Maintained by BuildSolver · Updated
AC size · 2,000 sq ft
What size AC for a 2,000 sq ft house
A 2,000 sq ft house needs anywhere from 1 ton to 4.5 tons of cooling in the 14 climates below. The low end is a tight 2015 house in Seattle, WA and the high end is a 1985 house with attic ducts in Phoenix, AZ. At the low end 1 ton is a load, not a unit you can order. The 400 to 600 sq ft per ton rule gives 3.33 to 5 tons for all of them. Check your zone first.
Run your own house in the calculator. It starts with a 2,000 sq ft two-story house in Albuquerque, NM, built in 1985 with ducts in the attic.
- Type the 5-digit ZIP of the job. The calculator looks up the climate zone and its design temperatures.
- Enter the conditioned floor area, stories and year built. The form starts at 2,000 sq ft.
- Pick air tightness, foundation and window type, and check the box if the ducts run through an unconditioned attic.
- Read the cooling load and tonnage, then find the row for your climate zone in the table below to see how the envelope changes the size.
Example result for the default inputs
ZIP 87102 · Bernalillo County, NM · IECC zone 4B · elevation 4,982 ft · design 95°F DB / 66°F WB cooling, 14°F heating
Cooling load
26,317BTU/h
≈ 2 ton (nearest 0.5) · SHR 0.97
Heating load
39,261BTU/h
- Furnace input bin 60,000 BTU/h at 80% AFUE
- Heat pump 60,000 BTU/h at 47°F (40,650 at design temp)
- Flagged for a dual-fuel system
Load breakdown by component
| Component | Cooling | Heating |
|---|---|---|
| Transmission (walls, ceiling, floor, glass, doors) | 7,547 | 25,332 |
| Solar through glass | 12,253 | - |
| Infiltration | 863 | 7,386 |
| Internal gains (people, appliances) | 2,920 | - |
| Ducts in unconditioned attic | 2,734 | 6,543 |
- These design temperatures are an approximate estimate for the IECC climate zone, not location-specific. For permit work use the design conditions for your exact location.
- These are preliminary design conditions. For a permit load, take the design temperatures from ASHRAE Handbook - Fundamentals 2021, Chapter 14.
For estimation purposes only. Consult a licensed engineer for final designs.
Sign up with your email. Back on this page in the same browser, your inputs are filled in. Calculate once more and download the PDF. No card.
Or continue in the chat as a guestRoom-by-room Manual J and branded PDFs · Pro plan
How the tonnage in the table is calculated
Each of the 28 cells in the table is its own run of the BuildSolver load engine on a 2,000 sq ft house, using the whole-house Speed Sheet simplification of ACCA Manual J 8th Edition. The AC size hub has the full method and every floor area side by side.
- House geometry
footprint = 2,000 / 2 = 1,000 sq ft; side = 32 ftThe engine models a square two-story footprint with 8 ft ceilings, which gives about 2,024 sq ft of gross wall and 1,000 sq ft of ceiling under the attic.- Tonnage
tons = Q_cool / 12,000, rounded to the nearest 0.5Loads are rounded to the nearest half ton, which puts this floor area between 1 ton and 4.5 tons.- Square feet per ton
sq ft per ton = 2,000 / (Q_cool / 12,000)Computed from the unrounded load. Across this table one ton covers 464 to 2,076 sq ft.
AC size for a 2,000 sq ft house in 14 climate zones
Each row is the same 2,000 sq ft two-story house on a slab with 4 occupants and glass at 15% of floor area. Only the climate zone and the envelope change. The first house column is a 1985 build with average air sealing and ducts in a vented attic. The second is a 2015 build with a tight envelope and ducts inside conditioned space. Tons are rounded to the nearest half ton. Each cell also shows the load in BTU/h and how many square feet one ton covers.
