Only if the manufacturer explicitly states it's safe and provides a dedicated essential oil tray or diffuser. Putting essential oils directly into the water tank of most humidifiers can damage the unit and void the warranty.

Yes, they can provide relief. Increased humidity can help soothe irritated nasal passages and throats, loosen mucus, and reduce coughing. For allergy sufferers, proper humidity can also help reduce airborne irritants like dust.

Distilled or demineralised water is highly recommended to prevent mineral dust (white dust) and scale build-up, especially in hard water areas common in parts of the UK. Tap water can lead to more frequent cleaning and the potential release of mineral dust into the air.

Regularly! Ideally, daily rinsing of the water tank and base, and a thorough cleaning with vinegar or a descaling solution once or twice a week is recommended to prevent mineral build-up and bacterial growth.

- Cool mist humidifiers (evaporative or ultrasonic): Release cool, invisible mist. Safer for children and pets as there's no hot water. Evaporative uses a fan and wick, and ultrasonic uses high-frequency vibrations.

- Warm mist humidifiers: Boil water to release warm, visible steam. Can be perceived as more soothing, may kill airborne bacteria, but poses a burn risk.