What B2B Buyers Should Compare First
A prehung French door arrives as a complete, factory-assembled unit: the door slab (or slabs) already mounted on hinges inside a machined frame, with the lockset bore, strike plate, and often the glazing installed before shipment. The buyer’s job is not to assemble a door — it is to verify that the unit’s dimensions, handing, material, and performance ratings match the opening, the climate, and the project schedule.
That single distinction drives most sourcing decisions. A slab door leaves frame fabrication, hinge mortising, and weathersealing to the site. A prehung unit moves that work into a controlled factory environment, which is why commercial projects specify prehung almost by default — the quality of the seal and the alignment of the frame no longer depend on the skill of whoever is on site that day.
For B2B procurement, four comparison axes matter more than any brochure claim: size and rough opening mathematics, configuration (single vs double, interior vs exterior), material and glazing performance, and supplier capability. The rest of this guide works through each in the order buyers typically evaluate them.
Prehung French Doors Explained: Components and Configurations
A prehung French door unit consists of several parts that must all be specified together:
- Door slab(s) — single or paired, with lites (glass panes) divided by muntins or left as a single full-lite panel.
- Frame and jamb — the machined surround, cut to a specific jamb width that must match the finished wall thickness.
- Hinges — typically three per leaf for standard heights, more for tall or heavy units; hinge finish and type (fixed pin, adjustable) affect long-term alignment.
- Lockset preparation — bore and mortise cut for the specified hardware, including multipoint locking on exterior units.
- Glazing — tempered, insulated (double or triple), laminated, or decorative, already set and sealed.
- Threshold, sill, and weatherseal — critical on exterior units, often minimal on interior units.
The key difference from a slab door is that the frame is already squared and the slab is already hung. On site, the installer sets the whole assembly into the rough opening, shims it plumb and level, and fastens it. That reduces the most common failure point in French door installation — a frame that is twisted or out of square, which causes the doors to bind and the seals to leak.
Single vs Double Prehung French Doors
A single prehung French door uses one hinged leaf in a frame. It is the right choice where the opening is narrow, where only one leaf needs to operate, or where the second panel is fixed (a “French door with sidelite” configuration).
A double prehung French door — often called a French pair — uses two leaves in one frame. The two common variants are:
- Active/active: both leaves operate, with an astragal or T-astragal sealing the meeting stile. Common for interior room dividers and for exterior openings up to roughly 6 ft wide.
- Active/inactive: one leaf operates daily; the second is held by flush bolts and opened only when moving furniture or for full-width access.
For B2B buyers, the decision usually comes down to traffic pattern and opening width. A double unit wider than about 6 ft (1.8 m) starts to put significant load on hinges and the header, and the hardware spec should reflect that.
Size and Dimension Guide
Sizes for prehung French doors are usually quoted in feet and inches in North American projects and in millimeters elsewhere. The dimensions below reflect the common nominal sizes buyers ask about, but the governing number is always the rough opening (RO) — the framed gap in the wall — not the door size.
| Nominal door size | Typical use | Approx. rough opening (verify with supplier) |
|---|---|---|
| 72 in (single or pair) | Narrow single leaf or compact pair | Depends on jamb width; add frame + shim allowance |
| 96 x 72 | Tall single or pair, feature openings | Height-driven; header height critical |
| 96 x 80 | Tall wide pair, large interior or exterior openings | Requires reinforced header |
| 72 x 76 | Compact pair, older or retrofitted openings | Often used where ceiling height is limited |
| 72 x 80 | Standard interior pair | Most common interior French pair size |
The general RO formula is: rough opening width = door/frame width + shim and leveling allowance (commonly 1–2 in total), and rough opening height = frame height + sill/threshold + shim allowance. These allowances vary by manufacturer and by whether the unit is interior or exterior, so the only safe practice is to request the supplier’s RO drawing and confirm it against the actual framed opening before the frame is closed in.
Two practical warnings. First, nominal sizes are not standardized across manufacturers — a “72 x 80” from one factory may not match another’s. Second, on exterior units, the RO must also account for flashing and drainage detailing, which adds to the effective opening. Buyers who lock in sizes before confirming the RO drawing are the ones who end up with change orders. For a deeper breakdown of how nominal sizes map to actual frames, see our size guide.
Interior vs Exterior Prehung French Doors
The two categories look similar in a catalog and behave very differently on site.
Prehung interior French doors are built for appearance and smooth operation. Frames are thinner, glazing is often tempered or laminated for safety rather than thermal performance, and weathersealing is minimal or absent. The common sizes cluster around pairs such as 72 x 80, with 72 x 76 used where ceiling height is restricted. Hardware is typically passage or privacy sets, not multipoint locks.
