Learning center

What is a Window?

A window is an opening in a wall or roof that admits light and air into a structure, usually fitted with glass framed to open and close. Beyond aesthetics, windows serve an essential function — they’re a major part of a home’s insulation, comfort, and energy efficiency.

While most people focus on the kitchen layout or the number of bedrooms when buying a home, few realize how important windows are to the home’s overall performance and value.

Modern homes typically have one window opening for every 100 square feet of exterior wall space. If each window is roughly 6 feet by 3 feet, that means about 15% of your wall space is glass — the weakest area of your home’s insulation system.

Poor-quality windows can cause:

• Heat loss during the winter
• Heat gain during the summer
• Increased utility bills
• Reduced comfort
• Faster wear on HVAC systems

The R-value measures how well a material resists heat flow — the higher the R-value, the better the insulation. Older or low-quality windows usually have very low R-values, which can make up to 20–30% of total heat loss in a home.

“Windows can be one of your home’s most attractive features. Unfortunately, they can also account for 10–50% of your heating and cooling bills. During the summer, poorly insulated windows make your air conditioner work 2–3 times harder.”
— U.S. Department of Energy

Window Anatomy

Understanding the parts of a window helps you explain how they work — and why quality matters.

Component	Description
Frame	The outer structure that supports the entire window and holds the sash and glass in place.
Sash	The moving or stationary part of the window that holds the glass. In double-hung windows, both sashes can move up and down.
2 or 3 Panes of Glass	The transparent part of the window. Modern windows often use double or triple glazing for insulation, with argon or krypton gas between panes.
Glass Strength         Spacer	Single or Double strength glass. This is the thickness of the glass; single strength is similar to the equivalent of a picture frame whilst Double strength gives your home more protection and efficiency.     A narrow metallic bar on non-metallic strip separating and sealing the panes of glass, reducing condensation and improving energy efficiency.
Weatherstripping	Material placed where sashes meet the frame to prevent air and water leaks.
Grilles	Decorative dividers that give the appearance of smaller panes of glass.
Head	The top horizontal piece of the window frame.
Jambs	The vertical sides of the window frame.
Sill	The bottom horizontal piece of the frame that helps drain water away from the wall.
Balance System	Mechanism that assists in opening and closing the sash smoothly (common in double-hung windows).

Each component plays a vital role in the window’s operation, energy efficiency, and longevity.

Window Functions

Windows are a balance of light, air, and insulation — they must let in light and fresh air while keeping heat, cold, and moisture out. To do this, modern windows combine multiple panes of glass, sealed airspaces, insulating gases, and durable framing materials.

How Heat Moves Through a Window

Heat moves through windows in three main ways:

• Conduction – direct heat transfer through the solid materials (glass, frame).
• Convection – air movement between panes or around the frame.
• Radiation – heat energy moving in waves (sunlight or indoor heat escaping).

A high-quality window is designed to reduce all three types of heat transfer.

Why Windows Have Gas Between the Panes

Modern energy-efficient windows use two or three panes of glass, and the space between those panes is filled with an inert gas — typically argon or krypton. These gases are denser than air, which helps slow down heat transfer between the inside and outside of a home.

Gas Type	What It Does	Best Use
Argon Gas	Non-toxic, odorless, and 38% denser than air. Slows heat transfer and reduces condensation on interior glass.	Standard in double/triple-pane windows.
Krypton Gas	Even denser than argon, providing higher insulation. However, a shortage and costs most companies no longer use Krypton.	Used in triple-pane or narrow-spaced windows.

How It Works:
The gas between the panes acts as an invisible blanket, reducing the movement of hot or cold air through the glass. This helps keep your home warmer in the winter, cooler in the summer, and reduces the strain on your heating and cooling systems.

The gas also reduces sound transmission, creating a quieter indoor environment.
Both argon and krypton gases are completely safe and environmentally friendly.

How Seal Failure Happens

Each insulated glass unit is hermetically sealed — meaning it’s airtight. Over time, exposure to sunlight, temperature swings, and moisture can weaken the seal around the glass.

When a seal breaks:

• The insulating gas (argon or krypton) slowly leaks out.
• Air and moisture enter the space between panes.
• This creates condensation or fogging that you can’t wipe away.
• Once the gas escapes, the window loses much of its energy efficiency.

Seal failure can happen in low-quality or poorly installed windows, or when the frame material expands and contracts too much with temperature changes.
This is one reason 100% first generation vinyl performs so well — being first generation it expands and contracts without effecting the glass, preventing stress on seals.

