It comes down to the layout and how the suite is zoned. Two units mean your sleeping area and your living area run as separate zones, so one person can sleep cool while the other keeps the living room warm, and two smaller units serving two zones tend to run quieter than one unit pushing air across a whole suite. Because the per unit rate drops when there are two on the agreement, the second one adds about seventeen dollars a month rather than doubling the cost. We will confirm the exact count on your suite before you sign anything.