brickeyee misses the boat a touch. I've fooled mostly with Ademco/Honeywell at my house, but it has a 12V sealed lead acid battery in the panel (think of a small version of a car battery). You'll probably have this regardless of wired/wireless sensors. It keeps the panel running for a time when the power goes out. Wired sensors run off AC via a power supply in the panel, and the battery if AC goes off. Wireless sensors each have their own battery in addition to this. For a wired system, contacts at doors windows are just switches and don't use any power. Other devices (motion, smoke, etc) do. We have mix of the two- wireless for the original alarm, wired that I added when we remodeled. The wireless ones have been more of a pain (alarm starts to behave odd when battery on motion detector runs low). But I did have a few recessed contacts that were messed up between when I put them in and when all the finish work was done. Replacing those took some effort. Whether you then have a wired or wireless (cellular) connection to central station monitoring is another thing entirely.

In my previous house I had a wired alarm and the sensors were not that obvious. There was a hole drilled in the base of the window sill under the window and a pencil-diameter sensor dropped into it (the wires running back to the panel were inside the sill under the sensor). The other half of the sensor (a magnet) was just epoxied onto the bottom of the window frame. I have a Honeywell wireless alarm in my current house, and they have many options for sensors. I am using one on my windows that mounts on a double-hung window next to the latch, so its quite visible, but there are others that would work. Some of the wireless sensors also have a set of wired contacts, so you can use the wireless sensor/transmitter along with any type of contact switch (e.g., lever action, water sensor, etc.). Bruce

I installed my own alarm system that I purchased on line at www.aesecurity.com - talk to Shermin Eisner. It turned out better than I expected. If you go that route, purchase the 1 year monitoring thru them and it includes technical support (~$180 for the year). The tech support was superb. I used a wired approach since it was a new home but they also sell wireless systems as well. If you have the studs exposed - then wiring things up is easy. If not - then go with wireless. You can also do a hybrid approach where some sensors are wired and some are wireless. The monitoring is provided via Emergency24 and I think is costs about 180 dollars a year - a lot less than ADT was charging me in my last house. I am very happy that I installed my own system. Now I can expand my system without calling ADT and getting robbed (in my last house they charged me over 400 bucks just to add another keypad). I have a good knowledge of electronics and programming and that certainly helped. It was easy to do and fun - and I have an incredible system that would have cost a fortune if I had a commercial company install. You can set up multiple partions so that the same alarm system can control two areas independently - that might work for the duplex with renters. Make sure you factor your long term plans into the contoller selection for handling the partitions and number of zones - make sure you have the ability to expand. I used magnetic sensors on the doors, glass break sensors for windows, and then motion sensors. I am also in the process of firing up exterior IR beams that will be connected to my lighting system so that I can get some advanced warning before someone breaks in - and the alarm conroller has on board relays that can be programmed to provide this interface. I live in a remote area and can't get the movie Deliverance out of my mind - I can still hear the banjo's playing right now! Good luck with the system.

Who set up your internet and wifi connection, someone you know or the company providing the service (like the phone or cable companies)? You should contact them and tell them you want to make sure your wifi signal is "encrypted with WPA2 and not open". There are different flavors of encryption (encoding) for wifi signals and WPA2 is the strongest/hardest to break into. It's easiest if the person helping you is in your home to make the changes. If and when your wifi signal has strong encryption (WPA2) and a good password, then the potential for an outsider to connect to your wifi signal is very, very low. If your PC is off at the time, all they could do is use the connection and not access any personal information. Even if that's done when you're using it, it's not likely any personal information is at risk. After the person makes the router changes, they may need to change the settings on your Chromebook for you so that you can continue to use it. I don't want to try to give you instructions on how to assess and change (if necessary) your router settings because from a distance I might make your situation worse. Good luck