Condensation — What’s Really Happening

Condensation forms when warm, moist indoor air meets a cool surface — like a cold window pane. The moisture in the air turns into water droplets on the surface.

In double-pane or triple-pane windows, condensation between the panes means the seal has failed and the insulating gas has leaked out, leaving an empty space for moisture to collect.

When that happens:

• The glass becomes cloudy or streaked.
• You may notice a foggy appearance you can’t clean off.
• The window loses much of its insulating ability.

Prevention:
High-quality windows prevent condensation through:

• Properly sealed insulated glass units (IGUs).
• Warm-edge spacers that reduce temperature differences at the glass edges.
• Non-porous frame materials that resist warping and seal damage.
• Argon or krypton gas that stabilizes internal temperature.

Window Types

Vinyl – Contractor Grade – What is a Contractor Grade Vinyl Window or Door

• Entry level contractor grade vinyl windows & doors are products that reach the minimum standard of efficiency (still classed as efficient).
• Contractor grade vinyl frames are typically made with thin, hollow polyvinyl chloride often utilizing reprocessed or recycled plastic rather than pure virgin vinyl. It has minimal titanium dioxide making it brittle to heat and cold.
• They have fewer chambers and weaker welded corners, effecting efficiency and durability. 
• Frame Warranty = 1 to 3 years, 10 – 20, Very Limited Lifetime Warranty with multiple stipulations

Vinyl – 100% First Generation – What is a 100% First Generation Vinyl Window or Door

• 100% First generation vinyl frames are made with of 100% virgin chloride resin mixed with titanium dioxide (for UV protection), impact modifiers and stabilizers.
• Creating a durable, non-corroding and energy efficient frame that does not need painting leading to typically the best warranties on the market.
• Frame Warranty = Lifetime Limited Transferrable Warranty (Be wary of big named brands, this does not mean better quality, warranty or price. In fact typically the opposite)

Fiberglass – What is a Fiberglass Window or Door

• Fiberglass frames are created through pultrusion, where glass fiber strands are pulled through a resin bath and heated dies to create the frame.
• Frame Warranty = Limited Warranty, 10 Years

Composite – What is a Composite Window or Door

• Composite frames are manufactured by blending materials like wood fibers, polymers and plastic resins.
• Only 2 materials are needed to be classed as composite.
• Frame Warranty = Limited Warranty, 10 Years

Aluminum

• Pros: 
  • Strong and durable, low cost and can be made in small sizes.
• Cons: 
  • Poor insulation conducts heat and cold, prone to seal failure.
  • Low glass pack quality
  • Least efficient.
• Warranty: Short term, low efficiency option.
  Typically, 20 years glass, 10 years frame and hardware, 2 years labor

Fibrex & Ultrex

• Pros:
  • Multiple finishes and design options.
  • More glass space.
• Cons: 
  • Exterior finishes fade leading to maintenance costs (all are coated finishes)
  • Does not do well or cover exposure to excessive localized heat (ie the sun)
  • Non-insulated frames
  • Limited long-term testing; more expensive and a short-term solution.
• Warranty: Typically, 20 years glass, 10 years frame and hardware, 2 years labor

Fibrex – What is a Fibrex Window or Door

• Fibrex is a composite material – 60% thermoplastic & 40% wood fiber. Wood fiber is often sawmilling waste or small wood chips grinded down that is typically used for paper and insulation.
• Thermoplastic is used to try and increase longevity of a wood based frame.
• Frame Warranty = 10 Years

Ultrex – What is a Ultrex Window or Door

• Ultrex is a pultruded fiberglass composite, pulling continuous glass fibers through a resin bath, a heated die and coated with an acrylic finish.
• Frame Warranty = Limited Lifetime – 10 Years – 5 Years

Why do Manufacturers and Salespeople talk about their windows strength and being strong?

• There is a perception that the strength of a window frame makes it a better window.
• What is it tested against?
• For example, Vinyl, There any many different variations of quality within the vinyl family and typically the lowest quality options are selected to discuss and test against.
• If the frame is that much stronger and they believe to have a better-quality window, why are the manufacturers warranties inferior with multiple stipulations and reduced timeframes – typically 20 – 10 years?
• The boast is not matched by the manufacturers and salespeople’s actions/warranties.
• These window frames typically also have no insulation in them with just hollow air gaps reducing efficiency.
• Typical products that discuss this: Composite, Fibrex, Fiberglass, Ultrex.

