Diamond Certified Companies are Rated Highest in Quality and Helpful Expertise.

  • Why this rating is the most accurate.
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Diamond certified companies are top rated and guaranteed

Why Trust Diamond Certified Window Companies Rated Highest in Quality?

Photo: Alexander Company (2012)

You are the customer. If your goal is to choose a window company that will deliver high customer satisfaction and quality, you’ll feel confident in choosing a Diamond Certified window contractor. Each has been rated Highest in Quality in the most accurate ratings process anywhere. And you’re always backed by the Diamond Certified Performance Guarantee. Here’s why the Diamond Certified ratings and certification process will help you find a top-rated window company and is unparalleled in its accuracy, rigor and usefulness:

1) Accuracy: All research is performed by live telephone interviews that verify only real customers are surveyed, so you’ll never be fooled by fake reviews.

2) Statistical Reliability: A large random sample of past customers is surveyed on an ongoing basis so the research results you see truly reflect a Diamond Certified company’s top-rated status.

3) Full Disclosure: By clicking the name of a company above you’ll see the exact rating results in charts and read verbatim survey responses as well as researched articles on each qualified company.

4) Guaranteed: Your purchase is backed up with mediation and the Diamond Certified Performance Guarantee, so you can choose with confidence.

Click on the name of a Diamond Certified company above to read ratings results, researched articles and verbatim customer survey responses to help you make an informed decision.

More than 200,000 customers of local companies have been interviewed in live telephone calls, and only companies that score Highest in Quality in customer satisfaction–a 90+ on a 100 scale–as well as pass all of the credential-based ratings earn Diamond Certified. By requiring such a high score to qualify, the Diamond Certified program eliminates mediocre and poorly performing companies. Read detailed information about the ratings and certification process.

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Jeff Alexander is second-generation owner of Alexander Company, a Diamond Certified company since 2012. He can be reached at (650) 525-4171 or by email.

Jeff Alexander

diamond certified contributor profile and expert article

Jeff Alexander: A Clear Opportunity

By James Florence, Diamond Certified Resource Reporter

BURLINGAME — Long before he was second-generation owner, Jeff Alexander could see the clear opportunity his family’s window contracting business represented. “My dad started Alexander Company in 1971, and my brother, John, and I started getting involved as teenagers,” he recounts. “At first, we were helping in the field, but we gradually moved into sales and management. As the company continued to grow, we both saw a lot of opportunity for the future and decided to stick with it. Today, we’re second-generation owners, and since we both have kids who work for the business, we’re looking at possibly a third generation.”

After four decades in the business, Jeff says he still enjoys the simple satisfaction that comes from seeing the results of his work. “I like the transformation that occurs as we take a project from start to finish. It’s very satisfying to see how our work improves a home’s appearance and enhances the homeowner’s view.”

A resident of the San Francisco Peninsula, Jeff expresses his appreciation for work and life in the Bay Area. “I can’t think of a better place to live and work. Besides the nice weather, there’s a lot of opportunity here, which has helped us build a good customer base over the years.”

Outside of work, Jeff spends his time on a variety of active pastimes. “I enjoy playing golf and going to professional sporting events. Besides being a Giants and 49ers fan, I’ve jumped on the Golden State Warriors bandwagon in the last couple of years, as a lot of other people have.” Jeff also likes getting out and about with his wife, Rosie, and exploring San Francisco, the Wine Country and other parts of the Bay Area.

In regard to a professional philosophy, Jeff emphasizes the importance of integrity. “Our aim is to supply our customers with honest, professional service and run our business with integrity,” he affirms. “Basically, we try to treat our customers the same way we’d want to be treated.”

When asked the first thing he’d do if he were to retire tomorrow, Jeff says he’d head to a tropical locale. “I would probably take a trip to Hawaii and just take a couple of weeks to rest and regenerate. After all, what better way to decompress than by relaxing on a beach?”

Ask Me Anything!
Q: What’s your favorite restaurant?
A: Waterfront Restaurant in San Francisco.

Q: What’s your favorite season?
A: Summer—I enjoy the warm weather and long days.

Q: Music or talk radio?
A: It depends on what I’m doing. When I’m running around during the day, I usually listen to sports talk radio, but when I’m home on the weekends, I like listening to music.

Q: What was your favorite toy as a child?
A: My bicycle.

Q: What do you like on your pizza?
A: Salami and mushrooms.

