@sri_srikrishna Space is different tradeoff, agree.
If by efficiency you mean more total units, then you need to account for the cost of more fans. Total cost (including filter replacement) would then be higher.
@斯里克利希纳空间是不同的权衡，同意吗。
如果效率指的是更多的总单元，那么你需要考虑更多风扇的成本。总成本（包括过滤器更换）将更高。