Window and Door Replacement London: How to Boost Energy Efficiency

17 March 2026

Walk down any street in London, Ontario and you will see the city’s building history in its windows and doors. Brick century homes in Old North with wavy glass, postwar bungalows with aluminum sliders, 1990s two-storeys with builder-grade vinyl. Those assemblies frame the view and shape curb appeal, but they are also the points where a house wastes most of its energy. When a client tells me their living room feels drafty despite a hard-working furnace, I look first at the windows and doors, then at how they were installed. Swapping a tired unit for a high-performance one, and installing it properly, can change the feel of a home overnight and trim utility bills for decades.

This guide distills what matters in window and door replacement for our climate. It draws on projects across the city, from White Oaks to Stoney Creek, and aims to help you ask sharper questions when you compare quotes for window replacement London or door installation London Ontario.
Where the heat really goes
In a London winter, your house loses heat in three main ways at windows and doors. Conduction through the glass and frame, air leakage around the perimeter and through sash joints, and unwanted heat transfer tied to solar gain and nighttime radiative cooling. You can feel the combined effect on a windy January night when the blinds sway slightly and the room cools near the couch.

Glass is the largest surface, so its thermal performance matters. A clear, single pane has a U-factor around 5.7 W/m²·K by European measure, which is very poor. A standard double-pane unit with air fill sits near 2.8. Add a low emissivity coating and argon gas and you can get down near 1.6 to 1.8. Good triple-pane units with multiple low-e coatings can reach roughly 0.8 to 1.2. Lower is better. For context, the Ontario Building Code sets minimums that reputable window installation London Ontario professionals will meet as a baseline, and most homeowners do better than minimum when they replace.

Air movement is the other thief. Older sliders and hung windows can leak significantly at the meeting rails and tracks. If you feel a draft, that is not the glass, it is air. On doors, worn weatherstripping, bent hinges, and a sagging threshold can leave a visible light gap that stays open even with the deadbolt latched. Energy often escapes there faster than through the insulated core itself.

Finally, solar heat can hurt or help depending on season and orientation. South-facing glass can give welcome heat in February, but west-facing patio doors can overheat a kitchen in July. Picking the right glass package for each exposure, not just ordering the same everywhere, lets you bank winter sun without baking in August.
The case for a planned upgrade, not a piecemeal fix
I meet plenty of owners who try to solve isolated comfort issues by replacing one or two units a year, usually the worst offenders. That can work, but it also means you live for years with mismatched sightlines, uneven comfort, and a patchwork of warranties. A planned window and door replacement London project, even if phased across two seasons, gives you better leverage on price, consistent finishes, and the ability to tune glass to each face of the house.

A couple in Oakridge asked me to address a cold family room. Their patio slider rattled, and the floor by the baseboard stayed chilly. We could have swapped just the slider. Instead, we did a careful measure, found the adjacent picture window was the larger culprit, and replaced both with a low-e triple, warm-edge spacer, and a properly flashed sill pan. They kept the same overall look, the room temperature stabilized by roughly 2 to 3 degrees on windy days, and their gas bill through the following winter dropped by about 10 percent. Not a laboratory result, but a common story when the weakest links get addressed together and installed right.
Glass choices that pay back in our climate
Energy Star certification for Canada is a good filter to start with. Beyond the label, the details matter. For window replacement London Ontario, I typically consider three variables: pane count, coatings, and fill gas.

Double pane is the value play. With a soft-coat low-e layer and argon fill, a high-quality double can deliver a noticeable improvement at a reasonable cost. It suits homes where budget per opening is tight or where frames are small, such as on some bungalows where triples add weight that complicates operation.

Triple pane shines on larger units and problem rooms. The second cavity lowers conductive and convective losses. If the goal is quiet bedrooms facing a busy street or improving comfort beside a tall picture window, a triple with two low-e layers is worth the premium. Some homeowners tell me they feel less radiant chill when sitting near big panes after a switch to triples.

