The short answer
When bids for the same building are far apart, the vendors are usually pricing different jobs, or pricing the same job with different labor, insurance and safety. The cheapest bid is often the riskiest line item.
1. They are pricing different scopes
- Different glass counts, or exterior only vs. inside and out
- Frames, sills, screens and tracks included in one bid and left out of another
- Entrances and lobbies at a different cadence
2. They assumed different access
Access changes the labor per pane. One bidder plans poles and lifts, another rope descent, another a swing stage. If the scope does not name the method, the totals cannot be compared. See rope descent vs. suspended scaffolding.
3. Who actually does the work
Many companies bid the job and subcontract it to crews you never meet and cannot vet. W2 crews are trained, insured and accountable to the company you hired. Subcontracted labor brings uncertainty about training, coverage and who is liable if there is an incident.
4. Insurance and safety cost money
- General liability and workers comp
- Site-specific safety plans
- Technician certification before at-height work
- Equipment and anchor inspection on a schedule
A bid that is low because these are missing moves the risk to your property.
5. Frequency and mobilization
Recurring programs price lower per visit than one-time cleans, because regular service keeps glass from building up. High-rise work carries mobilization costs that some bids spread differently across visits.
6. Unknown anchor status
If anchors are uncertified, someone has to inspect, test and certify them before rope work. One bid includes it, another assumes it is done. See the roof anchor and fall protection compliance guide.
How to compare bids on the same footing
- Send every vendor the same scope. Use the commercial window cleaning RFP template.
- Require pricing per visit, by building and elevation, with add-ons as line items.
- Ask: W2 or subcontractors? Certificate of insurance naming the property? Site-specific safety plan? References on buildings like yours?
- Treat a slow certificate of insurance or a vague safety answer as the answer.
How S&K prices
S&K prices on the real labor a building takes: height and access, glass count and sides, glass condition and frequency. The walkthrough ends in a clear, fixed proposal. Get a ballpark first with the pricing calculator.
