The right entrance door for an Ontario house is, nine times out of ten, an insulated fibreglass slab with a polyurethane core, a multi-point lock and a properly flashed sill. Steel is the honest budget choice and the better call on a side or garage-to-house entry. Wood belongs on heritage streets and under deep porches, and asks for maintenance in return. Here is how the three compare on heat, strength, upkeep and price, plus the details that decide whether the door still seals in year ten.
Fibreglass, steel and wood compared
Every exterior door is a sandwich: an insulating core between two skins, hung in a frame. The skin decides how it looks and how it takes abuse. The core decides how warm it is.
| Measure | Fibreglass | Steel (insulated) | Wood |
|---|---|---|---|
| Typical slab R-value | R-5 to R-6, up to R-7 on thicker cores | R-5 to R-6 with a thermal break, less without | R-2 to R-3 |
| Core | Polyurethane, composite stiles and rails | Polyurethane or polystyrene behind 24–26 gauge steel | Solid stile-and-rail or engineered lumber |
| Impact | Will not dent; a corner strike can crack it | Dents permanently | Dents and gouges, but sandable |
| Freeze-thaw | Stable | Stable, telegraphs frame movement | Swells in spring, shrinks in January |
| Rust and rot | Neither | Rusts at the bottom rail once salt finds a scratch | Rots at the bottom rail without an overhang |
| Upkeep | Factory finish, 15+ years | Paint touch-ups every few years | Refinish every 2–4 years when exposed |
| Service life | 25–30 years | 15–20 years when weather-exposed | 30+ maintained, under 15 if neglected |
| Installed, Simcoe County 2026 | $2,200 – $4,500 | $1,300 – $2,600 | $3,500 – $8,000+ |
| Best for | Almost every front door here | Side, garage-to-house, budget entries | Heritage homes with a deep porch |
Prices are supplied and installed for a standard 36 by 80 inch pre-hung unit, before glass surrounds. A full system with two sidelites and a transom runs $5,000 to $11,000.
Fibreglass
A compression-moulded fibreglass skin holds a deep woodgrain, takes a stain, and does not care that Barrie swings from minus 25 in January to plus 30 in July. Composite stiles and rails mean no rot at the bottom rail, exactly where steel and wood fail first. The trade-off is price, plus the fact that a cracked skin is a replacement rather than a patch.
Steel
Steel buys the most resistance per dollar at the skin, which makes it the right choice for a garage-to-house door, a side entry or a rental.
Ask one question before you sign: does the slab have a thermal break between the inner and outer skins? Without one the steel conducts straight through and you get frost on the interior face on a cold morning, even though the foam behind it is fine.
Wood
Solid wood is the only material that looks like solid wood, and on a century home in Orillia or a stone front in Aurora that matters. It is also the weakest insulator here, roughly half the R-value of an insulated slab.
It needs a covered porch or storm door plus a refinish every two to four years on a south or west wall. Skip either and the finish greys and checks inside five winters.
The core does the insulating, not the skin
Slab R-value comes from the foam. Polyurethane lands around R-5 to R-6 in a standard 1 3/4 inch slab; polystyrene, common on entry-level steel, reads lower. Two numbers get lost in most quotes.
- Whole-door U-factor is the honest figure. It averages slab, glass, frame and edge, and always reads worse than the slab R-value suggests.
- Air leakage beats R-value for felt comfort. A compression weatherseal, an adjustable strike and a sweep that touches the threshold do more than one more R point of foam.
Ontario sets no minimum U-factor for a like-for-like door swap. Supplementary Standard SB-12, which caps U-values for glazed doors in new construction and additions, does not reach a slab dropped into an unchanged opening. The specification is entirely on you and your supplier.
Locks decide security, not the slab
Almost nobody comes through the panel. They come through the lock, strike or jamb.
Multi-point locking
A multi-point lock throws three or more points from one handle lift, usually a centre latch plus hooks or rollers near head and sill. Two things follow: forced entry has to break the frame in three places at once, and compression is even top to bottom, so the weatherseal actually seals.
