The biggest loan you can get depends on what work you want to get done and how much it will cost. There is a limit on the amount of the loan you can get that follows normal practices. Your loan amount may be less than the amount you were quoted, and you will be responsible for the difference.
Only one loan is available for each home and homeowner. You can only use the loan to pay for products or work that is recommended by an energy advisor, and qualifies for the grant.
You can get some funds before work starts to pay for the work. The rest of the loan will only be issued after the work is done, and an inspection proves it was done right.