AC Tonnage Per Square Foot: Chart & Calculator

AC Tonnage Chart by Square Footage

This chart shows the typical central AC tonnage for a whole house with average insulation and standard 8 ft ceilings. Find your home's square footage on the left, then use the column that matches your climate. If you fall between two sizes, hot climates round up and cold climates round down, and that's the safest default. To size the whole system interactively - and to see what a central AC (split system) actually is - use our central AC size calculator. Mobile and manufactured homes size differently, because thinner walls and belly ductwork change the per-square-foot math, so use the mobile & manufactured home AC sizing calculator for those.

One thing worth clearing up before you read the numbers, because it confuses a lot of people. A whole house and a single room of the same square footage do not need the same tonnage, and a house usually needs less per square foot than one big open room does. The reason is that a house is chopped up by interior walls, only some rooms are in use at once, and the load gets spread across the whole envelope instead of hitting one space. A single 1,000 sq ft open room with afternoon sun and people in it is a much harder job than a 1,000 sq ft house with three bedrooms. So if you are sizing one room rather than a house, use our AC tonnage calculator instead, which works from room dimensions.

AC Unit Size Chart for 1,100 to 4,000 Sq Ft Homes

This AC unit size chart fills in the home sizes that fall between the rows above, and it splits the climate five ways, the same as the calculator does. Every figure is what the calculator returns for average insulation with the ducts inside the house, so it works as an air conditioner size chart for a whole home and not for a single room.

1,100 sq ft. Plan on 2 tons in a mixed or temperate climate and 2.5 tons in either hot one. Poor insulation moves the mixed-climate answer to 2.5 as well, so what size AC unit for 1,100 square feet you need depends on the walls as much as the weather.

1,900 sq ft. The calculator gives 3.5 tons in a mixed climate, 4 tons in dry heat and 4.5 tons on the Gulf Coast, which is the whole spread of AC tonnage for 1,900 sq ft house sizing. If a quote for a 1,900 sq ft house AC size came back at 3 tons, that is the right answer only in a temperate or cold climate.

2,300 and 2,400 sq ft. Through the mixed and temperate zones, 2,300 sq ft house AC size comes to 4 tons, and it is 3.5 tons up north. At 2,400 sq ft a mixed climate gives 4.5 tons on one story, and two stories or good insulation bring it down to 4.

2,600 and 2,800 sq ft. A mixed climate puts 2,600 sq ft house AC size at 5 tons, which is the largest single unit sold for homes, and 2,800 sq ft gets the same 5. In both hot climates either size is already past one system.

3,300 to 4,000 sq ft. The right AC unit for 3,300 sq ft house plans is a single 5 ton system only in a cold climate. How many ton AC for 3,500 sq ft is 5.5 there and 6.5 in a mixed climate, and how many tons for 4,000 sq ft is 6 in the cold zone and 7.5 in the mixed one, always as two systems, for example a 4 ton and a 3.5 ton.

You will see a table like this called an AC sizing chart, an air conditioner sizing chart, an air conditioner tonnage chart or an HVAC tonnage chart. They are all the same thing, because a ton is 12,000 BTU of cooling per hour whatever the equipment is called.

How Many Tons of AC Per Square Foot? The Math Behind the Chart

The answer comes out between 0.0015 and 0.0023 tons, depending on the climate. The calculator works in BTU per sq ft and one ton is 12,000 BTU, so AC tons per sq ft is just the BTU rate divided by 12,000. That division gives HVAC tonnage per sq ft directly, and AC tonnage per square feet or air conditioner ton per sq ft is the same small decimal.

To calculate AC tonnage per square foot for your own house, multiply the square footage by the BTU rate, then divide by 12,000. A 2,400 sq ft home in a mixed climate is 2,400 × 22 = 52,800 BTU, and 52,800 ÷ 12,000 = 4.4 tons, which rounds to 4.5. We round to the nearest half ton and not up, because rounding up every time is how houses end up with oversized units.

Insulation then scales the answer. In the calculator, Poor multiplies it by 1.15 and Good by 0.90, so that same 2,400 sq ft house is 5 tons with poor insulation and 4 tons with good.

