Its a known fact that if you invest in a certified intruder alarm system your insurance company will offer you a reduced insurance premium. Whilst it means paying money up front you'll save in the long term. Often discounts upto 15% can be negotiated with your insurance broker.
Get a range of quotes before you install and first speak to your insurers to see if they demand a specific brand or level of security.
Searching your local business directory for a home security quotation is the best place to start.