A single-wide or double-wide loses heat through a thinner, tighter envelope than a site-built house. This guide walks through the building science — R-value, blower door testing, and where blown-in insulation does the most good — plus the current Efficiency Maine programs that can cover a large share of the cost.
Manufactured and mobile homes built to the HUD code use narrower framing and thinner cavities than a conventional stick-built house — a 2x3 or 2x4 wall instead of a deeper 2x6, and a shallow belly cavity instead of a full basement or crawlspace. That leaves less physical room for insulation, and the materials that were installed at the factory decades ago have often settled, been damaged by rodents, or torn loose from a sagging bottom board.
On double-wide homes, the marriage line where the two halves join is a common and often overlooked air-leakage and heat-loss pathway. Ductwork frequently runs through the unconditioned belly cavity, so even a well-sealed duct can lose conditioned air into a cold space before it ever reaches a supply register.
None of that is visible from inside the house. It shows up as cold floors, ice buildup on skirting vents, frozen pipes, and heating bills that don't match the size of the home. The two diagnostic tools that identify exactly where and how much heat is escaping are the ones this guide focuses on first: R-value and the blower door test.
What R-value actually measures, how it's calculated, and the R-value targets that make sense for a Maine mobile home.
Read the breakdownHow a fan-pressurization test is performed, the standards behind it, and what CFM50 and ACH50 numbers mean for heat loss.
Read the breakdownWhy blown-in insulation is generally the right call for existing cavities, zone by zone — roof, walls, belly, and marriage line.
Read the breakdownThe current insulation rebate program, up to $8,600, plus the mobile home‑specific initiative and how the paperwork works.
Read the breakdownWhat to look for in a mobile-home-experienced installer, plus two Maine companies that do this work.
Read the breakdownInsulation upgrades completed on or after October 1, 2026 qualify for rebates up to $8,600, with eligibility verification required for at least one household member. Programs are subject to change — confirm current terms at efficiencymaine.com.
Insulation alone rarely fixes a cold mobile home. Air sealing, insulation, and ventilation are one interconnected system — which is exactly why a blower door test, not a guess, should define the scope of work.
See how Efficiency Maine's tiered rebates, up to $8,600, apply to a mobile home insulation project.