HUD’s thermal and climate zones for manufactured homes are three overlapping maps that dictate how a home must be built for the place it will sit: a thermal zone map that sets insulation performance, a wind zone map that sets structural resistance to lateral loads, and a roof load zone map that sets snow and rain capacity. Each home is rated for a specific zone in each of the three systems, and those ratings appear on the home’s data plate. A home cannot legally be installed at a site whose zone requirements are stricter than the home’s ratings.
The Three Thermal Zones
HUD’s thermal zones are defined in 24 CFR 3280.506. The country is split into three regions based on heating and cooling demand, and each region has a maximum overall heat transmission coefficient, called a Uo value, for the whole home. Lower Uo means less heat escapes through walls, ceiling, floor, and windows combined, so colder zones demand tighter construction.
- Thermal Zone 1 covers the southern tier of states, where cooling drives design. Maximum Uo is 0.116 Btu per hour per square foot per degree Fahrenheit.
- Thermal Zone 2 spans the middle of the country. Maximum Uo drops to 0.096, which requires better-insulated walls, floors, and windows than Zone 1.
- Thermal Zone 3 covers the northern states. Maximum Uo is 0.079, and manufacturers must factory-install storm windows or insulating glass on every unit.
The zone for any specific location comes from the map in the regulation, not from state lines. Some states straddle two zones, so the delivery address of the home determines which Uo value applies.
Wind Zones
Wind zone designations under 24 CFR 3280.305(c) set how much lateral force the frame, walls, and fasteners must handle. There are three zones, each tied to a design wind speed.
- Wind Zone I (70 mph) covers most of the interior United States.
- Wind Zone II (100 mph) covers coastal counties and other higher-risk areas. Homes must be designed by a licensed professional engineer or architect to resist Exposure C wind loads at 100 mph.
- Wind Zone III (110 mph) applies to the most wind-vulnerable coastal areas, mainly along the Gulf Coast, the southern Atlantic coast, and parts of Hawaii. Design loads jump to 110 mph under the same engineering requirement.
The regulation lists the specific counties in Zones II and III. Every county not on those lists defaults to Zone I. The wind zone the home was designed for must appear on its data plate, and a Zone I home cannot legally be installed in a Zone II or III county.
Roof Load Zones
The roof load zones address the downward force of snow, ice, and heavy rain. Under 24 CFR 3280.305(c)(3), the three-zone map sets minimum roof live loads:
- South Zone: 20 pounds per square foot.
- Middle Zone: 30 psf.
- North Zone: 40 psf.
These loads apply to the horizontal projection of the roof, so a steeper pitch does not reduce the design requirement. The roof trusses, load-bearing walls, and the connections between them all have to carry the rated load.
The 40 psf North Zone ceiling is not always enough. In mountainous and high-altitude areas where ground snow loads routinely exceed the standard zones, HUD can set stricter requirements through rulemaking. When it does, the roof snow load is calculated at 60 percent of the ground snow load for wind-exposed sites and 80 percent for sheltered sites.3eCFR. 24 CFR Part 3280 Subpart D – Body and Frame Construction Requirements If a home is designed above the standard zone minimum, the actual design load must appear on its data plate. Anyone placing a manufactured home in a mountain community should check with the local building authority for a required load above the basic zone minimum.
Moving a Home Across Zones
The rule that catches people off guard: a manufactured home should never be placed in a more restrictive wind, thermal, or roof load zone than the one it was built for.4U.S. Department of Housing and Urban Development. Manufactured Housing Homeowner Resources Buy an older home in one part of the country, try to move it to a colder or windier part, and the installer may not be able to legally set it.
Federal installation standards at 24 CFR 3285.103 require a compatibility check before initial installation at any site. The installer verifies that the home’s design zones, shown on the data plate and its zone maps, match or exceed the requirements at the destination:
- The home cannot go into a wind zone that exceeds its design rating, as defined by county or local designations.
- The home cannot go into a roof load zone that exceeds its rated capacity.
- The home cannot be installed in a thermal zone higher than the one it was built for, based on the heating/cooling certificate and insulation zone map.
Moving in the other direction is generally fine. A Thermal Zone 3 home can go into Zone 1 or 2; it will simply be more heavily insulated than the climate calls for. A Wind Zone III home can go into a Zone I county. Before any relocation, confirm zoning, transportation, and placement rules with the local authority having jurisdiction over the destination site.
Wind Zones II and III also carry anchoring requirements that go beyond a stronger frame. The installation standards call for longitudinal ground anchors on the ends of each transportable section, plus a vertical tie at every diagonal tie-down location, with all anchoring equipment certified by a registered professional engineer, a registered architect, or a nationally recognized testing laboratory.6GovInfo. 24 CFR 3285.402 – Ground Anchor Installations The zone rating on the data plate is only half the story; the anchors in the ground are the other half, and improper anchor depth or spacing is the most common failure point in hurricane investigations.
Finding Your Home’s Zone Ratings
Every manufactured home has a data plate, and that’s where the zone information lives. The regulation at 24 CFR 3280.5 requires the plate to be permanently affixed inside the home, near the main electrical panel or another readily accessible and visible location.7eCFR. 24 CFR 3280.5 – Data Plate In practice, look inside kitchen cabinets, on bedroom closet doors, or in utility rooms.
The plate lists the manufacturer, plant address, serial number, model designation, date of manufacture, and certification label numbers for each transportable section. It also carries maps showing the wind zone, roof load zone, and thermal zone the home was designed for, sometimes combined with the heating/cooling certificate and insulation zone map on the same document.8U.S. Department of Housing and Urban Development. Manufactured Housing HUD Labels (Tags)
Do not confuse the data plate with the HUD certification label, which is a small metal tag riveted to the outside of each transportable section. The exterior label confirms federal compliance but contains no zone information. For wind, thermal, and roof load ratings, you need the interior data plate.
If the data plate is missing or unreadable, the Institute for Building Technology and Safety can issue a replacement performance certificate based on the serial number and manufacturer information. IBTS cannot help with modular homes, park-model or tiny homes, RVs, or any manufactured home built before June 15, 1976, when the federal standards took effect. If the original data plate is unavailable, IBTS issues a substitute performance certificate based on the dealer location rather than the original design data, so the zone information may not exactly match what was originally specified.
Newer DOE Energy Standards on the Horizon
The thermal zone Uo values in 24 CFR 3280.506 are not the whole picture for new homes going forward. The Department of Energy has finalized separate energy conservation standards for manufactured homes under 10 CFR Part 460, adapted from the 2021 International Energy Conservation Code. These standards use their own three-zone climate map and set prescriptive insulation R-values, window U-factors, and duct leakage limits that are generally stricter than HUD’s baseline. For multi-section homes in the coldest DOE zone, for example, the standards call for R-21 walls, R-38 ceilings, and R-30 floors.9eCFR. 10 CFR Part 460 – Energy Conservation Standards for Manufactured Homes
Compliance dates are tied to the publication of final enforcement procedures, which DOE has not yet issued. Single-section homes will have to comply 60 days after those procedures are published, and multi-section homes 180 days.10Federal Register. Energy Conservation Standards for Manufactured Housing Until that trigger date arrives, manufacturers follow the existing HUD thermal zone Uo values. If you are buying a new home, ask the dealer whether the unit was built to the older HUD minimums or the newer DOE requirements; the difference in insulation performance and long-term energy costs can be significant.