Yes. Ordinary window glass blocks nearly all UVB but lets a large share of UVA straight through.

That single fact undoes the assumption most of us run on — that being inside means being covered. You do not burn indoors, because burning is UVB and the glass handles that. But UVA passes through, and UVA is the one behind pigmentation, dark spots, and the slow loss of firmness people call photoaging.

So the damage that shows up in a mirror ten years from now is precisely the kind that window glass does nothing about.

I want to be clear about the scale before going further: nobody should be alarmed about a lunch break by a window. But if you sit at a desk beside glass for eight hours a day, five days a week, that is a meaningful amount of exposure that has never entered your sun-protection thinking at all.

See the UV shield range →

Which Glass Blocks UV, And Which Doesn't

Not all glass behaves the same way, and the differences are larger than most people expect.

Type of glass	Where you find it	What it lets through
Standard float glass	Most home and office windows	Blocks nearly all UVB, lets much of the UVA through
Laminated glass	Car windscreens, some modern buildings	Blocks the large majority of both, because of the plastic interlayer
Tempered glass	Car side and rear windows	Blocks most UVB, lets significant UVA through
Low-E coated glass	Newer commercial glazing	Blocks more UVA than plain float glass, but not all
Tinted glass	Varies widely	Tint alone tells you nothing — darkness is not the same as UV filtering

The last row is worth pausing on, because it catches people out constantly. A darkly tinted window can let through more UVA than a clear laminated one. Tint reduces visible light and glare, which feels like protection and is not the same thing at all.

The practical takeaway: your car windscreen is doing real work, your home and office windows mostly are not, and how dark the glass looks tells you almost nothing.

Car side windows are their own case, and a bigger one than most drivers realise — we went into that separately in Do UV face shields work.

Sitting By A Window At Work

This is the version of indoor exposure that actually adds up, and almost nobody counts it.

A window seat is a good seat. Better light, a view, less of that airless feeling. It is also the same position, at the same distance from the same glass, for around forty hours a week, fifty weeks a year.

Three things make it worth thinking about rather than ignoring.

The exposure is one-sided. You are usually facing a screen with the window to your left or right, so one side of your face receives it, and the other does not. Over years, that asymmetry can show — the same pattern drivers develop, arriving by a different route.

It is completely invisible. There is no warmth, no redness, nothing to remind you it is happening. Sunburn tells you when you have had too much; UVA never does.

And it stacks on top of everything else. This is not instead of your outdoor exposure. It is in addition to the commute, the walk to lunch, the weekend.

If you work from home, look at where your desk actually is. A lot of people set up beside a window for the light without ever considering it as a sun-exposure decision.

Do You Get UV On Cloudy Days?

Yes, and this is the second belief worth dismantling.

Cloud scatters ultraviolet radiation rather than absorbing it. On a lightly overcast day, a substantial share of UV still reaches the ground, and thin high cloud can occasionally scatter it in ways that push readings up rather than down.

What cloud reliably removes is the sensation. It takes away the heat and the glare, which are the two signals people actually use to decide whether they need protection. So an overcast day feels safe while delivering meaningful exposure, and that combination is exactly why people burn on days they were sure were fine.

The same logic covers winter. The UV index falls in winter, but it does not reach zero, and it rises with altitude — which is why a bright cold day in the mountains can deliver more UV than a warm one at sea level.

If you want to know what the reading actually is where you are, rather than guessing from how it feels, that is what our checker is for.

Check your UV index — free →

What Actually Stops Indoor UV

Four options, and they are not equally useful.

Option	What it does	Where it falls short
Window film	Blocks most UVA at the glass itself	Fixed installation, needs a landlord's permission, only protects that one window
Blinds and curtains	Block UV when closed	You lose the light you sat there for, and most people leave them open
Sunscreen indoors	Works, if reapplied	Same reapplication problem as outdoors, and few people do it for an indoor day
A UV face shield	Blocks 99% of UVA and UVB, moves with you	Visible, and not right for every workplace

 Being fair about it: if you have one problem window and you own the place, film is a genuinely good answer and cheaper than anything else here. It solves that window permanently, and you never think about it again.

