The length of time it takes to sterilise a room using UV light (or ultraviolet germicidal irradiation) will vary depending on a few factors:

  1. The size of the room
  2. The quality / strength of radiation from the UV-C bulbs
  3. How empty or cluttered the room is

To fully sterilise a room and inactivate Covid-19, the required dose of UV-C is 22mJ/cm2. The National Emerging Infectious Diseases Laboratories (NEIDL) reports that they exposed materials containing the SARS-Cov-2 virus to a UV-C tube lamp, and found that a dose of 5mJ/cm2 resulted in a 99% reduction of the virus. The NEIDL team extrapolated that a stronger dose of 22mJ/cm2 would result in a reduction of 99.9999%.

Room Size

The larger a room is, the longer it will take to sterilise. This is because the UV radiation must be built up to reach the required dosage, and the further the light is from the UV bulbs, the longer it will take to build up to the required dose. As a result, air and surfaces closer to the device will be sterilised quite quickly, where surfaces further away will require more time to reach and fully disinfect. 

Steriliser Quality

There is a vast range of UV sterilisers on the market today, falling across various pricepoints. Most (if not all) of the UV sterilisers aimed at home usage produce much lower levels of UV radiation – this is for two reasons: (a) it results in cheaper units and therefore lower prices, and (b) UV radiation is harmful to people, plants and animals if exposed, so lower strength UV radiation reduces the risk of severe harm being caused by devices used by the general public.

Therefore, if you’re looking to fully and effectively sterilise a room, a standard household UV steriliser is unlikely to do the job for you. Hospitals and medical facilities have used UV sterilising for many years now to ensure their premises are thoroughly sterilised, and it is this hospital-grade UV sterilising technology that is required in order to achieve a thorough disinfection. These devices produce stronger doses of UV-C radiation, meaning that they can reach the required 22mJ/cm2 dose in a matter of minutes.

    Clutter / Room Layout

    The main disadvantage of UV as a method of disinfection is that it can only sterilise what the light falls on, and the light cannot penetrate through objects. As a result, if a room is filled with clutter and/or furniture, or if a room has an unusual shape, it may require multiple disinfection cycles moving the device around to reach all common touchpoints. You may need to move the UV steriliser between cycles to ensure that the light reaches into areas that may have been shadowed or blocked when the device was positioned for a previous cycle.

    The size and design of your UV steriliser will also impact how long it will take to sterilise a room. Some sterilisers produce radiation in all directions, while others disinfect only in one direction (head-on). Similarly some sterilisers are shorter, allowing the light to reach lower touchpoints (e.g. seats and under beds / tables), while others are taller to reach higher touchpoints (such as tabletops and light switches). Having a device that can reach both high and low touchpoints may therefore reduce the length of time required to sterilise a room, and avoid needing to run additional disinfection cycles to reach varying touchpoints.

    The Muv-X UV room steriliser is a flexible and scalable UV steriliser. The unit can be used at its base height, or can be stacked onto its protective case to provide extra height – allowing the light to reach higher touchpoints. Similarly multiple units can be stacked together if required, to increase sterilising capability and reduce the length of time it takes to sterilise a room.

    To help you calculate how long it will take to sterilise a room using the Muv-X UV steriliser, we have provided some figures in the tables below. If you require additional information or assistance with working out sterilising duration for your premises, please contact us at [email protected].