@sri_srikrishna @TySopko I haven't measured but I suspect that four filters will last approximately four times longer than one (one can reason why this is likely), so effectively the same cost. Plus less wear and tear on the fan.
@sri_srikrishna@TySopko我还没有测量过，但我怀疑四个过滤器的使用时间大约是一个过滤器的四倍（可以解释为什么可能会这样），所以实际上成本是相同的。此外，风扇的磨损也更少。