A window specification schedule connects each opening ID to a verified product and size, operation, glass package, whole-window performance, finish, hardware and installation scope. It records who verifies dimensions, who determines project requirements and which documents govern the order. The schedule is a procurement and comparison record; it does not replace engineering, local approval or product-specific installation instructions.
Canadian planning context. Technical examples from other regions are identified in the guide; approval and performance requirements must be checked for the actual building and jurisdiction. Original explanatory diagrams are not construction details.
- Use one opening ID across inventory, drawings, quotes, delivery labels and acceptance records.
- Separate desired performance from the evidence that the exact ordered configuration meets it.
- State units and test context; centre-of-glass data cannot substitute for whole-window ratings.
- Describe removal, retained construction, wall connections and finishes as explicitly as the factory product.
- Approve substitutions by documented differences in product, performance, appearance, scope, price and schedule.
01 /A schedule is a shared agreement about what goes where
A brochure can describe a product family well while leaving a particular order ambiguous. The supplier may offer several glass packages, operating types, finishes and hardware options under the same series name. A schedule bridges that gap by assigning an exact intended configuration to each opening. It also makes a quotation review manageable: rather than search paragraphs for the bedroom casement, you can compare the W04 row in every offer.
Keep the preliminary homeowner inventory separate from the verified order schedule. The inventory describes existing conditions and goals; the order schedule records the supplier's confirmed dimensions and selections. A third document, the installation scope, explains how the new unit connects to the actual wall. Small projects may combine these records, but they still need distinct fields and clear responsibility. Never let a typed approximate dimension become an order dimension simply because it appears in a neat table.
02 /The opening and product fields
| Field | What to record | Question to resolve |
|---|---|---|
| Opening ID and location | W04; upper bedroom; rear elevation | Does everyone use this same identifier? |
| Assembly | Individual units, mullions and fixed/operable arrangement | Factory combined or joined on site? |
| Manufacturer and series | Full names plus exact quoted configuration | Is the glass or hardware option part of this model? |
| Verified dimensions | Supplier convention, units, revision and verifier | Who carries ordering and fit responsibility? |
| Handing and operation | Diagram and viewing convention, not an unexplained left/right word | Does it clear furniture, screens and exterior obstructions? |
| Interior/exterior finish | Colour name or code and finish sample | Are jambs and accessories matched? |
| Hardware and screens | Handle, locks, restrictors, operator and screen type | Can occupants use and service it? |
| Glass composition | Pane package, coatings, gas, spacer and special glass | Which elements are verified and which are marketing shorthand? |
A diagram is often safer than the words 'left-hand'. Manufacturers use viewing and handing conventions that may differ. Mark the view as seen from inside or outside and have the supplier confirm it. For mixed fixed and operable units, show which sections open. Do not rely on a showroom sample to establish the operation of a different size or configuration.
03 /Separate performance requirements from product evidence
Create two columns: the project's requirement, determined by the appropriate designer or authority, and the offered product's documented value. This makes a missing piece visible. 'High efficiency' is not a measured requirement; 'ENERGY STAR' does not identify every other performance characteristic the building needs. Energy, air leakage, water resistance, structural capacity, acoustic performance, safety glazing and operating clearances answer different questions.
| Subject | Record | Avoid |
|---|---|---|
| Thermal | Whole-window U-factor with units and exact model reference | Comparing centre-glass to whole-window values |
| Solar and daylight | SHGC and visible transmittance for the offered configuration | Assuming the lowest SHGC is best in every room |
| Air/water/structural | Applicable performance designation, size limitations and source document | Treating an energy label as proof of all ratings |
| Acoustic | Tested assembly and metric where sound is a design goal | Using pane count alone as a noise rating |
| Safety and access | Applicable glazing, operation, clear opening and restrictor decisions | Assuming a nominal frame size establishes compliance |
| Certification/incentive | Exact directory entry and applicable program evidence | Assuming a brand logo makes every configuration eligible |
NRCan's ratings guidance distinguishes U-factor, solar heat gain and visible transmittance. Use those terms consistently and retain the rating source. This schedule does not prescribe a universal target: climate, orientation, shading, building design and local requirements shape the choice. Consult ENERGY STAR ratings and labels and submittals for the evidence trail.
