# Dehumidifier.lk

> Dehumidifier.lk is a Sri Lankan educational publication about indoor humidity. Dehumidifier.lk explains how the island’s 70–90% relative humidity causes mould, dust mites, allergies, rust and damp damage, how dehumidifiers pull that moisture out of the air, and how to size one for a room. Dehumidifier.lk is published by the team behind DRYAir (dryair.lk), Sri Lanka’s dehumidifier specialist since 2016, and sends readers who want to buy to DRYAir’s Colombo showroom and online store.

## Key facts

- Sri Lanka’s outdoor relative humidity typically sits at 70–90%; the healthy indoor range is 40–60%, and Dehumidifier.lk recommends holding rooms at 45–55%.
- Mould can start growing above about 60% relative humidity; dust mites dry out and die off below about 50%.
- A dehumidifier removes water vapour from indoor air to a set humidity level, collecting it in a tank or through a continuous-drain hose. An air conditioner only dries air while it is actively cooling.
- Sizing rule of thumb: 12 L/day up to ~34 m²; 20 L/day up to ~50 m²; 35 L/day up to ~80 m²; 50 L/day up to ~110 m². Go one size up for ground floors, basements or visible mould.
- Where to buy: DRYAir (https://dryair.lk), 112 Lauries Rd, Colombo 00400. Phone and WhatsApp +94 75 666 00 00 (24/7), protect@dryair.lk. Delivery within Colombo 1–15, usually 1–2 working days; showroom pickup available. 365-day warranty, serviced by DRYAir’s own Colombo team.
- Publisher: Dehumidifier.lk is published by the team behind DRYAir (disclosed on every page).

## Models sold by DRYAir

- [DRYAir DA-12LC](https://dryair.lk/products/da-12lc-dryair-dehumidifier): 12 L/day, 12–34 m² (about 130–370 sq ft). Bedrooms, studies, wardrobes and small cabins.
- [DRYAir DA-20L](https://dryair.lk/products/da-20l-dryair-dehumidifier): 20 L/day, 20–50 m² (about 215–540 sq ft). Living rooms, offices, apartments and hotel suites.
- [DRYAir DA-35L](https://dryair.lk/products/da35l-dryair-dehumidifier): 35 L/day, 35–80 m² (about 375–860 sq ft). Open-plan floors, shops, stores and archives.
- [DRYAir DA-50L](https://dryair.lk/products/da-50l-dryair-dehumidifier): 50 L/day, 50–110 m² (about 540–1,180 sq ft). Warehouses, halls, plant rooms and basements.

## Pages

- [Front page](https://dehumidifier.lk/): Today’s stories, live Colombo humidity, the explainer and reader questions.
- [Where to buy a dehumidifier in Sri Lanka](https://dehumidifier.lk/where-to-buy/): Stockist details, model-by-room sizing table and buying checklist.
- [Sri Lanka Humidity Index](https://dehumidifier.lk/humidity-index/): Live humidity for 12 cities, damp-risk calculator and dehumidifier size finder.
- [Archive](https://dehumidifier.lk/archive/): Every story, searchable.
- [Explainers](https://dehumidifier.lk/section/explainers/): What humidity is, how it is measured and how a dehumidifier removes it.
- [Health](https://dehumidifier.lk/section/health/): Mould, dust mites, allergies, asthma and sleep — what damp air does to the body.
- [Home](https://dehumidifier.lk/section/home/): Walls, wardrobes, books, leather and electronics — protecting what you own.
- [Monsoon](https://dehumidifier.lk/section/monsoon/): Season-by-season plans for Sri Lanka’s two monsoons and the months between.
- [Office](https://dehumidifier.lk/section/office/): Server rooms, archives and open-plan floors — keeping people, paper and IT dry.
- [Commercial](https://dehumidifier.lk/section/commercial/): Showrooms, shops, stores and stockrooms, where damp turns into lost inventory.
- [Hospitality](https://dehumidifier.lk/section/hospitality/): Hotels, villas, spas and function spaces that must smell fresh every day.
- [Industry](https://dehumidifier.lk/section/industry/): Warehouses, plant rooms and cold stores — protecting stock, machinery and product.
- [Buyer’s Guide](https://dehumidifier.lk/section/buyers-guide/): Sizing, running costs, features and where to buy in Sri Lanka.
- [About](https://dehumidifier.lk/about/): Publisher, editorial standards, corrections.

