Home security alarm systems can provide a feeling of safety and relative certainty in an uncertain world. But buying a home security alarm system, monitored by an outside company, is a big decision. In addition to the cost of system installation, you will likely have to pay monthly fees for monitoring and if you want to add more components than those included in the basic package — even just a door or a window or two — your price can balloon quickly. Whether you hire a large national company or a smaller local company — and there are plenty of each in Snohomish County — interview a few to compare your options for home security alarm, said crime prevention officer Aaron Snell with the Everett Police Department."You can find information about the security alaram system you really want," he said. "Sometimes they try to over-sell you, and sometimes they may under-sell you.