Just installed one on my 13.5 BTU so I can run with generator. The Supco SPP6 should be all you need (Same capacitor regardless of unit size). Less than $10.00 and relatively easy to install if you don't mind getting on your roof and opening up the AC. I found that many AC units don't come with any start capacitor much less a hard start version. Before, even on shore power, we would notice the compressor would drag and even on occasion trip the shore breaker. With the capacitor in place, the compressor start is almost instant.