I often wondered why A/C is sized in terms of tonnage. Does not seem intuitive. So a little bit of GOOGLING turned up these definitions. Still does not seem intuitive. Why not just use BTU's or KW as is? 1)[left][left]Why is AC rated in tons?[left][left]A [b]ton[/b] is the cooling capacity of an air conditioning system. One [b]ton[/b] is equal to the amount of heat required (288,000 Btu) to melt one [b]ton[/b] of ice in a 24-hour period. A one-[b]ton[/b] air conditioner is [b]rated[/b] at 12,000 Btu per hour (288,000/24). ... Typical residential central heating systems provide up to 5-[b]tons[/b] of cooling. 2)[left][left]Why AC rating is in Ton?[left][left][left][b]Why AC rated[/b] in [b]Tons[/b], Not in kW? ... Quantity of heat is termed in Tons means if an [b]air conditioner[/b] is able to remove 1000 kilocalories of heat or 4120 kilojoules or 12000 BTU of heat in an hour that [b]AC rated[/b] as 1 [b]Ton[/b] of [b]AC[/b] because 1000 Kilocalories or 4120 kilojoules or 12000 BTU equal to one [b]Ton[/b] of heat. So why not just say an A/C unit is rated at 12K BTU for 1 ton or 36K BTU for a 3 ton? It's just a term, but the term ton, one thinks of a ton of bricks or a truck that weighs tons. Our confusing language![/left][/left][/left][/left][/left][/left][/left][/left][/left]

I’m wanted to replace the capacitor and contactor in my AC so I opened the panel, noted the ratings, ordered a dual run capacitor from amazon. Capacitor arrived, I went back out there only to notice that the original round capacitor only has 2 terminals and one pair of wires attached. There is no second capacitor in sight. Will someone kindly explain? Don’t all ac units have a start and a run capacitor? Thanks in advance for your help.