Low-e coatings are not all the same. A high solar gain low-e on south windows can let in more winter sun and still manage heat loss. On west and east exposures, where late afternoon or morning glare can be intense in summer, a coating with a lower solar heat gain coefficient controls overheating. It does not have to be complicated. A good London Ontario windows supplier can specify a higher gain glass for the south elevation and a more moderate one everywhere else.

Argon is standard. Krypton, which performs better in thinner cavities, shows up in some triples but usually at a higher cost. In typical vinyl frames with standard cavity widths, argon balances performance and price for most homeowners.

One last piece inside the glass unit is the spacer that separates the panes at the edge. Warm-edge spacers reduce condensation risk at the perimeter and control the temperature drop that makes a couch near the window feel cold. They are not as flashy as low-e marketing, but they show up in day-to-day comfort.
Frames and what they mean for longevity
Vinyl dominates the London windows and doors market. Good vinyl frames have multi-chamber profiles that add stiffness and thermal breaks. They require almost no maintenance. In mid-tier products, look for welded corners and reinforcement in larger sashes.

Fiberglass frames are stiffer and more dimensionally stable with temperature swings. They hold paint well and make sense for tall, narrow units or where you want slimmer sightlines. They often cost more than vinyl but less than wood-clad.

Wood-clad offers a warm interior with exterior protection. It suits older homes where interior trim and proportions matter. You get excellent thermal performance but accept more maintenance on the interior finish over the years.

Aluminum is rare for residential replacement here, except as cladding or in specialized products. Its conductivity works against energy goals unless it includes a substantial thermal break.

Whatever the frame, think about colourfastness and expansion. Dark exteriors soak up more sun. In a south or west exposure, a dark vinyl frame can grow and shrink more over the seasons than a light one. Good manufacturers account for this, but it reinforces the need for careful installation joints that allow movement without opening gaps.
Installation makes or breaks performance
High-performance glass will not fix a gap at the sill. The best window installation London Ontario teams focus as much on the rough opening as the unit itself. Here is what I expect https://iad.portfolio.instructure.com/shared/bf1f78e61af8b500e356183dc927ad4d722aadbea1df87b8 https://iad.portfolio.instructure.com/shared/bf1f78e61af8b500e356183dc927ad4d722aadbea1df87b8 to see on site.

The sill needs a path to shed water outward, not into the wall. That often means a sloped sill or an installed sill pan, either a formed membrane or pre-made composite, lapped properly with the weather barrier. I have opened walls during renovations and found blackened sheathing below a retrofit window where a bead of caulk was asked to do the job of flashing. It never ends well.

The sides and head get a layered air and water management approach. Backer rod and low-expansion foam fill the gap for insulation and air seal, but not as a structural wedge. Then, flexible flashing or tapes tie the nailing flange or frame to the house wrap, shingled so any water travels outward. Finally, the exterior gets integrated trim or capping that directs water off the face.

Interior air sealing is as important as the outside. A continuous interior bead at the drywall or plaster line prevents warm, humid house air from finding its way to a cold exterior plane where it can condense. You should not rely solely on spray foam. Foam insulates well, but it is not your only air or vapor control.

Full-frame replacement versus insert comes up on every project. Inserts tuck a new frame into the old one. They are faster, keep interior finishes largely intact, and often save money. They can be a fine choice if the existing frame is square, rot-free, and the old flashing details are sound. Full-frame removes everything down to the studs and rebuilds the opening with new insulation, flashing, and trim. It costs more and disturbs finishes, but it is the only way to fix water damage, correct size or alignment issues, and reset the weather management from scratch. In brick veneer homes common across London, full-frame replacement gives you a chance to use brickmoulds and flashings that integrate cleanly with the masonry.
Doors that insulate, seal, and secure
An exterior door is a moving wall. It needs to insulate, close tightly, and stand up to daily use. For door installation London Ontario, most clients weigh steel versus fiberglass.

Insulated steel doors have a polyurethane or polystyrene core and a durable skin. The better ones carry an insulated slab and an insulated frame with continuous weatherstripping. They resist warping, take paint well, and offer strong security at a sensible price. Steel doors London Ontario suppliers carry a wide range of panel profiles that fit brick homes and newer builds alike.