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Choosing the Right Window Contractor


BURLINGAME — When planning for a window replacement project, it’s crucial to hire the right contractor. Here are some attributes to look for in a window contractor: Longevity If a window contractor has been in business for many years, it indicates… Read more

Expert Video Tip

Video: The Key to a Successful Window Project

Complete Video Transcription:

BURLINGAME — Host, Sarah Rutan: When replacing your home’s windows, your most important decision will be which company you choose to work with. Today we’re in… Read more




Milgard Windows
Norco Windows
Pella Windows
PGT Windows
Silver Line Windows
Simonton Windows
Weather Shield
Kolbe Millwork
American Craftsman
Loewen Windows
Marvin Windows
Anlin Window Systems
CertainTeed Windows
Champion Windows
Empire Pacific
Jeld-Wen Windows
Andersen Windows
Kolbe Windows

bay replacement windows
retrofit windows
sliding window replacement
window weatherstripping
window sash repair
double-hung windows
wood window installation
picture window replacement
wooden window repair
home window replacements
storm window installation
vinyl replacement windows
window replacing services
exterior window replacement
window pane replacement
awning windows
home window repair
insulated windows
casement windows
crank windows installation
home jalousie windows
window sash replacement
broken window repair
window screen repair
vinyl window installation
new windows
replacement windows
aluminum windows
basement window repair

Broadmoor Village
Daly City
El Granada
Emerald Hills
Foster City
Half Moon Bay
La Honda
Loma Mar
Menlo Park
Moss Beach
Palomar Park
Portola Valley
Princeton by the Sea
Redwood City
San Bruno
San Carlos
San Gregorio
San Mateo
Sharp Park
South SF
West Menlo Park


American Window and Door Institute (AWDI) (www.awdi.com)
California Association of Window Manufacturers
Energy Star (www.energystar.gov)
Efficient Windows Collaborative (EWC) (www.efficientwindows.org)
National Fenestration Rating Council (NFRC) (www.nfrc.org)
Stained Glass Association of America (http://stainedglass.org)
Window & Door Manufacturers Association (WDMA) (www.wdma.com)

Know What You Want
Determine Your Goals and Desires for Your New Windows

Before you make your initial phone calls or sit down to interview window contractors in San Mateo, you’ll want to have a clear idea of the scope of your project, the type of windows you want and what you’re looking for in a contractor. Many homeowners write down ideas and keep a file of questions and samples. This enables them to present a clear and coordinated list to each contractor they interview.

Start by asking yourself these questions:

  • Do I want a Diamond Certified company that is rated best in quality and backed by the Diamond Certified Performance Guarantee?
  • What is my main goal in getting my windows replaced? (This can be energy efficiency, aesthetics or increasing your home’s resale value.)
  • Are there other fringe benefits I hope to gain?
  • What is my budget for window replacement?
  • What type of material do I want the windows to be made from?
  • Is there a specific design aesthetic or look I want from my new windows?
  • Do I plan to live in this home long-term, or is it a rental property or a house I plan to sell?
  • What characteristics am I looking for in a San Mateo County window contractor? This could include communication skills, starting the job on time, sticking to the schedule during the job, warranties or guarantees, and follow-up care.
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What To Ask In Person
Questions to Ask When You Meet Window Contractors in Person
  • How much time will the entire job take, from ordering the new windows through installation?
  • Will I be able to stay in my home during the installation?
  • Will my new windows reduce my electric bills?
  • Do you have any recent, completed window replacement projects in my area of San Mateo County where I can see how the windows look from the street?
  • Do you have recent window repair/new window installation customers I can call as references?
  • How do you finish the windows after installation? If I want the window frames painted or stained, do you offer that service or do I have to hire a separate contractor?
  • How would I handle service issues after the window installation is complete?
  • Are you responsible for warranty work if there’s ever a problem with my new windows?
  • What can I do to make the window installation or window repair process faster and easier?
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  • What To Ask References
    Benefit From Previous Customers’ Experiences with Local Window Contractors in San Mateo County

    It’s best to choose a Diamond Certified window contractor because all certified companies have passed an in-depth ratings process that most other companies can’t pass. So you’ll have confidence choosing a Diamond Certified window company in San Mateo County and the greater Bay Area. Diamond Certified reports are available online at www.DiamondCertified.org for all certified companies. And you’ll never be fooled by fake reviews. That’s because all research is performed in live telephone interviews of actual customers.

