency in building for better utilization of resources and ensuring improvement in the ecological changes and declining ecosystems.

Energy efficient buildings, is a simple and very innovative idea to introduce required changes in the existing buildings and practical measures that save energy when new buildings are built and designed.  With the introduction of new regulations and policy in the existing sans 204 and national building regulations, the government of South Africa is taking a step ahead towards making the country a cost-efficient country!!

Many modern and especially commercial buildings have been built without much consideration of passive design and rely strongly on technology such as Heating, Ventilation, and Air-Conditioning (HVAC) systems and electric heaters to provide a comfortable indoor climate. Using electricity for these functions is very inefficient and costly.

What Is SANS 10400 – XA?

The SANS 10400-XA standard is a summary of the SANS 204 and other standards into a single reference for homeowners to ensure compliance with the energy efficiency requirements of the National Building Regulations (NBR).  These Requirements include:

• Buildings should face north so as to make most of the sunlight along with Suitable roof overhangs to maintain the adequate temperature during both summers and winters.
• Use of energy efficient heating, ventilation and air-conditioning (HVAC) systems wherever required;  
• At least 50% of water heating must be done through a solar water heater or heat pumps or any other energy efficient manner.

The SANS 10400-XA is part of the National Building Regulations (NBR) and must be adhered to. Municipalities are responsible for assessing and approving development applications including their adherence to the NBR.

The SANS 10400–XA Regulations

The latest amends in South African National Building Regulations (NBR) list the following regulations and adherence to which is mandatory to all homeowners.

• XA1 – all homeowners must use energy efficiently and reduce the greenhouses emissions and use energy within the given limits.
• XA2 – not more than 50% of the annual volume of domestic hot water should be heated through electrical resistance heating, i.e., 50% or more of hot water used must be heated by energy sources other than electricity.
• XA3 – compliance with the XA1 Regulations must be accomplished by one of three methods. If homeowners or competent party build in accordance with SANS 10400–XA, then the buildings will be ‘deemed to comply’ with National Building Regulation XA1.

Which buildings are affected by the SANS 10400 XA requirements?

Buildings that consume energy as a result of human occupancy are the main target of the new regulations. All new buildings must comply with these regulations, and any additions or extensions to existing buildings must be strictly made in compliance with the new regulations. If the existing building is unaffected by an addition, only the addition will have to comply with the regulations.

How is compliance achieved?

To avoid delays in achieving planning approval and receiving occupancy certificates, homeowners should communicate to their architects and the professional teams that the home must be designed in accordance with the SANS 10400–XA Regulations. Compliance with the SANS 10400–XA Regulations requires that the design of new buildings satisfy certain conditions. There are basically three routes by which homeowners can comply with the new regulations, these three routes are-

• The Prescriptive Route
• The Reference Building Route
• The Performance Route

The Prescriptive Route is generally available to all persons and will commonly be used for houses and smaller buildings. This route requires that a set of rules is adhered to for water heating, insulation and glazed areas, i.e., windows, glass doors, and roof lights.

Homeowners need to choose the most practical and cost-effective route, depending on their financial resources and project timelines.

What documentation must be completed?

Once the plans are ready for submission, the Appointed Person (or Responsible Person, if a professional has not been appointed) must inform the local authority and Building Control Officer which compliance route has been chosen, by completing a set of four documents (Forms 1 to 4). These forms can be downloaded from the SABS website (www.sabs.co.za).

• FORM 1: DECLARATION BY THE HOMEOWNER FOR APPROVAL OF BUILDING CONSTRUCTION.

Mainly the roles and duties of the homeowner are discussed here. The competent person making a declaration wherein the means for SANS 10400 -XA regulations have to be satisfied.

• FORM 2: APPLICATION FOR APPROVAL AS AN APPROVED COMPETENT PERSON.

In this step, the Competent Person agrees to take on full responsibility for all the energy-related duties in this section the competent must declare that he/she has the qualification, knowledge and contextual experience necessary for completing the work with compliance to the regulations.

• FORM 3: DECLARATION BY A COMPETENT PERSON.

Under this the Competent Person is required, to make a declaration that the person is the best for the task at hand and has strictly adhered to the regulations. This form also has the second part which states the critical design information of building and its energy consumption.

• FORM 4: CERTIFICATE OF COMPLETION BY OF THE STRUCTURAL, FIRE INSTALLATION OR FIRE PROTECTION.

Here, the Competent Person has to make sure that he/ she has completed and attested the Certification of Completion. It is also the responsibility of the approved competent person who will retain the role of seeing all the energy aspects of the project.  

Option 1: Compliance through the Prescriptive Route

As compliance through the Prescriptive Route does not require the appointment of a Competent Person, it is likely to be the route most widely used in cases where the homeowner would prefer the simplicity of following the prescribed rules, rather than trying a more innovative approach to achieving energy performance standards.

What must be done to follow the Prescriptive Route?

To meet the minimum requirements of the Prescriptive Route, Schedule A of Form 1 must indicate that this route has been chosen, and the design must adhere to certain rules. This requires that decisions be made on the following:

1 Water heating: – The location, capacity, and type of hot-water installations must be planned to ensure that at least 50% of the water will be heated by means other than electrical resistance heating.

