This is the best monitoring system on the market. It measures temperature and humidity, monitors for water leaks, and can alert you when a door or window is open. Expansion is very efficient, since one hub can monitor lots of sensors. The dashboard is accessible via a phone app or web browser, and the interface is really good -- exceptionally easy to use. I've tried systems from d-Link (which go offline all the time) and Accu-Rite (good system, but only for temperature and humidity, not water leaks or door/window openings); none offer the features, reliability, and ease-of-use of WallyHome. And surprisingly, WallyHome is cheaper. Go figure. I've been using the new version 2 of WallyHome for about 3 months, and previously used version 1. WallyHome has saved me big $$ and headaches: It alerted me to a water leak in the basement before it got big, alerted me to clogged AC drain before the problem got big, alerted me to the fact that our heating/cooling system failed while we were on vacation, etc. In each case, this system caught the problem long before I would have otherwise and saved me from big problems. I'm a huge fan of this system and think every homeowner should have one. The system plus 3 additional sensors (4 in total) is about $200 and can save you many times that. A home without WallyHome is like a car without seatbelts or airbags. I have absolutely no affiliation with Wally, and paid full price for the system. I'm just really grateful to the team that put together the system that has paid for itself many times over. Great product.