    If you can’t find a Diamond Certified window contractor within reach, you’ll have to do some research on your own. If you do, it’s wise to call references provided by your window company. Keep in mind, though, that the references they give you are not equal in value to the large random sample of customers surveyed during the Diamond Certified ratings process. That’s because reference lists are usually hand-selected instead of chosen randomly from among all their customers. Meaning the window contractors will likely give you a few customers to call that they know are satisfied.

    If you do call references on your own, specifically ask for a list of the company’s 10 most recent customers. This will help avoid them giving you the names of only customers they know were satisfied. Talking to these references can give you an insider’s view on how the San Mateo County window contractors performed on previous jobs. So call several references and ask them specific questions about the contractor you’re considering. Here are some sample questions that can help you determine whether a contractor is a good fit for you:

    • Were you satisfied with the window installation and the service from _(San Mateo window company name)_?
    • What was the type and scope of job they did for you (window replacement, window repair, whole house window installation, new wood windows, etc.)?
    • Did the San Mateo County window contractor you hired complete the work on time?
    • Did the contractor consistently inform you of the project status?
    • Were there unexpected costs? If so, what were they?
    • If you live in a smaller town such as Portola Valley, Brisbane, Colma, Moss Beach, Sharp Park, Woodside or Palomar Park, did they charge extra to travel to your home?
    • Did the window installers show up on time?
    • Did they clean up after finishing the window installation?
    • If you need new windows in the future, would you use this window contractor again?
    • Would you recommend them?
    • Can I visit your home to see the completed window installation?
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  • Review Your Options
    Final Questions Before Hiring a Good Window Company in San Mateo County

    The Diamond Certified symbol has been awarded to companies that scored Highest in Quality in an accurate ratings process.

    Your choice of window contractor impacts every part of your job, from the ease of the installation to how long your new windows last. So before deciding on the best window contractor in San Mateo County for you, it’s important to consider the following questions.

    • Are the San Mateo County window contractors knowledgeable on the products they offer? Can they tell you which products best suit your needs and why (i.e. aluminum windows, insulated windows, vinyl windows, energy efficient windows)?
    • Is the window installation company sensitive to your budget? Can they offer various products that fit your resources? Most contractors will give you bids for Good, Better and Best options that include a choice of product, design, prices, brand names and services.
    • Can the window contractors meet your needs in terms of scheduling, products and installation preferences?
    • Do the window contractors offer warranties that cover product failure or installation errors?
    • Are all guarantees in writing?

    It’s also smart to note your own expectations, realizing that some may not be congruous with the project. For example, it may not be realistic to expect a consistent schedule or a quiet worksite when having new windows installed. You’re most likely to be satisfied with the process when you talk with your contractor before the job begins and discuss realities and expectations from both your view and the window contractor’s.

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  • How To Work With
    Attract the Best Local Window Installers to Bid on Your Job

    In this buyer’s market, you might be surprised to find you’re not the only one who is interviewing and selecting potential candidates. San Mateo County window companies, including those in the larger cities of Redwood City, San Bruno, Foster City, San Mateo, Daly City and South San Francisco and even some in the smaller towns, can also be selective about which jobs they accept.

    Bids take time and expense to prepare, and many contractors have lost money and faced difficult dealings with unreasonable homeowners. That can make them choosy about with whom they do business. So it’s reasonable that some local window contractors show a lack of interest or don’t respond to all job requests.

    There are some ways you can encourage good window contractors to bid on your job.

    • Be honest if you’re accepting bids from and interviewing other local window contractors, but assure the window companies that you’re gathering three bids, not dozens.
    • Look for good value, not just the lowest price for new windows. The first question that window contractors often hear is “How much will my new windows cost?”, so it’s important to show them you understand the importance of quality and overall value.
    • Shop among local window contractors in San Mateo County. Most like to stay in the local area, as it allows them to provide better service in a timely fashion. It also shows the contractors you’re serious about quality products and installation, as some fly-by-night contractors travel long distances to install cheap products that local contractors may not be able to compete with price-wise.

    Get the Most Out of Your Contract with Local Window Contractors in San Mateo
    You’ve found the San Mateo County window contractor that meets all your requirements. Now is the time to ask for a contract that includes written confirmation of price, quality and timing for the entire job. They should also be willing to provide you with written job start dates, major milestones and intended completion dates.

