What's the biggest rebate stack on a heat pump conversion?

In Massachusetts and a few northeast states with aggressive utility programs, an oil-to-heat-pump conversion can stack up to ~$14,000 in 2026: $8,000 HEEHRA (income-qualified), $2,000 federal 25C tax credit, plus $3,000–$4,000 from Mass Save / Eversource / National Grid utility rebates. Even non-income-qualified households can typically stack federal 25C + utility rebates for $4,000–$6,000 total. The single highest 2026 incentive concentration is in MA, CT, RI, ME, and NH — driven by aggressive state climate goals + tight winter electricity capacity that utilities want to shift away from oil/gas heat.