How to start a window installation business that measures twice and gets paid once

Window and door installation rewards precision over speed. An order a quarter inch too wide means the factory builds the unit again and the crew comes back. A skipped flashing step becomes a stained ceiling after the first hard rain. A house built before 1978 changes how your crew is allowed to pull the old sash. In return, the trade offers large tickets on whole-house replacements, steady small work from broken glass and sticking doors, and referrals from every trade that works on the outside of a house. Below we cover the work, licensing and certification, insurance and bonds, tools and trucks, pricing, first customers without rented leads, and the seasons.

This guide comes from owners who run crews of their own and is general information only, so get legal, tax and insurance answers from a professional. Licensing, permits and building codes come from states, counties and cities and get revised, so check each rule with the agency behind it before relying on it.

What kinds of jobs does a window company do?

Most residential window and door companies earn their money from a mix of these:

• Replacement windows. The core of the trade. An insert (or pocket) replacement sets a new unit inside the existing frame. A full-frame replacement strips the opening down to the framing, which lets you inspect and flash it properly but disturbs more trim inside and out. You will quote both, so learn both.
• Entry, patio and storm doors. Prehung entry doors, sliders, hinged patio doors and storm doors, plus new locks, handles and hinges. Homeowners choose doors for appearance and security as much as for energy ratings.
• Glass and repair work. Fogged insulated glass units, cracked panes, worn balances, slider rollers and tracks, torn screens. Small tickets, and a first meeting with a household that may want a full set later.
• Emergency securing. A pane broken by a storm or a break-in, boarded or temporarily glazed the same day, then repaired properly once the glass is made. Expect night calls and insurance paperwork.
• Egress and new openings. Basement bedroom windows that need a bigger hole in a foundation wall and a window well outside. It is structural, code-heavy work that often calls for a concrete cutting partner.
• New construction. Setting units for builders and remodelers, who control the schedule and the payment terms.

Decide early whether you will sell your own jobs or install for someone else. Manufacturers, dealers and retailers hire subcontract crews to install what they sell. That can fill a calendar in year one, but the customer, the price and the review belong to the company that hired you. Selling your own work means evenings at kitchen tables and a real sales process, and in return every customer and every referral stays on your list.

Do you need a license to install windows and doors?

Often, in some form, and the answer changes from one town to the next. On its licenses and permits page, the SBA notes that licensing turns on two things, the kind of work a business does and where it does it, and it puts construction on a short list of activities that towns and counties often regulate. For window and door work, the patterns look like this:

• A trade classification for glass and glazing work.
• A broader contractor or home improvement license (or registration) whose scope includes replacing windows and doors.
• Registration, business licensing and job permits handled mainly by the city or county where the work happens.

California shows the trade classification model. Its Contractors State License Board describes the C-17 glazing contractor as one who selects, cuts, assembles and installs glass and glass substitutes, fabricates and glazes frames, panels, sashes and doors, and installs those items in any structure. Other states draw the lines differently, and rules get amended, so we won't summarize them here. Find your state in our directory of state startup guides, then read the licensing agency's own definitions and exemptions; the contractor licensing guide walks through a typical application.

Then call the building department in each town you plan to serve. Ask when a window or door replacement needs a permit and an inspection, and ask about the two code topics that trip up new installers:

• Safety glazing. Codes require safety glass in hazardous locations, such as doors, glass beside doors, and glass near tubs, showers and stairs. Boulder County, Colorado, for one, states in its safety glazing handout, which is based on the 2021 International Residential Code, that new windows and window replacements must comply with those requirements. A federal standard, 16 CFR 1201, also covers glazing materials used in doors, storm doors, sliding patio doors, and bathtub and shower enclosures.
• Emergency escape openings. Bedrooms and basements need a window a person can climb out of. The City of Boise's code handout on escape and rescue openings, for example, exempts a replacement window from the opening size and sill height rules only when it is the manufacturer's largest standard size that fits the existing frame or rough opening, in the same operating style or a style with an equal or larger opening area, and the replacement isn't part of a change of occupancy. Swap a bedroom casement for a smaller slider without checking, and you may have shrunk the only escape route from a bedroom.

Hurricane country adds product rules. Florida's product approval statute lists windows, exterior doors, skylights, shutters and impact protective systems among the products that must be approved through one of the methods the statute sets out. Before selling impact windows on any coast, ask the local building department what approvals and opening protection it expects.

Which certifications should a window installer get?

