Energy-efficient windows are designed to provi... 06.12.2023 ecowindows energyefficiency windows
Windows are one of the most significant weak points in the house because, naturally, more energy escapes through the glass surface than through walls, for example. That's why replacing old and underperforming windows is an essential contribution to saving energy and increasing the comfort of your home.
Energy-efficient windows are designed to provide excellent thermal insulation and help to keep the temperature inside your house stable. They prevent the transfer of heat or cold from the outside to the inside and vice versa. Their outstanding insulation capabilities reduce the need for heating and cooling, which ultimately lowers energy consumption and costs.
But what exactly makes windows energy efficient, and why are they so critical to increase the comfort of your home and lower your expenses in the long term?
How can you find out if a window is energy efficient?
The most important criterion to measure the energy efficiency of windows is the heat transfer coefficient, the so-called U-value, which is affected primarily by the total number of glazing layers, their dimension, the type of gas within their cavity, and the characteristic of coatings on the various glazing surfaces.
The U-value measures the heat permeability of building elements and indicates the heat flow through the window. It describes how much heat is allowed through the window from the inside to the outside. The value follows a simple rule: the lower the window's U-value in W/(m²K), the higher the performance of the glass. [i]
When determining the U-value of a window, several factors are taken into account. The U-value of a window Uw is calculated with the Ug (glazing), the frame material Uf (frame) and the coefficient of the edge bond Ψg.
When selecting new windows, it is worthwhile to choose the ones with the lowest possible U-value to reduce energy costs effectively.
ECOWINDOWS standard double-glazed windows start with Ug-values as low as 1.10. This performance can be further enhanced depending on the window system. For example, our premium ECO WOODALU system with triple-glazing offers values as low as Ug 0.5.
Components of energy-efficient windows.
A window is a complex construct with several optimally fitted elements. The most important part here is the glazing, as the most energy can escape through the glass surface. Therefore, heat-insulating glazing is highly recommended.
Modern energy-efficient windows feature double- or triple-glazing with Argon gas filling and Low-E (low-emissivity) coatings that, generally speaking, prevent the heat in the interior from escaping to the outside. This performance is reflected in improved Ug-values compared to glass without Low-E coating. [ii]
The frames and seals must also ensure optimal insulation and thus reduce energy loss through the window, for example, with multi-chamber profiles or draft-proof seals. Energy-efficient windows are well-sealed, which reduces the amount of air leakage. Unaddressed leakages can be a significant source of heat loss or gain. When old, outdated, or falsely installed windows create unwanted drafts, heating and cooling systems must work harder to keep a room comfortable.
The material of the window also plays a significant role. Quality European- and German-made windows offer an excellent thermal insulation effect, regardless of whether they are made of PVC, aluminium, wood or a combination of wood and aluminium. However, every material has unique properties and advantages, which should be matched with the individual requirements of your house.
To sum it up, the overall quality of the construction of a window is crucial: Only if all elements of the window are optimally coordinated with one another can the window fulfil its full potential and contribute to an environmentally friendly, healthy and cost-efficient building.
How much energy can be saved with energy-efficient windows?
Various studies indicate that replacing old windows with windows featuring thermal insulation glazing easily saves several hundred Euros (dollars) a year on small-family homes. [iii]
Further, research shows that modernisation is particularly beneficial for windows with single-glazing but also for windows with outdated, uncoated insulation glazing. Compared to modern insulation glazing, this is where the most significant savings can be achieved.
Outdated single-glazed windows have a very unfavourable heat transfer coefficient of 4.7 W/(m2K) in the best scenario - in most cases, this value is even worse. In a research study, this value was compared to modern windows with Low-E coating with a Uw-value of 0.95 W/(m2K) and a g-value of 62%. When replacing the single-glazed windows, around 491 kWh of energy or 49m3 of natural gas could be saved per window unit per year. [iv] (ECOWINDOWS offers windows with Uw-values starting at Uw 0,97 (ECO ALU 70) and going as low as Uw 0.58 (ECO WOODALU PH+)!)
New windows, many advantages.
