Not so safe, but it all depends where you live in the city and all that. Downtown / midtown is the best, anything else is hit or miss. Areas on Moross St. by Grosse point are just as nice as anywhere else. Also, even though Detroit is arguably the most dangerous city in the country, suburbs are very safe.
Air conditioning tonnage has nothing to do with weight. A ton, as used in the HVAC field, is a term that describes how much heat the AC unit can remove from a home in one hour. The measurement for heat is the British thermal unit (BTU). One ton of air conditioning can remove 12,000 BTUs of air per hour. A four ton unit can move 48, 000 BTUs and so on. Therefore, the more tonnage an AC unit is rated at, the more air it can cool.
A cooling tower ton is defined as: 1 cooling tower ton = 1 TONSevap = 1 TONScond x 1.25 = 15000 Btu/h = 3782 k Calories/h = 15826 kJ/h. The equivalent ton on the cooling tower side actually rejects about 15,000 Btu/h due to the heat-equivalent of the energy needed to drive the chiller's compressor. ton of refrigeration = 1 TONScond = 12000 Btu/h = 200 Btu/min = 3025.9 k Calories/h = 12661 kJ/h = 3.517 kW. A ton is the amount of heat removed by an air conditioning system that would melt 1 ton (2000 lbs.) of ice in 24 hours: 288000 BTU/24 hr = 12000 BTU/hr.