Reading the grade
Deadbolts and locksets are graded by ANSI/BHMA:
- Grade 3 is basic residential. Fine on a shed, not a front entry.
- Grade 2 is the sensible minimum for a house entrance door.
- Grade 1 is the commercial tier: 250,000 cycles and a ten-strike hammer test.
The parts nobody itemises
- Three-inch screws through the strike plate into the stud, not the 3/4 inch screws in the box.
- A reinforced box strike instead of a stamped plate.
- Non-removable hinge pins or a hinge stud on any outswing door.
- Laminated glass in any lite within arm’s reach of the deadbolt.
A fibreglass door with a multi-point lock and a stud-anchored strike beats a steel door with one deadbolt in a stamped plate, every time. Our entrance door range lists the hardware that comes standard.
Sidelites and transoms cost more heat than people expect
Glass around the door is the biggest energy decision in the order. A plain 36 by 80 inch slab is about 1.9 m². Add two 12 inch sidelites and a transom and the assembly grows to roughly 3.5 m² of area that performs worse per square metre than the slab it surrounds.
The arithmetic: an insulated slab sits near U 1.0 W/(m²·K), a good double-glazed Low-E sidelite with argon and a warm-edge spacer near 1.6. The full assembly loses roughly two and a half times the heat of the bare door.
If you want the light, buy it properly.
- Specify the Low-E and argon package you would put in a window, not builder-grade clear glass.
- Ask for ENERGY STAR certified glazed units. Canada has used a single national standard since 2020: U-factor 1.22 W/(m²·K) or lower, or an Energy Rating of 34 or higher.
- Consider one sidelite instead of two, or a half-lite door instead of a full lite. Most of the daylight, a fraction of the loss.
Threshold, sill pan and water
Doors are tested under NAFS (AAMA/WDMA/CSA 101/I.S.2/A440) for structural load, air leakage, water penetration and forced-entry resistance. One rating deserves attention: LW means limited water penetration resistance, permitted only on side-hinged doors. On an exposed wall with no overhang, that is not the door you want.
- Sill pan. A formed pan with end dams and a back leg sends water past the seal back outside instead of into the subfloor.
- Adjustable threshold. The cap gets raised or lowered after the door settles, so the sweep touches without dragging.
- Sloped sill and drip cap. Water has to leave. Caulking the full perimeter, bottom included, traps it instead.
What each elevation needs
- South and west: heat and UV. Several manufacturers limit finish warranties on dark colours without an overhang. Check before choosing black.
- North: coldest, no solar gain. Prioritise whole-door U-factor and weatherseal. Interior frost shows up here first.
- The prevailing weather side, usually west and southwest here: driving rain. Insist on a real water-penetration rating and a sill pan.
- Garage-to-house: the Ontario Building Code treats this as a separation between garage and dwelling. Confirm the required rating and self-closing hardware with your municipal building department.
Six ordering mistakes we keep fixing
- Buying the slab and reusing the old frame. The frame carries the lock, the seal and the water management. A new door in a racked frame is a new door that leaks.
- Ignoring swing direction. Inswing or outswing, left or right hand, changes the lock, the sill and whether the door blocks a stair.
- Ordering glass without a privacy plan. Full-lite doors look excellent in a showroom and expose your hallway at night.
- Leaving a wood or unfinished fibreglass slab unsealed. An unsealed bottom rail wicks water within one season.
- Measuring the slab instead of the rough opening. Pre-hung units are sized to the opening, not to the door you are removing.
- Assuming no permit is needed. A same-size replacement in the same location generally does not require one, but enlarging the opening or altering the header does. Confirm with your municipality’s building department first.
Getting the specification right
Ask any quote to state four things in writing: slab material and core, whole-door U-factor, lock type and ANSI/BHMA grade, and how the sill will be flashed. A quote naming all four is comparable. One reading “premium entry door, installed” is not.
TopView Windows & Doors installs with our own crew across Simcoe County and York Region, no subcontracting, and warrants both product and installation. We cover the HST on window and door replacement, and our guide to window and door financing in Ontario tracks which rebates are still open in 2026. Book a measure through our contact page or call (647) 448-8439.
