Quote Per Pane vs Per Window vs By the Hour Decision Matrix

Why this matters

How you quote a job determines whether you're profitable, defensible in a dispute, and competitive in the local market. Per-pane is fast and unambiguous but undervalues second-floor work and storm-window detail. Per-window hides the pane count and gets you crushed on French doors and grids. Hourly is honest about labor but loses bids against fixed-price competitors and trains customers to clock-watch your crew. This matrix gives a defensible rule per job type and explains the line-item math so any tech can quote in the driveway without a calculator argument with the homeowner.

When each model is the right call

The three models map to three distinct job shapes. Mixing models on one job (per-pane outside, hourly for grid detail) is acceptable when documented; switching models mid-job is the path to a chargeback.

• Per-pane: residential one-time wash with mixed grid styles; restoration work where pane count = labor count; commercial storefronts where each pane is identical.
• Per-window: recurring residential maintenance where the customer wants a single line item year-over-year; small commercial pre-quoted on a stable unit count.
• Hourly (T&M): post-construction cleanup with unknown debris severity; hard-water restoration on a unknown stage mix; high-rise rope work where setup-to-clean ratio is unpredictable.

Quick checks - what to count before you quote

Walk every elevation before you put a number on paper. Count and photograph each of the following:

• Total openings (sashes that move): each opening typically has 2 panes outside + 2 inside = 4 panes; storm window adds 2 more; grid (true-divided-light) multiplies by grid count.
• Special-condition windows: stained glass (do not WFP), leaded panes (do not razor), single-pane antique (do not pressure-wash), egress basement well (extra time, OSHA confined-space adjacent), skylight (separate ladder set or roof-access fee).
• Access difficulty: ladder-only access vs WFP-reach vs roof-walk required vs lift required (rare on residential, common on commercial 4-story+).
• Frame condition: clean frames squeegee fast; chalking aluminum doubles per-pane time; peeling paint triples it (you're now also painting protector while you work).

Photograph everything you count. The most common chargeback is "you missed the kitchen bay" - which you didn't, but the customer thinks you did because they don't remember confirming the count.

Per-pane matrix

Per-pane is the cleanest model for residential one-time jobs. Multipliers stack from the base rate:

Document the count on the work order. "44 panes interior, 44 panes exterior, 12 storm windows, 2 skylights, 4 grid units (16 squares each)" is unambiguous; the customer signs it before work starts.

Per-window matrix

Per-window is the right call for recurring accounts where the customer wants a single annual or quarterly invoice line. The math you do once, applied year-over-year. Pricing inputs:

• Count openings (operable + fixed).
• Apply an internal per-pane labor estimate (typically 2.5 to 4 panes per opening for residential).
• Set a per-window price that holds across the route.

The trap: if a customer adds a sunroom in year 3, you need a documented "by the window" definition. Three rules that hold up:

1. An opening with operable sashes counts as one window per side cleaned (interior + exterior = 2 in the count).
2. A fixed-glass opening over 12 sq ft counts as one window; under 12 sq ft (small transom, half-bath) counts as half.
3. A French door is counted as the door + the panes; do not bundle into a flat "door" without specifying pane count.

Hourly matrix - when T&M is the honest answer

Hourly is correct when scope is genuinely unknown. Three rules:

• Quote a 2-hour minimum (covers travel, setup, breakdown) regardless of actual on-site time.
• State the hourly rate, the 2-hour minimum, and the increment (15-minute, 30-minute, or full-hour) in writing before work starts.
• Photograph and timestamp the start and end - hourly disputes are won and lost on photo timestamps.

When hourly is the wrong call: any job where the customer can plausibly estimate scope themselves. If the homeowner can count 30 windows and you tell them "we'll see how long it takes," they assume you're padding and shop the next bid. Hourly works when scope is genuinely opaque - post-construction, restoration of unknown severity, first-time commercial route during a discovery visit.

Confirming the choice with the customer

The conversation in the driveway, one of three openers depending on the model:

• Per-pane: "I counted 88 panes including the storms; at our restoration rate, that's [total]. Sign here to confirm the count and the inclusions before we start."
• Per-window: "32 windows on the maintenance route, billed quarterly at the contract rate. Any additions to the property notify us 30 days before service to adjust the count."
• Hourly: "2-hour minimum, [rate]/hour, billed in 30-minute increments. I expect 4 to 6 hours based on the scope; I'll text a 1-hour-remaining notice."

Never mix models without saying so. "Per-pane on the exterior, hourly on the restoration of the 4 etched panes" is fine if it's written; the same phrase spoken in the driveway gets misremembered into a flat price.

Confirming the math is right - dry run before commit

Before sending the quote, run the math against three checkpoints:

References

• IWCA I-14.1, Window Cleaning Safety Standard (industry consensus on scope of work definitions).
• OSHA 29 CFR 1910.333(c)(3), Working Around Energized Conductors (overhead clearance for ladder access pricing).
• ASTM E2128, Standard Guide for Evaluating Water Leakage of Building Walls (relevant to post-installation cleanup scope).
• IRS Publication 535, Business Expenses (record-keeping standards for T&M billing documentation).