That is correct. People will typically get loans for larger purchases like solar panels so that they don't need to pay everything upfront, but for smaller purchases like maybe $1,000 a loan isn't really worth it, and you'll need funds set aside to pay the contractor now and expect to see the money back when you file.

Also worth checking state/local incentives. In my state our gas company has weatherization rebates. They did air sealing and added insulation to our attic (up to a certain R value) all for free - they billed it directly to the gas company. When they were out here, I paid for a bit of extra insulation because I thought we needed it, but the base amount was completely free.