Investing in energy-efficient windows is worthwhile in many ways. Even if energy efficiency and the resulting heating cost savings are the main reasons for replacing windows, new windows fulfil other essential functions, too.
Modern windows also offer improved burglary protection, reliably preventing the window from being forced open. They also increase living comfort as their weather tightness prevents drafts, which means that the room climate becomes warmer and much more pleasant. Modern manufacturing methods also enable excellent sound insulation for windows so that the interior is always wonderfully quiet - even when there is a lot of noise outside.
Is your home ready for new energy-efficient windows?
In summary, energy-efficient windows are vital in reducing energy consumption in homes by improving insulation, harnessing natural light and heat, and minimising air leakage. When properly installed and used in conjunction with other energy-efficient strategies, they can significantly contribute to a more sustainable and comfortable living environment.
Whether you are building a brand-new home or already own one and your current windows are several decades old and single-glazed with rusted or rotten and insufficiently thermally insulated frames. There is no doubt about investing in quality energy-efficient windows.
Just ask yourself the following:
- Do you want to reduce your energy consumption and power bills?
- Do you want to eliminate unpleasant drafts and improve your home's comfort?
- Would you like to make necessary upgrades and increase your home's value?
If you answered 'yes' to the above questions, you should definitely upgrade the windows in your home. Overall, windows are a long-term investment, and high-performing windows also increase the value of your property, which can be an advantage if you want to sell or rent your house later on.
ECOWINDOWS can assist you in finding the right building solution for your home. We offer a wide variety of German and European windows, doors, shading solutions, and ventilation systems, which are also suitable for Passive House building's high standards and requirements.
If you would like to learn more about our product range or discuss your building project in more detail, please do not hesitate to contact us today.
We look forward to hearing from you!
[i] Unlike the desired high R-value, a lower U-value indicates better performance and insulation. The R-value is the reciprocal of the U value and vice versa (R = 1/U and U = 1/R).
[ii] There exist several types of coatings that should be matched to your home's specific location, position and heating requirements. For example, there are "normal" Low-E coatings with a g-value between 0.5 and 0.7, which allow a large part of the solar radiation to pass through. This effect is good in winter because it reduces the heating load, but in summer, it isn't good because overheating can occur. Once the heat is in the room, it can no longer escape through the glass due to the Low-E coating. On the other hand, there are also Low-E coatings with a reduced g-value (0.2 to 0.3), i.e. most solar radiation is rejected and does not reach the inside. This effect is good in summer because it reduces the risk of overheating. In winter, however, this also minimises the fact that the interior is heated by the sun. The heating load in winter is, therefore, higher. But don’t worry about the details - ECOWINDOWS can assist you in finding the best solution for your home!
Many New Zealanders are familiar with windows fogging up on the inside on cold days – a phenomenon typically associated with the poor thermal performance of single-glazed windows and aluminium joinery without a thermal break separating the aluminium on the outside from the one on the inside.
(You can read more about internal condensation and how to prevent it here).
What surprises many of our customers is that their new, highly efficient double- or triple-glazed windows can fog up on the outside on cold days. Many people may not realise that outside condensation is actually a sign of the high quality and performance of their new windows.
External condensation - Why is it happening?
Let's look at what causes condensation outside windows, featuring highly efficient double- or triple-glazing with Argon-filled cavities and Low-E coatings. Two conditions are required for condensation to develop on the outside glass:
1) The outside glass must be colder than the surrounding air, and
2) the air must be saturated with moisture.
When the saturated air meets the colder outside glass, some of the moisture in the air condenses on it. This effect can be aggravated in areas with high humidity levels, such as places near water, when in the early morning hours, the air is warming up faster than the outside glass, thus increasing the temperature difference between the cold glass and the air.
A sign of high quality and performance!
The important point is that outside condensation is a sign of good quality windows and glass doing their job of keeping the warmth inside the house. After all, if the exterior glass stays cold, then the double- and triple-glazed windows do not allow the heat inside to escape.
Once the sun has had a chance to warm up the outer glass to the same temperature as the air, the external condensation will disappear, and you will once again have an uninterrupted view from your dry, warm and healthy home!
