I dont know about heat but an ac crown sc4000 dc and a sc4500 ac,The 4500 will out run out pull and flat out work the 4000 the trucks look almost the same on the outside but the 45oo will have 1/2 charge at the end of shift where as the 4000 is down to 1/3.Both about the same hrs.But diffrent operators.I also know all the operators want that ac truck over the dc one.Such a change from This is my truck and I dont want nobodys but mine that I normaly get.