New windows and doors are one of the biggest investments you’ll make in your home. The right installer makes your home quieter, more comfortable and more energy efficient for decades. The wrong one can leave you with leaks, drafts, voided warranties and a long fight to get your money back.
After more than 16 years of replacing windows and patio doors across Los Angeles County, we’ve seen what separates a great installation from a costly mistake. This guide covers the most common pitfalls homeowners run into, the red flags to watch for, and the questions to ask before you sign anything.
Quick Checklist: Before You Hire Any Window Contractor
- Verify the contractor’s license on the California Contractors State License Board (CSLB) website
- Get at least 2–3 written, itemized estimates for the same scope of work
- Confirm exactly which brand, product line and glass package you’re being quoted
- Ask who will actually install your windows: employees or subcontractors
- Get both the manufacturer warranty and the installation warranty in writing
- Never pay more than California law allows as a down payment
- Read recent reviews on Google, not just testimonials on the contractor’s own website
- Ask whether a permit is needed and who pulls it
Pitfall #1: Not Checking the Contractor’s License
In California, contractors doing home improvement work generally must be licensed by the Contractors State License Board. An unlicensed installer may be cheaper, but you lose important protections: there may be no bond, no workers’ compensation insurance and little recourse if something goes wrong.
What to do: Ask for the contractor’s license number and look it up at cslb.ca.gov. Confirm the license is active, the business name matches, and check for any complaints or disciplinary actions.
Pitfall #2: High-Pressure Sales Tactics
“This price is only good if you sign tonight.” “My manager approved a special discount for today only.” If you’ve heard lines like these, you’ve met the in-home sales model. It’s built around commissioned salespeople, long presentations and inflated “list prices” that get dramatically discounted to create urgency.
What to do: A fair price will still be fair tomorrow. Take the quote, compare it with others and decide on your own schedule. A reputable company will give you a written estimate and let you think it over.
Pitfall #3: Paying Too Much Up Front
California law limits how much a contractor can collect as a down payment on a home improvement contract. In most cases, it’s $1,000 or 10% of the contract price, whichever is less. Progress payments after that should match work actually completed or materials actually delivered.
What to do: Be very cautious of anyone asking for 50% (or the full amount) before work starts, or asking for cash only. Never let payments get ahead of the work.
Pitfall #4: Vague, Non-Itemized Quotes
A quote that just says “Replace 10 windows – $15,000” makes it impossible to compare contractors and easy for corners to be cut. Two quotes with the same price can describe very different jobs.
What to do: Ask for a written estimate that lists:
- The window brand and specific product line or series (for example, Milgard Trinsic or Jeld-Wen vinyl)
- Frame material, glass type (dual-pane, Low-E, tempered where required) and grid options
- Installation method (retrofit vs. full new-construction frame replacement)
- Removal and disposal of old windows
- Interior and exterior trim, stucco patching or caulking
- Permit fees, if required
- Start date and estimated completion time
Pitfall #5: Choosing on Price Alone
The lowest bid often skips something: a cheaper builder-grade product, subcontracted labor, no permit or a shortcut on waterproofing. On the other hand, the highest price isn’t a guarantee of quality either. Big-box stores and national franchises often add significant overhead for advertising, commissions and middlemen.
What to do: Compare quotes line by line for the same product and scope. Then weigh price together with reviews, warranty and who’s doing the installation.
Pitfall #6: Not Knowing Who Will Install Your Windows
Many companies, including many big-box retailers, sell you the windows and then hand the installation off to a subcontractor you’ve never met. Installation quality is the single biggest factor in how your windows perform. Even the best window will leak or stick if it’s installed poorly.
What to do: Ask directly: “Are your installers your own employees or subcontractors?” and “Who is responsible if there’s a problem with the installation?”
Pitfall #7: Overlooking the Warranty Details
“Lifetime warranty” can mean very different things. There are usually two separate warranties: the manufacturer’s warranty on the window itself, and the installer’s warranty on the labor. Some product warranties can be voided by improper installation.
What to do: Ask for both warranties in writing. Find out what’s covered (glass seal failure, hardware, frames, labor), for how long, whether it transfers if you sell your home, and who you call when you need service.
