How to Maximize Energy Efficiency in Your Manufactured Home
In a manufactured home, the biggest energy losses are usually under the floor: leaking ducts, a crushed or disconnected crossover duct, and insulation that has dropped out of a torn belly. Fix those first. Then seal the air leaks you can reach, keep the sun off the roof and windows, and only after that consider new heating and cooling equipment.
The order matters. A new heat pump connected to leaking ducts ends up heating and cooling the space under the home along with the rooms.
What to fix, roughly in order
Energy upgrades for a manufactured home
| Upgrade | Effort and cost | Who does it |
|---|---|---|
| Repair the crossover duct and seal duct leaks | Low to moderate; the work is under the home | A heating and cooling contractor or a weatherization crew |
| Patch the belly and replace fallen insulation | Moderate | A contractor who works on manufactured homes |
| Weatherstrip doors, caulk gaps, seal around pipes | Low | You |
| Repair skirting | Low | You |
| Reflective coating on a metal roof | Moderate | A roofer, or a careful owner |
| Shade: window awnings, sun screens, trees | Low to moderate | You; the community may need to approve it |
| Replace windows | High | A contractor; a permit may apply |
| New heating and cooling equipment | High | A licensed contractor; a permit applies in California |
Start under the home: the belly, the ducts and the crossover
The floor of a manufactured home has insulation between the joists, held up by a sheet of tough material fastened beneath the frame. That sheet is the belly, also called the bottom board. In most homes the heating and cooling ducts run inside the same space. When the belly is cut open for a plumbing repair and never patched, or torn by animals, the insulation sags or falls out and the ducts are left exposed to outside air.
A double-wide or other multi-section home has a duct run in each section, joined by a large flexible duct under the home called the crossover. It hangs below the belly, which makes it the most exposed part of the system. A crossover can be crushed, torn or pulled loose, and one lying on the ground takes on moisture. When it fails, half the home gets little conditioned air while the equipment keeps running.
ENERGY STAR notes that in a typical house a sizable share of the air moving through the ducts is lost to leaks, holes and poor connections. Its guidance on duct sealing recommends mastic sealant or metal tape; cloth duct tape does not last.
You do not have to crawl under the home to find out where you stand. Open the skirting access panel and look with a flashlight, or take photos with your phone.
From inside, the signs are a room that never reaches the set temperature, weak airflow at some floor registers, or one half of a double-wide that is always warmer or cooler than the other. Leave the repair itself to someone equipped to work under a home.
Seal the air leaks you can reach
This is the low-cost part, and an owner can do most of it in a day:
- Replace worn weatherstripping on exterior doors and add a door sweep where you can see daylight.
- Caulk gaps around window frames and where pipes and wires pass through exterior walls.
- Look under the kitchen and bathroom sinks. The holes where pipes come up through the floor are often much larger than the pipes, and they open straight into the belly.
- Lift a floor register and check the joint between the duct and the floor. Seal gaps there with metal tape or mastic.
Skirting belongs on this list too. Complete skirting keeps wind from blowing across the underside of the floor; replacing panels is covered in exterior projects you can do yourself.
Keep the sun off the roof and windows
In the California and Arizona heat, the roof and the west-facing windows take most of the load in summer.
A reflective coating on a metal roof bounces back sunlight that would otherwise heat the ceiling. Seams and fasteners are sealed first, which also makes the job roof maintenance. Check that the product suits your roof material. HCD’s guidelines for California do not treat a liquid roof coating as a re-roof; removing the old roof covering and replacing it does need a permit.
At the windows, exterior shade works better than interior shade because it stops the heat before it reaches the glass. Window awnings and sun screens on the south and west sides are the usual choices, and a community may need to approve them. Replacement windows cost far more. In California, HCD’s guidelines say a permit is required at least when the opening is enlarged or reduced or a bedroom exit window is replaced, so ask HCD before a same-size swap too.
Seasonal routines are covered in the summer heat checklist and, for cold desert nights, in winterizing a manufactured home in Arizona.
Heating and cooling equipment comes after the ducts
Maintenance first: change the filter on the schedule the manufacturer gives, keep the outdoor unit clear of plants and debris, and have the system serviced yearly.
When equipment has to be replaced, two points are specific to manufactured homes. Furnaces and water heaters generally have to be models approved for use in a manufactured home, so hire a contractor who works on them. And an older home’s electrical service may limit what it can carry, which the contractor should check before quoting.
A heat pump moves heat instead of burning fuel, so one system both heats and cools; ENERGY STAR explains how air-source heat pumps work. A ductless mini-split is a heat pump with an indoor unit mounted on a wall and no ductwork at all. That makes it worth asking about when the ducts under the home are in poor shape.
In California, HCD’s alteration guidelines list installing or replacing a furnace, air conditioner, heat pump or water heater as work that needs a permit. In Arizona, take permit questions to the Arizona Department of Housing. This is general information, not legal advice.
Smaller savings inside the home
LED bulbs, a low-flow showerhead, a lower water heater setting and a programmable thermostat all trim the bill a little, and none needs a contractor. Do them, but do not expect them to make up for a disconnected duct. More routine upkeep is in maintaining a manufactured home over the long term.
Rebates and weatherization help
Before you pay for anything, check two sources.
- Your utility. Electric and gas utilities may offer rebates for duct sealing, insulation, heat pumps and efficient water heaters. Read the conditions before the work is done; some programs require a participating contractor or an application in advance. If the community bills you for utilities, ask the office which utility serves it and whether residents can apply.
- Weatherization assistance. The federal Weatherization Assistance Program pays for efficiency work in the homes of income-qualified households, owners and renters alike, through state and local agencies. The Department of Energy explains how to apply, and California’s Department of Community Services and Development describes the programs it administers; your county’s local service provider handles questions about eligibility.
A full heating and cooling replacement is a large expense, and some owners look at it alongside a refinance. That is a separate decision with its own costs: refinance options depend on the home, the land status and current guidelines, and all financing is subject to credit approval.