Bennett Baths & Exteriors — High-Performance Vinyl Line

Our First-generation vinyl windows are designed to combine affordability with superior efficiency.

Key Features:

• Multi-chambered frames for improved insulation
• Fusion-welded corners for strength and air-tight performance
• Low-E glass and argon gas for temperature control
• Sound-reducing technology
• Low maintenance and easy to clean
• Wide variety of colors and styles
• Lifetime warranty on frame and glass

Customer Value:
Bennett Baths & Exteriors windows are the perfect choice for homeowners wanting excellent performance, comfort, and energy savings — all at an affordable price.

Window Cost

Wood

• Pros: Beautiful, classic look.
• Cons: Requires regular maintenance to prevent rot and decay. Shorter lifespan unfortunately not the same quality as years past.
• Requires painting.
• Made with fast growing lumber/compressed wood (low quality)
• Rots, Splits, Cracks, Discolor, Gaps/Insects, Mold & Mildew issues.
• Price Range: $2000–$6000 per opening on average
• Warranty Limited: 20/10/2 – Short term solution with multiple warranty stipulations.
  Typically, 20 years glass, 10 years frame and hardware, 2 years labor

Wood with Aluminum Exterior

• Pros: Look good when initially installed.
• Cons: Requires regular maintenance to prevent rot and decay.
• Made with fast growing lumber/compressed wood (low quality)
• Exterior Aluminum: Conducts heat and cold, sweats, rots, splits, cracks. This also leads to high air infiltration, leaks, Insects, mold & mildew issues.
• Price Range: $2000–$6000 per opening on average
• Warranty Limited: 20/10/2 – Short term solution with multiple warranty stipulations.
  Typically, 20 years glass, 10 years frame and hardware, 2 years labor

Fiberglass and Composite

• Pros: Multiple finishes and design options.
• Cons: Exterior finishes fade leading to maintenance costs (all are coated finishes)
• Does not do well or cover exposure to excessive localized heat (ie the sun)
• Frame can chalk
• Non-insulated frames
• Limited long-term testing; more expensive and a short-term solution.
• Price Range: $2000–$8000 per opening on average
• Warranty Limited: 20/10/2 – Short term solution with multiple warranty stipulations.
  Typically, 20 years glass, 10 years frame and hardware, 2 years labor

Fibrex and Ultrex

• Pros: Multiple finishes and design options.
• More glass space.
• Cons: Exterior finishes fade leading to maintenance costs (all are coated finishes)
• Does not do well or cover exposure to excessive localized heat (ie the sun)
• Non-insulated frames
• Limited long-term testing; more expensive and a short-term solution.
• Price Range: $2300–$8000 per opening on average
• Warranty Limited: 20/10/2 – Short term solution with multiple warranty stipulations.
  Typically, 20 years glass, 10 years frame and hardware, 2 years labor

Vinyl – Contractor Grade

• Pros: Non-conductive, energy-efficient, low maintenance, affordable.
• Cons: Low quality vinyl or re-furbished/recycled vinyl. 
• Thin-walled frame structure, lacking reinforcement and less durable welding techniques.
• Can warp or expand in high heat if low quality; limited color choices.
• Frame is bulky, can chalk, lose shape, split and crack
• Prone to air leakage.
• Low efficiency glass pack
• Used largely in new homes with brand names to give illusion of efficiency. Named brands typically have the most stipulations and worst warranties
• Price Range: $1000–$4000 per opening on average
• Warranty: Lifetime Limited with multiple stipulations. 
• A Lifetime Warranty is what the manufacturer decides they believe is the lifetime of their product that they are willing to cover – This can be as low as 2 Years which with contractor grade products is often the case to let builders get through their 1-2 warranty that they legally have to offer.

Bennett Baths & Exteriors Choice

Vinyl – 100% First Generation

• Pros: Multiple finishes and design options.
• Non-conductive, energy-efficient, low maintenance, affordable.
• More glass space and low air-infiltration
• Will not lose it shape, split, corrode or crack.
• Some with insulated frames for extra efficiency and multi-chambers (Not all) at Bennett Baths & Exteriors our frames are insulated.
• Does not chalk
• Lifetime warranties on frame, hardware and glass pack (Not all) included at BBE.
• Accidental glass breakage warranty (Not all) included at BBE.
• Certain Finishes/Colors will not fade with a lifetime warranty
• Cons: Exterior coated finishes typically have up to a 10 year warranty (same as all exterior coated finishes)
• Still different variations and qualities
• Price Range: $1750–$5000 per opening on average
• Lifetime Limited Warranty with minimal stipulations
  (Depending on the manufacturer, named brands typically have the most stipulations and worst warranties as they are not truly designed to be long term replacement windows. More towards branding and selling)

Window Replacement Benefits

Upgrading old windows isn’t just aesthetic—it’s practical.