Fiberglass mimics wood grain convincingly and handles damp conditions without swelling. It insulates very well and resists dents better than thin steel skins. If a stained wood look without the upkeep is the goal, fiberglass stands out.

For either, look at the quality of the threshold and the sweep, ask about adjustable sills, and consider multipoint locks that pull the slab tightly against the weatherstripping at several points. If you can see daylight anywhere with the door closed, energy is flowing out. Steel door installation London Ontario teams that work regularly in our freeze-thaw cycles also pay attention to sill pan flashings and sealant compatibility with PVC or aluminum components so the assembly stays tight for years.

Patio door installation deserves its own care. Sliding units are popular for decks and small patios, but older sliders are often the worst leakers in a house. Modern sliders with better rollers, interlocks, and insulated glass solve much of that. For larger spans or a premium feel, hinged French doors or tilt-and-slide systems create a better seal when closed. Pay attention to the track or sill height. Lower profiles reduce trip hazards but must still manage water in driving rain. Where there is no overhang and the exposure is severe, I prefer a slightly taller, well-flashed sill over a flush look that can puddle under wind-driven rain.
The envelope connection when siding is in play
On projects where the cladding is also due, coordination with siding companies London homeowners trust can elevate performance. With siding off, you can properly assess the sheathing, upgrade house wrap to a more robust, vapor-open membrane, add exterior insulation, and integrate window flashings perfectly. On brick walls, aluminum capping over existing wood trim is common, but it should never be the only defense. Good capping directs water out and sheds it off the head, but it still relies on the layers behind it. Where I see rot, it is usually behind pretty capping that hides a lack of flashing.

If you plan window and doors London Ontario replacements within a year or two of recladding, phase them in the same season. It avoids pulling capping twice and allows a clean tie-in to new materials.
A focused checklist when choosing products and partners Verify Energy Star for Canada certification and review U-factor and SHGC values suited to each elevation, not just a single spec for the whole house. Ask about installation details: sill pans, flashing tapes, foam type, and how the team integrates with brick or siding. Compare frame materials, not only price: vinyl for value and low maintenance, fiberglass for stability, clad wood for character. Confirm hardware and sealing: multipoint locks on doors, robust weatherstripping, warm-edge spacers. Scrutinize warranties and service, including who handles glass seal failures and how long labour is covered. What to expect from a proper site measure and quote
A good London window and door company will spend time on the rough openings, not just pull numbers from a plan. They will measure each unit twice, check for out-of-square frames, probe for soft spots in sills, and look at water staining that hints at flashing failure. In basements, they will confirm egress requirements for bedrooms. For tempered safety glass, they will note panes within a certain distance from the floor or a door, which the code requires. For window replacement London, Ontario, where many homes have brick veneer, they should explain how brickmould sizing affects sightlines and how they will match mortar or caulk colours to avoid a patchwork look.

The written quote should separate product, installation, and any carpentry or masonry repair. If there is suspected rot, it should allow a unit price for replacement of damaged framing. Transparent pricing prevents disputes on tear-down day.
Budget, savings, and what the numbers look like
Energy savings vary widely, mostly with the baseline you start from and how airtight the new assembly is. Across my projects, full window and exterior door upgrades in leaky older homes often reduce heating costs by 10 to 25 percent. In a relatively tight 1990s home with builder-grade double panes, you might see more like 5 to 15 percent, with comfort improvements leading the value story.

Think in ranges. If a household spends 1,600 to 2,200 dollars a year on natural gas and electricity for space conditioning, trimming even 12 percent translates to 190 to 260 dollars annually. Over 20 years, with future energy price uncertainty, that matters. The non-energy benefits also carry weight. Less condensation on panes reduces risk to sills and drywall. Better sound attenuation improves sleep on busier streets. UV-filtering coatings preserve floors and furniture.