Want to learn more about our product range? Contact us today for a free quote!
Unfortunately, in New Zealand houses, it is still common to find condensation on the inside of the windows on cold days.
High indoor humidity and condensation on colder, non-absorbent surfaces such as poorly insulated single-glazed windows or non-thermally broken aluminium window frames can promote mould growth on walls, ceilings, curtains and carpets. These conditions can lead to serious health problems, such as asthma, a severe respiratory disease that is sadly overrepresented in New Zealand, especially in children.
Fortunately, two measures can prevent condensation and reduce humidity in your home:
- Improving the thermal performance of your windows and doors; and
- managing humidity levels through ventilation.
1. Improving the thermal performance of your windows and doors.
Double- or triple-glazing, particularly with Low-E coatings and cavities filled with Argon gas, will dramatically improve the thermal performance of windows and virtually eliminate inside condensation.
In fact, high-performance triple-glazing can achieve R-values similar to those the New Zealand Building Code requires for walls. So, choosing triple-glazing for your home will not only prevent condensation problems, but also reduce heat loss and significantly lower your heating bills.
ECOWINDOWS offers an extensive range of high-quality, rigorously tested European joinery, including uPVC, wood, aluminium and wood-aluminium - all specifically designed for double- and triple-glazing.
In New Zealand, aluminium is one of the most popular frame materials for windows and glazed doors: It is light, strong, durable, and requires little maintenance. However, the quality of thermally-broken aluminium joinery differs widely among suppliers. Inside condensation remains an issue with aluminium frames that are not, or insufficiently thermally separated, even if double- or triple-glazing is installed. Installing double-glazing in old, non-thermally broken aluminium joinery will therefore solve only part of the condensation problem, as you may still experience condensation on the joinery.
If you want to install new aluminium windows, you should know the required critical features of quality aluminium window systems. With ECOWINDOWS' range of thermally-broken aluminium joinery, you can rest assured that the frames will remain condensation-free under New Zealand conditions.
Please note that even with high-quality double- or triple-glazing, you may still get condensation on the outside of the glazing on cold days. This occurrence is not the same as inside condensation and is not a defect but a sign that the glass is performing well and does its job of keeping the warmth inside.
2. Managing humidity levels through ventilation.
Ventilation is vital for maintaining a healthy indoor climate and managing humidity and CO2 levels.
However, in winter, relying solely on opening windows to ventilate is not ideal, as you want your heated air to stay inside. In practice, we tend not to ventilate sufficiently in winter if ventilation relies on opening windows.
An alternative is a domestic ventilation system that draws air from the ceiling space into the conditioned space. But unless such systems feature a heat recovery system, the cold air from the ceiling space is again battling the heated air in your rooms. And even with a heat recovery system, domestic ventilation systems can be complex to install because they require ducting. In houses with skillion (flat) roofs or multi-level homes, it may not be possible at all to retrofit a domestic ventilation system.
ECOWINDOWS offers a ventilation solution that's perfect for retrofitting. It includes fans with heat recovery systems that are installed in the external walls, similar to a bathroom extractor fan. Our low-maintenance system is affordable, easy to install and clean, and needs very little space, making it the ideal solution for a comfortable and healthy room climate.
Contact us to learn more about our window, door, ventilation or shading solutions. We would happily advise you on the best solutions for your home.
We are already out of the door and have opened a window to the beach.
We would like to thank all our valued clients and partners for your continued support and trust in ECOWINDOWS.
2022 was another exceptionally busy year for us. We worked on numerous exciting projects and already look forward to equipping many more Kiwi homes with our energy-efficient windows and doors in the coming year.
But before we take on the tasks of the new year, our team will take a well-deserved break over the holiday period:
Our office and showroom will be closed from Thursday, 22nd December 2022 and reopen from Monday, 9th January 2023.
We wish you and your families a Merry Christmas and happy holidays and look forward to seeing you again in 2023.
Thomas, Bjorn & the ECOWINDOWS Team
Whether you are building new or renovating, our high-quality thermally broken aluminium windows are an excellent choice to meet and exceed the new requirements under clause H1 of the Building Code and to increase your home’s comfort and energy efficiency.