    The contract you sign with a San Mateo County window company should protect you and your property as well as your contractor’s interests. For this reason, never sign a blank or incomplete estimate. Read the entire contract and understand the terms before you sign it. And don’t be afraid to write in your own requests or put in writing the verbal agreements you’ve made with your representative.

    For instance, start and end dates are important, but there are factors you and your installer can’t control, such as the weather. That’s why it’s a smart idea to add a no-later-than clause to your contract. This stipulates the date by which all work must be completed. Even if inclement weather or problems with the products delay installation, this clause will give you assurance that your job will be finished on time. If a quick turnaround is important to you, you may want to consider adding a bonus for early completion to your contract as well.

    Confirm any warrantees or guarantees for your new windows at this time. Some window installers in San Mateo County only guarantee certain window brands or installations. Also verify that manufacturer warrantees apply to the windows you’re having installed and that the installers are qualified for the job.

    Don’t forget about related construction issues that may not be covered by a standard contract. For example, regardless of how careful your window installer promises to be, crushed flowers, damaged shrubs and rutted lawns are often unexpected hazards that come with hiring a contractor. But you can protect your property and yourself by being proactive.

    Before work begins, ask the job supervisor to accompany you on a pre-work inspection to determine the original condition of the property. List or photograph your landscaping and property before the work begins, and talk with your contractor about reasonable expectations for protecting your home and yard during the window installation process. When you’ve reached an agreement about the condition of the property, both you and the contractor should sign and date the document. After the work is done, do a final inspection together and confirm your expectations were met.

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  • Be a Good Customer
    Be a Good Customer for Window Contractors in San Mateo County

    It’s the window company’s responsibility put in quality windows using the best possible installation techniques. But you play a big part in the success of your new window installation, too. Here are a few simple steps you can take to be a good customer when hiring a San Mateo County window contractor.

    • Be clear and upfront with the window contractor or window company representative. Let them know what you want from your windows, the long-term outcome you’re expecting and specific ways they can satisfy your expectations.
    • Before you hire a window contractor in San Mateo County, restate your expectations and goals, and reiterate to the window company representative your understanding of the agreement. Most problems with local window contractors occur because of a breakdown in communication. By being clear about your expectations and theirs, you can avoid most conflicts.
    • Remember, a friendly smile goes a long way!
    • Ask your window installer if you should call to check on the progress or if he will call you with updates.
    • Be sure your service representative has a phone number where they can reach you at all times while they’re installing your new windows. (The work will move along more smoothly if your window company can reach you for updates, questions or authorizations.)
    • When your contractor contacts you, return calls promptly to help keep the window installation on schedule.
    • Pay for the new windows and installation work promptly.

    Why would you want to be a good customer? Window installation contractors in San Mateo County appreciate customers who are straightforward, honest and easy to work with. Your good customer behavior sets the tone from your end and contributes to a good relationship.

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Check The Work
Check the Window Installation and Window Repairs Against the Invoice

When the work is completed, most good window contractors in San Mateo County will give you a written invoice that details all the work done.

This invoice usually includes:

  • The name and physical address of the San Mateo area window contractor.
  • A list of all window installation / window repair work performed.
  • An itemized list of all new windows or window replacement parts.
  • The total window installation cost, including the amount due for labor.

Any applicable warrantees or guarantees provided by the window manufacturers or the window installers.
It’s smart to compare the written invoice to the work that was actually done. Ask your window company representative to walk through the job with you and show you the window repairs and installation. Your window company should be willing to talk you through the process and give you special instructions for operating your new windows and maintaining them for years to come. If you have any further questions, this is the time to ask. Once a contractor leaves your property, they may not be liable for any further work or information not discussed before the completion of the job.

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Written Warranties
Ask the San Mateo County Window Installers for Written Warranties

Before your window contractors leave the jobsite, confirm any warranties. Remember, not all window companies in San Mateo County back up their work. But if the company you’ve chosen does guarantee the new windows and their installation services, they should give you a written warranty, including:

  • The window contractor’s name and physical address.
  • Terms of and limitations on the new window warranty. (What is covered by the warranties, including whether the contractor will replace or repair your windows or give you a refund if there is a warranty claim.) Exclusions should be in writing.
  • Your responsibility if you need warranty work or replacement windows (i.e., if you have to pay for labor when filing a claim for window warranty work or pay a prorated amount).
  • If the new window warranty coverage is transferable to the new owner if you sell your home.
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Top 10 Requests
Homeowners’ Top Requests for San Mateo County Window Contractors

The top requests for new and replacement windows in San Mateo County are listed below. Read the paragraphs below for the definition of each type of window repair and replacement services.