Where film stops helping is that you do not stay at one window. You move to a meeting room, you step onto a balcony, you drive home, you walk to the car. A shield covers your face wherever it happens to be, which is a different kind of usefulness rather than a straightforwardly better one.

Our shields block 99% of UVA and UVB, and the figure is stated plainly on the UV face shield product page rather than buried in a description.

Get a UV shield — from ₹4,399

Why This Matters More For Pigmentation

For most people, indoor UV is a slow background factor worth knowing about and not worth losing sleep over.

For anyone dealing with melasma or stubborn pigmentation, it is a different conversation. Melasma is driven substantially by UVA, and the reason it is so hard to shift is that the trigger never really stops. Treatment works on the pigment already present. Nothing stops it returning except removing the trigger consistently — and if you have been diligent outdoors while sitting beside a window all week, you have been removing part of it and leaving the rest.

This is also why dermatology guidance from bodies such as the American Academy of Dermatology and the Skin Cancer Foundation treats sun protection as a daily habit rather than an outdoor one. It is not a substitute for medical treatment — speak to a dermatologist about that — but the exposure side is the part you control.

The full comparison of physical barriers against sunscreen for pigmentation is in UV shield vs sunscreen.

A Sensible Response, Not An Anxious One

It would be easy to read all of this and conclude you need to protect yourself every waking moment. That is not the takeaway, and a brand telling you it is would be selling rather than informing.

What is actually worth doing is smaller than that.

Notice where your desk sits relative to the nearest window, and whether one side of your face is getting all of it. Stop using how hot or bright it feels as your signal, because on overcast days that signal is simply wrong. If one window at home is the main culprit and you can fit film, fit it. And on the days you are in and out repeatedly — errands, meetings, the school run — that is when wearing something is easier than reapplying something.

Sunscreen still matters. Nothing here replaces it. This is about the exposure you were not counting at all.

Frequently Asked Questions

Does UV come through windows?

UVA does. Standard window glass blocks nearly all UVB, which is why you do not burn indoors, but lets much of the UVA through — and UVA drives pigmentation and photoaging.

Can you get sun damage sitting by a window?

Over time, yes. The exposure is low-intensity but constant, one-sided if the window is to one side of you, and it accumulates across a working week without any sensation to signal it.

Do car windows block UV?

Windscreens do, because they are laminated. Side and rear windows are usually tempered glass and let significant UVA through, which is why drivers often show more damage on the window side of the face.

Do you need sunscreen indoors?

If you spend long stretches beside a window, it is worth considering. For a room away from direct glass, exposure is minimal.

Do you get UV rays on cloudy days?

Yes. Cloud scatters ultraviolet radiation rather than absorbing it, so a substantial share still reaches you — while removing the heat and glare that normally tell you to cover up.

Does tinted glass block UV?

Not necessarily. Tint reduces visible light, not ultraviolet. A dark tinted window can let through more UVA than a clear laminated one.

Is window film better than a UV shield?

For one fixed window, film is an excellent solution. A shield covers your face wherever you go, so they solve different problems rather than competing.

Do you need sun protection in winter?

Less than in summer, but not none. The UV index falls in winter without reaching zero, and it rises with altitude, so bright cold days at height can deliver more than expected.

Conclusion

Window glass stops the sun that hurts and lets through the sun that ages. That is the whole point of this page, and it is the reason indoor exposure goes unnoticed for years — there is no burn, no warmth, nothing that registers as sun at all.

None of this means being anxious about daylight. It means the mental rule most of us use — outdoors means protect, indoors means fine — is not quite right, and neither is the one about cloudy days.

If you want to do something about it, film handles one window well, and a shield handles your face everywhere. Ours block 99% of UVA and UVB and start at ₹4,399 — the full range is on the UV shields collection page. And if the exposure you are worried about is on your neck rather than your face, the UV Sun Scarf covers that.

Shield up — ₹4,399