To whom it may concern. We live in Nederland, TX which is a small town on the Southeast Texas Gulf coast. We were hit by hurricane Ike in 2008 and immediately drove back in town after evacuating. Prior to leaving, I had done some research on generators big enough to power not only the essentials but some of the ammenities as well. For those out there that are skeptical or wondering how much power is needed to run the central A/C units, I can say to you that I purchased the portable 15kw guardian generator from Home Depot and was very pleased to find out that noy only did the generator run the essentials such as freezers and regrigerators, but also had no problem running two brand new 4 ton central units as well as pool pumps. The A/C units were staged so that one compressor turns on and the other comes online approximately 4 minutes later. If you have two units requiring start up at the same instance, then the 20kw would be a better bet. I just converted my portable unit to a tri-fuel intake so that I can now use natural gas instead of gasoline. The Generac unit performed extremely well and the only change I would make for myself would be an upgrade to a QuietSource 22.5kw or 25kw in the future. Thank you for a great and reliable product.