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Does a Bathroom Have to Have a Window

Have you ever looked at the tiles in your bathroom? Have you ever noticed the mold between the tiles? This can be the cause of poor ventilation in your bathroom. When there is excess humidity and moisture in your house’s air system, this can cause severe damage to your home. 

According to the international residential code, bathrooms do not need a window if there is a ventilation fan and an artificial source of light. If either of those is missing a bathroom must have a window.

Having a window in your bathroom is ideal but placing a window in your bathroom is not always an option for everyone. Therefore there are also a few other ways to redirect the moisture from your bathroom. You can read more about this below. 

Having a Window in Your Bathroom as Ventilation System

From all the areas in your house, your bathroom will be the one that gets the wettest. As described above, a window in your bathroom will allow the bathroom to ventilate. Without a window or another kind of ventilation system, the humidity will not be able to escape your bathroom. When there is too much moisture and dampness in your bathroom, this will cause all sorts of problems like:

  • Mold and mildew growth The mold in your bathroom doesn’t only look unclean. It can also cause health issues like allergic and respiratory reactions. 
  • Smell It can happen that you don’t see the moisture building up in your bathroom walls and ceiling. Another way to know that the bathroom doesn’t have enough ventilation is when it starts to smell. The smell comes from the hidden mold caused by the moisture that can’t escape because of a poor ventilation system 
  • Damage to your house when you don’t ventilate your bathroom can damage your house structure. When certain areas in your home, like the wood in your ceiling, for instance, stays wet or damp for too long, this will cause rotting. A rotted roof will cause leakage and will also come down if the wood becomes too thin. 
  • Chipping paint when moisture gets into your bathroom walls it can cause the paint to chip or scratch easily. Repainting the walls won’t help if the room stays too damp.
  • Discomfort As you might be able to imagine, it can be unpleasant to be in a damp environment. It can cause difficulty breathing, the mirror will constantly be foggy, and your towels will have trouble drying. 

In the end, if you don’t have a form of ventilation in your bathroom, then a window is essential and necessary.  


Apart from being an excellent ventilation system, a window also brings a lot of light, brightening up the room. If your bathroom window is too close to your neighbors and you feel like you don’t have enough privacy, this is easily solved by putting in a tinted window or hanging up a specially made bathroom curtain.

In What Cases Can a Bathroom Not Have a Window?

According to IRC R303.3 Bathrooms a bathroom can not have a window when the following two conditions are met:

  • Artificial source of light
  • Local exhaust system

What this means is that if you have a bathroom fan and a light, it is OK not to have a window in the bathroom. Keep in mind that the bathroom fan should always vent to the outside.

Some ways to reduce moisture in bathrooms are:

If you are interested in more ways to ventilate your bathroom when you don’t have a window, you can find more information here.

To prevent your bathroom from falling apart due to poor ventilation, it is essential to clean it regularly so that air can circulate. Make sure to turn on the dehumidifier or exhaust fan when using the shower and leave them on until the bathroom is dry.

How Important is it to Have a Window in a Bathroom?

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Having a window in your bathroom is essential if you don’t have another kind of ventilation system.

Depending on where you are located in the world, some governments require by law that households must have a window in their bathroom. The window gets seen as a safety measure for the structure of your house. When you have a different kind of ventilation system, you will not meet the requirements of this specific state.

Other governments or local codes oblige having some form of ventilation system in your bathroom. In this case, a window is not essential.

The primary importance of having a window in your bathroom is that the moisture has a place to escape. If the window is the only ventilation system in your bathroom, you will need a window of at least three square feet.

Does a Bathroom Window Have to be Tempered?

Tempered glass is a special kind of glass that is a lot stronger than ordinary glass. Suppose the glass breaks. Then it will break into many small pieces forming a pellet. Meaning that the chances of cutting yourself due to sharp edges are slim. This is the same kind of glass that sits in a car window.

Only if you meet all the following requirements below then tempered glass in a bathroom window is not required.

  • The glass window is smaller than nine square feet.
  • The glass sits higher than 18 inches above the floor
  • The top of the window is higher than 36inches above the floor
  • The window is further than 36inches from where you walk.

When installing a bathroom window, it is recommended to use a tempered glass window for your safety.

Should Bathroom Window be Frosted?

Frosted glass is glass that you can’t look through from the outside, giving you more privacy when you are in the bathroom. A bathroom window does not have to be frosted. It is your own choice. Other options to stop the feeling of people being able to peak into your bathroom could be hanging up a curtain, for example.

A Bathroom Fan is Absolutely Vital in a Windowless Bathroom

If you don’t have a window in your bathroom, then a bathroom fan is vital. When a bathroom doesn’t have a window or fan system, it is impossible to draw enough moisture out of your bathroom.

When moisture and damp air sticks around for too long, this will cause mold and mildew growth, leakage, chipping of paint, and discomforts like foul odors.

Bathroom Exhaust Fans

There are a few different kinds of exhaust fans. The fans come with other specifications and in various sizes and styles.

If you are looking to install a bathroom fan check out my guide to learn what to look for when choosing a bath fan. I cover everything from airflow to duct size in great detail.

What to pay attention to when buying an exhaust fan system:

  • Noise production
    Different kinds of fans have different types of specifications. The amount of noise that comes from the fan gets referred to as a sone. If you don’t want a fan to make too much noise, it is best to buy a fan with a rating between 0.3 and 1.2 sones.
  • Airflow
    Depending on the size of the bathroom and what is included is what will determine the amount of airflow that your exhaust fan must produce. If you have a shower and a tube, it might be best to install two smaller fans instead of one big fan.
  • Aesthetic design
    The fans are rectangular or round and are fitted with a grill. If you don’t have light in your bathroom already, it is possible to buy a fan with an installed light system. If this is the only way you can lighten up the bathroom, it is essential to look at the amount of wattage the lights can maximumly obtain.

Here, you can read about how to keep a windowless bathroom fresh.

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