Basement Window Replacement in Utah: Egress, Moisture, and Light

Utah basements are a defining feature of our housing stock. Most homes along the Wasatch Front have full or partial basements, and many homeowners eventually finish that below-grade space to add bedrooms, family rooms, home theaters, or home offices. The windows in that basement play a critical role in three areas: safety (egress code compliance), durability (moisture and waterproofing), and livability (natural light and ventilation).

Whether you are finishing a basement for the first time, replacing aging windows that leak, or adding egress windows to bring a bedroom up to code for a home sale, this guide covers everything you need to know about basement window replacement in Utah.

Why Basement Windows Matter More Than You Think

Basement windows are the most abused and neglected windows in most Utah homes. They sit partially or fully below grade, exposed to soil moisture, runoff, and the freeze-thaw cycling that Utah's climate delivers from October through April. Many basements in homes built during the 1980s-2000s construction booms along the Wasatch Front still have their original, builder-grade windows -- single-pane, aluminum-frame units that leak air, admit moisture, and provide minimal light.

Replacing those windows is not just an upgrade -- it is often a necessity. Failed basement windows are a leading source of moisture intrusion in Utah homes, and moisture in a finished basement leads to mold, musty odors, damaged drywall, and ruined flooring. The cost of remediating water damage from a failed basement window far exceeds the cost of replacing the window properly.

Types of Basement Windows

Hopper windows

Hopper windows hinge at the bottom and tilt inward. They are the most common non-egress basement window because they are compact, affordable ($150-$300 installed for a standard size), and their inward-opening design prevents rain and snow from entering the window well. Hopper windows work well in utility rooms, laundry rooms, and unfinished spaces where you want basic light and ventilation without egress compliance.

Casement windows

Casement windows are the preferred choice for basement egress installations. Their crank-operated sash opens 100% of the window area, maximizing the clear opening for emergency escape. A standard 30x48-inch casement window provides far more clear egress opening than a double-hung or slider of the same size. For a detailed comparison of how casement windows stack up against double-hung in all applications, see our window style comparison guide.

Sliding windows

Sliding (glider) windows move horizontally and are sometimes used in basements where the window opening is wider than it is tall. They only open 50% of their total area, so they need to be significantly larger than a casement to meet egress requirements. Sliding windows are a reasonable choice for non-egress basement locations where you want a wider light opening.

Glass block

Glass block windows provide light and security but do not open. They are used in basement utility areas where ventilation is not needed and the primary concerns are light, security, and moisture resistance. Glass block cannot serve as egress windows and is declining in popularity as homeowners prefer operable windows for air circulation.

Fixed windows

Fixed (non-operable) windows are sometimes used in basements alongside operable windows to maximize natural light. A fixed window next to a casement egress window, for example, doubles the light entering the room while the casement handles ventilation and egress.

Egress Requirements for Utah Basements

Every basement bedroom and habitable space in Utah must have egress-compliant windows. The requirements mirror those for above-grade bedrooms:

• Minimum clear opening area: 5.7 square feet (5.0 square feet at grade level)
• Minimum clear opening height: 24 inches
• Minimum clear opening width: 20 inches
• Maximum sill height: 44 inches from the finished floor

For basements, the sill height measurement starts at the finished floor level. If you have not yet finished the basement floor, account for the planned floor height (subfloor, insulation, and flooring material) when sizing the window. A window that meets the 44-inch sill height requirement with a bare concrete floor might exceed it after you add 2-4 inches of subfloor assembly and carpet.

For the full breakdown of Utah egress code, including common mistakes and the inspection process, read our egress requirements guide.

Moisture Protection for Below-Grade Windows

Moisture management is the single most important factor in a successful basement window installation in Utah. Our clay-heavy Bonneville Lake bed soils swell dramatically when wet, creating hydrostatic pressure against foundation walls. That pressure pushes water toward any penetration in the foundation -- and a window opening is the largest penetration you have.

