Believe it or not but it's hard to get someone to provide you with a J- manual load study, so I am asking the rule of thumb ? re: sq footage. I have 1400 sq ft on the 2nd level of my home. It has 4 room and bathroom how many BTU furnace would I need for that area
You can calculate a Manual J yourself. Click on the bullseye at the top of this page and download the 30 day version.
There is no such thing as a proper sq ft rule.
Yes. Buy the 30 day version. You can do 4600 sqft in 2 hours while towing a 16 month "helper" around. Or 30 minutes alone.
Otherwise, call your power company and ask for conversation assistance. Out here they'll come and do it for you also. And for free.