You will see this number written a few ways. AC tonnage per sq ft, HVAC tonnage per square foot and HVAC tons per square foot all mean the cooling capacity a house needs for each square foot of floor. Air conditioner tons per square foot times the floor area gives the size in tons, and because one ton covers hundreds of square feet, AC unit tonnage per square foot is a small decimal. On a builder's sheet it appears as AC tons per sf, and in short form as AC ton per square foot or AC ton per sq ft. The table answers how many tons per square foot for HVAC. Its last column turns that upside down and gives how many sq ft per ton of AC, or how many square feet per ton of cooling.

So going from square footage to AC tonnage is one multiplication, and going from AC tons to square feet is one division. If a quote does not land within half a ton of that math, ask the contractor what moved it.

How Many Square Feet Does 1 Ton of AC Cover?

Flipping the question around: 1 ton of AC covers roughly 400 to 650 square feet, depending on your climate and insulation. In Miami or Houston, plan on the low end of that range. In Minneapolis, the high end. (Working from a BTU rating instead? First convert BTU to tons, then read the coverage off this table.) Here's the coverage for every standard size:

The table gives you the range. Below we have gone through each size one at a time, because the range is wide and where you land inside it is the whole question. And a warning before you read them: the ranges assume the ductwork can actually carry the air. An older home built for a smaller system may have ducts sized for only 600 to 800 CFM, which is not enough for 2.5 tons no matter what the square footage says. Our HVAC airflow calculator turns any tonnage into the CFM it needs. If you are stepping up a size, get the ducts checked with our duct size calculator before you buy. For the full spec sheet of each size - installed cost, airflow, duct size, watts and amps in one table - see AC unit by tonnage.

1 Ton AC Unit Square Footage

One ton covers roughly 400 to 650 sq ft. That is one big room, a studio or a small apartment, not a whole house. So a 1 ton AC unit covers how many square feet in practice? In a mixed climate the calculator above only returns 1 ton below about 680 sq ft, and ducted central systems for houses start at 1.5 tons. So a 1 ton AC sq ft figure is a room-sized number, and a ductless head or a window unit is the product for it, not central air.

1.5 Ton AC Unit Square Footage

A 1.5 ton unit covers roughly 600 to 950 sq ft. That is a small house, a large apartment, or a finished basement. Take the low end in the South and the high end up north. Below about 600 sq ft you are into single-room territory, and at that point a ductless head usually makes more sense than a whole central system.

Narrowed to a mixed climate, 1.5 ton air conditioner square footage is tighter than the full range, and the calculator lands on this size from about 680 to 950 sq ft. 1 1/2 ton AC unit square footage means the same thing written as a fraction, which is how some data plates and quotes show it.

2 Ton AC Unit Square Footage

Two tons handles roughly 900 to 1,300 sq ft. This is the size people most often discover they have and then start doubting, so it is worth being clear about where the line falls.

Homeowners report a 2 ton system running a 1,150 sq ft house in South Carolina without complaint. The same 2 tons in a 2,350 sq ft house had the unit running all day and never catching up, and in a 1,650 sq ft house an installer called it undersized outright. So if your house is over about 1,300 sq ft and the AC runs constantly on hot afternoons, the size is the first thing to check, not the refrigerant.

In a mixed climate our calculator puts the square footage for 2 ton air conditioner sizing at about 960 to 1,230 sq ft, and a 2 ton AC unit square feet figure above 1,300 only holds in a cold climate.

2.5 Ton AC Unit Square Footage

At 2.5 tons you are looking at about 1,150 to 1,600 sq ft. It is the usual answer for a mid-size single-story home, and it is also the step where ductwork starts to matter more than tonnage. A house built for 2 tons will not automatically move the extra air, so if you are upgrading rather than replacing like for like, that is the moment to have the duct sizing looked at.

At mixed-climate rates, 2.5 ton AC unit square feet comes to about 1,230 to 1,500, so a house of 1,500 sq ft sits right on the edge between this size and the next one up.