New Windows
New windows are usually installed in new construction and major remodels. New windows differ from replacement windows because they have a nailing fin along the outer frame and are nailed in from the outside of the home before siding or exterior trim is installed. Installation is a more in-depth process because it requires replacing the entire window unit (including the window frame and window glass).

Replacement Windows
When existing windows deteriorate, replacement windows are often the solution to upgrade efficiency, security and appearance. San Mateo County window contractors usually install replacement windows in existing window spaces, using the existing trim and cladding. Drop-in replacement windows are designed for minimal disruption of the existing structure and are often the least expensive option.

Window Repair
Window installers in San Mateo County can repair old windows and broken windows, including window glass, window frames and the tracks of sliding and double-hung windows. Some local contractors even specialize in repairing and restoring old windows to maintain historic homes. Others provide routine maintenance for modern windows.

Vinyl Windows
Vinyl windows are a favorite of San Mateo County homeowners in Daly City, Menlo Park, Redwood City, Burlingame and other cities because they are inexpensive, durable, energy efficient and nearly maintenance-free.

Double-hung Windows
Perhaps the most popular type of window, double-hung windows consist of upper and lower window sashes that slide vertically in side window jambs. They have a maximum opening of one-half the total window area.

Storm Windows
Storm windows are added to existing windows to increase efficiency and keep out inclement weather. Storm windows can be permanent or temporary and are mounted externally or internally to existing windows.

Aluminum Windows
Known as strong, durable and easy-to-configure, aluminum windows are often used to showcase beautiful views. They are also a less-expensive option in homes and light commercial buildings. Aluminum windows are not traditionally the most efficient, but more recent aluminum windows are more energy efficient than previous designs.

Energy Efficient Windows
Energy efficient windows are often designated with an Energy Star label. These windows are known to drastically reduce energy bills. Most energy efficient windows are insulated and protect against heat loss and gain, maintaining indoor air temperature.

Casement Windows
Casement windows are those that are attached to the window frame by hinges located on the side of the windows. (Windows that are hinged at the top are called awning windows, while windows attached at the bottom are hopper windows.) Casement windows may contain leaded glass and often open inward.

Bay Windows / Bow Windows
Bay windows are popular in San Mateo County because they project outward from the main walls of a home in a bowing fashion. Also known as bow windows, bay windows create a larger living space or the illusion of a larger room depending on the type of bay window. Bay windows also add architectural interest and increase the amount of natural light that flows into a room.

Popular Brands of New Windows in San Mateo County
Many homeowners and window installers in San Mateo County have favorite window brands. The most-requested window brands are listed below.

Champion Windows
Champion Windows are popular home replacement windows that are custom-made and professionally-installed. Champion Windows also manufactures Energy Star windows and other energy efficient replacement windows.

Milgard Windows
Vinyl windows, aluminum windows, fiberglass windows and sound control windows for homes and light commercial buildings such as hospitals and schools are all available in San Mateo County from Milgard.

Simonton Windows
Some window contractors in San Mateo County install new construction and replacement windows by Simonton Windows. These include awning windows, double-hung windows, garden windows, casement windows, radius windows, single hung windows and single slider windows.

Andersen Windows
Andersen Windows is one of the most trusted brands of new windows. Andersen dealers in San Mateo County offer replacement windows in a full range of materials and styles.

Pella Windows
For more than 85 years, Pella Windows has been making and installing windows. Home window styles available from Pella include casement, awning, double-hung, single-hung, sliding, bay/bow windows and specially-shaped windows that add architectural detail to your home.

PGT Windows
PGT Windows are custom impact-resistant windows meant to increase the style, safety and security of your home. Available windows include new construction and replacement windows with aluminum and vinyl frames. PPG also manufactures hurricane windows.

Loewen Windows
Loewen Windows exclusively manufactures wooden windows, including awning windows, casement and double-hung windows, picture windows, access windows, transoms and custom windows. Loewen wooden windows are made from Douglas Fir and Mahogany.

Marvin Windows
From energy efficient to fully customized designs, Marvin Windows is one of the most recognized window manufacturers. Marvin Authorized Installing Retailers in San Mateo County sell and install all types of Marvin Windows.

