If you have an MVHR unit installed in your home or building, it is important to check the MVHR filters several times a year and replace them when necessary. MVHR filters ensure that fine dust and polluted air particles are filtered out of the incoming air before it enters your home through the MVHR unit. In this way, the filters contribute to healthy and clean indoor air quality. Over time, however, MVHR filters become contaminated with dust and dirt particles. As a result, less clean air can flow through them and your ventilation system operates less efficiently. If you do not replace your MVHR filters regularly, bacteria and mould can also develop on the filters.