3 Ton AC Unit Square Footage

A 3 ton unit covers roughly 1,400 to 1,900 sq ft, and this is the most common central AC size in American homes.

But the spread inside that range is real. One owner reports 3 tons cooling 1,400 sq ft comfortably. Another with an 1,844 sq ft house on the same 3 tons said it could not keep up once the outside temperature passed 90°F, while holding the house at 70°F. Both are inside the range. The difference is not the square footage, it is how hard you are asking the system to work and how well the house holds heat out. If you are at the top of the range in a hot climate and you like the house cold, size up.

If you only want one 3 ton AC square footage figure, use 1,635 sq ft, which is the mixed-climate midpoint. In our calculator, 3 ton air conditioner square footage for a mixed climate runs from 1,500 to about 1,770 sq ft, and the square footage for 3 ton air conditioner sizing drops to roughly 1,180 to 1,390 in a hot and humid state.

3.5 Ton AC Unit Square Footage

Three and a half tons stretches from about 1,650 to 2,250 sq ft. This size does not exist in every product line, which is why some quotes jump straight from 3 to 4 tons. It is worth asking for, because the jump from 3 to 4 is a big one to make on a house sitting in the middle. An older ranch of about 1,465 sq ft with poor insulation was sized at 3.5 tons by its installer, which is well above what the square footage alone suggests, and that is the envelope doing the talking rather than the floor plan.

Run the numbers for a mixed climate and 3.5 ton air conditioner square footage is about 1,770 to 2,050 sq ft, which is why 2,000 sq ft in a moderate climate lands on this size.

4 Ton AC Unit Square Footage

Four tons takes you from about 1,900 to 2,600 sq ft. At this size a single system is usually still fine for a one-story home, but a two-story house of the same footage often does better with zoning or a second system, because the upstairs will always run warmer than the downstairs no matter how much capacity you buy.

For a mixed climate, 4 ton AC unit square feet works out to about 2,050 to 2,320, and 4 ton air conditioner square footage only reaches 2,600 in a cold state.

4.5 Ton AC Unit Square Footage

For a mixed climate, a 4.5 ton answer covers about 2,320 to 2,590 sq ft, and the table below gives the other climates. But here is the catch with 4.5 ton AC unit square footage. No 4.5 ton unit is made for houses, so a 4.5 ton answer is 54,000 BTU of load that has to be covered by either a 4 ton or a 5 ton. A 5 ton unit is 111% of that load, inside the 115% that Manual S allows, while a 4 ton is 89% of it, just under the 90% floor. That is why our cost calculator prices a 4.5 ton answer as the 5 ton.

So when the chart says 4.5 tons, expect a quote for 5. In a humid climate, ask for a two-stage or variable speed model, because it can run below full output and still dry the air.

5 Ton AC Unit Square Footage

A 5 ton unit covers roughly 2,400 to 3,300 sq ft, and it is the largest standard residential size. Above this you are not buying a bigger unit, you are buying a second system, because residential equipment stops at 5 tons. So if a contractor quotes you a single unit for a 3,500 sq ft house in a hot climate, ask them to show you the load calculation, because the answer is usually two systems. Our cooling load calculator gives you the whole-house number to check that against.

Our calculator puts 5 ton air conditioner square footage in a mixed climate at about 2,590 to 2,860 sq ft, and the 5 ton AC unit square feet figure of 3,300 belongs to cold states only.

AC Tons to Square Feet by Climate

The same tonnage covers a bigger house in a cooler place, so AC tons to square feet is not one number. The ranges above are trimmed to where most homes fall. This table shows the house size where our calculator lands exactly on each tonnage in each of its five climates, so the hot and humid column sits a little under those ranges and the cold column a little over them.

So read across, not down. A 3 ton air conditioner square feet figure of 1,285 in Houston and 2,000 in Minneapolis are both correct, and quoting one city's number for the other is how a house ends up a full ton off. Converting AC tonnage to square feet always starts with the climate.

What Size AC Do I Need for My House?

