How to Use Essential Oils in a Diffuser Safely

A diffuser is the simplest way to enjoy essential oils. It spreads a light scent through a room without putting anything on the skin. Used well, it can make a space feel fresher, cozier or more energizing. Used carelessly, it can irritate eyes and lungs or bother children and pets. This guide covers the main types of diffuser, how to use one step by step and how to do it safely.

Types of essential oil diffusers

• Ultrasonic diffusers are the most popular. They mix a few drops of oil with water and use vibrations to send out a fine, cool mist. Most have timers and auto shut-off.
• Nebulizing diffusers use no water. They break pure oil into tiny particles, so the scent is strong and they use oil quickly. They suit large rooms and short sessions.
• Evaporative (fan) diffusers blow air across a pad holding a few drops. They are simple and quiet.
• Heat diffusers and aroma lamps warm the oil with a candle or electric plate. Heat changes the scent a little, and open flames need close supervision.
• Reed and passive diffusers use reeds, clay, wood or fabric to give off a gentle scent with no power at all. They are a good choice for small spaces such as closets.

How to use an ultrasonic diffuser, step by step

• Place it well. Choose a flat, stable surface at least a couple of feet off the floor, away from the edge, out of reach of children and pets, and away from wood finishes and electronics that the mist could damage.
• Add water. Use room-temperature tap or distilled water, as the manual recommends, up to the fill line. Do not overfill.
• Add the oil. Start with only 3 to 5 drops for a typical small diffuser. Follow the manufacturer’s instructions for larger units.
• Close and switch on. Choose a short or intermittent setting.
• Empty and wipe it after use. Standing water can grow mold and bacteria.

Do not add carrier oils, thick resins or vanilla extract to an ultrasonic diffuser unless the manual says they are safe; they can clog it.

How long to run a diffuser

More is not better. A common guideline is to diffuse for about 30 to 60 minutes, then turn the diffuser off for at least as long. Many people find the scent fades from their notice after a while anyway, a normal effect of getting used to a smell. Running a diffuser all day or all night in a closed room increases the chance of headaches, nausea or irritated airways. Keep a door or window slightly open so the room stays ventilated.

Simple diffuser blends to try

These drop counts are for a small ultrasonic diffuser:

• Clean and bright: 2 drops lemon, 2 drops peppermint.
• Wind down: 3 drops lavender, 1 drop chamomile.
• Fresh air: 2 drops eucalyptus, 2 drops orange.
• Cozy evening: 2 drops orange, 1 drop cedarwood, 1 drop frankincense.

For tips on choosing oils that work together, see how to dilute and blend essential oils.

Diffuser safety

Children

Do not diffuse in a room where a baby sleeps, and avoid strong oils such as peppermint, eucalyptus and rosemary around young children. Keep the diffuser and oil bottles out of reach: the water tank is easy to tip, and swallowing essential oil can make a child very sick. See essential oils and kids for age-by-age guidance.

Pets

Cats, birds and small animals are particularly sensitive to essential oils in the air, and droplets can settle on fur and be licked off. Diffuse only in rooms that pets can leave, never in a small closed room with a pet inside, and keep the diffuser where it cannot be knocked over. Watch for drooling, coughing, wobbliness or breathing changes, and call a vet if they appear. The guide are essential oils safe for pets explains more.

People with asthma, allergies or medical conditions

Strong scents can trigger asthma, migraines or allergy symptoms in some people. Ask everyone in the home before diffusing, and stop if anyone feels unwell. During pregnancy, check with a doctor or midwife first.

Diffusers are for scent, not medicine

Diffusing essential oils does not clean the air of germs, prevent illness or treat any condition. Enjoy a diffuser for its scent and atmosphere, and see a doctor for health concerns. The basic essential oil safety rules apply to diffusing too.

Cleaning and caring for a diffuser

Unplug the diffuser before cleaning. After each use, empty the water and wipe the tank dry. About once a week, or when switching oils, clean it as the manual directs. Many manufacturers suggest a little water with white vinegar, a short run, then a rinse and gently wiping the ultrasonic plate with a cotton swab. Never submerge the base, and never use harsh cleaners. A clean diffuser smells better and lasts longer.

Frequently asked questions

How many drops of essential oil go in a diffuser?

For most small ultrasonic diffusers, 3 to 5 drops is plenty. Larger models may call for more, so check the manual.

Is it safe to sleep with a diffuser on?

It is better to use a timer so the diffuser runs for a short time as you fall asleep, then switches off. Do not diffuse overnight in a room with a baby, young child or pet.

Can a diffuser be used without essential oil?

Yes. Many ultrasonic diffusers work as small humidifiers or night lights with just water.

Why does the scent seem to disappear after a while?

This is usually nose fatigue. The brain tunes out a steady smell. It is a good reason to diffuse in short sessions rather than adding more oil.

Is it safe to diffuse around cats?

Use great caution. Diffuse only briefly, in a room the cat can leave, and avoid oils known to be risky for pets.

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Top image: Aroma diffuser by The Mo1111, CC BY-SA 4.0, via Wikimedia Commons.