How do i know if my new asphalt shingles qualify for a energy saving credit? Can I take deduction if roof was installed 2016?

For 2018 returns, the only products eligible for the Energy Credit are solar products.

If the roof was installed in 2016, you can amend your 2016 return to include the expense.  Metal roofs with appropriate pigmented coatings, or asphalt roof with appropriate cooling granules specifically designed to reduce the heat loss or gain of your home could qualify for the credit.

The Energy Star website lists several Owens Corning Duration products that qualify.  To be sure your product qualifies, contact the place you purchased it from.