Can a windowless bathroom ever work? Yes, but experts say you must consider these 5 things first

When you think about a windowless bathroom, cramped, dark and dingy might spring to mind, but with the right design and considerations, this doesn't have to be the case.

As long as you've nailed the five key components of this space – including ventilation and lighting, which we explain later – you'll be well on your way to creating a beautiful bathroom.

To find out how to bring your windowless bathroom to life – whether it's an understairs toilet or a compact en suite – we've rounded up the best expert tips below.

1. Ventilation

Extractor fans are a must-have in every bathroom, but they're particularly important in windowless spaces, as the steam has nowhere to go. Michael Zohouri, founder of Pyramid Eco, suggests leaving it running for at least 20 minutes after your shower, but potentially longer if the room is still damp.

"I'd recommend a decent extractor fan with a humidity sensor for a windowless bathroom," he says. "The sensor helps because you're not relying on someone remembering to switch it on. It'll respond when moisture levels rise and keep running until they've dropped. You also need to make sure the fan is powerful enough for the size of the room."

While some people turn their extractor fan off due to the noise, energy costs or potential cold, Michael says you could be "creating a much bigger problem with condensation and mould".

To ensure your extractor fan works properly, you'll need to see if there is a sufficient gap underneath the bathroom door so replacement air can get in.

Finally, Michael advises checking that your ducting vents outside rather than into your loft – otherwise, you're just transferring damp air from one part of your home to another.

2. Lighting

A lack of natural light is one of the biggest problems in a windowless bathroom, but Massimo Buster Minale, founder and creative director of Buster + Punch, offers a solution.

"Rather than relying on a single overhead fitting, layer different light sources to balance practical light with atmosphere. Start by using ambient lighting to provide an even spread of light throughout the bathroom, using flush IP44 wet rated ceiling lights or spotlights to replace the lack of natural daylight.

"Then, introduce task lighting around the mirror, with wall lights positioned above or either side to provide light for everyday use without harsh shadows or a portable lamp for ease."

You may also want to add a dimmer switch to your bathroom lighting design, which will allow you to adjust the ambience to the time of day, in line with your circadian rhythm.

3. Decoration

Contrary to popular belief, painting everything white isn't going to make your windowless bathroom feel bigger and brighter, according to interior designer Katie Malik. In fact, it can actually make it look cold and clinical when there isn't any natural light.

"Instead, I’d recommend softer, warmer shades such as creamy whites, warm off-whites, pale greige or subtle blush tones," she recommends. "These colours create a much more welcoming atmosphere and work beautifully with warm lighting."

"If you prefer a little more colour, soft sage green, muted powder blue or pale earthy tones can also work really well. The trick is to choose colours with gentle undertones rather than anything too dark or overpowering."

To help your smaller space look bigger, Katie recommends using moisture-resistant satin or soft-sheen paint finishes to help reflect the light, and choosing large-format tiles to reduce the number of visible grout lines, which can sometimes look too busy. You could also use the same tiles across the floors and walls to "help blur the boundaries of the room".

"An oversized mirror is also one of the simplest ways to make a small bathroom feel more spacious. Position it where it can reflect your lighting, and it will help distribute light around the room."

If you're in need of some inspiration, our content director Laura Crombie completely transformed her dated downstairs bathroom using carefully placed colour, patterned flooring and a light-reflecting mirror (see below).

4. The right finishes

Your windowless space might be small, but this doesn't mean you can ignore the basic rules of bathroom design. When it comes to choosing floor and shower wall surfaces, Michael Zohouri recommends porcelain tiles, which don't absorb much water and are easy to wipe down, as well as a bathroom-specific paint on the ceiling to avoid mould spots.

"One thing I'd spend a bit more on is the waterproofing behind the shower tiles. People sometimes think that because they've tiled a wall, it's waterproof. It isn't. Water can still get through grout and joints, so you need a proper tanking system underneath in areas that get regularly soaked," he adds.

"I'd avoid standard MDF around the sink or bath. Once water gets into the edges, it swells and starts falling apart. If you want a vanity unit, look for one specifically designed for bathrooms, and make sure any exposed edges are properly sealed."

5. Odour prevention

If you have a windowless bathroom with poor ventilation (see point one), you may notice that smells linger longer than usual, as there is nowhere for the odour to go.

Other than investing in the best extractor fan and ensuring it vents outside, Michael Zohouri recommends looking into the following:

"I'd start looking at anything that stays wet. Bath mats, towels, shower curtains, even the silicone around the bath. People leave damp towels hanging in a bathroom with no window, and they're surprised when the room starts smelling. I'd move them somewhere with better airflow so they can dry properly."

"After a shower, pull the shower curtain across so it can dry properly, and use a squeegee on the shower walls. It takes about 30 seconds and means there's less water sitting around."

So, before you brush off your windowless bathroom as a lost cause, remember that there are plenty of ways to inject some life into it – from a clever layered lighting scheme to choosing the best type of finish.

For more advice and inspiration, have a browse through these downstairs toilet ideas and these smart bathroom storage ideas that are perfect for compact spaces.