These are the home sizes people ask about most. All numbers assume a whole house with average insulation. If yours is a 1970s home with original windows, nudge up half a ton; a tight new build, nudge down.

Before a contractor has seen the place, what size air conditioner do I need for my house comes down to the four things this AC square footage calculator asks for: Home Size, Climate, Insulation and Ductwork. AC tonnage by square feet sets the starting figure and climate moves it the most. The other two are worth about half a ton each, and at 2,200 sq ft either one takes 4 tons to 4.5. That is the honest answer to what size AC do I need for my home at this stage. So work out the AC size for house and climate first, then make any quote that is more than half a ton away explain itself.

AC Tonnage for a 1,000 Sq Ft House

A 1,000 sq ft house needs about 2 tons in most of the US, rising to 2.5 tons in hot, humid states and dropping to as little as 1.5 tons up north. That's 18,000–30,000 BTU/hr.

If you are shopping for a 1,000 sq ft AC unit, the 2 ton answer is a 22,000 BTU load in a mixed climate, and good insulation is enough to bring it down to 1.5 tons. What size AC for 1,000 sq ft also depends on the product, because a central air conditioner for 1,000 square feet sits at the small end of what ducted equipment comes in, so a ductless system is worth pricing next to it.

What Size AC Unit for 1200 Square Feet?

A 1,200 sq ft house needs about 2 to 2.5 tons in a moderate climate, 2.5 to 3 tons in the hot South, and 2 tons in cold northern states. This is the size where a 2 ton unit stops being a safe default, so if yours is 2 tons and struggling on hot afternoons, it is probably genuinely undersized rather than faulty.

In our calculator, how many tons for 1,200 sq ft comes to 2 tons flat for a mixed climate, a load of about 26,500 BTU, and it only moves to 2.5 with poor insulation or ducts in the attic. Going over the AC tonnage for 1,200 sq ft has a cost of its own. One owner of an 1,150 sq ft house replaced a 2 ton system with a 2.5 ton and reports that it barely runs long enough to manage the humidity, to the point of buying a dehumidifier. So if the house was comfortable on the old size, do not let a replacement quote add half a ton without a load calculation behind it.

What Size AC Unit for 1300 Square Feet?

For 1,300 sq ft, plan on 2.5 tons in a moderate climate, 3 tons in hot and humid states, and 2 tons up north. You are inside the 2.5 ton coverage band here with a little room to spare, which makes this one of the easier sizes to get right.

Worked out in BTU, 1,300 sq ft AC tonnage is about 28,500 for a mixed climate, a little under 2.5 tons. For 1,300 sq ft house AC size in dry heat, the calculator gives the same 3 tons it gives on the Gulf Coast.

What Size AC Unit for 1400 Square Feet?

A 1,400 sq ft home lands on 2.5 to 3 tons, going to 3 or 3.5 tons in the South and 2 to 2.5 tons in cold climates. Owners report 3 tons cooling 1,400 sq ft comfortably, so if your quote says 2.5 and the house is in a hot state, ask what the load calculation actually returned before you accept the smaller size.

On the numbers, 1,400 sq ft AC tonnage starts from a 31,000 BTU load in the middle of the country, slightly more than 2.5 tons. That is why AC tonnage for 1,400 sq ft tips over to 3 tons as soon as the insulation is poor or the ducts run through the attic.

AC Tonnage for a 1,500 Sq Ft House

For 1,500 sq ft, plan on 2.5 to 3 tons in a moderate climate, 3 to 3.5 tons in the South, and 2 to 2.5 tons in cold states. This is the single most common house-size question we see, and the honest answer is that 1,500 sq ft sits right on the line between 2.5 and 3 tons, which is exactly why climate and insulation matter so much here.

How many tons do I need for a 1500 square foot house? The exact math gives 33,000 BTU for a mixed climate, or 2.75 tons, and our calculator rounds that tie up to 3. Good insulation settles it at 2.5. So AC tonnage for 1,500 sq ft is the one case where the insulation answer decides the size on its own, and what size AC unit for 1,500 square feet you get quoted tells you which way the contractor read the house. How many tons for 1,500 sq ft in a hot state is 3.5, dry or humid.

