P purchased a residence at 100 Maple Hill Road in Glencoe, Illinois. The house included a security system that had been installed in 1980 by D. P then constructed a bathhouse at his property that could not be accessed through the residence, but did share one common wall with the house. The bathhouse contained a natural gas-fueled water heater and a natural gas-fueled barbeque grill affixed to an exterior wall. D maintained the security system that was in place. On August 16, 1988, D submitted a letter, for P's approval, containing an estimate of work to be done. The original letter listed the following items: one digital dialer transmitter; one smoke detector; five heat detectors-replace; one temperature switch -- 45°; one heat detector - electrical room; one fire horn; one fire signal; and one building temperature signal. The letter also listed a price of $675 as the amount for the items as installed and additionally provided that the terms were one-half down, balance upon completion. It is undisputed that this letter became the final written contract between the parties. P did not sign the letter but made several handwritten modifications and additions contained in the letter changing the original terms proposed by D. P crossed out the 'temperature switch' and 'fire horn' items. P changed the 'installed' price from $675 to $575 and added the notation 'battery incl.' P also added the term '$287.50 plus 100 for #2414 battery 8/22/88.' P also inserted the following provision: 'system to be in good working order and guaranteed for at least 12 months.' The system was installed sometime shortly after the letter was exchanged. On September 13, 1995, a fire occurred at P's home. The fire originated in the bathhouse in the area of the grill. The fire activated the burglar alarm at P's residence. When police officers responded to the alarm, they noticed the southeast wall of the home engulfed in flames. The police then summoned the fire department. By the time the fire department arrived, P and his wife had already exited the residence. P sued D. Count I alleged breach of contract. Count II alleged negligence. D filed a motion for summary judgment. It was granted, and P appealed.