CertainTeed Windows
All standard and custom home windows are available in San Mateo County from CertainTeed Windows. CertainTeed was one of the first window manufacturers to offer vinyl windows. They also offer energy efficient, Low-E glazed windows.

Kolbe Windows
New construction windows, historic home windows, replacement windows, custom windows and commercial windows are all available in San Mateo County from Kolbe Windows.

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Glossary Of Terms
Glossary of Terms for New Home Windows and Window Contractor Services

Below are terms and descriptions that will help you navigate your way through your replacement window installation from beginning to end.

aluminum windows
Glazed window with aluminum sash and mullions. Aluminum windows are known for strength, value and flexibility in installation configurations to maximize views.

Also known as: aluminum storm windows, aluminum window frames, aluminum replacement windows, aluminum clad windows, aluminum window replacement, aluminum window repair, residential aluminum windows, aluminum frame windows

awning windows
Awning windows have a hinged upper sash that swings outward for ventilation.

Also known as: ventilation windows, awning window replacement, awning replacement windows

bay windows
Bay windows are a unit of three windows, usually made up of a large center fixed window unit and two flanking windows positioned at 30-, 45- or 90-degree angles that project out from the wall. Bay windows may increase the size of a room or may give the appearance of a larger room depending on the construction. Some bay windows have built-in seating and are used as window seats.

Also known as: bow windows, angle bay windows, window seat windows, bay bow windows, bow bay windows, replacement bay windows

casement windows
Windows that are side-hinged or pivoted are known as casement windows. Casement windows have a single sash that cranks outward, to the right or left.

Also known as: crank out windows, casement replacement windows, vinyl casement windows, casement window repair, wood casement windows, steel casement windows, aluminum casement windows, double-hung casement windows, French casement windows, metal casement windows

dormer windows
Dormer windows protrude from the roof of a house. Dormer windows usually include one or more window panes.

Also known as: gable fronted dormer windows, hipped roof dormer windows, flat roof dormer windows, shed dormer windows, wall dormer window, link dormer window, window dormers

double-hung windows
Windows that have two operable sashes which slide vertically in the frame to open and close are known as double-hung windows.

Also known as: sash windows

double glazing windows
Any window made with two thicknesses of glass that are separated by airspace. Double-glazed windows increase energy efficiency and insulate against heat transfer and sound transmission.

Also known as: dual glazing windows, double glazed windows, insulated glazing, insulated glazing windows, double glazing sash windows, double glazed sash windows, energy efficient windows, conservatory windows, Energy Star windows, insulated glass, double-pane windows

dual-action windows
Windows with sashes that open for ventilation and swing open from the top or the side to allow cleaning of the outside glass.

Also known as: sliding windows, swinging windows

Energy Star windows
Energy Star is a government program that established a set of guidelines for energy efficiency. Windows that are Energy Star Qualified meet efficiency requirements and can save seven to 15 percent on home energy bills compared to non-Energy Star windows. Most Energy Star windows are insulated windows or double-paned or triple-paned windows that keep temperature-controlled air in the home and heat or cold out.

Also known as: energy efficient windows, insulated windows, energy efficient vinyl windows, energy efficient window replacements, energy efficient glass windows, energy efficient home windows, energy efficient wood windows

fixed windows
Non-venting or non-operable windows made of fixed glass are referred to as fixed windows. Fixed windows are also known as picture windows and can be reglazed and replaced on-site.

Also known as: picture windows, fixed casement windows, fixed picture windows, fixed vinyl windows

hopper windows
Windows with a top sash that swings inward. Hopper widows are often used in basements and other areas where ventilation is wanted but large windows are not required.

Also known as: casement windows, ventilation windows, basement hopper windows, hopper style windows, vinyl hopper windows

insulating glass
Insulated glass is usually a combination of two or more panes of glass with a sealed air space between the panes that is filled with a harmless gas. This space may be filled with an inert gas, which increases the insulation properties. Most major window companies offer insulated windows as part of their standard catalog.

Also known as: insulated windows, energy efficient windows, Energy Star windows,  insulated glazing, insulated glass, IG, double insulated glass, insulating glass, insulated replacement glass, insulated window glass, insulated glass windows, low-e insulated glass, insulated glass units, window glass insulation

jalousie windows
Windows with a series of overlapping, horizontal louvers that move together are called jalousie windows. Window louver panels open to maximize airflow through the openings.

Also known as: venetian blind windows, shutter windows, blind windows, aluminum jalousie windows, jalousie windows replacement

Window mullions are a vertical structural element that divides window panes and separates side-by-side windows.

