Is window UVA exposure as strong as direct sunlight?

No, glass does reduce UV levels compared to being directly outdoors, but it doesn't remove UVA exposure entirely, so it's still worth accounting for over repeated indoor or driving time.

What kind of SPF is best for everyday indoor and driving use?

A lightweight, broad-spectrum SPF that sits comfortably under makeup or alone tends to suit daily indoor and commuting use best, since it doesn't need reapplying the way outdoor exposure often requires.

The SPF Gap: UVA Through Car and Office Windows

Q: Does glass block UVA rays?

Standard window glass blocks most UVB but lets a significant portion of UVA through. Laminated glass, like windscreens, filters more UVA than the tempered glass typically used in side windows and office glazing.

Q: Do I need SPF if I'm indoors or driving?

Yes, if you spend time near windows, such as during a commute or at a desk with natural light, cumulative UVA exposure can add up over time. A broad-spectrum SPF applied each morning covers this.

Q: Which side of my face gets more sun in the car?

In right-hand drive UK cars, drivers typically face more cumulative UV exposure on the right side of the face and forearm. Applying SPF evenly across the whole face is still the more reliable approach.

Quick answer: Ordinary window glass blocks most UVB but lets a significant amount of UVA through, so time spent driving or near sunny office windows can still expose skin to ageing UVA rays. A broad-spectrum SPF worn daily, even on car-commute or desk-bound days, closes this often-missed gap.

Does glass block UVA rays?

Standard window glass is reasonably effective at blocking UVB rays, which are the main cause of sunburn, but it's much less effective against UVA rays, which penetrate glass to a meaningful degree. UVA makes up the majority of the UV radiation that reaches the earth's surface, and it's associated with longer-term changes in the appearance of skin over time, including how skin looks as it ages.

Because UVA doesn't cause the immediate, obvious redness that UVB does, it's easy to underestimate how much exposure is happening through a car windscreen, side window, or office glazing over the course of a normal day, especially during a spell of bright but not necessarily hot weather. Laminated glass, such as that used in windscreens, tends to filter out more UVA than the tempered glass typically used in side windows and standard office windows, which is one reason some people notice more visible sun exposure on the side of the face and arm nearest the window when driving. This isn't about avoiding windows altogether, but about recognising that being indoors or in a vehicle doesn't fully remove UV exposure the way it's often assumed to. A broad-spectrum SPF that protects against both UVA and UVB is the most reliable way to close this gap, and our SPF and sunscreen collection has options suited to daily wear under makeup or alone.

SPF cream texture styled near a sunlit window

Do I need SPF if I'm indoors or driving?

Yes, it's worth applying SPF even on days that are largely spent indoors or in a car, particularly if you're near windows for extended periods, such as during a commute, a desk positioned near natural light, or a long drive. Because UVA passes through most standard glass, the cumulative exposure from repeated short periods near windows over weeks and months can add up, even though no single session feels like meaningful sun exposure.

This is a different consideration from the more obvious need for SPF during direct outdoor exposure on a hot day, which is why it's often missed once a heatwave ends and the weather feels less overtly sunny. A broad-spectrum SPF applied as part of a morning routine covers this scenario without requiring reapplication throughout an indoor day, since there's no sweating or water exposure to reduce its effectiveness the way there would be outdoors. For people who spend a lot of time driving for work, or who sit consistently near a window, this is one of the more overlooked pieces of a UK skincare routine, since our climate rarely delivers the kind of intense, obviously sunny days that prompt SPF use by habit. Our SPF and sunscreen range includes lightweight, everyday formulas designed for exactly this kind of low-key, ongoing exposure, and pairs well with our pigmentation and dark spots collection if you're also managing existing sun-related concerns.

Which side of my face gets more sun in the car?

In the UK, where cars are right-hand drive, drivers typically face more cumulative UV exposure on the right side of the face and the right forearm, since that side sits closer to the side window for the duration of a journey. Passengers in the front-left seat experience the equivalent pattern on their left side.

Over years of regular driving, this asymmetric exposure is sometimes visible as subtly different tone, texture, or pigmentation between the two sides of the face, a pattern that has been documented anecdotally and in some clinical observations related to long-distance and professional drivers. This doesn't mean occasional driving causes noticeable changes quickly, but it does support the case for applying SPF to the whole face, not just areas that feel more exposed to direct sun. If you're concerned about uneven tone that may be linked to years of window-filtered UV exposure, our pigmentation and dark spots collection is a good starting point, and the British Association of Dermatologists has useful general information on sun and skin.

SPF isn't just a heatwave habit — it's worth building into your daily routine year-round, windows or no windows. Have a look through our SPF and sunscreen collection, and if you'd like advice tailored to your own exposure and skin concerns, our team is happy to help via a consultation.

Educational content only — not medical advice. Noticeable changes in skin tone or new pigmentation are worth having assessed by a dermatologist.