My parents want to upgrade the Heatpump and indoor unit, they claim that it runs constantly on hot days, it is a 23 year old house and the insulation isnt the greatest, I dont want to replace it with a reccomended size for the insulation issue, how much bigger of a unit may I step up to befoe short cycling occurs, I have also heard of swaping reccomended size units between indoor unit and out door unit The house is a bi level house approximately 2800 square feet 1500 up stairs and 700 down stairs with a single garage below the master bedroom (square footage listed did take out the garage space)