Air purifiers work by having the air drawn through the machine. The various parts of the machine clean the air as it passes through them. There are many different types of air purifiers with many different features. The following is a list of those features and things to consider when choosing.
It is important to remember that air is lazy. Whereas water will flow to the lowest point to find a level, air will not. So if you have an air purifier in one room the air quality in an adjacent room may not be significantly affected. So portable air purifiers are room specific.
The things that are in the air that you may want to remove fall into the following categories.
Particles such as pollen, dust, dust mite faeces, shed skin, tiny fibre ends from material, smoke particles, mould spores and dust.
Organic compounds including pesticides, herbicides and some solvents.
Odours such as smoke, cooking odours, animals and organic odours from sewers and other rotting material.
VOCs are volatile organic compounds used as solvents in some paints and some cleaning products.
Bacteria and viruses are very tiny and can either be trapped in a filter or killed using specific types of filters.
At The Healthy House we recommend the air in the room be changed at least 3 times an hour. This provides a good level of cleaning and will keep up with the normal flow of air into and out of a room. If the room has high traffic or doors and windows are continuously opened and closed you may need a larger unit.
You may find that the size of room a unit is recommended for on our website is different than the size claimed on the box. This will be due to manufacturers using different multiples of ACH. By standardising them you can compare like for like.
We assume that the standard room height is 2.2 metres. So a 10 sq metre room actually has a volume of 22 cubic metres.
The following excerpt is taken from the Health and Safety Executive website
“How is noise measured?
Noise is measured in decibels (dB). An 'A-weighting' sometimes written as 'dB(A)', measures average noise levels, and a 'C-weighting' or 'dB(C)', measures peak, impact or explosive noises. You might just notice a 3 dB change in noise level, because of the way our ears work. Every 3 dB doubles the noise level. So what might seem like small differences in the numbers can be quite significant.”
The following list shows different common noises in the range from 10 to 70 dB.
|40dB||lowest level of urban ambient noise|
|60dB||an air conditioning unit|
|70dB||a loud radio|
An air purifier of 45dB may seem quiet in a room full of people but will seem loud in a bedroom while you are trying to sleep.
There are 2 main running costs with an air purifier: electricity and replacement filters.
The cost of the electricity will depend on the size and speed of the motor, and over what period of time it is running.
The cost of replacements depends on the amount of pollutants in the air and the cost of a filter.