There are rebates and financing programs from time to time. The landscape shifts. Some federal programs have paused or changed, while utility-backed offers, such as those linked to energy audits, come and go. Before you sign a contract, check current incentives with Enbridge Gas and Natural Resources Canada, or ask your London Ontario windows and doors contractor to flag active programs. If an energy audit with a blower door test is required, schedule it early so the paperwork aligns with installation.
Timing and seasonality in London’s climate
You can replace windows and doors in winter, and good crews in London do. They stage rooms so the opening is out for a short window, protect floors, and seal off work areas to contain heat loss. Caulks and foams have temperature limits, so winter installs use products rated for the cold and often need slightly longer cure times. Summer installs make finishing and paint touch-ups easier, and you avoid the scramble of the first cold snap when schedules are packed.

If your home has high indoor humidity in winter, plan to control it during and after the upgrade. New, tighter assemblies can show condensation if interior humidity stays high, especially when it suddenly gets cold. Bathrooms and kitchens need strong, properly vented fans. If you have an HRV, ensure it is balanced. A comfortable indoor relative humidity target might sit near 35 percent at minus 10 outside, dropping as the temperature dives. Your contractor cannot manage your humidifier, but they can point you toward better habits that protect the new units.
Permits, code, and inspections
Most like-for-like window replacement London projects do not require a building permit when you do not change the size of the opening or structural elements. Once you alter structural framing, enlarge openings, or add new ones, permits come into play. For bedrooms, egress sizes and sill heights apply. Safety glass is required near doors and in certain large or low windows. Electrical surprises sometimes appear in older walls, and any electrical work needs to follow ESA rules. A seasoned installer will flag potential permit issues during the quote and can coordinate with professionals if required. It is better to ask up front than to scramble mid-project.
Common pitfalls and how to avoid them
Choosing glass without respect to orientation can backfire. I have seen west-facing kitchens with dark blinds down all afternoon because the low-e selected let in too much summer heat. Tailor SHGC by elevation when possible.

Relying solely on caulk outside and foam inside invites trouble. Sealants age. Flashings that direct water out live longer and keep sheathing dry. On brick, head flashings with proper end dams and drip edges are your friend.

Focusing on slab insulation for doors but ignoring thresholds causes drafts. The bottom of the door is the most abused zone. It needs durable sweeps, solid sill support, and correct compression. Multipoint locks fix poor seals at the mid-rail.

Assuming any installer understands masonry. Brick veneer is common in London, but not all details are equal. Ask how the team will handle weep holes, lintels, and how they will fasten without cracking brick or compromising the air space.

Ignoring trim and capping aesthetics. A perfectly sealed window can still look wrong if the exterior trim ratios do not suit the façade. Ask to see sample profiles and colours in daylight, not only in a showroom.
London market considerations and picking the right partner
Search results for window replacement London Ontario and london windows and doors return a crowded field. That is good for competition and choice. Look for companies that do both product and installation, or those that collaborate tightly with vetted installers. Ask how long crews have been with the firm. Longevity matters as much as brand. Some of the best outcomes I see come from teams that also handle siding, soffit, and roofing, or from partnerships between window specialists and siding companies London homeowners already trust. The envelope is a system. When one group understands how their work touches the others, details get handled correctly.

Local references help. Ask to see a house two seasons after installation, not just a fresh job. Look for clean caulk lines, no buckled capping, and sill details that still look tight. Inside, ask the homeowner how the room feels in February on a windy night.
Preparing your home for installation day Clear access to each window or door, moving furniture and taking down blinds or curtains within a couple of meters. Disarm or notify any sensors on doors and windows if you have a monitored alarm system. Create a staging area in the garage or a cleared room for new units, keeping pets and kids away from work zones. Cover nearby electronics and treasured items. Even tidy crews generate some dust when removing old frames. Walk the site with the lead installer to confirm swing directions, grille patterns, and hardware finishes before they set the first unit. Living with your new assemblies
Once installed, your windows and doors ask for modest care. Keep weep holes clear at the bottom of frames so water can escape. Inspect and clean weatherstripping annually. Do not paint moving vinyl components or weatherstrips. On doors, adjust the threshold if you notice daylight with the door closed after seasonal shifts. Operate multipoint locks as instructed so they engage fully without forcing the handle.

