A single device is optimal for a typical room, however can accommodate a bigger area with several systems. https://k3wajb3bo5lrh7euslx5tehtdfhzcnguvcjcabwwdxips55h65lq.webpkgcache.com/doc/-/s/www.drugoffice.Gov.hk%2Fgb%2Funigb%2Ftwickenhamhvac.co.uk%2Fair-conditioning-installation.html