## Articles

- [Damp desks, dying servers and mouldy files: humidity in the Sri Lankan office](https://dehumidifier.lk/articles/humidity-in-offices-server-rooms-archives/) (2026-09-29): The air conditioning is on, yet the office feels clammy, the file room smells, and the server cupboard keeps throwing errors. Why offices need to manage humidity as well as temperature.
- [Rust never sleeps: humidity control for Sri Lankan warehouses, factories and plant rooms](https://dehumidifier.lk/articles/industrial-humidity-warehouses-plant-rooms/) (2026-09-28): Corroded machinery, caked raw materials, sweating floors and cartons that collapse on the shelf. On an industrial scale, humidity is measured in lost stock and downtime.
- [“The room smelled damp”: how Sri Lankan hotels lose reviews to humidity](https://dehumidifier.lk/articles/hotels-guest-rooms-musty-smell/) (2026-09-27): A guest opens the door, drops their bags and breathes in. If the first thing they notice is a musty smell, the review is half-written. Why humidity is a hospitality problem — and how to fix it.
- [Sri Lanka’s invisible flood: the water hanging in the air of your home](https://dehumidifier.lk/articles/sri-lanka-invisible-flood/) (2026-09-24): Every room on the island holds litres of water you cannot see. Here is what relative humidity really means, why Sri Lankan homes sit at 70–90%, and the number every household should aim for instead.
- [What size dehumidifier do I need? The Sri Lankan buyer’s guide](https://dehumidifier.lk/articles/what-size-dehumidifier-do-i-need/) (2026-09-21): Litres per day, square metres, tanks, drains and decibels — how to choose the right dehumidifier for a bedroom, apartment, shop or warehouse, without paying for capacity you don’t need.
- [The uninvited tenant: why mould keeps coming back to Sri Lankan homes](https://dehumidifier.lk/articles/mould-in-sri-lankan-homes/) (2026-09-18): You scrubbed the wall, bleached the grout and repainted the ceiling. Three weeks later the black spots are back. The problem was never the wall — it was the air.
- [Seven dehumidifier myths, busted](https://dehumidifier.lk/articles/dehumidifier-myths/) (2026-09-14): “It will eat my electricity bill.” “My AC already does that.” “It will make the room too dry.” We put the most common doubts about dehumidifiers to the test.
- [Sleeping with a million mites: how damp air fuels asthma and allergies](https://dehumidifier.lk/articles/dust-mites-asthma-humidity/) (2026-09-10): The most common indoor asthma trigger on the island is smaller than a full stop, lives in your pillow, and drinks straight from the air. Take the humidity away and it dies of thirst.
- [Inside the box: how a dehumidifier actually works — and why your AC isn’t enough](https://dehumidifier.lk/articles/how-a-dehumidifier-works/) (2026-09-03): A fan, a cold coil and a bucket. The idea is simple, the physics is elegant, and it explains why an air conditioner can leave a cool room feeling clammy.
- [The monsoon damp survival guide: a room-by-room plan for Sri Lankan homes](https://dehumidifier.lk/articles/monsoon-damp-survival-guide/) (2026-08-27): Two monsoons, two inter-monsoons and not much dry weather in between. Here is when the damp peaks where you live, and exactly what to do about it in every room.
- [Fungus on the lens, rust in the laptop: what humidity does to your electronics](https://dehumidifier.lk/articles/humidity-electronics-cameras-rust/) (2026-08-20): Salt air and 80% humidity are quietly corroding circuit boards, fogging lenses and killing hard drives across the island. The fix costs far less than the damage.
- [Sarees, school books and grandfather’s leather bag: saving heirlooms from the damp](https://dehumidifier.lk/articles/protect-clothes-books-leather-from-damp/) (2026-08-13): The wedding saree with brown spots. The photo album glued shut. The leather bag wearing a grey coat. How Sri Lankan wardrobes and bookshelves lose their treasures — and how to stop it.
- [Humidity is a line on your balance sheet: dry air for Sri Lankan businesses](https://dehumidifier.lk/articles/humidity-control-for-business-sri-lanka/) (2026-08-06): Caked spices, mouldy stock, rusting machinery, damp hotel rooms and failing servers. For shops, warehouses, hotels and offices, humidity is a cost you can measure — and cut.
- [Cold, clammy and mouldy: the hill-country damp problem in Nuwara Eliya and Kandy](https://dehumidifier.lk/articles/hill-country-damp-nuwara-eliya-kandy/) (2026-07-30): In the hills the air is cool, the mist rolls in by four o’clock, and the bedsheets never feel quite dry. Why hill-country homes fight a different kind of damp — and how to win.