• Energy Savings: Up to 25–30% reduction in heating and cooling costs.
• Comfort: Reduced drafts, consistent indoor temperature.
• Noise Reduction: Double or triple-pane glass helps keep outside noise out.
• Home Value: Replacement windows often return 70–80% of their cost at resale.
• Low Maintenance: Modern materials never need painting or refinishing.

“Exterior makeovers like siding, roofing, and window replacement not only improve curb appeal—they also provide one of the highest returns on investment.”
— Remodeling Magazine, Cost vs. Value Report

Warranties

Lifetime Limited Warranties

• The words of Lifetime Warranty is used across the board in the remodeling industry unfortunately, even though 90% of people using these words do not have a true Lifetime Warranty so be careful and below are some explanations and things to look out for.
• The words Lifetime warranty is a marketing term and is not a guarantee that every component is covered forever.

• What is a Lifetime to the manufacturer = The is the Years that the manufacturer decides that the product will last.

This could be anything from a 1-year warranty (that is correct 1 year does not sound like a lifetime does it) to the lifetime you own the home. They only need one item to be classed as lifetime to advertise a lifetime warranty.

• Examples of these warranties and stipulations
• Lifetime warranty on moving parts only
• Lifetime warranty that is based on years 1-10 / 10-20 / Prorated.
• Multiple things that it does not cover in some warranties, argon gas in the window once it has left the factory, moving parts, discontinued glass or parts, chalking, fading, warping (up to hunter units, fractions/manufacturers discretion), products exposed to excessive localized heat plus many more.

What to look for in a Lifetime Limited Warranty

• Covers the full frame from manufacturers defects for the Lifetime you own the home.
• Covers the Glass Pack insulating sealed glass unit from manufacturers defects for the Lifetime you own the home.
• Covers all moving parts from manufacturers defects for the Lifetime you own the home.
• Covers the screen frame from manufacturers defects for the Lifetime you own the home. This will never cover the screen mesh itself, however if needed is easy to replace the screen at a local hardware store using the existing screen.
• All of the above is covering the full window

Extra Bonus options a plus.

• Includes Accidental glass breakage for the Lifetime you own the home.
• Is a Transferrable Warranty if you sell the home or pass it onto loved ones.

20/10/2 Limited Warranties

• Typically, these types of warranties are from brands that you know/heard of as they advertise heavily on a regular basis on the TV, Radio, Mailbox, Public contractor grade stores. Some are in contractor warehouses for the public and have individual franchises across the US. Pella warranty, Renewal by Anderson warranty, Anderson warranty, Jeld-Wen warranty just some names you will recognize. Below is not from one individual company and guidelines to look out for.

• With a Warranty that has the terms 20/10 you are automatically purchasing a window which is a short-term solution that will need to be replaced.
• If it has a 2, that is typically covered for 2 years labor only.

• Be careful as companies and salespeople will still inform you that you will be getting a lifetime warranty even though it is for a period of 20/10 years with multiple stipulations.
• What is a Lifetime or 20/10 to the manufacturer = This is the Years that the manufacturer decides that the product will last.

This could be anything from a 1 year warranty (that is correct 1 year does not sound like a lifetime does it) to the lifetime you own the home or a 20/10 which could be 20 years glass and 10 years frame. You only need one item to be classed as lifetime/20 year to advertise a lifetime or 20 years warranty.

• Examples of these warranties and stipulations
• 20 years on glass or frame (typically glass)
• 10 years on frame or glass (typically frame and possibly hardware)
• Moving parts with a lower separate warranty.
• Multiple things in some warranties it does not cover, argon gas in the window once it has left the factory, discontinued glass or parts, chalking, fading, warping (up to hunter units, fractions/manufacturers discretion), products exposed to excessive localized heat plus many more.

What to look for in a 20/10/2 Warranty

• When there are much better warranties available, this is not a good coverage option.

• If you still want this route here are suggestions to look for.

• 20 Years Glass
• 20 Years frame (if possible)
• 10 Year hardware