If you are open to portable ACs too and want to find out what unit size you need, you can check the Portable AC Size Calculator.
Why Mobile Homes Need a Different AC Sizing Approach
Manufactured homes are not built the same way as site-built houses, and that difference has a big impact on how you should size your cooling system. Standard residential AC calculators assume conventional framing, attic insulation, and ductwork running through conditioned spaces. None of that applies to most mobile homes.
Manufactured homes typically have integrated factory duct layouts that run underneath the floor through the belly of the home. These underfloor duct runs are exposed to outdoor temperatures, ground moisture, and sometimes rodent damage. In multi-section homes like double-wides, a crossover duct connects the two halves and is one of the most common failure points in the entire HVAC system.
The thermal envelope of a manufactured home also differs. Depending on whether the home was built to HUD minimum standards or to ENERGY STAR specifications, the insulation levels, window performance, and air sealing can vary significantly. That is why our calculator uses regional approximations informed by the ENERGY STAR manufactured-home sizing guidelines as the baseline, which accounts for these specific construction differences, rather than a generic BTU-per-square-foot formula.
Bigger Is Not Better: The Oversizing Problem
One of the most common pieces of bad advice in the HVAC world is "just go bigger to be safe." This is especially harmful for manufactured homes. Here is what actually happens when you install an oversized air conditioner:
The sizing tables this page uses, including the HUD-standard construction assumptions that make manufactured homes different from site-built ones, are published in our mobile home sizing methodology.
- Short cycling: The oversized system cools the air too fast, the thermostat is satisfied before the system has had time to properly dehumidify, and the compressor shuts off. Then the temperature rises slightly and it kicks back on. This on-off cycle repeats constantly.
- Poor humidity control: Dehumidification requires sustained run time. Short cycling means the system never runs long enough to pull moisture out of the air, leaving your home feeling cold and clammy.
- Higher energy costs: Starting up a compressor uses more energy than running it continuously. Frequent starts and stops waste electricity.
- Shorter equipment life: The mechanical stress of constant cycling wears out compressors faster than steady-state operation.
Fixed-speed (non-inverter) systems are especially sensitive to oversizing because they can only run at full capacity or not at all. Inverter systems are more forgiving because their compressor can slow down, but even inverter units should not be wildly oversized. Our calculator is designed to prevent oversizing by providing a conservative baseline and only adjusting upward when justified by specific home conditions.
AC Size by Mobile Home Dimensions
Mobile homes come in standard footprints, so the same questions come up constantly. Baselines below assume a HUD-standard (non-ENERGY STAR) home - the conservative case; a certified ENERGY STAR manufactured home typically drops half a ton. Run your exact state and conditions through the calculator above for the qualified range.
What size AC for a 14×60 mobile home?
A 14×60 single-wide is 840 sq ft. Baseline: 2 tons (24,000 BTU) in mixed climates like Missouri or Virginia, rising to 2.5-3 tons in the hottest states (Louisiana, Texas, Arizona). Poor underbelly insulation or heavy afternoon sun pushes toward the top of the range.
What size AC for a 14×70 mobile home?
A 14×70 single-wide is 980 sq ft. Baseline: 2.5 tons (30,000 BTU) in mixed climates and 3 tons across the hot South and Southwest. This is the most common single-wide size, and the most common mistake is inheriting an oversized 3.5-ton unit from a "bigger is safer" replacement.
What size AC for a 16×80 mobile home?
A 16×80 single-wide is 1,280 sq ft. Baseline: 3 tons (36,000 BTU) in mixed climates and 3.5 tons in hot-humid or hot-dry states. At this size, duct condition matters as much as tonnage - a leaky underfloor trunk can waste a quarter of the cooling before it reaches the far bedroom.
Is Your Problem Size or Airflow?
Many manufactured home owners assume their AC is too small because certain rooms never cool properly. But the actual problem is often airflow delivery, not equipment capacity. Here are the symptoms that usually point to duct or airflow issues rather than undersized equipment:
- Some rooms never cool down while others are freezing
- Weak airflow coming from registers even though the system is running
- Noisy ducts - rattling, whistling, or popping sounds
- The evaporator coil or system freezes up periodically
- High electricity bills despite having a large AC unit installed
Research on manufactured home HVAC systems has found that duct leakage can significantly reduce delivered cooling and worsen comfort, especially in underfloor duct systems. That means a properly sized 3-ton system might only deliver a fraction of its cooling to the living space if the ducts are leaking badly into the underfloor cavity.
Our calculator includes a duct-risk scoring system specifically for this reason. If your inputs suggest significant duct problems, the calculator will flag that replacing the equipment alone may not solve your comfort issues and that duct inspection should come first.
Central AC vs Mini-Split for Manufactured Homes
This is one of the most common questions from manufactured home owners, and the answer depends heavily on your specific situation. Here is a balanced comparison.