Pitfall #8: Ignoring Permits and Energy Code Requirements
In California, replacement windows typically need to meet Title 24 energy efficiency requirements, and many cities, including Los Angeles, require a permit for window and door replacement. Skipping the permit can cause headaches when you sell your home or file an insurance claim.
What to do: Ask whether your project needs a permit, who will pull it, and whether the windows being quoted meet current California energy code requirements. Requirements vary by city, so check with your local building department if you’re unsure.
Pitfall #9: The Wrong Window for Your Home
A window that’s perfect for a coastal home in Santa Monica may not be the best choice for a hot San Fernando Valley afternoon. Frame material, glass coatings, window style and operation all affect comfort, noise and energy bills.
What to do: A good contractor asks about your goals (energy savings, noise reduction, security, appearance, budget) and explains the trade-offs between options. If you’re being pushed toward one product without explanation, ask why.
Pitfall #10: Retrofit vs. Full-Frame Confusion
Retrofit installation places the new window inside your existing frame, which is often faster and avoids damage to stucco and interior walls. Full-frame (new construction) replacement removes the old frame completely and may be needed if the frame is damaged or rotted. Each has its place, but you should know which one you’re paying for.
What to do: Ask which method the contractor recommends for your home and why, and make sure it’s written in the contract.
Pitfall #11: Not Reading Real Reviews
Testimonials on a company’s own website are hand-picked. Independent reviews tell you how a company actually treats customers, especially when something goes wrong.
What to do: Read recent Google reviews. Look for comments about the installation crew, cleanliness, communication, and how problems were handled. A company that responds professionally to reviews is usually one that cares about follow-through.
Pitfall #12: Signing Without Understanding Your Rights
In California, home improvement contracts must be in writing and include specific information and notices. If you sign a contract in your home, you generally have the right to cancel within three business days (five business days for homeowners 65 and older), and the contract must explain that right.
What to do: Read the entire contract before signing, including the fine print. Make sure every verbal promise (start date, cleanup, specific products) is written down. If something isn’t clear, ask before you sign.
Red Flags at a Glance
- No license number, or a license that doesn’t match the business name
- “Today only” pricing or pressure to sign during the first visit
- A large deposit, or cash-only payment
- A one-line quote with no brand, model or scope details
- Can’t tell you who will do the installation
- Vague answers about warranties and permits
- No physical address or local track record
Questions to Ask Every Window Contractor
- What is your CSLB license number?
- Are your installers employees or subcontractors?
- Exactly which brand, product line and glass package is in this quote?
- Is this a retrofit or full-frame installation, and why?
- What warranties come with the windows and the installation, and are they in writing?
- Will this job need a permit, and who pulls it?
- How long will installation take, and how will you protect my floors and furniture?
- What is the payment schedule?
- Can I see recent reviews or photos of jobs near me?
Frequently Asked Questions
How many quotes should I get for window replacement?
Two to three written, itemized quotes for the same products and scope of work is usually enough to understand fair pricing in your area.
How much deposit should a window contractor ask for in California?
For most home improvement contracts, California limits the down payment to $1,000 or 10% of the contract price, whichever is less. Check the CSLB website for current details.
How long does window replacement take?
It depends on the number of windows and the installation method, but many retrofit jobs for a typical home can be completed in a single day once the windows arrive.
Are big-box stores cheaper for window replacement?
Not always. Big-box stores often use subcontracted installers and add overhead to the price. Local window companies that use their own installers can often offer comparable or better products at a lower price. Compare itemized quotes to know for sure.
Get an Honest Quote From a Local Window Company
American Reliable Windows & Doors has served Los Angeles County homeowners for more than 16 years. We’re licensed and bonded, we use our own installers (no subcontractors and no commissioned salespeople), we work with top brands like Milgard and Jeld-Wen, and most jobs are done in one day.
Call us at (818) 787-1101 or request a free estimate. We’ll give you a clear, itemized quote with no pressure.
This guide is general information, not legal advice. For the latest rules on contracts, licensing and permits, visit the California Contractors State License Board at cslb.ca.gov or your local building department.