Also known as: window divider, window column, aluminum mullions, aluminum window mullions, mullion replacement, replacement mullions, removable mullions, wooden mullions, wood window mullions

picture windows
Non-venting and non-operable windows are generally referred to as picture windows. Also know as fixed windows, picture windows only consist of window frames and glass. Most picture windows are double-paned or insulated to be more energy efficient since they have such a large surface area.

Also known as: fixed windows, non-opening windows, plate glass windows, picture replacement windows, vinyl picture windows

Thermal resistance to the transfer of heat through windows. Windows with higher
R-value have greater insulating properties.

replacement windows
Replacement windows are custom ordered to fit inside the jambs and sill of your existing windows. Replacement windows are usually less expensive to install than installing new windows that require new frames, jambs and window sills.

Also known as: window replacements, vinyl replacement windows, wood replacement windows, aluminum replacement windows, window pane replacements

single glazing
A single pane of glass installed in a window sash. Single-glazed windows are not as energy-efficient as double-glazed windows.

Also known as: conservatory windows, sun room windows,

single-hung windows
Single-hung windows look similar to double-hung windows, except the top sash is fixed and stationary, so only the bottom section opens.

storm windows
Mounted outside or inside the main glass, storm windows are often found in cold climates or as a retrofit of existing windows. Storm windows increase the efficiency of glass windows and can be mounted temporarily or permanently.

Also known as: replacement storm windows, aluminum storm windows, interior storm windows, home storm windows, vinyl storm windows, triple track storm windows, custom storm windows, combination storm windows, exterior storm windows

vinyl windows
Windows made with vinyl, a plastic material, cladding and window units. Vinyl windows are popular because they are relatively inexpensive and maintenance-free.

Also known as: replacement windows, vinyl home windows, vinyl casement windows, maintenance-free windows, vinyl bay windows,

window casing
Also known as window trim, window casing is exposed molding of various widths, thickness and shapes that covers the framework of window and door units.

Also known as: window trim, interior window casing, flexible window casing, decorative window casing, exterior window casing, window interior casing, window molding

window cladding
Cladding is material applied to the outside faces of windows to provide a durable, low-maintenance exterior surface. Cladding often provides protection from the elements and adds an aesthetic touch. It may also be referred to as window capping, which is a specialized field offered by few window contractors.

Also known as: cladded windows, clad windows, vinyl-clad windows

window sash
Window sashes are single frame assemblies of stiles and rails (explain stiles and rails) that hold the glass.

Also known as: window frames, window sashes, window sash repair, double-hung window sash, wood sash windows, antique window sash, window sash replacement

wood windows
Wood windows are those with wooden frames. They are a natural option, so they require more maintenance than vinyl windows, and they must be protected from moisture to avoid warping and rot.

Also known as: wooden windows, wood replacement windows, wood clad windows, custom wood windows, wood casement windows, wood double-hung windows, wood storm windows, aluminum-clad wood windows, exterior wood windows, wood window replacements, historic windows, historic wood windows

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Frequently Asked Questions
Frequently Asked Questions for Local Window Contractors

Q: Why choose a Diamond Certified Window Company?
A: Diamond Certified ends the guessing game by helping you choose a window contractor with confidence by offering a list of top-rated local companies who have passed the country’s most in-depth rating process. Only window companies rated Highest in Quality earn the prestigious Diamond Certified award. Most local window companies can’t pass the ratings. American Ratings Corporation also monitors every Diamond Certified company with in-depth and ongoing research and ratings. And your window installation purchase is backed by the Diamond Certified Performance Guarantee. So you’ll feel confident choosing a Diamond Certified window company for your new windows.

Q: How will replacing my windows improve the comfort of my home?
A: New windows will make your home quieter and more secure. Depending on the windows you choose, you may also notice a marked difference in the temperature of your home as well. Double-paned windows are insulated to keep out the heat of the summer, and maintain heat during the winter.

Q: Will replacing my old windows save me money?
A: Old windows and windows that are improperly installed are the biggest cause of energy loss in the home, costing you money every day. New windows will save you money over the life of the window by cutting heating and cooling costs. Some homeowners report savings of up to 30 percent on their utility bills after installing new windows. New windows can also increase the life of your furnishings and carpeting by keeping out harmful rays of the sun, so you’ll save money by not having to replace expensive furnishings.