Glass units are sealed systems, but seals can fail after many years. Fog between panes is the tell. Good manufacturers back insulated glass for 15 to 25 years, sometimes longer. Keep the paperwork and serial numbers that come with each unit, usually on a jamb sticker. If a sash fogs within warranty, a reputable London window and door supplier will process a replacement without drama.
Putting it all together
Energy efficiency is not only about R-values on a spec sheet. It is about a house that stays warm on a bitter February evening without the furnace running flat out, a family room that does not fog the panes when the pasta pot boils, and a front door that latches quietly and seals with a soft pull. It is the winter sun warming the floor in a south-facing kitchen without baking you in July. Window and door replacement London projects that achieve that balance share the same ingredients: smart glass choices by orientation, frames that suit the home and climate, and a crew that treats the rough opening as carefully as the unit itself.

If you start with those principles, use Energy Star as a baseline, ask direct questions about installation details, and coordinate with other envelope work, you will feel the difference at your fingertips and in your monthly statements. Whether you are planning a single patio door installation this spring or a whole-house window and doors London Ontario upgrade paired with new siding, the steps above will guide you to a home that looks sharper and performs better, season after season.

<h2>Business Information (NAP)</h2>

Name: McCallum Aluminum Ltd

Address: 3392 Wonderland Rd S, London, ON N6L 1A8, Canada

Phone: (519) 433-4223

Website: https://mccallumaluminum.on.ca/

Email: inquiries@mccallumaluminum.on.ca

Hours: 
Monday: 8:00 AM – 4:00 PM 
Tuesday: 8:00 AM – 4:00 PM 
Wednesday: 8:00 AM – 4:00 PM 
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Friday: 8:00 AM – 4:00 PM 
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https://mccallumaluminum.on.ca/

McCallum Aluminum Ltd is a experienced window and door installation company serving the London Ontario region. 
For window replacement in London, Ontario, contact McCallum Aluminum Ltd at (519) 433-4223 or visit https://mccallumaluminum.on.ca/. 
McCallum Aluminum Ltd provides professional installation for patio doors, helping homeowners improve comfort across nearby communities. 
To find McCallum Aluminum Ltd on Google Maps, use: https://www.google.com/maps?cid=10246687099425416717. 
Looking for a affordable installer near you? Call (519) 433-4223 and learn more at https://mccallumaluminum.on.ca/.

<h2>Popular Questions About McCallum Aluminum Ltd</h2>

What does McCallum Aluminum Ltd specialize in? 
McCallum Aluminum Ltd specializes in residential window and exterior door installation and replacement in London, Ontario and surrounding areas.

Where is McCallum Aluminum Ltd located? 
3392 Wonderland Rd S, London, ON N6L 1A8, Canada. Google Maps: https://www.google.com/maps?cid=10246687099425416717

What areas do you serve? 
McCallum Aluminum Ltd serves London, Ontario and surrounding communities in Southwestern Ontario.

What are the business hours? 
Monday–Friday: 8:00 AM – 4:00 PM. Saturday–Sunday: Closed.

How do I request a quote or estimate? 
Call +1 (519) 433-4223 tel:+15194334223 or visit https://mccallumaluminum.on.ca/ and use the contact form.

Do you install patio doors and entry doors? 
Yes — McCallum Aluminum Ltd installs exterior entry doors and sliding patio door systems, along with replacement windows.

How can I contact McCallum Aluminum Ltd? 
Phone: +1 (519) 433-4223 tel:+15194334223 
Email: inquiries@mccallumaluminum.on.ca mailto:inquiries@mccallumaluminum.on.ca 
Website: https://mccallumaluminum.on.ca/ 
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<h2>Landmarks Near London, Ontario</h2>

1) Victoria Park https://www.google.com/maps/search/?api=1&query=Victoria%20Park%2C%20London%20ON — Visiting downtown? Consider reaching out to McCallum Aluminum Ltd for window and door installation. 
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