| Zone | Reference ZIP | Cooling design, zone estimate | 1985 house, attic ducts | 2015 house, ducts inside |
|---|---|---|---|---|
| 1A | Miami, FL 33101 | 92°F | 3.5 tons40,443 BTU/h · 593 sq ft/ton | 1.5 tons19,800 BTU/h · 1,212 sq ft/ton |
| 2A | Houston, TX 77002 | 96°F | 3.5 tons43,005 BTU/h · 558 sq ft/ton | 2 tons21,063 BTU/h · 1,139 sq ft/ton |
| 2B | Phoenix, AZ 85003 | 110°F | 4.5 tons51,737 BTU/h · 464 sq ft/ton | 2 tons25,356 BTU/h · 947 sq ft/ton |
| 3A | Atlanta, GA 30303 | 95°F | 2.5 tons29,190 BTU/h · 822 sq ft/ton | 1.5 tons18,966 BTU/h · 1,265 sq ft/ton |
| 3B | Las Vegas, NV 89101 | 100°F | 2.5 tons31,126 BTU/h · 771 sq ft/ton | 1.5 tons20,384 BTU/h · 1,177 sq ft/ton |
| 3C | San Francisco, CA 94103 | 84°F | 1.5 tons20,665 BTU/h · 1,161 sq ft/ton | 1 ton13,483 BTU/h · 1,780 sq ft/ton |
| 4A | St. Louis, MO 63101 | 92°F | 2 tons26,347 BTU/h · 911 sq ft/ton | 1.5 tons17,320 BTU/h · 1,386 sq ft/ton |
| 4B | Albuquerque, NM 87102 | 95°F | 2 tons26,317 BTU/h · 912 sq ft/ton | 1.5 tons17,534 BTU/h · 1,369 sq ft/ton |
| 4C | Seattle, WA 98101 | 84°F | 1.5 tons17,184 BTU/h · 1,397 sq ft/ton | 1 ton11,561 BTU/h · 2,076 sq ft/ton |
| 5A | Chicago, IL 60614 | 91°F | 2 tons25,776 BTU/h · 931 sq ft/ton | 1.5 tons16,323 BTU/h · 1,470 sq ft/ton |
| 5B | Denver, CO 80202 | 93°F | 2 tons25,205 BTU/h · 952 sq ft/ton | 1.5 tons16,087 BTU/h · 1,492 sq ft/ton |
| 6A | Minneapolis, MN 55401 | 90°F | 2 tons23,297 BTU/h · 1,030 sq ft/ton | 1.5 tons15,135 BTU/h · 1,586 sq ft/ton |
| 6B | Billings, MT 59101 | 92°F | 2 tons23,022 BTU/h · 1,042 sq ft/ton | 1.5 tons15,090 BTU/h · 1,590 sq ft/ton |
| 7 | Duluth, MN 55802 | 86°F | 1.5 tons19,167 BTU/h · 1,252 sq ft/ton | 1 ton12,601 BTU/h · 1,905 sq ft/ton |
3 of the 28 sizes above are under 1.5 tons. Those numbers are loads, not equipment sizes, because the ducted lineup this calculator sizes against starts at 18,000 BTU/h.
Only 3 of the 28 engine results land inside the rule-of-thumb range of 3.33 to 5 tons, the 1985 house in zones 1A, 2A and 2B.
Phoenix, AZ splits the widest. The 1985 house with attic ducts needs 4.5 tons and the tight 2015 house with its ducts inside needs 2 tons, 2.5 tons apart on the same floor area.
The highlighted Albuquerque row is the calculator's starting point. There the 1985 house needs 26,317 BTU/h, or 2 tons, and a heating load of 39,261 BTU/h at 14°F. Built tight in 2015 with the ducts inside, the same house needs 1.5 tons. A 500 sq ft per ton quote would put 4 tons on both. Size each house from its own row, then check the existing ducts and registers before you write the quote.
Standards and data sources
- ACCA Manual J 8th Edition - residential load procedure. The tables use its whole-house Speed Sheet simplification, which gives a single load for the whole house.
- ACCA Manual S - equipment selection against the Manual J load, including the 115% limit on cooling capacity for a single-speed unit. Selection is a separate step and part of the Pro plan.
- IECC 2021 climate zones (PNNL county map) - ZIP to county to climate zone. The zone sets the design temperatures, solar factor and envelope defaults for each row.
What the table leaves out
- Every row is one standard 2,000 sq ft house. On a real job, insulation, glass, orientation and air leakage move the load, and in this table the 1985 and 2015 builds in Phoenix, AZ already land 2.5 tons apart.
- Each row uses an approximate design temperature for its IECC climate zone, from 84°F in the San Francisco zone to 110°F in the Phoenix zone. These are not location-specific, and ASHRAE Handbook - Fundamentals 2021, Chapter 14, lists the city values.
- The engine treats both stories as one zone. The page cannot split the load between floors, and a bonus room over a garage is not modeled.
- Whole-house load only. Room-by-room Manual J and Manual S equipment selection are part of the Pro plan.
Common sizing mistakes on a 2,000 sq ft house
- Quoting 5 tons because the house is 2,000 sq ft. That is the top of the 400 sq ft per ton rule. The St. Louis, MO row puts the 1985 house at 2 tons and the 2015 house at 1.5 tons.