2 Insulation: – Insulation must be specified as follows

• Roof and ceiling insulation type and thickness.
• Hot-water pipe insulation thickness (only on exposed pipes).
• External wall insulation (only where external walls are non-masonry).
• Under-slab insulation (only where in-slab heating is installed).

3 Glazed areas: – The total glazed area as a percentage of the net floor area must be indicated –

• If it is more than 15%, the glazed area must be designed to comply with SANS 204.

PERFORMANCE REQUIREMENTS

These are areas which have different climatic influence, and are tabulated below according to the different climatic zones in South Africa ranging from 1 to 9 these climatic factors must definitely be taken into account before selecting the route either prescriptive or reference building:

Option 2: Compliance through the Reference Building Route

If the Prescriptive Route requirements pose technical difficulties or are unaffordable, the homeowner may wish to pursue compliance through the Reference Building Route. This option permits a greater degree of flexibility and creativity, allowing the professional team to introduce innovative energy-efficient solutions to achieve an energy performance that is the same or better than that which would have been achieved by the strict application of the Prescriptive Route. The factors influencing the choice of this compliance route are:

• The scale of the home.
• The wanted aesthetics of the home.
• The ability set of the expert team.
• Client preferences and willingness to pay for energy modeling.

What does the Reference Building Route involve?

A Reference Building is initially designed according to the homeowner’s vision and needs, with all the elements required to comply with the Prescriptive Route being included. Thereafter, the design can be modified with recommendations from the professional team. The annual energy usage and demand is calculated and compared with the performance of the Reference Building (the base case). If the modified design shows an equivalent or improved energy usage compared with the Reference Building, it complies with the regulations.

What must be done to follow the Reference Building Route?

To meet the requirements of the Reference Building Route, the homeowner must appoint a Competent Person who, along with the architect, will ensure that the required documents are submitted to the local authority timeously. The homeowner must also sign the following two SABS forms before the plans can be submitted for approval:

• Form 1: ‘Declaration by the person responsible for preparing an application for approval of the erection of the building in terms of section 4 of the act.’
• Form 2: ‘Application for acceptance as an approved Competent Person in terms of Regulation A19.’

Case Study: Joe Slovo, Cape Town: Sustainable low-income settlement

The Joe Slovo settlement is situated in the suburb of Langa, 10 km east of the Cape Town CBD. The low-cost houses in the settlement include the following sustainable design elements in compliance with SANS 10400-XA

• Improved thermal performance of buildings through insulated ceilings, roof overhangs, and double story, duplex block design, i.e., reducing external wall exposure
• Improved energy services through energy efficient water heating through solar water heaters (150-litre low-pressure evacuated tube systems).

The images show the houses in Joe Slovo and conventional low-cost houses in Delft that were used to compare the impact of the sustainable features.

Solar water heaters- SWH were installed on all houses. A community survey conducted after occupation showed that the SWH were most appreciated measure. Prior to the installation households used an average of 8 kettles per day for water heating. Even on cloudy days in winter, the SWHs were found to produce 30 to 40°C warm water.  

Energy Efficient lights -The houses were equipped with CFL lights. It is noted that safe disposal and replacement system is required to sustain this measure as poor residents may replace broken CFLs with cheaper incandescent light bulbs.  

Thermal design features- The thermal design was optimized with the help of a computer modeling package. The houses are a double story and have shared walls reducing their exposure to outside air. Most houses are north facing with roof overhang shading windows on the top floor in summer.

Conclusion

So, from the overall discussion, we can conclude that energy efficiency has  become of a requirement rather than just a choice the global greenhouse emissions are increasing day by day destroying the ecological balance , if these signs further ignored the world as we know it will deteriorate,  However, successful government intervention plans policies regulation and increasing awareness has turned the tide and bringing in a new wave of change although the quantum of change is very small it is helping in spreading more awareness.

 It is important to note that the design and plans for extensions and Improvements of the above mentioned must be made in compliance with the newly set regulations. Usually, the SANS 10400 -XA serves the role of providing the  energy requirements for a building for the compliance with National Building Regulations regarding energy usage while the SANS 204 is more concerned with specifying the actual design requirements so as to achieve the desired levels of energy efficiency in the long run to make sure easy sustainability because countries like South Africa which fall under the economically backward  countries already have a very limited amount of resources and if the country continues to consume the resources at its current pace then in the next few decades South Africa will run out of energy sources and must depend on the underdeveloped renewable resources.

While there has been lots of regulations and policies, the response and awareness created through such plans and policies in South Africa is still very little. There is surely demand of more plans and policies and amendments in the existing SANS 10400-XA due to the in compliance and loopholes in the regulations. It is a very necessary and ideal time for intervention in averting such massive scale energy crisis. Reports and research have shown that the buildings are the largest consumer of energy, right after the construction sector in South Africa.

Thus SANS 10400-XA can be said to be a stepping stone in averting a massive energy crisis in South Africa although the SANS 10400 is an incomplete attempt and requires lots of revision and amendments in the foreseeable future it can be concluded that the SANS 10400-XA is definitely a founding stone in revolutionizing energy efficiency in buildings in South Africa.

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