Window sill replacement costs around $400, on average, but your total could fall anywhere between $150 and $700, depending on the size, material, and other factors.
Window sill replacement costs $400, on average, or between $150 and $700, depending on the type of window, the size, the material you choose, and a few other factors. Your window sill protects your home from water damage. While it’s often considered just a functional part of the window, it also affects your home’s curb appeal, so function and style are important to consider when replacing a sill.
If you notice your window sill is not functioning as it should or needs a refresh, use this guide on window sill replacement costs to see how much you need to budget for the project.
Window sill replacement costs can vary quite a bit, falling between $150 and $700 per window. The price range is so wide because various key factors influence the total cost.
The size of your window and window frame will play an important role in the replacement cost. Larger window sills demand more materials for replacement, and they tend to take longer to replace, which can push labor costs higher. You can expect to pay an average of between $6 and $12 per linear foot of window sill for the materials alone.
The table below includes some standard replacement costs based on the size of your window.
| Window Width (inches) | Material Cost |
|---|---|
| 12 | $75–$150 |
| 24 | $145–$290 |
| 36 | $215–$430 |
| 48 | $290–$575 |
| 60 | $360–$720 |
| 72 | $430–$860 |
| 84 | $500–$1,000 |
| 96 | $575–$1,100 |
There are a few different window sill materials you can choose from, each of which comes with varying costs. Most modern window sills are vinyl or wood with window capping over them, and most homeowners choose a material that matches their window frame material for a more cohesive appearance. Aluminum is the most affordable option, while marble is the most expensive.
The table below includes average material costs only and doesn't include labor costs.
| Sill Material | Material Cost (per linear foot) |
|---|---|
| Aluminum | $6–$7 |
| Vinyl | $6-$9 |
| Wood | $6–$10 |
| Composite | $8–$10 |
| Fiberglass | $8–$12 |
| Marble | $8–$12 |
Since the window sill is located outside your home, the accessibility of your window will be a major factor when it comes to the cost of labor for replacement.
Replacing window sills on the second floor will be more expensive because your installer will need to do all the work from a ladder, which takes more time and introduces risk. Additional safety equipment might be required to get the job done safely.
Similarly, if you have outdoor landscaping features that make the window less accessible, like outbuildings, trees, or decks, you could end up paying a bit more for labor.
Window sills primarily route water away from your exterior wall, but they also affect your home’s curb appeal. Standard sills are flat and rectangular, but you might pay more for a sill with a more appealing design. Some design options that could increase your total include:
Patterns routed into the outer edge of the sill
Stone veneer placed over the sill material
Decorative trim around the sill to complete the look
On average, you can expect to pay around $1 to $3 more per linear foot for these options.
Labor will account for a small portion of the window sill replacement costs, in most cases, making up between 30% and 50% of the total. On average, the labor will cost between $75 and $200.
Remember that the accessibility of your window will determine labor charges, so sill replacement on windows on the second floor or near obstructions will cost more than replacement on easily accessible, first-floor windows.
Replacing a window sill yourself rather than hiring a window repair company near you will save you an average of around $150, or between $75 and $200 per window, depending on the material and accessibility.
Replacing a window sill is relatively straightforward if you know what you’re doing, but mistakes can be costly. Window sills must sit at the proper angle and have adequate caulking and sealing around the edges to protect from rain and snow. If you use the incorrect angle or make a mistake when caulking around the sill, you could be at a higher risk of water getting into your home and causing severe damage.
If you have experience with replacing windows and DIY home improvement, you can likely tackle the job yourself to save money. However, we recommend hiring a professional who replaces window sills to ensure things get done properly the first time. The money you save on a DIY sill replacement will pale in comparison to the potential repair costs you’ll face if you make an error.
Since window sills play such a pivotal role in protecting your home and boosting curb appeal, there are a variety of add-ons many homeowners consider or need to think about before diving in.
Window repair: Since most homeowners replace sills and windows simultaneously, damage to your sill might also mean damage to your window frame. If you do need repairs as well, expect to pay an average of $400 for the cost of repairing window frames.
Window replacement: If your sill and window are outdated or have sustained severe damage, you might need to replace the entire window and sill together. Expect to pay between $100 and $800 per window that you need to be replaced, on top of the cost of sill replacement.
Water damage repair: If your sill has rotted or failed and caused leaking inside your home, you might need to consider replacing the damaged building materials, including insulation, drywall, electrical wiring, and more. On average, the cost of this add-on will sit around $500.
Decorative veneers: Some homeowners choose more visually appealing stone or marble veneers to sit over their sills, creating a more upscale look or one more cohesive with the rest of your home’s exterior. Veneers can add between $25 and $200 per window, depending on the length and material.
Decorative sill trim: Adding decorative trim around your window sill is a great way to achieve a more elegant curb appeal. Opting for this add-on can add anywhere between $8 and $25 per linear foot to your total, depending on the material and how ornate it is.
With the average cost of window sill replacement sitting around $400, many homeowners will, understandably, look for ways to save money on the project. There are a few ways to keep costs down when replacing a window sill.
Choose your sill material carefully. The material costs for window sill replacement vary based on the type of sill you choose. You can keep costs down—potentially saving up to around $40 per 3-foot window—just by choosing a less expensive material. You should, however, consider matching your window frame material for the best appearance.
Consider a DIY replacement. If you’re comfortable with window repair and confident in your ability to caulk around your new sill properly, you could save an average of $150 per window by doing the job yourself.
Avoid decorative upgrades. Window sills come in various shapes and sizes, and you can keep costs down by keeping your sill design simple. Avoid routed sills and more involved exterior window trim if you want to keep costs down.
Replace multiple sills at once. If you’re having issues with one sill, it’s likely only a matter of time before your other window sills experience similar problems. You can reduce labor costs a bit by having the professional who’s already on site replace multiple sills in one go.
Carry out any necessary window repairs at the same time. Similarly, if your window sill has leaked and caused damage to your window or building materials inside, you can save some money on labor by having those repairs carried out by your professional during the same visit.
Yes, you can replace a window sill by itself without removing the window or replacing other components. Window sills are exterior pieces that sit under your window and are attached from the outside, so you can remove the sill and replace it without compromising the rest of the window. However, if your sill is rotted or causing leaks in your home, have a professional inspect the rest of the window frame, surrounding materials, and seals to ensure you won’t have any ongoing problems.
Composite, stone, and fiberglass window sills last 30 to 40 years with routine maintenance and re-sealing. Vinyl, wood, and aluminum sills last for around 20 years. The exact life span of your sill depends on the material, the climate in your area, and if you perform window sill maintenance. Excessive rain can cause materials and seals to break down more quickly, and intense sunlight can cause sills to fade and protective coatings to degrade more quickly. Call in a professional if you suspect your sills are at the end of their life span.
The most obvious sign that your window sill needs replacing is if it’s leaking. You might also want to consider replacing them if they’re near the end of their life span or if you’re also replacing the windows above them. Inspect your sills for damage, cracks, rot, and broken seals to identify when they need repairs or replacement. Finally, if you notice mold on your window sills, they’ve sustained moisture damage and will likely need to be replaced.