- Reusing the tonnage from a job in another market. Carry the Phoenix, AZ tonnage to a San Francisco, CA job and you have sold 3 tons more equipment than the house asks for.
- Sizing off the nameplate of the unit coming out. It may have been picked by rule of thumb, and matching it repeats whatever oversizing the last installer chose.
- Letting the heating load set the AC. Duluth, MN asks the 1985 house for 63,738 BTU/h of heat and 1.5 tons of cooling. Pick the furnace and the AC from their own loads.
What to check on a 2,000 sq ft house
The 2,000 sq ft houses on this page are two-story, three-bedroom homes with the bedrooms upstairs, matching the 4 occupants in the load. The second floor carries more of the cooling load because it sits under the attic and gets the heat that rises from below, so one system on one thermostat often leaves the upstairs warm. Expect the first comfort callback from the upstairs bedrooms in July.
- The quick form treats the house as one zone. On a two-story house the upstairs often carries more of the cooling load on a hot afternoon, so check the duct split between floors before you trust one thermostat.
- At this size, look at two small systems or one zoned variable-speed system. The whole-house number here sets the total. The room-by-room Manual J in the Pro plan gives each room's load, so you can add up each floor.
- Stair openings move air between floors. Put returns high on the second floor so the upstairs air gets back to the air handler.
Questions about AC size for 2,000 sq ft
What size AC do I need for a 2,000 sq ft house?
Climate and construction decide it. In the table on this page the answer runs from 1 ton in Seattle, WA to 4.5 tons in Phoenix, AZ. Chicago, IL puts the same house at 2 tons as a 1985 build and 1.5 tons as a 2015 build. On this page any size under 1.5 tons is a load, not a unit you can order. The ducted lineup starts at 18,000 BTU/h, so those houses take a mini split. Enter your ZIP and the house details in the calculator for your own number.
How many BTU does a 2,000 sq ft house need for cooling?
The cooling loads in the table run from 11,561 to 51,737 BTU/h. Per square foot that is 5.8 to 25.9 BTU/h, so no single BTU per square foot number fits a house this size. 3 of the 28 runs on this page round to a size under the 18,000 BTU/h floor of the ducted lineup, where the job goes to a mini split. Run the actual house in the calculator above for its number.
Is a 5-ton AC too big for a 2,000 sq ft house?
ACCA Manual S limits a single-speed cooling unit to 115% of the Manual J load. By that limit a 5-ton single-speed unit is oversized for every house on this page, including the 1985 house in Phoenix, AZ at 51,737 BTU/h. Going down from 5 tons stops at 18,000 BTU/h, 1.5 tons, where the ducted lineup this calculator sizes against ends. Loads under that number belong to a mini split.
What size furnace goes with a 2,000 sq ft house?
The heating loads in the same runs go from 11,218 to 63,738 BTU/h, the highest for the 1985 house in Duluth, MN. With the engine's AFUE default for the year built, those loads call for furnace inputs from the 40,000 to the 80,000 BTU/h bin. At the warm end one run comes in light enough that the engine asks for electric resistance heat rather than a furnace. The furnace size calculator shows the heating result for a single ZIP.
Why does a 2,000 sq ft house need a different size in Phoenix and Seattle?
Design temperature and solar load. The table uses 110°F for the Phoenix zone and 84°F for the Seattle zone, so the same 1985 2,000 sq ft house needs 4.5 tons in Phoenix and 1.5 tons in Seattle.
Can I quote a 2,000 sq ft job from this table?
Use it for the first conversation with the homeowner. Albuquerque, NM puts the same 2,000 sq ft at 2 tons or 1.5 tons depending on how the house was built, so run the load for the actual house before you order equipment. Room-by-room Manual J and Manual S equipment selection are in the Pro plan. If the job needs a permit, ask the building department whether it requires a load report from ACCA-approved software.
Used on the same job
- Manual J calculator The whole-house load for the actual house from its ZIP code.
- HVAC design temperatures by ZIP The outdoor design conditions behind every row of the table.
- HVAC CFM calculator The airflow the ducts have to carry at the tonnage you picked.
- BTU to tons converter The same load in tons, kW or MBH for a data sheet in other units.
Size the actual house in chat
Start with the ZIP. Then describe the house you are quoting, including the windows, insulation and where the ducts run, and the assistant runs the same load tools, asks for what is missing and explains the result in terms you can show the homeowner.
Open the chat