Benefits of Mechanical Ventilation System
Natural ventilation has its shortcoming: on days when there is little wind, some parts of the house will be poorly ventilated; on cold days, the incoming air may be too cold for comfort; or you may have hay fever and need to shut windows during the pollen season. The effects of inadequate ventilation include increased interior humidity and higher levels of interior pollutants.
However, you can take steps to improve ventilation. These include fitting air vents in windows to increase background ventilation, and extractor (exhaust) fans in the kitchen and bathroom to remove moisture. Alternatively, you may want to install a mechanical ventilation system.
Can a mechanical ventilation system help?
The answer to this question is probably “yes”. The range of benefits an efficient, well-installed mechanical ventilation system can bring include: a continual renewal of stale inside air with fresher air from outside; reduced levels of pollutants in the home; and the option to close up your home during times of peak pollen counts or high pollution levels. Depending on the allergens and irritants that trigger your allergic symptoms, such a system may be worth considering for these reasons alone.
To see how a mechanical ventilation system could reduce the severity or frequency of allergic symptoms, you have to look more closely at what a system could do. A reasonable expectation is that it actively refreshes the air right through your home by extracting stale air inside and replacing it with fresher air from outside. In addition, during winter a ventilation system is likely to help decrease house-dust mite numbers by bringing in cold air from outside, so lowering relative humidity inside.
Research suggests that in countries with several months of very cold weather mechanical ventilation alone can greatly reduce house-dust mite numbers. An explanation could be that the long period of low relative humidity during the winter so reduces the mite population that it cannot recover during the warmer, more humid summer months.
In more temperate climates, recent studies have shown that despite shorter warmer winters, a mechanical ventilation system will reduce mite-allergen levels in the home.
If you are sensitive to mites, you need to bear in mind that a mechanical ventilation system can help only if it is part of an overall dust-mite management programme, including such elements as anti-mite barrier covers on bedding and mite-unfriendly furnishings and floor surfaces.