The Better Business Bureau warns consumers to be extremely cautious when answering the door to people selling alarm systems.

More than 2,000 complaints were made to the bureau against burglar alarm companies in 2008, a 68 percent increase over the previous year, according to a bureau news release.

Many complainants allege that the salesperson used high-pressure sales tactics and made claims that were not included in the final contract. In addition, there have been reports that some companies are not attaining the correct licensing to sell door-to-door or legally sell and install alarm systems in areas where they are soliciting.

BBB offers the following advice, among other tips, for consumers:

* Deal only with reputable firms and visit www.bbb.org to check out companies.

* Don’t be pressured into buying something you don’t want or need. A reputable company will let you check out the offer and compare bids from several installers.

* Some companies will offer a “free” alarm system. While the equipment and installation may be free (make sure this is in writing), there is a monthly monitoring fee. When comparing costs, make sure to compare all the costs.

* Check out the company that will be monitoring your system. Ask if it is the same company you are signing a contract with. If not, make sure to obtain the name, address and phone number of this company.

* Study the contract carefully. Confirm information such as: installation price, monthly price, length of the contract (most contracts are for at least two years); and incorporation of any free or discount offers.