A vendor quotes a price for window replacement leads. You multiply that price by the number of inquiries you want, compare the total with your budget, and the order looks reasonable.
That quote gives you the numerator for one early-stage calculation. It doesn’t tell you how much you paid for a qualified opportunity, a booked replacement job, or completed work. Those later numbers depend on what happens after each inquiry arrives.
Before you buy window leads again, carry the vendor spend through the full chain. Use your records for qualification, estimates, bookings, completed work, revenue, and gross margin. The vendor may end up earning more budget. It may deserve less. Your closed-job math should decide.
Window Leads Cost Starts With an Incomplete Denominator
Price per inquiry answers a limited question: what did you pay for each name, call, or form submission the vendor delivered?
It does not account for inquiries outside your service area, requests for a service you don’t sell, duplicate contacts, or homeowners who aren’t ready for an estimate. It also stops before your team answers, qualifies, estimates, and books the work.
Define each stage before you open the spreadsheet. For a window replacement company, the chain might look like this:
Inquiry
A call or form submission attributed to the vendor.
Qualified opportunity
An inquiry that matches your service, service area, and buying window.
Completed estimate
A qualified opportunity that reaches an actual estimate appointment.
Booked job
A sold project that reaches your schedule under the definition your team uses.
Completed job
A booked project that is finished and can be matched to completed revenue.
The definitions matter more than the labels. If “booked” means an estimate appointment in one report and a sold project in another, you cannot compare the numbers.
Calculate Window Replacement Leads Through Completed Work
Use one date range and one attribution rule. Assign a letter to each input:
- S = vendor spend
- I = attributed inquiries
- Q = qualified opportunities
- E = completed estimates
- B = booked jobs
- C = completed jobs
- R = completed revenue attributed to the vendor
- M = gross margin expressed as a decimal
Then run the calculations:
Cost per inquiry = S / I
Cost per qualified opportunity = S / Q
Cost per booked job = S / B
Cost per completed job = S / C
Attributed gross profit = R x M
Gross-profit contribution after vendor spend = (R x M) – S
That final figure still is not net profit. It does not subtract overhead or other expenses. It simply carries the marketing source through completed revenue using the gross margin you provide. If you need the broader measurement framework, use the cost-per-booked-job guide before comparing channels.
A Hypothetical Window Leads Cost Worksheet
The figures below are hypothetical and intentionally tidy. They show the arithmetic only. They are not averages, expected performance, or a window-industry benchmark.
Assume you record these results for one vendor during one review period:
- Vendor spend: $8,000
- Attributed inquiries: 40
- Qualified opportunities: 24
- Completed estimates: 16
- Booked jobs: 8
- Completed jobs: 6
- Completed attributed revenue: $60,000
- Your estimated gross margin: 35%
The inquiry cost is $8,000 / 40 = $200.
The qualified-opportunity cost is $8,000 / 24 = $333.33.
The cost per booked job is $8,000 / 8 = $1,000. The cost per completed job is $8,000 / 6 = $1,333.33.
Completed attributed gross profit is $60,000 x 0.35 = $21,000. After subtracting the $8,000 vendor spend, the hypothetical gross-profit contribution is $13,000.
The two booked jobs that are not yet completed need a status. They may be pending, canceled, or outside the reporting period. Do not count their contract value as completed revenue just to finish the calculation. Mark open work as pending, record cancellations as cancellations, and update the worksheet when each job’s status changes.
Compare Purchased Leads and Direct Campaigns the Same Way
Purchased lead access and a direct campaign can both produce useful work. Either can also waste money. Compare them with the same stage definitions, date range, and completed-revenue rule.
For each source, record spend, inquiries, qualified opportunities, completed estimates, booked jobs, completed jobs, and completed gross profit. Keep unattributed calls in a separate row. If a source cannot be traced past the inquiry, treat its later-stage result as unknown instead of filling the gap with a guess.
Then check what each agreement says you retain if you stop paying. For each source, document whether you keep the ad account history, service-specific landing page, tracking setup, and inquiry records. That difference does not replace the closed-job math, but it belongs beside it.
Let Your Numbers Decide Whether to Buy Window Leads Again
Do not approve the next order from the quoted lead price alone. Run one recent period through qualification, booked work, completed work, and gross profit. Label estimates, keep pending jobs open, and use the margin from your own records.
If you want to compare that vendor with a pipeline built around your company, read the window and siding marketing guide. It explains how search, paid social, landing pages, tracking, and follow-up fit together so you can judge a direct campaign on the same completed-job basis.