EPA lead-safe certification. This one is a legal requirement on older homes. Under EPA's lead renovation rule (the Renovation, Repair and Painting program, or RRP), paid work that disturbs paint in housing, preschools or child care buildings from before 1978 must be done by a certified firm, and EPA spells out that this includes sole proprietorships. Each worker needs to be a certified renovator or to have been trained on site by one. Window jobs get no small-job break. The rule's minor repair exemption, defined in 40 CFR 745.83, does not reach any job that includes replacing a window, however little paint is involved. Then there is paperwork. 40 CFR 745.84 requires handing the owner EPA's lead pamphlet no earlier than 60 days before the job starts, with a signed receipt from the owner or proof of mailing dated a week or more ahead. Under 40 CFR 745.86, the records stay on file for 3 years after the work is done. As of its June 2026 update, EPA's RRP page lists fourteen states and one tribe that run their own programs, so confirm whether EPA or a state agency certifies firms in your area.

InstallationMasters. The Fenestration and Glazing Industry Alliance (FGIA) runs InstallationMasters, which it describes as a nationwide training and certification program for new construction and replacement installers of windows and exterior glass doors in residential and light commercial markets. Its program handbook says the program is voluntary and offers replacement, new construction and combined segments. Installer candidates need a year or more of hands-on installation experience on a construction site. Trainees with less can take the class and the exam, then become certified after 12 months of verified experience. A score of 70% passes, and certification is valid for four years. For a new company, it gives you something concrete to show when a homeowner or builder asks how you know your crew installs correctly.

The installation standard. ASTM E2112 is the standard practice for installing exterior windows, doors and skylights. Its scope covers windows, sliding and swinging patio doors and skylights in new and existing construction, mainly residential and light commercial, and it says the manufacturer's installation instructions prevail when they conflict with the practice. Read the instructions for every product line you sell, along with each manufacturer's warranty terms for installation.

Manufacturer and dealer requirements. If you plan to install for a manufacturer or retailer, its list becomes your checklist. A Renewal by Andersen posting for subcontract installation crews, read in October 2026, asks for at least 3 years of window installation and remodeling experience, your own truck, trailer and tools, a certified lead renovator certificate, and coverage that includes $1 million each-occurrence general liability and $1 million combined single limit auto liability.

What safety rules apply to a window crew?

Once you hire, OSHA's construction rules apply. Under 29 CFR 1926.501, anyone on your payroll working on a house 6 feet or higher above the level below needs guardrails, a safety net or a personal fall arrest system, unless another provision of the rule allows a different measure. Second-story openings, units over a porch roof and windows above a walkout basement all put your crew in that zone. The same section covers holes, skylights included, that sit more than 6 feet above a lower level.

Glass brings its own hazards: large units are heavy, and a cracked pane can let go without warning. Handle glass with cut-resistant gloves and sleeves and suction cups, plan the carry path through the house before anyone lifts, and put two people on any unit that needs two. For training records and crew routines, see job site safety basics.

Which insurance and bonds should a window company carry?

Tell your agent about second-story installs, older homes, board-ups, subcontracted crews and any glass you cut. The usual core coverages:

• General liability. The NAIC describes this coverage as protecting you against claims of bodily injury you cause and harm to other people's property, among other events. For a window company, picture a leak behind new trim that stains a ceiling months later, a sash dropped onto a car, or a neighbor's child cut on a broken pane left in the yard. Ask how the policy treats damage that shows up after the job is finished.
• Workers' compensation. The NAIC says it's mandatory for employers in nearly every state. Subcontract crews raise a classification question with tax and premium effects, so read employee vs independent contractor first.
• Commercial auto. The NAIC notes that a commercial auto policy may also cover vehicles you rent or don't own, such as an employee's own car driven on company business. Our commercial auto guide goes further.
• Tools and product in transit. A trailer carrying a full house of custom units is carrying product that has to be reordered from the factory if it breaks. Ask how it is covered on the road and parked overnight.

Bonds come up in two places for this trade. Some licensing agencies and cities make a bond part of home improvement registration, so ask when you apply. And if you bid glazing packages on commercial or public buildings, such as storefront glass or replacement windows in a school, the owner may require bid, payment and performance bonds before you can submit. The SBA's surety bond program guarantees those bonds for small businesses that qualify. Builders and dealers who hire installation crews may also ask for a certificate of insurance naming them as additional insured. Our surety bonds guide and contractor insurance guide cover both.

What equipment and vehicles does a window company need?

Start with what this season's booked jobs require. Staging and lifts can be rented until you are using them every week.

• A truck with an enclosed trailer, or a van with racks, big enough to carry one job's units with blankets and straps so frames don't rub on the drive.
• Ladders in several lengths, ladder stabilizers, planks, and fall protection gear for upper openings.
• Removal and setting tools: flat bars, a reciprocating saw, an oscillating multi-tool, a glazing knife, a long level, composite shims, a drill, an impact driver and a trim nailer.
• Sealing supplies: caulk guns, sealants and flashing tapes the manufacturer approves, and low-expansion foam made for windows and doors.
• A portable bending brake and aluminum coil, if you wrap exterior casings and sills.
• Glass handling gear: suction cups, cut-resistant gloves and sleeves, and an A-frame or rack for loose glass units.
• Door tools: a lockset boring jig, plus a router or sharp chisels for hinges and strikes.
• Lead-safe supplies for pre-1978 homes: plastic sheeting, tape, a HEPA vacuum and cleaning verification cards.
• Floor runners, drop cloths, a shop vacuum, a laser measure, and a tablet for photographing every opening.

