In the town of Hurley, Wisconsin, an unreasonably warm summer saw temperatures rising into the mid-90s for a weeklong stretch in July. This was almost 20 degrees above the average high temperature of 77 degrees for this hottest month of the year. This unexpected heat wave resulted in a significant increase in household purchases of central air conditioning systems, which are uncommon in this part of the country. Which determinant or determinants of demand were most likely factors in the households' decisions to purchase these air conditioning systems, and how would these purchases affect the demand curve for central air conditioning systems?