This is a great device. We've never had windows open as much as since we have it, and believe me, it means a lot of headaches that go away every week without an

This is a great device. We've never had windows open as much as since we have it, and believe me, it means a lot of headaches that go away every week without any coffee or paracetamol. The next time we move house, proper ventilation is definitely one of the first things we'll check.