Exterior prehung French doors are built as a weather and thermal barrier. They require:
- Insulated glazing with a rated U-factor and solar heat gain coefficient (SHGC) appropriate to the climate zone.
- A proper sill with drainage, plus flashing integration at the head and jambs.
- Weatherstripping and, on better units, a multipoint locking system that compresses the seals at multiple points.
- A frame material that resists moisture — thermal-break aluminum, uPVC, or a properly finished wood or fiberglass system.
The practical consequence for procurement: interior and exterior units should never be specified from the same line item. They differ in frame profile, glazing, hardware, and price, and mixing them up is one of the more expensive errors in bulk ordering.
Material and Glazing Comparison for Commercial Projects
Material choice drives durability, maintenance, and thermal performance more than any other single decision.
| Material | Strengths | Trade-offs | Best fit |
|---|---|---|---|
| Solid wood | Warm appearance, easy to repair, takes any finish | Requires ongoing maintenance; moisture movement | Interior feature doors, covered exterior openings |
| Thermal-break aluminum | Dimensional stability, slim sightlines, low maintenance, strong for large units | Higher material cost; thermal performance depends on the break and glazing | Exterior, large spans, high-wind or coastal sites |
| uPVC | Good thermal performance, low cost, low maintenance | Bulkier profiles, color options limited, less structural rigidity | Cost-driven exterior projects in moderate climates |
| Fiberglass | Dimensionally stable, good thermal performance, paintable | Higher cost than uPVC; quality varies widely | Exterior units where wood look plus durability is needed |
Glazing is where energy performance is actually determined. Buyers should specify, at minimum, the U-factor, SHGC, and visible light transmission for the project’s climate zone, and confirm that safety glazing (tempered or laminated) is used wherever required by local code. Decorative glazing — divided lites, textured or leaded glass — adds cost and can reduce thermal performance slightly, so it should be a deliberate choice rather than a default.
Hardware deserves equal attention. Hinge count and finish, lockset grade, and whether the unit uses a multipoint lock all affect how the door performs after a few thousand cycles. On double prehung French doors, the astragal and flush-bolt hardware are frequent failure points if specified cheaply.
Supplier Comparison Table: What to Evaluate
Supplier capability is where similar-looking products diverge. The table below lists the criteria that actually predict project outcomes.
| Evaluation criterion | What to ask | Why it matters |
|---|---|---|
| Size and configuration flexibility | Can the supplier produce custom sizes and single/double configurations? | Standard-only suppliers force compromises on RO fit |
| Material range | Which materials and glazing options are available in-house? | Affects whether one supplier can cover mixed projects |
| Pre-shipment testing | Air-tightness, water-tightness, wind resistance testing | Predicts real-world weather performance |
| Certification and code fit | Can profiles and fittings be adjusted to local building codes? | Avoids rejection at inspection |
| MOQ and lead time | Minimum order quantity and quoted production window | Drives project scheduling and inventory cost |
| Documentation | Packing list, proforma invoice, full customs documents | Determines how smoothly the shipment clears |
| Shipping mode | FCL and LCL capability | Affects freight cost per unit on partial loads |
| Customization depth | OEM, ODM, private label, custom color and hardware | Matters for distributors and branded programs |
A useful discipline for B2B buyers is to score suppliers on these criteria before comparing price. Price differences of 10–15% between suppliers are often explained by testing, documentation, or material grade — not by margin.
How One Manufacturer Approaches These Standards
As a manufacturer, our approach at Jusen Door and Windows is to treat the criteria above as the production specification rather than as sales points. We supply directly from our factory, which removes middleman markup and keeps pricing competitive on bulk orders, and we build both solid wood and thermal-break aluminum systems, including system windows, casement and sliding doors, sunrooms, and aluminum entrance doors.
Because projects differ by market, we adjust profile structure and fittings to match the local building codes of the target market rather than forcing a single standard profile. Every unit goes through pre-shipment inspection covering air-tightness, water-tightness, and wind resistance, and we handle full customization on size, color, glass, and hardware — including OEM, ODM, and private label programs for distributors.
On the logistics side, we ship both FCL and LCL direct from the factory and provide the packing list, proforma invoice, and full customs documentation that importers need. If your project involves mixed configurations or a code requirement that needs to be verified against a drawing, contact our team with the opening schedule and we can confirm feasibility before you commit.
Procurement and Installation Considerations
Once specifications are settled, three operational factors determine whether the project stays on schedule.
