1976-1994 manufactured homes have extreme energy costs with no retrofit path

Manufactured homes built between 1976 and 1994 — the first generation under HUD Code — meet basic safety standards but are extremely energy-inefficient by modern standards. They were built with minimal insulation (R-7 walls vs R-21 in modern code), single-pane windows, and unsealed ductwork. Residents in these homes pay energy bills 70-80% higher than comparable modern manufactured homes, often $200-$400/month in heating and cooling costs. For households with median income around $35,000, energy costs can consume 10-15% of gross income — the definition of energy poverty. The obvious fix would be retrofitting, but manufactured home construction makes this nearly impossible: the walls are typically 2x3 framing (not 2x4 or 2x6 like site-built), limiting insulation depth. The belly board under the home restricts access to ductwork and floor insulation. Adding exterior insulation changes the home's profile and may violate park aesthetic rules. Weatherization programs exist but are chronically underfunded and often exclude manufactured homes due to cost-effectiveness calculations that penalize homes with shorter expected lifespans. The structural reason this persists is that HUD didn't meaningfully update energy standards until 1994, and the 2024 update — the most significant in 30+ years — only applies to new construction, leaving millions of existing units with no viable upgrade path.