## FAQ

- What humidity level should my home be? Keep indoor relative humidity between 45% and 55%. Below 60% mould struggles to grow and below 50% dust mites dry out, while staying above 40% keeps skin, eyes and wooden furniture comfortable. Most Sri Lankan homes sit at 70–90% without help, which is why a dehumidifier makes a visible difference.
- Isn’t an air conditioner enough to dry the air? Only partly. An air conditioner removes some moisture while it is cooling, but it stops drying once the room reaches the set temperature, and most rooms are not air-conditioned all day. A dehumidifier controls moisture directly, to a humidity number you choose, with or without cooling — including in cupboards, stores and rooms where an AC is never switched on.
- Can a dehumidifier help with allergies and asthma? It can remove two of the biggest triggers. Dust mites and mould both need damp air; holding a bedroom below about 50% humidity starves dust mites of water and stops new mould growth. It does not cure asthma, so keep following medical advice, but many families notice fewer night-time symptoms once the room is dry.
- Which dehumidifier size do I need? Size by floor area and dampness. As a guide: a 12 litre-per-day unit covers a bedroom up to about 34 m², 20 L/day a living room or office up to about 50 m², 35 L/day open-plan spaces up to about 80 m², and 50 L/day halls or warehouses up to about 110 m². Go one size up for ground floors, basements or rooms that already show mould.
- Where can I buy a dehumidifier in Sri Lanka? DRYAir (dryair.lk) sells, installs and services dehumidifiers from a showroom at 112 Lauries Rd, Colombo 4, with delivery across Colombo 1–15, a 365-day warranty and 24/7 help on +94 75 666 00 00. Order online, on WhatsApp or by phone.
- What is the ideal humidity for an office? Keep office work areas between about 40% and 60% relative humidity, ideally 45–55%. In that range people feel comfortable, paper and furniture stay stable, and mould and dust mites cannot establish themselves. Many Sri Lankan offices drift above 65% outside working hours when the air conditioning is off.
- Do server rooms need a dehumidifier? Many small server rooms and IT cupboards in Sri Lanka benefit from one. Equipment makers specify an operating humidity range, and an air conditioner that cycles on and off lets humidity swing and condensation form on cold surfaces. A dehumidifier with a humidistat keeps the room stable; larger data centres use dedicated precision cooling instead.
- How do I protect office files and records from damp? Store them in a dedicated, closed records room held at about 45–55% relative humidity, on shelves away from outside walls, in boxes rather than open piles. Check monthly for musty smells and spotting, and run a dehumidifier with a humidistat so the room stays dry nights and weekends too.
- What humidity should a warehouse or factory store be kept at? For most general goods, raw materials, packaging and machinery, keep storage areas below about 60% relative humidity. Hygroscopic materials, electronics, documents and some food ingredients need tighter control, and products with their own storage specifications should follow them. Measure over several weeks to see the real pattern, including nights and weekends.
- Why is my warehouse floor wet when there is no leak? The floor is colder than the air’s dew point, so moisture from humid air condenses on it — often after a cool night or when warm, humid air flows in through open loading doors. The fix is to lower the air’s humidity so its dew point sits below the floor temperature, and to limit how long doors stay open.
- Can a portable dehumidifier handle a warehouse? For zones up to roughly 100 m² — plant rooms, store cages, spare-parts rooms, sections of a warehouse — high-capacity portable units of 35–50 litres a day with continuous drainage work well, and several can be combined. Very large open buildings with doors that open constantly may need a professionally designed ducted system.
- Why do hotel rooms smell musty? When a room sits closed with the air conditioning off, its humidity rises to match the outdoor air, often above 80% in Sri Lanka. Carpets, curtains, mattresses and wardrobes absorb that moisture, and mould and bacteria growing in them release the musty-smelling compounds guests notice. Air fresheners mask it; drying the room stops it.
- How can hotels keep unoccupied rooms fresh? Keep a dehumidifier or the room’s humidity control running while the room is empty, set to around 50–55%, with doors and windows closed. Air rooms only on dry, sunny days, clean the AC drip trays and filters regularly, and check wardrobes, curtains and under beds for early mould during the monsoon.
- What humidity should a hotel linen room be kept at? Around 45–55% relative humidity. Linen must go in completely dry and be stored off the floor on open, ventilated shelving. Above about 60% humidity, stored towels and sheets pick up a musty smell and can develop mildew spots, meaning rewashing, replacement and complaints.
- What is a normal humidity level in a Sri Lankan house? Without air conditioning or a dehumidifier, most Sri Lankan homes sit between 70% and 90% relative humidity, rising above 90% on monsoon nights. The healthy range is 40–60%, and 45–55% is the best target for health and property.