Rough opening verification. Before production, confirm the RO drawing against the actual framed opening. Tolerance matters: a frame that is out of plumb or out of square by more than a small margin will cause binding regardless of how well the unit was made. Buyers should build a verification step into the construction sequence, not assume the opening is correct.
Working with french door installers. Prehung units reduce installation labor, but they do not eliminate skill requirements. A competent installer will check the opening, set the unit plumb and level, shim at hinge points and the lock side, insulate the gap, and — on exterior units — integrate flashing and seal the sill correctly. When hiring french door installers for a commercial project, ask for evidence of prehung exterior installation experience, not just general carpentry. A typical two-person crew can set a standard prehung pair in a few hours once the opening is prepared, but exterior flashing and sealing add time that should be reflected in the schedule.
Cost factors in bulk procurement. Unit price is only part of the landed cost. The main variables are:
- Material and glazing specification (the largest single driver).
- Size and configuration — custom sizes and double units cost more than standard singles.
- Hardware grade, including whether multipoint locking is specified.
- Testing and certification requirements for the destination market.
- Order volume and shipping mode — FCL loads reduce freight cost per unit versus LCL.
- Documentation and customs handling.
Buyers comparing quotes should normalize for all of these before concluding that one supplier is cheaper. A quote that omits testing or documentation is not a lower price; it is a different scope. For a fuller breakdown of how these factors translate into project pricing, see our pricing page.
Choosing Between Options: A Decision Framework
With the comparison criteria in hand, the choice usually resolves into a few clear scenarios:
- Choose solid wood if the doors are interior feature units or sit under a covered exterior opening, and the project can support periodic maintenance.
- Choose thermal-break aluminum if the units are exterior, spans are large, or the site faces wind, salt, or extreme temperature swings.
- Choose uPVC if the project is cost-driven, the climate is moderate, and profile bulk is not a constraint.
- Choose fiberglass if a wood appearance is required on an exterior opening with lower maintenance.
- Choose a single prehung French door where the opening is narrow or only one leaf needs to operate.
- Choose a double prehung French door where the opening is wide and daily traffic justifies two operating leaves.
- Choose active/inactive where the second leaf is rarely used and security or sealing is a priority.
On the supplier side, the deciding factors are usually testing discipline, code fit, and documentation quality rather than headline price. A supplier that can adjust profiles to local code, test before shipment, and provide complete customs paperwork removes more project risk than a marginally lower unit price.
Common Buying Questions
What is the difference between a prehung French door and a slab door?
A slab door is the door panel alone. A prehung French door includes the slab already hinged into a machined frame with lockset preparation and, usually, glazing installed. Prehung units shift frame fabrication and hinge alignment into the factory, which improves seal quality and reduces on-site labor.
What sizes are available, including 72 in, 96 x 72, 96 x 80, 72 x 76, and 72 x 80?
All of these are common nominal sizes, but nominal dimensions are not standardized across manufacturers. A 72 in unit may be a single leaf or a compact pair; 96 x 72 and 96 x 80 are tall units used for feature openings; 72 x 76 and 72 x 80 are typical interior pairs. Always confirm the rough opening drawing rather than ordering from the nominal size alone.
What is the difference between single and double prehung French doors?
A single unit has one hinged leaf in the frame. A double unit has two leaves, either active/active (both operate, sealed by an astragal) or active/inactive (one operates daily, the second is held by flush bolts). Double units suit wider openings but place more load on hinges and the header.
Are prehung interior French doors different from exterior prehung French doors?
Yes, substantially. Interior units prioritize appearance and operation, with minimal weathersealing. Exterior units require insulated glazing with rated U-factor and SHGC, a drained sill, flashing integration, weatherstripping, and often multipoint locking. They should never be specified as the same line item.
How do I compare suppliers of prehung French doors for B2B projects?
Score suppliers on size and configuration flexibility, material range, pre-shipment testing, code fit for the destination market, MOQ and lead time, documentation completeness, and FCL/LCL capability — then compare price. Price differences between suppliers are usually explained by testing, material grade, or documentation scope.
What should I consider when hiring french door installers?
Look for experience with prehung exterior units specifically, including flashing and sill sealing. Confirm the crew will verify the rough opening, set the unit plumb and level, shim at hinge and lock points, and insulate the frame gap. Installation time depends heavily on how well the opening was prepared before the unit arrives.
What drives cost in bulk procurement?
Material and glazing specification is the largest factor, followed by size and configuration, hardware grade, testing and certification requirements, order volume, shipping mode, and documentation. Normalize all of these across quotes before comparing unit prices.
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