Sunlight is good for your home, but if you see that your hardwood floor is changing color near big windows, sliding doors, or skylights, you should do something about it. The good news is that you can slow it down a lot by using the right combination of window control, finish care, and simple habits.
We also move heavy furniture every day, like beds, sectionals, pianos on casters, and more, as part of our job installing and refinishing hardwood floors. Most “sun damage” problems get worse because the same areas are exposed to the sun unevenly and the finish wears away.
The honest truth first: you can’t stop all color change
The truth is that you can't stop all color changes. Over time, wood changes color on its own because of light and oxidation. The National Wood Flooring Association (NWFA) says it clearly: “Wood color change is a normal thing.” This change of color is natural, and nothing can be done to stop it.
NWFA | Source (PDF of Problems, Causes, and Cures)
You can do the following:
- Make the change happen more slowly,
- make it more even,
- and protect the finish so your floor looks good for longer.
Quick takeaway: You don't want “zero change.” It's slower, more even, and easier to take care of.
Why sunlight changes hardwood color (it’s not only UV)
A lot of people blame UV light, and it is a big part of it, but visible light is important too. A summary of research by the U.S. Forest Service (Forest Products Laboratory) says, “Violet light is the part of the visible spectrum that extends photodegradation… beyond the zone affected by UV.”
Summary of research by the U.S. Forest Service
Studies of indoor conditions also show that UV-VIS light can change the color of both coated and uncoated wood. This change depends on the species and coating.
Example of an indoor study (MDPI)
The best ways to protect hardwood floors from sun (ranked)
Here's a simple comparison of what works best in real homes.
| Method | What it’s best for | Pros | Limits |
|---|---|---|---|
| Shades / blinds / curtains | Big daily sun hits | Fast, affordable, adjustable | Needs consistency |
| UV / solar-control window film (NFRC-rated) | Keeping light + reducing UV/glare | Keeps views, helps with UV and glare | Doesn’t stop all visible-light change |
| Low-E windows / glass upgrades | Long-term comfort + surface protection | Helps with heat + can reduce UV impact | Higher cost, bigger project |
| Maintain / recoat your finish | Keeping floors protected + even-looking | Extends life, improves appearance | Needs correct products + timing |
| Rotate rugs + move furniture | Preventing “tan lines” | Free, very effective | Requires a habit |
The U.S. Department of Energy says that “window films… help block against solar heat gain and protect against glare and ultraviolet exposure.”
U.S. Department of Energy (Energy Saver)
NFRC also says that it tests, certifies, and labels window films for energy performance on its own, which is useful when you want to compare products.
Step 1: Control sunlight at the window (the biggest win)
Use coverings like a “sun schedule”
Use things like a “sun schedule” to cover things up. Set a simple schedule for rooms that get a lot of direct sun, like those that face south or west:
- Close the blinds during the hottest parts of the day
- and open them when the sun moves off the floor.
This is also what experts in the field say to do. Kyle McAllister, the Hardwood Director at Shaw Residential, says that wood floors oxidize when they are in direct sunlight. He suggests using shades or blinds to make the light less bright.
The Spruce is an expert source.
Consider UV / solar-control window film (choose certified ratings)
Think about getting window film that blocks UV rays and sunlight. If you want light without blasting the floor, film is a great choice. The Department of Energy says that films can help cut down on glare and UV exposure without blocking views.
Things to look for:
- NFRC-rated film or performance data that is clearly written down (so you don't have to guess).
- A good mix of sunlight and visible light (it can feel like a cave if it's too dark).
Pro tip: A combination of film and light curtains usually works better than just “super dark” film, since you can change it every day.
Low-E glass (best long-term comfort + surface protection)
Low-E is worth talking about if you're already replacing windows. Berkeley Lab says that low-e coatings let visible light through while blocking heat. They also say that they “reduce damage to interior surfaces from UV light.”
Step 2: Protect the floor’s finish (so sun doesn’t “eat through” faster)
Think of the finish on your wood as sunscreen. Color changes and dull spots show up faster when it's worn down.
Know the difference: recoat vs full refinish
A lot of homes don't need a full sand-to-bare-wood refinish. Sometimes all you need to do to restore protection is a screen and recoat (also called buff and coat).
We have a simple test on our blog: the water test. If the water beads, the finish is still there; if it soaks in, it's time to refinish.
Related article on Weles: “Understanding How Often to Refinish Hardwood Floors”
Don’t strip your finish with the wrong cleaner
Sunlight and strong cleaning don't go well together. McAllister warns that chemicals like ammonia, vinegar, and bleach can damage the finish on a wood floor over time in a guide that quotes experts in flooring and restoration.
Source of expertise (The Spruce)
Simple rule for cleaning: If a cleaner sounds like a kitchen hack, it probably won't be good for your floor. Take care of your finish brand according to its instructions.
Watch heat + humidity swings near sunny windows
The sun can quickly warm up a room, especially if it's closed off, which can cause humidity changes that stress wood. According to NWFA, sunlight coming through windows can make things hotter and cause problems with performance when air exchange or HVAC use is low (the “Greenhouse Effect”).
NWFA / Hardwood Floors Magazine: HVAC Systems and the Greenhouse Effect
Step 3: Stop “tan lines” by rotating rugs and moving furniture
Uneven exposure is what usually causes those sharp lines. For instance, the rug blocks light while the floor that is exposed changes faster.
To help even out the color in areas where shadows were left, NWFA suggests moving furniture or rugs from time to time.
Source of NWFA publication (PDF)
Plan for easy rotation (realistic):
- In bright rooms, change the area rugs every two to three months.
- Change the way your furniture is arranged once or twice a year (even a few inches can help).
- If you can't move big furniture, just turn the rug and add a runner where the sun hits.
Josh Rudin, who owns ASAP Restoration, says that moving furniture around and using rugs can help wear and tear happen more evenly over time.
The Spruce is an expert source
A useful tip for moving companies (from our job sites): When you move furniture, lift it instead of dragging it. To avoid scratches, use felt pads or sliders instead of sun fade.
If your floor is already sun-faded: what actually works
- Change the way the rugs are laid out or open up covered areas to make the light more even. This often lowers contrast over time.
- If the finish is worn but the wood is still in good shape, restore protection by recoating and screening.
- If the finish has failed in more than one area or the discoloration is deep, you need to do a full refinish.
Here are the costs and trade-offs of refinishing versus replacing: “Refinishing vs. Replacing Hardwood Floors”
FAQ
No. NWFA says it's normal and can't be completely stopped. Window coverings or UV protection can slow it down, but they can't stop it completely.
No. Photodegradation can happen with visible light, especially violet wavelengths, in addition to UV-only effects.
Yes, a lot of the time, especially if you want light without heavy curtains. The DOE says that films can help with glare and UV exposure, and the NFRC certification can help you compare performance.