Windows are one of the most attractive features of your home. They provide light, views, ventilation, and warmth from the sun during winter. Unfortunately, poorly selected windows can be a major source of heat loss in the winter, accounting for between 10 and 25 per cent of your heating bill. During summer, your air conditioners will be forced to work harder to cool the hot air indoors.
Although energy efficient windows may cost a lot more initially, they will not only improve comfort and the usability of living space, but also save energy and minimise heating and cooling costs. Essentially, over the life of an energy efficient window, the savings obtained from reduced air leakage and better thermal performance will be far greater than the cost of purchase.
Here are some properties of energy efficient windows that will save you money:
- Reduced airflowUnregulated airflow through the windows creates uncomfortable draughts and leads to heat loss.Energy efficient windows that are fitted with compression seals minimise uncontrolled airflow, provide great ventilation when opened and provide superior resistance to uncontrolled airflow compared to sliding seals placed on vertical sliding windows.
- Reduced heat lossOne way to determine the energy efficiency of a window is by checking the U-value. The lower the U-value of the whole window, the less heat it loses. Research shows that the cost of heat lost through a window is higher than the purchase cost of purchasing an energy efficient window.
There are different factors that affect the U-value of windows, including:
- The type of glazing material – Instead of clear float glass, you can take advantage of advances in glazing technology that controls heat loss through the window. Low emissivity (low-E) glass features special surface coatings that reflect between 40 and 70 per cent of the heat that is usually transmitted through clear glass, while allowing maximum sunlight to pass through.
- The number of glazing layers – The traditional approach to enhancing the energy efficiency of windows is to increase the number of glass and air layers. Each layer of glass and air/gas space resists heat flow. So, double or triple-glazed windows with air or gas filled between each pane offer more insulation, saving in heating costs.
- The cavity size between layers – The width of the air spaces is also important, as cavities that are too wide tend to have greater U-values. This means that they allow too much heat transfer.
- The types of gas in the cavity – Energy efficient windows are usually manufactured with inert gases (krypton or argon) in the cavities between the panes. These gases transfer less heat compared to air.
- The design, material and type of frame – There are different window frames available, so you can choose one depending on the visual appearance, maintenance, or budget. Generally, any frame material can improve energy efficiency when designed correctly. So, try to get the most energy efficiency from the frame material of your choice.
When checking the U-value, ensure that it is for the whole window and not just for the glass.
- Elimination of “hot” and “cold” spots in the roomEnergy efficient windows can effectively keep outdoor elements out, eliminating “cold” and “hot” spots in the rooms. They block cold weather from getting into your home, allowing you and your family to stay warm in the winter. During summer, they also protect the interior from the extreme heat, so your rooms remain cool and pleasant with little or no air conditioning.The fact that your heater and air conditioner don’t need to work hard results in lower energy usage. So, you spend less on electricity bills and on other ways of warming up your rooms, like burning fossil fuels.
- Reduced maintenanceSince energy-efficient windows reduce energy transfer between the indoors and outdoors, the incidence of condensation building up is significantly reduced. This translates to lower risk of mould growing and a more comfortable indoor environment for family members with allergies or suffering from asthma. Additionally, the UV-resistant film virtually eliminates dirt buildup and water spots on the outside, which reduces the amount of time and money spent on supplies for cleaning windows. You also spend less money on drugs for managing allergies.If you consider that excess UV radiation could also damage your furniture, getting energy efficient windows will save you money that would be spent on furniture maintenance.
- Tax creditMany people are not aware of the considerable tax credit offered by many municipalities for simply upgrading to energy-efficient windows. For instance, homeowners can receive up to $40 per unit in grants issued by the Canadian government for new windows.It is important to note that the original Home Renovation Tax Credit (HRTC) expired back in 2010. With the current tax credit programs, homeowners don’t have to wait until they’ve filed their annual income tax return in order to receive their home renovation tax credit. The tax-free grant money is sent within 90 days of the follow-up energy audit.
Installation workmanship affects whether or not you get to enjoy the advantages of energy-efficient windows. So, make sure that you choose reputable installers to handle your window installation or replacement project.