Not sure if this is broadly known yet but I received a newsletter yesterday from the local Utility company that states in order for a homeowner to obtain any future utility rebates for new AC installs, the contractor must provide proof that a Manual J and Manual S calculation were done.
I guess this means no more rule of thumb sizing of equipment in NJ. since I'm pretty sure most consumers are going to want the rebate.
Below is an excerpt that I copied from the news-letter
.....Central Air Conditioning or Air to Air Heat Pump.....
SEER 14/EER 12/HSPF 8.5 (must be matched system with ARI rating number)
ACCA Manual J and Manual S outputs are required showing that the installed system is sized with 15% variance of requirement and correctly selected for the dwelling...........
To ensure that New Jersey residents get the full benefits of an energy-efficient central air conditioner or heat pump (i.e. that it operates as efficiently as its energy rating suggests it should), the rebate will be processed only if your installing contractor submits documentation that the air conditioner or heat pump has been properly sized and installed.