Exterior waterproofing

The window frame must be sealed to the foundation wall with a continuous waterproof membrane. This is not caulk alone -- it is a peel-and-stick or liquid-applied membrane that covers the joint between the window buck (the frame insert into the concrete) and the surrounding foundation wall. The membrane should extend at least 6 inches beyond the window frame on all sides and integrate with the foundation's dampproofing or waterproofing system.

Interior moisture management

On the interior side, the window should be insulated around the frame with closed-cell spray foam (not fiberglass batts, which absorb water). A vapor barrier between the insulation and the interior drywall prevents condensation from forming inside the wall cavity. In Utah's dry climate, interior condensation is less common than in humid states, but it still occurs during temperature swings when warm, moist interior air meets the cold window frame.

Drainage below the window

Every below-grade window opening should have a drain path. The window well drainage should connect to the home's perimeter footing drain system or to a standalone drain line that carries water away from the foundation. Without proper drainage, the window well becomes a collection basin that funnels water directly against the window and foundation wall.

Utah-specific soil considerations

The Wasatch Front's clay soils are particularly aggressive. When wet, bentonite clay expands with enough force to crack foundation walls and push window wells inward. When dry, the soil shrinks and pulls away from the foundation, creating channels for future water infiltration. Proper backfill around the window well -- using clean gravel rather than native clay soil -- is essential for long-term drainage and stability.

Window Wells: Requirements and Best Practices

Code requirements

When a basement egress window opens into a below-grade area, Utah code requires a window well with:

• Minimum area: 9 square feet at the bottom of the well
• Minimum projection from the foundation wall: 36 inches
• Ladder or steps required if the well is deeper than 44 inches from the bottom to grade level

Best practices beyond code minimums

Code minimums are just that -- minimums. For a window well that works well in Utah's climate, go beyond the basics:

Oversize the well. A window well that is 12-15 square feet at the bottom (rather than the minimum 9) gives you more room for drainage, easier access for window cleaning, and a less claustrophobic feel from inside the room. It also makes emergency exit easier and faster.

Use a corrugated steel or polyethylene well liner. Corrugated galvanized steel wells are the traditional choice and are durable in Utah soils. Polyethylene (plastic) wells are lighter, resistant to rust, and increasingly popular. Either works. Avoid bare concrete block wells, which can crack under soil pressure.

Install a gravel drainage bed. Place 12-18 inches of clean, washed gravel at the bottom of the window well. The gravel provides a reservoir for water to collect and drain away, rather than pooling at window height. The gravel should connect to a drain tile that ties into the footing drain system.

Add a window well cover. A clear or translucent polycarbonate cover over the window well keeps rain, snow, leaves, and debris out while still allowing light through. The cover must be removable from inside the well without tools (for egress compliance), but it can be latched or weighted against wind.

Grade the surrounding soil away from the well. The ground surface around the window well should slope away from the foundation at a minimum 5% grade for the first 10 feet. This directs surface water away before it can enter the well.

Maximizing Natural Light in Utah Basements

Dark basements are a fact of life in below-grade construction, but smart window design can dramatically improve the livability of the space.

Window sizing for light

Bigger windows mean more light. If you are cutting a new opening for an egress window, consider going larger than the minimum code requirement. A 36x48-inch window lets in noticeably more light than a 24x36-inch window, and the incremental cost of the larger unit and opening is modest compared to the total project cost.

Window well design for light

The window well itself can enhance or reduce the light reaching your window. A larger well allows more light in. A well with a flared shape (wider at the top than at the bottom) catches more light. White or light-colored well liners reflect light into the opening rather than absorbing it.

Glass selection

Choose clear glass, not tinted or obscured, for basement windows where light is the priority. Low-E coatings are still important for energy efficiency but opt for a high-visible-light-transmittance (VLT) low-E coating. Some low-E coatings reduce visible light by 20-30%, which is an acceptable tradeoff on above-grade windows but a significant loss in a light-starved basement. For more on glass options and their light-transmission properties, see our glass guide.