What Size AC Unit for 1600 Square Feet?

For 1,600 sq ft, plan on 3 tons in a moderate climate, 3.5 tons in the hot South, and 2.5 tons in cold states. An installer looking at a 1,650 sq ft house on 2 tons called it undersized outright, which is worth knowing if you inherited a system with the house.

This is the most settled answer on the page. For 1,600 sq ft house AC size the load works out to 35,000 BTU at mixed-climate rates, almost exactly 3 tons, so how many tons for 1,600 sq ft only changes to 3.5 with poor insulation or attic ducts.

What Size AC Unit for 1700 Square Feet?

A 1,700 sq ft home needs about 3 to 3.5 tons, closer to 3.5 or 4 in Texas and Florida, and 2.5 to 3 tons in northern states. This is where the 3.5 ton size earns its place, because the jump from 3 straight to 4 tons is a big one for a house sitting in the middle.

The load here is about 37,500 BTU in a mixed climate, just over 3 tons, so 1,700 sq ft AC tonnage holds at 3 in the calculator and goes to 3.5 with poor insulation. How many tons for 1,700 sq ft in a hot state depends on the kind of heat, 3.5 tons where it is dry and 4 tons where it is humid.

AC Tonnage for an 1,800 Sq Ft House

An 1,800 sq ft home typically needs 3 to 3.5 tons, or about 4 tons in Texas or Florida heat, closer to 3 tons in mild or northern climates.

By our calculator the load is roughly 39,500 BTU at mixed-climate rates, so what size AC for 1,800 sq ft comes out at 3.5 tons, and good insulation brings it back to 3. How many tons for 1,800 sq ft goes to 4 with poor insulation or attic ducts, which is also what both hot climates return.

AC Tonnage for a 2,000 Sq Ft House

For 2,000 sq ft, the standard answer is 3.5 tons in a moderate climate. Hot and humid regions push it to 4–4.5 tons, while cold-climate homes usually do fine with 3. Two-story homes often land at the lower end because the upstairs and downstairs share walls with each other instead of the outdoors.

One number explains how much HVAC tonnage for 2000 sq ft home sizing takes: 44,000 BTU at mixed-climate rates, which is 3.67 tons before rounding. That is why AC tonnage for 2,000 sq ft is the most argued figure there is. It rounds down to 3.5, but poor insulation, attic ducts or 9 ft ceilings each push it to 4 on their own. So when you ask what size AC unit for 2,000 square feet and get two different answers, check those three things before you decide one contractor is wrong. And for how many tons do I need for a 2000 square foot house in the South, the calculator says 4.5 in dry heat and humid heat alike.

What Size AC Unit for 2200 Square Feet?

A 2,200 sq ft house needs about 4 tons in a moderate climate, 5 tons in the hot South, and 3 to 3.5 tons in cold states. At this size a two-story layout matters more than the square footage does, because the upstairs will run warmer whatever capacity you buy, and zoning usually solves that better than a bigger unit. Buying up a size to chase a humidity complaint backfires for the same reason, since the shorter run times remove less moisture, not more, and our dehumidifier capacity calculator is the cheaper way to deal with it.

The load is near 48,500 BTU in a mixed climate, so 2,200 sq ft house AC size is 4 tons almost exactly. What tonnage HVAC system do I need for my 2200 sq ft house in a milder place? The calculator says 3.5 tons in the temperate zone and the cold zone, and good insulation gives the same 3.5 in a mixed one.

AC Tonnage for a 2,500 Sq Ft House

A 2,500 sq ft house needs about 4.5 tons in moderate climates and 3.5–4 tons in cold ones. In the hot South you're at the 5 ton ceiling, and at 2,600+ sq ft down there, many contractors will already suggest splitting into two systems.

A mixed climate puts AC tonnage for 2,500 sq ft at a 55,000 BTU load, which falls in the 4.5 ton gap covered above and gets quoted as a 5. So what size AC unit for 2,500 square feet is a 5 ton question in the middle of the country and a 4 ton question in a cold or temperate one.