Here are four features that you should look out for when choosing quality aluminium window systems:
1. Wide thermal break bars
Extruded aluminium is a strong and durable material for window joinery that will last for decades with little maintenance.
However, because aluminium is also a formidable conductor of heat, it is crucial that the aluminium seen on the outside is separated from the one on the inside. This separation can be achieved by inserting thermal break bars in the frames.
Thermal break bars keep the internal and external aluminium profiles apart so that the warmth inside the room is not conducted through the frame to the outside on a cold day. Quality thermal break bars, made from a plastic material such as polyamide, should be as wide as possible (we recommend at least 30 mm wide) and designed with cavities and/or fins to create multiple pockets of still air.
2. Double seals
For best performance in terms of weather tightness and reduction of outside noise, quality aluminium window systems will feature two levels of seals all around to keep the opening sash tight when closed.
The main seal is usually fitted in the centre of the frame. The second one is attached to the inside of the sash profile.
3. No flanges
In New Zealand, windows have traditionally featured external flanges for installing windows on the outside, on top of the cladding. That’s not ideal because, for best thermal performance, windows should be installed recessed into the framing so that the windows line up with the wall insulation.
This recessed installation is particularly important for thermally broken aluminium windows to ensure that the inside part of the aluminium frame is not exposed to the outside air, as this would compromise the thermal break.
Therefore, good aluminium window systems do not come with external flanges, allowing the windows to be installed recessed from the outside, preventing thermal bridging around the perimeter of the window frames.
We can provide recessed installation details for different types of walls and claddings.
4. Internal glazing beads
Glazing beads are the small profiles that hold the glass in place. These should be located on the inside rather than the outside. This location prevents water from entering the glazing beads in the corners and adds to the safety of the windows.
In particular, with aluminium windows, the glazing beads can be removed quickly and easily, thus allowing the glass to be taken out. External glazing beads can therefore be a safety risk for windows located at ground level. Of course, should a piece of glass require replacing, especially on upper-floor windows, being able to do the replacement from the inside is preferable as it does not require scaffolding.
By choosing our ECO ALU series, you can be sure that our products meet all the above features.
In addition to aluminium joinery, we offer a wide range of quality PVC, wood and wood-aluminium windows, doors, and Passive House windows. We can also assist with ventilation and shading solutions.
If you’re in Hamilton, stop by our dedicated showroom to explore our comprehensive offer. We supply countrywide.
Please contact us if you want to learn more about our products.
After the first PVC window profile was developed in the 1960s, the triumph of these windows took its course in Europe, and more and more classic windows were replaced by PVC models.
Following their decades-long success in Europe, PVC windows have also become increasingly popular in New Zealand.
We explain everything you need to know about the window material.
Affordable in every shape
The scientific name for PVC is polyvinyl chloride. The material is highly suitable for window profiles because of its excellent thermoplastic properties and resistance to the elements.
PVC can be formed into almost any shape by heating. Due to this good formability, even individual frame shapes such as triangular or round windows can be created.
Since PVC is easy to process, the production costs for PVC windows are significantly lower compared to other window types made of wood or aluminium. As a result, you can get PVC windows at a reasonable price.
Excellent thermal insulation
The so-called multi-chamber profile gives PVC windows exceptionally high thermal insulation values.
The small chambers in the material are visible in the profile cross-section. These small cavities break up thermal bridges, transmitting much less heat than filling material.
The rule of thumb for PVC windows is that the more chambers there are in the profile, the better the heat protection for your home.
Easy maintenance
Maintaining a PVC window is particularly easy as the material is highly resistant to the elements and does not corrode, swell or rust.
Another advantage is that, unlike wooden windows, PVC windows do not require regular repainting as these window frames are highly weather-resistant.
Only regular cleaning with gentle household detergents is required to maintain the windows. The best cleaning advice is to rinse the surface with warm water, gently wash it with a pH-neutral detergent and a soft cloth, and then rinse repeatedly with warm water.
Since PVC windows are particularly resistant to environmental influences, they are very durable. Therefore, if you take care of your windows accordingly, you will benefit from your PVC windows for a lifetime.
