Nothing will make you realize how poorly your windows are performing quite like a cold winter’s day. And while your windows won’t actually freeze, it can certainly look (and feel) like that sometimes! Sure, there may be a complicated combination of environmental and technical performance factors at play when it comes to how your windows function, but at its core the issues often are straightforward. But when these issues reach a tipping point, your community may be forced to consider a major expenditure.
Let’s cover some common window performance issues and discuss possible next steps when it’s time to consider major refurbishment or replacement!
I’ve Got to Go Away … And I’m Worried About Condensation Damaging My Window Sills
Whether you’re just heading out to work for the day, or you’re heading south for the winter, having peace of mind that your windows are not causing a host of issues while you’re out is important for any condo owner. Aging windows can present a major source of unwanted heat loss, discomfort and of course, damaging condensation.
Condensation is the process where moisture (humidity) that is present in the air turns into water when it contacts a cold surface. Since window glass and frames are typically the coldest surfaces in your home, this is where condensation forms. If the glass is cold enough, the water can freeze. While it is normal for some condensation to form on windows during cold weather, excessive moisture can damage the finishes surrounding the window frame. Further, an excessive amount of condensation can result in mould growth, damage to the exterior walls and windows or, for those living in large buildings, the condensation can even appear as a leak and cause damage to suites below. When condensation occurs, water should be mopped up as soon as possible to minimize the damage.
Relative humidity (RH) is a measure of the moisture in the air. The higher the RH, the more moisture in the air and the greater likelihood that condensation will form on the windows. As an owner or resident, you should try to keep the RH at levels which will not cause excessive condensation - this may require some changes to lifestyle. These are a few ways to minimize risk of condensation forming.
Most mid and high-rise condominium suites are designed to receive their fresh air from the corridor and exhausted out bathroom/kitchen exhaust fans. Gaps around the suite entrance doors are provided to allow fresh air that is supplied to the corridors to enter your suite. In the winter, this fresh air is dry and helps remove moisture from the air in the suite. In this case, suite entrance doors should NOT be weather-stripped. Bathroom and kitchen exhaust fans should also be operated regularly.
Excessive numbers of plants contribute significantly to moisture in the air. Avoid placing plants on window sills because they increase the humidity immediately in front of windows. Also, avoid too many plants in the suite.
Where possible, turn air grilles to direct warm air flow downwards and across the window surfaces. This helps to keep the windows warm and to evaporate condensation that does form (in the summer, reverse this flow to point upwards to distribute cool air throughout the room).
Blinds or curtains should not be installed tight to windows or kept continuously closed, and furniture should not be placed tight to the windows. Having your curtains closed prevents air circulation over the window surfaces making the window colder and increasing condensation problems. Coverings should be kept fully open during the day to allow condensation that formed at night to evaporate.
Condensation forming on the inner surface of exterior sliding windows is a normal occurrence. Drain holes are provided at the bottom of these windows to remove the water.
For horizontal sliding windows, make sure both interior and exterior sliders are fully closed – this allows the window to function as intended and reduce risk of condensation forming.
Of course, these are just a few tips that can help. Discuss other options with your building envelope engineer. Remember that on those cold winter days, your interior humidity levels will need to be almost uncomfortably low in order to prevent condensation from forming. Condensation then becomes an issue to control and manage, rather than one to try to prevent outright.
Mind If I Move in Closer [to the Windows]? … Yes, Because then You’ll Feel a Draft
Water and air leaks are often a strong indicator that windows are aging and require replacement. So what makes a window feel drafty? Well, air leaks (often called drafts) can make a window feel drafty, but convective air flow issues are also often accused of being air leaks.
An air leak is caused when air moves through the building envelope due to pressure differences, finding paths through cracks or deficiencies in the wall and window systems. The pressure differences are created by wind, mechanical systems, and, well, physics – and result in a small stream of air disrupting your afternoon. Air leaks are made much worse when window components like weather stripping begin to deteriorate or window sashes/frames warp.
When warm interior air approaches the window, it is cooled (because glass is a very poor insulator). As the air cools, it falls, and warmer interior air rises to replace it. This air circulation, or convective air flow, happening near windows can cause you feel a cold stream of air, even if you window system is 100% air tight.
I Wish I Knew How … To Approach a Major Retrofit or Replacement
Deciding to replace your Corporation’s windows can cause as much controversy as a once-loved holiday tune. But just like the discomfort that can now come from once easy-listening, once beautiful windows don’t always perform well as they age. There are a number of triggers that will push Boards and owners to considering a major window retrofit or replacement, including air leakage (drafts), water leaks, ongoing glass unit replacement, faded and deteriorated frames, and occupant discomfort.
Increasingly, we’re also seeing high utility costs, or a desire to improve curb appeal or views as reasons Boards are pursuing major window projects. What makes window projects so sensitive, compared to, say, a required structural repair, is that there are often many owners who are reluctant to support such a substantial expenditure when it can sometimes be viewed as “non-essential”, whereas the concept of structural collapse is often easier to grasp. Windows are also one of the most viewed components of your building and one of the most invasive to repair/replace.
“Can’t we just put some caulking on it?”
Sometimes the answer is yes – but your first step should always be to evaluate your options as a community before embarking on a repair or replacement path. Project planning begins by engaging your engineer to conduct a Condition Assessment or Preliminary Design, a process that includes a site visit to review window component condition, in-suite conditions and configurations, and discussions with your Board about objectives and financial constraints. Your engineer can provide you with options, renderings, pros/cons, and cost estimates for repair vs. replacement strategies. They can even provide scenarios for how each option would fit into the long-term Reserve Fund Planning process. That way, you know that if you “just put some caulking on it”, you may face higher risk of leaks during the time replacement has been deferred!
It’s also important to obtain a Designated Substances Survey to identify potential asbestos or other harmful substances that may be contained within interior finishes or sealants. Proper abatement is essential for the safety of your owners and for the workers, and importantly adds cost to the project that must be planned for.
Once a repair or replacement option and funding plan are selected, it’s wise to complete a mock-up (carry out the scope of work at a sample unit) prior to soliciting pricing for the full project. A mock-up will help identify concealed conditions that impact price and will provide the Board and owners and opportunity to review the new windows in action. Having something tangible in place at one of your suites can also help to ease concerns about perceived value for investment.
Most importantly, involve your owners throughout the process, and listen to their feedback. Every condominium community is different and approaching major projects with an open mind (backed by solid engineering reports with options clearly laid out!) is an important and necessary step in the process.
Contact your engineer early on to review options, plan financing, and help guide your Board and owners through the process.
Say Lend Me A Coat … So I Can Reduce Incoming UV Radiation
Or more specifically, lend me a low-e, or low-emissivity, coating. Modern window systems are comprised of insulated glass units, thermally broken frames and a wide availability of high-performance coatings.
During the Preliminary Design phase, your engineer can help you review technical performance factors that impact window function and energy efficiency. Consider upgrades like low-e coatings, insulated glazing unit gas fill, high performance spacers, etc. to improve your bang-for-buck on major projects. These glazing and coating options serve the dual objective of reducing energy consumption and improving resident comfort.
So Nice and Warm … Maintain Your Upgraded Windows
Control condensation to protect finishes, review and re-tune mechanical systems, and plan for maintenance to get the most life out of your new windows.
Look out the window at this dawn!