There are many considerations that go into any home renovation, repair or upgrade project, and changing your windows is no exception. You may be forced to think about replacement following an accident such as a fire, playtime mishap or break-in. For these, you'll need emergency replacement services because of the potential security risk presented by a gaping hole in the windows. You may also simply want to upgrade your windows for improved security and aesthetics. Whatever the reason, these are the three most important decisions to be made:

1. Replacement versus repair

If the window frames are still sound, you can keep the frames and simply install glass in the openings. If the frames are not sturdy or you want to change the window design, you'll need to replace the entire casement, which is a lot more expensive to do. Repairing a single window is relatively inexpensive, but if you're working with multiple, consider saving up to have the work done all at once. Doing multiple windows allows you to get cheaper prices on the products and some savings on labour. If you're not sure about the quality of your frames, you can ask the contractor to come in and assess. Also check for signs of aging, wearing, warping or splitting in wooden frames or rusting and corrosion in metallic frames.

2. Cost-benefit assessment

This is important for upgrades, since you want to recoup some of your investment when you sell the house. The benefits of window replacement in the absence of need should be thought of in two ways:

• Immediate payoffs – if replacing your windows in favour of more secure and weather-proofed glass, consider the non-monetary benefit of a safer home and the monetary savings on your heating and cooling bills. You cannot attach a price-tag to feeling safe in your own home, particularly following a break-in, but if the price-tag attached to high-performance windows isn't worth the savings in energy bills, you may give the latter a pass.
• On-sale payoffs – certain upgrades will make your home more valuable depending on the market itself. Talk to a realtor about the value of getting different types of glass and frames; they are best placed to know what customers currently want. However, do not expect to get back the full cost of your investment; while buyers may love your upgrades, they may not be willing to pay extra for them.

3. Design and style

There are different window designs (frame) and glass options. You can have casements which are ideal for hard-to-access windows, double-hung windows that can be opened from both directions, double- or triple-pane windows whose glass includes an inert gas between the layers for higher insulation and other specialized glass options.

More features for better security and/or energy consumption cost more. Standard sizes and designs readily available at the glass shop will cost less than custom sizes or designs, such as premium screens, impact-resistance (good for windy areas), unique hardware finishes and bespoke colouring. Depending on your end goal, the extra cost may be worth the effect e.g. getting triple-paned glass for windows that receive direct sunlight can lower cooling bills.