I currently have an old 10 seer condensing unit with r22 and I want to put a new 13seer unit that has r22 so will I need to change the evaporator coil to are can I use the old one, also can I use the same old line set. Also are the high side and low side pressure the same as on my old 10 seer since both use r22, I no that 410a is a higher pressure but I don't know about the r22, do they make 13 up to 18 seer with r22 and 410a both. Is there a price difference between a 13seer with r22 and a 13seer 410a unit .

will I need to change the evaporator coil to are can I use the old one

Yes change the evaporator to match the condenser outside.

also can I use the same old line set

If you use the same refrigerant and the suction line size is the same as the size for the new unit.

also are the high side and low side pressure the same as on my old 10 seer since both use r22

Not exactly the same. Charge by charging chart on new unit.

I no that 410a is a higher pressure but I don't know about the r22, do they make 13 up to 18 seer with r22 and 410a both. Is there a price difference between a 13seer with r22 and a 13seer 410a unit .

Contact a local HVAC company for estimates. To many variables.