Question: I just picked up my new 50 amp RV but my old generator is still set up for 30 amps. Can I run my 15,000 BTU A/C at the house still?
Answer: First, if your generator can be set up for 50 amps, then do so. If the generator will only support 30 amps, then most likely you are limited to running one air conditioner at a time (in addition to use of other low-draw electrical outlets). Note that 30 amp service (120 volts X 30 amps) gives you approximately 3600 watts of power to use.
Here is a list of approximate wattage draws for common appliances (be careful this is only an illustration and may not be applicable to your specific application):
A/C 1600 - 2500 Watts Microwave 1200-2000 Watts PC Desk top 400 Watts TV 30-300 Watts (depends on size, B&W or Color) VCR 40-60 Watts Refrigerator/Freezer 400-1200 Watts Toaster/Toaster Oven 800-1500 Watts Hair Dryer 900-1500 Watts
So depending on how many watts your air conditioner(s) require, and what else you want to run simultaneously, you can estimate what you can operate off the generator. It is a matter of managing your power.
We are not sure what you mean by running the AC "at the house", but hope that this response is of help.