Central AC May Fit Better When:
- Your existing duct network is still in good condition
- Whole-home, single-system delivery is acceptable to you
- You want one thermostat controlling the entire home
- The replacement is straightforward - same location, same connections
Mini-Splits May Fit Better When:
- Your ducts are damaged, leaking, or you know the underfloor ductwork is compromised
- You have chronic hot and cold room imbalance that has never been resolved
- Room-by-room temperature control matters to you
- Underfloor duct repair would be expensive or difficult due to access
- You are retrofitting an older home where the duct system is suspect
The key takeaway is that neither option is universally better. The right choice depends on your duct condition, your comfort priorities, and your budget. Our calculator evaluates these factors and gives you a recommendation rather than a sales pitch. If you decide to go ductless, our mini split size calculator will size the right BTU and tonnage for each room.
One thing worth planning at the same time is heat. Manufactured homes very often run an electric furnace in the air handler rather than gas, which changes both the size you need and what a replacement costs, since electric units are rated in kilowatts and need a much heavier circuit. Our furnace replacement cost calculator has an electric option alongside gas, so you can price the heating side before a contractor bundles it into a single number. If you are replacing the AC and furnace together, the HVAC installation and replacement cost guides break down what each part of that quote should cover.
How Much Heat Does a Mobile Home Need?
The calculator above now sizes the heating side too, not just cooling. This matters because a mobile home loses heat faster than a regular house of the same size. The belly sits over open air on a chassis instead of a sealed crawlspace, the walls are thinner, and the envelope leaks more, so on a cold design night the same square footage needs more heat. In a cold state like Minnesota, an older single-wide can run close to 60 BTU per square foot, while a tight, newer home in the same climate is closer to 25. Down in south Texas or Florida the heating load is small and the AC is what drives your system size.
Basically, we take your climate, floor area, insulation, ceiling height, and ductwork and run the same design-day heat-loss math our whole-house load calculator uses, then add the extra loss from the exposed underbelly and belly ducts. The result comes back three ways so you can act on it: an electric furnace size in kilowatts, a gas furnace input rating in BTU, and a heat pump size in tons.
Most manufactured homes heat with an electric furnace built into the air handler, sized in kilowatts and rounded up to a stocked size like 10, 15, or 20 kW. That is the number you shop with, and it needs its own heavy circuit. If you are weighing gas against electric, or want to see the same heat load turned into a furnace nameplate, the furnace sizing calculator walks through both fuels, and the heat pump sizing calculator covers the ductless and dual-fuel options.
One decision rule worth keeping: in a cold climate a heat pump quietly loses output on the coldest nights, so size in backup electric strip heat or a dual-fuel setup rather than assuming the nameplate tonnage holds at 0°F. In a mild climate, heating is rarely the deciding factor, and the money is better spent getting the cooling size and the ducts right.
Why HVAC Quotes Vary So Much for Mobile Homes
If you have gotten quotes for AC replacement on a manufactured home, you may have noticed huge variation between contractors. This is not necessarily a sign of price gouging - there are legitimate reasons why manufactured home HVAC work costs vary widely:
- Duct repair scope: Some quotes include fixing underfloor duct issues; others do not even inspect them.
- Crossover duct: Replacing a deteriorated crossover duct on a double-wide adds both material and significant labor costs.
- Underbelly access: Getting under a manufactured home to work on ducts can be difficult depending on skirting, ground clearance, and terrain.
- Electrical upgrades: Older homes may need electrical panel upgrades or new circuits for modern equipment.
- System type: Packaged units, split systems, and ductless mini-splits all have different installation requirements.
- Labor and specialization: Not all HVAC contractors are experienced with manufactured homes, and those who are may charge a premium for their expertise.
Getting at least three quotes, and making sure each contractor specifies exactly what is included, is the best way to compare fairly.
DIY vs Professional Installation
DIY-friendly mini-split kits have made it possible for handy homeowners to install their own ductless cooling systems. These kits can significantly reduce upfront labor costs. However, there are real risks to consider:
- Sizing errors: Installing the wrong size, even with a kit, leads to the same oversizing or undersizing problems discussed earlier.
- Electrical capacity: Manufactured homes have specific electrical panel limitations that must be evaluated before adding equipment.
- Drainage and mounting: Improper condensate drainage or wall mounting can cause water damage - especially problematic in manufactured home wall construction.
- Warranty: Many manufacturers void the equipment warranty if installation is not done by a licensed professional.
- Commissioning: Proper refrigerant charge, airflow verification, and system testing require specialized tools and knowledge.
If you are considering DIY, use this calculator first to narrow down a likely size range. And even with a DIY install, having a licensed technician do the final commissioning and startup is a worthwhile investment.