Q: If I decide to sell my home, will new windows and doors increase the value?
A: Yes. New windows are one of the best home improvements you can make in terms of the return on your investment. Realtors report that Bay Area homes with new energy-efficient, maintenance-free windows can see return of up to 114% in resale value.

Q: What window materials do I have to choose from?
A: Your choices for new windows are wood, vinyl, steel, aluminum, fiberglass and composite. You’ll see the sash and the frame (the visible outer parts of the window installation units) from the inside and outside of your home, so it’s important to choose the material that gives you the look you want. It’s also important to select the material that has the attributes you’re looking for. For example, metal window frames can conduct heat and cold, so they may not be as energy efficient as wood or vinyl windows. Additionally, some window frame materials can be painted to match your home’s exterior or interior, so that may be an important consideration.

Wood windows can be painted and stained. The downside to wood windows is that they must be regularly maintained. However, most wood windows are made from rot-resistant woods. When maintained correctly, they can last as long as metal windows.

Vinyl windows are inexpensive, energy efficient and durable. And while they cannot be painted, they come in a variety of colors and are virtually maintenance-free.

Steel windows are rarely used in residential buildings, as they aren’t as energy efficient as other types of windows and the window must be painted so they don’t rust.

Aluminum windows are strong and durable. They also allow for greater flexibility in window design. However, they aren’t as energy efficient as other types of windows.

Fiberglass windows are durable, efficient and strong. The frames can be painted to match any home. Because of their quality and durability, fiberglass windows are some of the more expensive widows on the market.

Composite windows have sashes and frames made from more than one type of material. This allows the manufacturer to customize the windows to fit the exact needs of the consumer. Some composite windows have a wood interior that can be painted with more efficient material such as vinyl or aluminum that better resists weather. New composite windows can be made from recycled wood and plastic that can be painted but resist rot.

Q: How do I know which kind of windows are the best choice for me?
A: Your local window contractor will help you decide which manufacturer, style and material of windows is the best fit for your budget, home and aesthetic preferences. It’s wise to make a list of what you’re looking for in new windows so that your window installer can help you decide which windows best fit your needs.

Q: How much do new windows cost?
A: The cost of new windows greatly varies based on the type of windows you select, the manufacturer and the number of windows you have installed. It also depends on whether you’re having replacement windows installed (windows that are custom ordered to fit in place of your existing windows) or whether you’re having new window frames and jambs installed as well. Your window contractor can provide an estimate based on your specific requirements.

Q: How long will it take to install new windows?
A: That depends on the size and scope of your job. A simple window installation may take an hour, while installing new windows throughout an entire home may take several days or a week. Your window contractor should be able to give you an estimated time frame on your specific project.

Q: Can I put in new windows myself?
A: Like with many home improvement projects, you can replace your windows yourself. However, for most window replacement jobs, it’s better to hire a skilled professional. Professional window installers know the best materials and installation techniques for the job. And because they have so much experience removing old windows and installing new ones, they can do the job faster and much more effectively than can most homeowners.

Q: What about getting my new windows from a home improvement store?
A: Most home improvement stores sell new windows, and many advertise low prices. But you may sacrifice selection and quality by getting your new windows from a home improvement store. Most have a smaller selection, so you may not get the windows that best suit your home and your needs. And if they sell discount windows or off-brand products that are less expensive, you run a greater risk that the manufacturer will go out of business, leaving any warranties null and void. Another factor to consider is that most home improvement warehouses don’t provide installation or they rely on subcontractors. That means you can be caught between the retailer, the manufacturer and the installer if there are any problems with your windows.

Q: I’ve heard it’s important to hire a local window contractor that is an authorized installer. What does that mean and why should I look for a certified window installer?
A: Most major window manufacturers certify window contractors whom they have trained to install their specific products. These authorized installers also sell new windows and replacement windows. You’re likely to get a better installation, and some manufacturers even offer extended warranties on products their installers put in. And if something goes wrong later, you can avoid added hassle by hiring the same contractor for the purchase and installation of new windows one company will be responsible for the work.

Q: What happens if someone gets hurt while working on a job on my property?
A: When you hire a legitimate window contractor with the correct license, liability insurance and workers’ compensation insurance, you won’t have to worry. Under workers’ compensation insurance, every employee of the company is covered in the case of accident or injury. You will not be held responsible for damages. Make sure you ask your contractor to show you a copy of their active workers’ compensation policy.

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