Normalize the bids by board-foot and depth, verify the product is the same (Demilec vs Icynene vs BASF), confirm thermal-barrier scope is included, and check the workmanship warranty length. A 10-15 percent price spread on the same scope is normal; bids that are 25 percent below the others usually indicate undersized foam or off-ratio supplier.
More detail
Cincinnati spray foam quote variance has specific causes that homeowners need to identify before comparing topline numbers. The normalization steps. (1) Board-foot total. Convert each quote to board-feet (1 sqft x 1 inch thickness). For an attic with 1,500 sqft of surface and 5 inches of closed-cell, the board-foot total is 7,500 bf. If two quotes claim different surface areas or thicknesses, the cheaper one may be quoting less foam, not the same scope at a better price. (2) Foam product and ESR number. Demilec Heatlok HFO Pro (ESR-3526), Icynene MD-R-200 (ESR-2110), BASF Walltite HFO (ESR-3900), and similar major products are all reputable; cheaper unbranded alternatives may not be ICC-ES evaluated and may not meet code. Ask each installer for the specific product. (3) Thermal barrier scope. Some quotes include DC315 or drywall over the foam; others quote foam-only and expect the homeowner to handle the thermal barrier separately. Both are valid scoping choices but the apples-to-apples comparison requires noting the inclusion. (4) Workmanship warranty length. 1-year is the floor; 5-year is the upper end among credentialed Cincinnati installers. The cost-of-warranty difference is real but small (a 5-year warranty typically adds 3-5 percent to the contractor's overhead). (5) Pre and post blower-door testing inclusion. BPI-credentialed installers include both; non-credentialed installers may charge extra or skip the testing entirely. (6) Permit pulling and inspection scheduling. Code-compliant Cincinnati installers handle permits as part of the scope; cut-rate installers sometimes push permit responsibility to the homeowner. Cincinnati quote-variance reality. A typical Cincinnati 1,500 sqft attic closed-cell project from three credentialed installers spans $5,400-$7,200 (about 30 percent variance). The variance reflects crew availability, scheduling premium during peak season, and small differences in workmanship warranty terms; the actual scope is comparable. A fourth quote at $3,800 for the same scope almost always indicates undersized foam (3 inches instead of 5) or non-credentialed installer status. Choose the median quote from credentialed installers, not the lowest. The savings from picking the lowest quote (typically $1,500-$3,000) gets eaten by remediation costs if the install fails ($3,000-$8,000) or by reduced energy savings from undersized foam (lost $300-$600 per year over 10 years = $3,000-$6,000 NPV).