Crawl space encapsulation on its own does not qualify for the federal 25C energy efficiency credit, because a vapor barrier is a moisture measure rather than an energy one. Insulation and air sealing installed as part of the work can be eligible, which is why the invoice should itemise them separately.
What 25C covers
The Energy Efficient Home Improvement Credit covers specified categories including insulation and air-sealing materials meeting the applicable standards, up to an annual limit. It is a credit against tax owed, claimed for the year the work is placed in service.
Moisture control measures — liner, dehumidification, drainage — are not in the covered categories.
How to invoice so the eligible part is separable
Ask for the insulation and air-sealing materials to be shown as their own line items with their own costs, rather than folded into a single encapsulation price. A lump sum makes the eligible portion impossible to substantiate.
Keep the manufacturer documentation for any insulation product, since eligibility depends on the material meeting the relevant standard.
The bottom line
Do not buy encapsulation for the tax credit. If you are insulating as part of it, itemise that portion and ask a tax professional whether it qualifies for your situation.
For a number against your own crawl space, use the cost estimator, or call (910) 886-2018 and we will come and measure it.