AC Tonnage for a 3,000 Sq Ft House

At 3,000 sq ft you need roughly 5 to 5.5 tons in a moderate climate and 4–4.5 tons in cold states. In hot climates, the math says more than 5 tons, which in practice means two systems, not one bigger unit, since residential equipment stops at 5 tons.

The math for how many tons of AC for 3000 square feet comes to 66,000 BTU in a mixed climate, or 5.5 tons, so the calculator shows 5+ and points you to two systems. A 3,000 sq ft house air conditioner stays a single 5 ton unit only with good insulation or in a temperate climate.

AC Tonnage Per Square Foot in Texas (and Other Hot States)

Texas deserves its own mention because it's the most common "does the rule of thumb still apply?" state. It mostly does, just shifted: in the Dallas–Houston–San Antonio triangle, figure 1 ton per 450–500 sq ft instead of the national 500–600. Gulf Coast humidity adds latent load (moisture your AC has to wring out of the air before it can cool), and West Texas sun exposure does something similar through sheer heat. Florida, Louisiana, southern Arizona, and Georgia follow the same logic. If you're in any of these states, use the "Hot" column of the chart and don't be surprised when the answer looks half a ton bigger than what a national average would say.

Not every hot state is a humid one, and not every part of California is hot. The calculator treats Arizona, Nevada and inland California as hot and dry, and coastal California with the Pacific Northwest as temperate, which is the lowest tonnage per square foot outside the cold states. One owner in the Pacific Northwest reports a 3 ton heat pump that effortlessly cools a well insulated 2,200 sq ft two-story house. Enter that house in the calculator as temperate, Good insulation and 2 stories, and it returns the same 3 tons. So pick the climate by humidity as well as heat. Phoenix and Houston are both hot, but only one of them makes the air conditioner dry the air as well as cool it.

Why Square Footage Is Only the Starting Point

Square footage gets you the right neighborhood, not the exact address. Two 2,000 sq ft homes can genuinely need ACs a full ton apart. The factors that move the number: ceiling height (10 ft ceilings hold ~25% more air than 8 ft), insulation era, window area and direction, how many people live there, and whether the ductwork runs through a 130°F attic. Professional contractors capture all of this with a Manual J load calculation, and our calculators are built to approximate the variables that matter most from that method.

A square footage estimate and a real load calculation can land in the same place. One owner of a 1,368 sq ft house built in 1963, with old windows, reports a Manual J result of 30,000 BTU, which is 2.5 tons. Our calculator gives 30,000 BTU for the same square footage in a mixed climate with average insulation. When the two disagree by more than half a ton, do not average them. Ask which input is different, because one of them knows a fact about the house that the other does not. The optional panel in the calculator, More detail about your home, is where those facts go: Ceiling Height, Stories, Sun Exposure and People in the Home. Our guide to what a Manual J covers and costs explains the full version.

A new house is the other common surprise. Owners moving into a new build often say the unit looks small for the floor area. For 2,900 sq ft in a mixed climate the calculator gives 5.5 tons with average insulation and 4.5tons with good insulation over two stories. So a builder's smaller unit can be the right one, and the older house next door is not the yardstick.

Vaulted ceilings pull the other way. A 1,650 sq ft home in a mixed climate needs 3 tons with 8 ft ceilings, and 4.5 tons if every room were 12 ft high. A vault over one room lands between those two, so enter the average ceiling height across the whole house, not the tallest point.

So use this page the way contractors use rules of thumb: to sanity-check quotes and get in the right range. If a salesperson quotes 5 tons for your 1,500 sq ft house in Ohio, this chart is how you know to get a second opinion. For a proper estimate, run your home through the Tonnage Calculator AC room by room. And if you're checking what size your current unit is before replacing it, our tonnage-by-model-number decoder reads it straight off the data plate. The exact BTU-per-square-foot values and insulation factors this calculator uses are published in our methodology. And once you've settled on a tonnage, see what it costs installed with the central AC installation cost calculator.