10 Questions to Ask Before Hiring a Window Cleaning Company

Insurance and Licensing

These aren't optional questions — they protect you from significant financial exposure:

1. 1Are you licensed and insured? What does your coverage include? — Ask for a Certificate of Insurance (COI) specifically. General liability should be at least $1 million per occurrence. For any work above ground level, verify the policy covers work at height. A company that won't provide a COI on request is a red flag.
2. 2Does your insurance cover work-related injuries on my property? — Workers' compensation covers employees injured on your property. Without it, an injured worker could potentially pursue a claim against your homeowner's insurance. Confirm workers' comp is active and covers window cleaning work.

Scope and What's Included

The most common source of quote disputes is scope misunderstanding — these questions prevent it:

1. 1Does your quote include interior cleaning, or exterior only? — Never assume. Interior + exterior is typically 60–80% more than exterior-only. Confirm explicitly which you're getting.
2. 2Are screens removed and cleaned separately, or cleaned in place? — In-place screen 'cleaning' usually means a quick wipe that leaves debris, which falls on freshly cleaned glass the first time you open a window. Proper technique removes, washes, and reinstalls screens after the glass is done.
3. 3Is track and sill cleaning included? — Almost always a separate add-on. If track cleaning matters to you, get it quoted explicitly — it adds $3–$10 per window.
4. 4How do you handle hard water stains or other difficult deposits? — A good company will assess before committing to a result and will be honest about whether deposits require additional treatment or are beyond standard cleaning.

Technique and Equipment

These questions reveal whether you're dealing with a professional operation or a one-person-with-a-squeegee setup:

1. 1Do you use purified water or tap water? — Professional water-fed pole systems use deionized or reverse-osmosis water that leaves no mineral residue. If the answer is 'tap water from a bucket,' expect mineral spots.
2. 2What do you use for difficult deposits — razor blades, chemicals, or both? — A professional should have a clear answer and know which deposits require which treatment. 'We just spray and wipe' is not sufficient for glass with contamination beyond light film.

References, Reviews, and Guarantees

The last questions are about accountability:

1. 1Do you guarantee streak-free results? What's your policy if I'm not satisfied? — A professional company stands behind their work. Ask specifically what they'll do if you call the next day and find streaks or missed areas. Most reputable companies will return to address issues at no charge.
2. 2Can you provide recent Google reviews or references from customers with similar properties? — General review counts are less useful than reviews from people with similar homes or commercial properties. A company with 200 reviews but only from residential clients may not have experience with your commercial property.

Red Flags to Watch For

Beyond specific questions, these indicators should make you pause before booking:

• Refuses to provide a COI or says they're 'self-insured' (meaningless)
• Gives a firm quote over the phone for a multi-story home without asking about window count, story count, or contamination
• No verifiable online presence, reviews, or business address
• Quote is more than 40% below other quotes for the same scope — usually means scope exclusions, unlicensed workers, or no insurance
• Cannot answer the purified water question clearly
• Pressure to book immediately or 'this price is only good today'