- How do I measure the humidity in my room? Buy a digital hygrometer — a small thermometer-and-humidity display sold in hardware and electronics shops for a few hundred rupees. Leave it in the room for an hour away from windows and direct sunlight, then read the percentage. Check morning and night, because humidity rises as the air cools.
- Does opening the windows reduce humidity? Only when the outdoor air is drier than the indoor air, which in Sri Lanka is rare during the monsoons. Opening windows on a humid evening lets more moisture in. Ventilate on dry, sunny afternoons and keep windows closed during rain and at night.
- What does 12 litres per day mean on a dehumidifier? It is the amount of water the machine can remove from the air in 24 hours under test conditions, usually 30 °C and 80% relative humidity. At lower humidity it removes less, because there is less water to condense. Use the figure to compare models and size the unit to the room.
- Is a bigger dehumidifier better? Only up to a point. A larger unit dries a room faster and runs for shorter periods, which helps in very damp rooms, but costs more to buy and is bigger and louder. Match capacity to floor area, then size up one step for damp ground floors, basements or rooms with visible mould.
- Can one dehumidifier do the whole house? Rarely, unless the house is open-plan. A dehumidifier dries the air it can reach, and walls and closed doors block it. Put a correctly sized unit in the room that matters most — usually the main bedroom or a store — and move it or add units as needed.
- Why does mould come back after I clean it? Cleaning removes visible mould but not the damp conditions or the microscopic spores that are always in the air. If the wall or fabric stays above about 60–70% relative humidity, spores land and grow again within weeks. Lowering room humidity to 45–55% is what stops the cycle.
- Is black mould on walls dangerous? Any indoor mould can trigger coughing, sneezing, itchy eyes and asthma attacks, especially in children, older people and anyone with allergies or weak immunity. The colour does not tell you how harmful a mould is. Treat all visible mould as something to remove and prevent, not to live with.
- Does bleach kill mould on walls? Bleach can lighten stains on hard, non-porous surfaces such as tiles, but on porous surfaces like plaster, wood and fabric it often fails to reach the roots and adds more moisture. Use a detergent or a purpose-made mould cleaner, dry the surface fully, and then control humidity so it cannot regrow.
- Do dehumidifiers use a lot of electricity? Less than many people expect, if the unit is sized correctly and set to a humidity target. A dehumidifier uses power mainly while its compressor runs, and once the room reaches the set level it cycles on and off. Estimate cost by multiplying the rated watts by the hours the compressor runs, dividing by 1,000 for units (kWh), and multiplying by your electricity tariff.
- Can a dehumidifier make a room too dry? Not if it has a humidistat and you set it sensibly. Set it to 45–55% and it switches off when the room reaches that level. Rooms only become uncomfortably dry below about 40%, which is very hard to reach in Sri Lanka’s climate with a normal dehumidifier.
- Should a dehumidifier run all day? It can stay switched on all day with the humidistat set to around 50%, because it will only run its compressor when the humidity rises above the target. Keep doors and windows of the room closed while it runs so it is drying the room, not the outdoors.
- Can a dehumidifier help with asthma? It can remove triggers, not treat the condition. Dust mites and mould — two of the most common indoor asthma triggers — both depend on damp air. Keeping a bedroom below about 50% relative humidity starves mites of water and stops mould growth. Keep following your doctor’s advice and treatment plan.
- What humidity kills dust mites? Dust mites cannot drink and rely on absorbing moisture from the air. Research on house dust mites shows they lose water and die off when relative humidity stays below roughly 50% for extended periods, while they thrive at 70–80%. The effect takes weeks, so keep the room dry consistently.
- How often should I wash bedding to control dust mites? Wash sheets and pillowcases every week at 60 °C or hotter if the fabric allows, and dry them fully. Use allergen-proof covers on mattresses and pillows, and replace old pillows. Combine this with keeping the bedroom at 45–55% humidity for the best result.
- What is the difference between a dehumidifier and an air conditioner? An air conditioner is built to lower temperature and removes some moisture as a side effect while it is cooling. A dehumidifier is built to lower humidity; it condenses water out of the air and returns the air at about the same temperature or slightly warmer, to a humidity level you set. In humid Sri Lanka, rooms can be cool but still damp — that is where a dehumidifier helps.
- Does a dehumidifier make a room hot? A compressor dehumidifier adds a little warmth, because it releases the heat it removed from the air plus the heat of its motor. In practice the effect in a normal room is small, and drier air feels cooler on the skin because sweat evaporates more easily, so most people find the room more comfortable, not less.
- Where does the water go? Into a removable tank that you empty, usually once or twice a day in the monsoon, or through a hose into a drain if the model has a continuous-drain outlet. The unit switches itself off when the tank is full.