Unique colours and surface protection with acrylcolor
In addition to the energy-related advantages, PVC windows also offer a great choice of colours.
An enhancement with acrylcolor will add a unique design accent to your house facade and significantly further increase the durability of your windows.
Windows with acrylcolor require very little maintenance and are extremely easy to care for. The silk-matt, smooth and pore-free surface is insensitive to dust and dirt build-up. Therefore, peeling, chipping, and repainting are not required.
Acrylcolor is created in a so-called co-extrusion colouring process. This process enhances and protects PVC window systems in a long-lasting fashion. The white PVC base body and the coloured acrylic glass are permanently connected. As a result, the surface of the acrylic glass is inseparable from the primary body, giving PVC windows a long-lasting finish and extra protection.
The fusion of the two materials creates a satin-matt outer acrylcolor surface that can withstand any weather condition for decades to come. The colourful acryl coating is exceptionally durable and provides the window with high resistance against scratches and the effects of the weather.
UV Radiation Levels in New Zealand
Despite their decades-long proven durability worldwide, there are still some misconceptions about PVC windows in New Zealand. Most predominantly, it is said that PVC windows may not be suitable for the high UV radiation we experience here in New Zealand.
However, PVC window systems have been used internationally for many years in climates with greater weather extremes and higher UV radiation than those we are experiencing in New Zealand.
A comparison of irradiation maps of Europe and Oceania shows that the solar irradiation in New Zealand is comparable to those in Spain and Italy. In some areas in Spain, solar irradiation is even higher than in New Zealand. Still, these PVC windows are in perfect condition decades after their installation.
The internationally accredited Tropical S Severe Climate certificate proves that the PVC material of our windows withstands extreme and higher UV radiation levels than those in New Zealand.
Titanium Dioxide for Ultimate UV Resistance
The resistance of PVC windows is primarily guaranteed by using calcium-zinc stabilisers and titanium dioxide.
Titanium dioxide is a versatile substance used in many outdoor products continuously exposed to the elements. Its many useful features include refractive properties, robustness and colour vibrancy, making it an ideal additive for PVC window profiles.
In addition to being naturally resistant to the elements, titanium dioxide exhibits good UV absorption and light scattering properties. Therefore, when titanium dioxide is incorporated into the synthetic resins of PVC, it ensures that UV rays can’t penetrate and damage the product and its appearance.
This protection from weather, heat and UV damage is crucial for building materials such as windows, as they are expected to last for decades.
PVC Recycling Process
Today PVC windows can be almost entirely recycled. With professional disposal, old windows are added to the recycling cycle and can be used to manufacture new window profiles.
ECOWINDOWS PVC windows are manufactured with a high proportion of recycled material and are fully recyclable at the end of their life span. Old PVC is processed and converted to pellets, which allow it to be reused without loss of quality or material structure.
An old PVC window can be processed multiple times while keeping the same quality.
Conclusion
Windows made of PVC undoubtedly convince with a favourable price-performance ratio.
Their affordability, high thermal insulation values and the selection of colour designs of acrylcolor make PVC windows one of the most popular window materials.
Want to find out more?
Contact us today to learn more about our product range or get a free quote for your building project.
Unfortunately, many people living in New Zealand regularly experience moist and foggy windows inside their houses. This moisture on the inside of a window pane is typically caused by improper ventilation, poor building standards and low insulation values of the building components.
Something most people might not have seen so often is a fogging that occurs on the outside of a window.
If we see any fogging on thermal insulating glazing, the alarm bells will quickly ring. But in this case, the concerns are unfounded: A fogged-up window from the outside is completely harmless and even a good sign.
Why do windows fog up from the outside?
You will only notice this phenomenon if you have installed triple-glazed windows with high insulation values. With this type of glazing, moisture condenses on the outside of the window pane during colder nights.
This occurrence happens because of the temperature difference between the air and the window surface.
The panes fog up, especially in regions with high humidity, where the air heats up faster than the window pane. This is because the heat-reflecting layer on the outer window pane reflects the thermal radiation from the room back into the room where it will stay.