Product usually comes from a manufacturer through a distributor or dealer account, delivered to your shop or to the job. Open accounts early, and ask each supplier about current lead times, how it handles units that arrive damaged or wrong, and whether a custom size can be returned at all. Inspect every unit the day it arrives, not on the morning of the install.

How should a new window company price jobs?

Price by the opening. Each one carries its own product cost, set by size, style, frame material and glass, plus labor that depends on how the old unit comes out and how the new one is trimmed. The lines that move each opening's price:

Build each line from your real labor cost, overhead and target margin. Our guide to pricing window installation jobs works a full estimate through the arithmetic and sets minimums for glass and slider repairs, and how to price service jobs covers labor burden and overhead per hour.

Before the first contract, settle when you take money and when you order product. Many replacement sales close at the customer's kitchen table, which brings in the FTC's Cooling-Off Rule and its three-business-day cancellation right. A custom-size unit is hard to sell to anyone else, so consider holding the factory order until that period ends. Some states also cap deposits on home improvement work; the pricing guide covers both rules in its deposits section. Have a local attorney review your contract and cancellation forms before the first signature. Leave federal tax credits out of the sales talk, too: the IRS FAQ on the 2025 tax law says windows and doors placed in service in 2026 or later get no section 25C credit.

How do you get your first window and door customers?

Lead marketplaces sell window and door requests, and each one can cost a salesperson an evening of measuring and presenting. Angi's fiscal 2025 annual report describes match fees that pros owe for consumer matches whether or not they ever do the requested work. Networx's help center says a single pay-per-lead lead will go to up to 4 contractors. Google's Local Services Ads charge only for leads Google counts as valid, and Google ties each lead's price to where you work, the type of job and lead, and the bidding mode you pick. Some owners use these to fill an early calendar. The requests stop when the spending does.

What you own keeps working with no per-lead fee attached:

• A site built around measure-day questions. A page for each window style and frame material, a door page, a glass repair page, an older-homes page explaining your lead-safe process, and a gallery labeled with house style and town. Our contractor websites are built around pages like these.
• Your Google Business Profile, kept current with inside and outside photos of each install, each service you offer, and the towns you cover.
• A phone line that sorts urgent from planned. A shattered slider at 9 PM and a whole-house replacement quote need different answers. An AI receptionist can answer every call, ring whoever is on call for broken glass, and book measures with the number of openings and the home's age noted.
• The trades around you. Home inspectors, painters, remodelers, roofers and siding crews spot failed seals and rotted sills before the owner calls anyone. Listing agents want fogged glass fixed before closing, and property managers need broken panes replaced between tenants. For ways to start those relationships, read partnering with realtors and property managers.
• The street around each install. Ask the owner if you can put a sign in the yard while you work, and drop a short note at nearby houses when you finish.
• Your own records. A CRM that keeps each opening's size, brand and series, order number and install day on the address. When the owner calls about the back of the house or a failed seal, you quote or order from what is already on file.

Our windows and doors industry page shows the site pages, call handling and job records we set up for this trade.

How seasonal is window and door work?

• Cold regions: drafts, frost on the glass and heating bills prompt calls in fall and winter, while installs go easiest in mild weather. Winter installs can work one opening at a time, but sealants, foams and flashing tapes list application temperature ranges on their labels or data sheets, so check them before you schedule.
• Hot regions: rooms that overheat in the afternoon bring the summer calls, and glass choice turns on solar heat gain. Stock the glass packages that meet the ENERGY STAR requirements for your climate zone, and learn to read each rating on the NFRC label before a customer asks.
• Hurricane coasts: the National Hurricane Center dates the Atlantic season from June 1 to November 30. An impact sale closed in March leaves months to measure, order and install before the September peak, while a buyer who waits until August may find your install calendar already full.
• Everywhere: spring brings screen, slider and storm door work once people start opening their windows again, and broken glass calls arrive all year.

Factory lead times can shift with the season, so ask your suppliers for current numbers and tell buyers at signing. Plan cash for the gap between deposit and final payment (the cash flow guide for seasonal businesses walks through it), and use slow weeks to measure, follow up on open quotes and meet the trades that will send you spring work.

Neighboring trades have their own guides: starting a siding business and starting a remodeling business. The full series lives on the start a company hub. Once licensing, insurance and your first installer are sorted out, get a free launch plan for your site, phone setup and CRM before opening day.

Frequently asked questions