Supplementing with light tubes

For basement rooms where window placement is limited by the foundation structure or exterior landscaping, tubular skylights (light tubes) can supplement natural light. These are not windows, but they are worth mentioning because they can dramatically brighten a basement room that can only accommodate a small window.

Cost Breakdown for Basement Window Projects

Basement window costs vary significantly depending on the scope of work. Here are typical 2026 prices along the Wasatch Front.

Simple replacement (existing opening, same size)

Replacing an existing basement hopper or slider with a new, same-size vinyl unit: $250-$500 per window, including the window and installation labor. This assumes the existing opening is in good condition and no structural work is needed.

Egress window installation (new opening)

A complete new egress window installation, including foundation cutting, framing, the window unit, window well, drainage, and finishing: $2,500-$5,000 per window. Variables that push toward the higher end include poured concrete foundations (harder to cut than block), deep window wells requiring a ladder, and difficult soil conditions.

Egress window conversion (enlarging existing opening)

Enlarging an existing small basement window opening to meet egress requirements: $1,500-$3,500 per window. This is less expensive than a fully new installation because some of the foundation work is already done, but it still requires cutting, reframing, and usually a new or enlarged window well.

For context on how basement window costs fit into a whole-home window replacement budget, see our comprehensive cost guide.

Choosing the Right Installer

Basement egress window installation is specialized work that sits at the intersection of window installation, concrete cutting, waterproofing, and drainage engineering. Not every window contractor is qualified to do it well. Here is what to look for:

Foundation cutting experience. The installer should have demonstrable experience cutting residential foundation walls. This is different from standard window installation and requires specialized tools (concrete saws, core drills) and knowledge of structural reinforcement.

Waterproofing expertise. Ask specifically how the installer waterproofs the window-to-foundation junction. If the answer is "we caulk it," keep looking. Proper waterproofing involves membrane systems, not just sealant.

Licensed and insured in Utah. Verify the contractor's Utah construction license. Basement window work involves structural modifications, and an unlicensed contractor cannot legally pull the required permits.

Permit handling. A good installer will handle the building permit application and coordinate the required inspections. If an installer suggests skipping the permit, that is a disqualifying red flag.

Common Basement Window Problems in Utah

Water intrusion around the window frame

The most common problem. Causes include failed or absent waterproofing membrane, clogged window well drains, improper grading directing water toward the foundation, and deteriorated caulking. The fix depends on the root cause -- sometimes resealing the exterior is sufficient, but persistent leaks often require excavation and a full waterproofing repair.

Condensation on window glass

Basement windows are prone to condensation because the glass temperature is lower than above-grade windows (cooled by contact with the foundation wall and below-grade air). Upgrading to double-pane, argon-filled glass reduces condensation significantly. Ensuring adequate ventilation in the basement room also helps.

Difficult or inoperable windows

Older basement windows, especially aluminum-frame sliders, often become difficult to open after years of corrosion and paint buildup. If your basement windows are hard to operate, replace them -- especially if they are in a bedroom. An egress window that an adult cannot open easily is a safety hazard.

Inadequate window well drainage

Utah's clay soils frequently clog perimeter drains over time. If you notice water pooling in your window wells after rain or snowmelt, the drainage system likely needs cleaning or replacement. Ignoring this leads to the water intrusion problems described above.

Planning Your Basement Window Project

A successful basement window project starts with a clear understanding of your goals. Are you finishing a basement and need egress compliance? Replacing failed windows that leak? Upgrading small windows to bring in more light? Each goal drives different decisions about window size, style, and budget.

Start by identifying which rooms require egress windows. Then assess the condition of your existing windows and window wells. Get at least three quotes from contractors experienced in basement window work -- not just general window installers. And always verify that the proposed windows meet both the egress requirements and your goals for light, ventilation, and moisture protection.

Your Utah basement has the potential to be genuinely comfortable, livable space. The right windows, properly installed, are the foundation of that transformation. For more on choosing between window styles for every room in your home, visit our room-by-room recommendation guide.