04 /Write the installation scope beside the product
A factory product can arrive exactly as ordered while its installation scope remains unresolved. For each opening or a clearly defined group, record insert or full-frame work, what is removed, what remains and what inspection occurs after removal. Identify the sill-water-management detail, connection to the wall's water-resistive layer, perimeter air seal and restoration of interior and exterior finishes. These are scope questions for the responsible installer or designer, not instructions to improvise a universal flashing detail.
| Item | Responsible party | Required confirmation |
|---|---|---|
| Final survey | Named supplier/installer | Verified schedule and ordering convention |
| Opening preparation | Installer plus specialist if needed | Condition assessment and repair boundary |
| Anchorage and assembly | Responsible installer/designer | Applicable product and project detail |
| Water and air connections | Installer/designer | Compatible materials and wall-specific sequence |
| Cladding and trim | Named trade | Removal, restoration and finish standard |
| Permits and inspection | Party named in contract | Authority confirmation and closeout documents |
| Concealed damage | Owner and contractor approval process | Document before additional non-emergency work |
| Cleanup and disposal | Named contractor | Protection, waste and final cleanup scope |
Where construction is unknown, state the inspection and decision point rather than inventing a detail. An older stucco wall may require further investigation before its connection can be specified. A new window should not conceal unresolved deterioration. The installation guide explains the concepts; project details must fit the wall and product.
05 /Use alternates and substitutions carefully
An alternate is an option offered before agreement. A substitution changes an agreed product or detail later. Both need a comparison rather than a vague assurance that they are equivalent. Ask the supplier to list differences in dimensions, visible glass, sightlines, finish, operation, hardware, ratings, certification, warranty, installation requirements, availability and price. A product with a better thermal value can still be unsuitable if it reduces the required clear opening or changes a heritage profile.
Keep the original selection visible. Record the proposed replacement in a new revision and identify who reviewed the differences. Approval should name the exact affected openings and the agreed consequences for price and schedule. A phone call saying 'we upgraded you' is not a substitute for this record. If a professional established the original requirement, route the change through that reviewer. The supplier should confirm that the changed configuration remains supported by its evidence and installation documents.
06 /Review the schedule before release to fabrication
- Check every opening
Reconcile IDs, quantities and assembly parts against the field survey.
- Confirm selections
Review operation, handing diagrams, colours, glass and accessories; resolve all 'TBD' fields.
- Verify evidence
Match the offered product and configuration to the required performance and certification documents.
- Resolve responsibilities
Confirm measurement, installation, approvals, access and finishing boundaries.
- Record the approved revision
Name the document, date, reviewer and supplier acknowledgement; supersede earlier versions clearly.
Do not sign a fabrication release solely to preserve a promotional deadline when key fields remain unresolved. Custom products may be difficult to change once manufacturing begins. Ask the supplier when selections become fixed and what happens if verified dimensions or authority requirements alter the order. Your province's contract rights and the actual agreement also matter; a procurement worksheet does not replace them.
07 /Carry the schedule through delivery and ownership
At delivery, match carton and product identifiers to the approved opening schedule before products are distributed around the site. Record discrepancies with the affected ID. During installation, keep photos of concealed connections where agreed and collect any revised detail. At handover, add serial or order identifiers, care instructions, warranty documents and the installation date to the same record. This makes the schedule useful when a future service provider needs the glass package or hardware model.
An owner record should be understandable without the original salesperson. Keep a simple index: inventory, verified schedule, approved revisions, delivery record, acceptance list and product care/warranty documents. Large projects may need formal submittal and document-control processes; a house can still use the same principle at a smaller scale. Continue with delivery and storage and acceptance and punch lists.
FAQQuestions people ask
Is this an engineering specification?
No. It is a procurement and comparison framework. Qualified parties must determine project-specific performance, structure, compliance and installation details.
Can one rating cover every unit in a product series?
Do not assume so. Match the operation, glass, size limitations and offered configuration to the appropriate evidence.
What does 'equivalent product' mean?
It must be demonstrated against the actual requirements, not asserted from a similar brochure. Compare performance, geometry, operation, finishes, installation and warranty.
Should preliminary dimensions stay in the final schedule?
Only clearly marked as preliminary until the responsible supplier or installer replaces them with verified order information.
Who approves a revised schedule?
The parties responsible under the project and contract. Include any professional or authority whose requirements the change affects.