- When is the most humid time of year in Sri Lanka? It depends on where you live. The south-west monsoon, roughly May to September, brings the wettest months to Colombo, Galle, Ratnapura and the western hills. The north-east monsoon, roughly December to February, brings rain to Jaffna, Trincomalee, Batticaloa and the east. The inter-monsoon periods in March–April and October–November bring heavy thunderstorms island-wide.
- Should I open windows during the monsoon to reduce damp? Usually not while it is raining or at night, because the outdoor air is often wetter than the air inside. Open windows on dry, sunny afternoons when the outdoor humidity is lower, and use extractor fans in the bathroom and kitchen. Check the live outdoor humidity before airing the house.
- How do I dry clothes indoors during the monsoon without mould? Dry them in one closed room with a dehumidifier running and the door shut, spaced out on a rack. The dehumidifier captures the water that would otherwise soak into walls and furniture, and clothes dry in hours instead of days, without the musty smell.
- How do I prevent fungus on camera lenses in Sri Lanka? Keep lenses somewhere with relative humidity around 40–50%, ideally a dry cabinet or a room with a dehumidifier. Use them regularly, since light and air movement discourage fungus, never store them damp or in a closed camera bag for months, and avoid sealing them in plastic. Once fungus etches the glass it is often permanent.
- Can humidity damage a laptop or phone? Yes, over time. High humidity and condensation cause corrosion on circuit boards, connectors and battery contacts, leading to intermittent faults, dead ports and failed boards. Keeping devices in rooms below about 60% humidity and avoiding sudden moves from a cold air-conditioned room into warm humid air reduces the risk.
- Why does my equipment fog up when I take it outside? When a device or lens that has been in a cold air-conditioned room meets warm humid outdoor air, it is below the air’s dew point, so water condenses on and inside it. Let gear warm up gradually in a closed bag before opening it, and avoid switching electronics on while they are fogged.
- How do I stop my clothes smelling musty in the wardrobe? The musty smell comes from mildew growing in damp fabric. Store clothes only when fully dry, leave space between hangers, keep the wardrobe a few centimetres off outside walls, open it daily, and run a dehumidifier in the room to keep humidity at 45–55%. Wash affected clothes and dry them in sun or a dehumidified room.
- How do I store leather bags and shoes in humid weather? Clean and condition leather, stuff bags and shoes with acid-free paper, and store them in breathable cotton dust bags on an open shelf rather than in plastic or a sealed box. Keep the room below 60% humidity. Check them monthly during the monsoon and wipe off any early mould with a dry cloth outdoors.
- How do I protect books and old photographs from humidity? Keep books on shelves away from outside walls with a small air gap behind them, and avoid basements and ground-floor cupboards. Store photographs and documents in acid-free sleeves and boxes. Aim for a steady 40–50% humidity; a dehumidified room is far better than moisture-absorbing packets for a whole bookcase.
- What humidity should a warehouse be kept at? For most general goods — packaged food, textiles, paper, electronics, metal parts — keeping a warehouse below about 60% relative humidity prevents mould, caking, corrosion and packaging damage. Some products have their own storage specifications, so check manufacturer and regulatory guidance for pharmaceuticals, food ingredients and sensitive materials.
- Do hotels in Sri Lanka need dehumidifiers? Many do, especially rooms that are closed for days between guests, basements, linen stores and properties near the coast or in the hills. Unoccupied rooms with the AC off quickly reach high humidity, which causes musty smells and mould that guests notice and mention in reviews. Dehumidifiers keep rooms fresh between stays.
- How do I know if my business has a humidity problem? Look for musty smells, mould on walls or stock, caked or clumping products, curled labels and cartons, rust on shelving or machinery, condensation on cold surfaces, and electronics failing without clear cause. Then measure with data-logging hygrometers for a week or two to see the real humidity pattern.
- Why do houses in Nuwara Eliya feel so damp? The hill country is cool and often wrapped in mist and cloud, so the air is close to saturation. Cool air holds less water than warm air, which pushes relative humidity up, and cold walls and windows drop below the dew point at night, so water condenses on them. The result is damp bedding, musty wardrobes and mould on outside walls.
- Do dehumidifiers work in cold rooms? Compressor dehumidifiers work best in warm rooms and lose efficiency as temperatures fall towards the low teens Celsius, because their coil can frost. Most lived-in hill-country rooms stay warm enough for them to work well, especially with some heating. For very cold, unheated spaces, desiccant dehumidifiers are the specialist alternative.

## Contact

- Corrections and letters: protect@dryair.lk (subject “Dehumidifier.lk”)
- Buying advice: DRYAir, +94 75 666 00 00 (phone/WhatsApp, 24/7), 112 Lauries Rd, Colombo 00400