High-quality thermal insulation glazing hardly conducts heat from the inside to the outside. As a result, the outer pane stays cold, promoting the formation of condensation.
Windows fogged up from the outside are a natural, physical effect and thus proof of quality insulating glazing.
Roller shutters prevent the glass pane from cooling down
Condensation on the outside of a window usually only occurs in the early morning hours and disappears on its own when the temperature rises.
However, if you are bothered by the fact that your view is clouded in the early morning, it might be worthwhile to consider the installation of roller shutters. These can effectively protect the pane from cooling down.
When you lower the roller shutter during the night, an air cushion forms between the window panes and the slats, and the stored heat prevents the window from tarnishing.
Would you like to find out more about our product range?
Call us on (07) 825 8172 or send us a message using the contact form.
Like the rest of the world, we also have been following the developments in Europe with concerns in the past few weeks.
As an importer of European building solutions with many professional and personal ties, especially in Germany and Poland, we are affected by the current events – and we are so in two ways.
As a business, we are certainly impacted by the developments in Europe. In the last two years following the Covid pandemic, we have already experienced significant rises in energy prices and costs for transport and logistics. This trend will now most likely continue and intensify.
But as human beings, we are also personally affected and saddened by the damages this unnecessary war is causing. Our thoughts are foremost with the innocent civilians in Ukraine, who are suffering unimaginable tragedies and losses.
Nowadays, we live in a highly connected world. As a result, no matter how far away another country might be geographical, we will undoubtedly experience the effects of this war in one way or another.
What is ECOWINDOWS' reaction to the crisis in Europe?
Firstly, we are taking responsibility - for our customers.
We are doing everything we can to ensure our clients are not or, at least, only marginally affected by the current developments and will compensate potential extra costs as good as possible.
However, in the long run, we cannot rule out that orders, productions and deliveries may take considerably longer and, ultimately, prices for our products and their shipment to New Zealand might go up. Effects that, unfortunately, our customers and partners would also feel.
Secondly, we are also taking responsibility – as human beings.
Therefore, we support Doctors Without Borders and the UN Refugee Agency (UNHCR) to provide humanitarian relief efforts in Ukraine and its refugee crisis.
Our sincere thoughts are with the people of Ukraine these days.
What would an import ban on Russian oil to Europe mean?
Germany imports a third of its oil from Russia, which is the third-largest oil producer globally and the second-largest exporter. Many areas of our everyday lives depend on oil: transport, heating and production.
Following the war in Ukraine, oil prices have already risen sharply.
A ban on Russian oil means that almost everything would become more expensive: heating and driving, food that takes a lot of energy to produce. But also many other products like textiles, plastics and cosmetics.
Most notably, airlines, shipping companies and freight forwarders need oil for their transport. As a result, many products would also become more expensive due to these higher transport costs.
The consequences for industries and supply chains can be described as dramatic.
When an embargo stops the delivery of Russian oil to Europe, everything will become more expensive, and many small businesses will no longer be able to keep up. In a worst-case scenario, costs for the delivery of products, such as windows from Germany, will rise extensively.
However, we are preparing for all possible scenarios in this situation. Therefore, we are in constant and personal contact with our business partners in Europe to find the best possible solutions for all parties involved.
Also, many experts say Germany is much less dependent on Russia for oil than gas and coal. Numerous suppliers on the worldwide oil market could increase their production, at least in the medium term.
What’s the outlook?
Even though it is quite clear that it is impossible to replace Russia’s massive energy imports to Europe overnight, on a positive note, there still might be a glimpse of hope left in this rather grim scenario.
Remember that every crisis also brings great opportunities.
The current situation in Europe highlights our high dependence on fossil fuels, and, alongside that, also on other countries. There is a high chance that this crisis might raise greater awareness for renewable energy sources, sustainability, and potentially, in the long term, also a better building culture.
We are also getting a powerful reminder of the importance of peace and care for one another. And, despite the horrific situation, it is incredibly reassuring to see the flood of support from all over the world towards the people of Ukraine.
As the events unfold rapidly, we will keep you updated on the latest developments and their consequences for our business and our clients and partners.