What size AC for Seymour, IN? 2.5 tons for 2,000 sq ft

What size AC a 2,000 sq ft house in Seymour needs

2.5 tons central AC or heat pump, about 29,000 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 45% more than this climate needs. An oversized unit cools the air fast, shuts off before it pulls moisture out, and leaves the house cold and clammy.

If a contractor quotes you more than 2.5 tons for an average 2,000 sq ft house here, ask to see the Manual J load calculation behind it before you sign. That works out to one ton per 828 square feet in this climate. For a single room, size by the room: 14.5 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Seymour 1 Wsw (1 mi away). Jul is the hottest month, averaging a high of 84.7°F and a low of 64.4°F, with about 20 days a year at 90°F or more. That gives a design temperature of 89°F against 75°F inside.

What it costs to run

About 1,362 kWh a year at SEER2 14.3, or roughly $232 at Indiana's average residential rate of 17.04¢ per kWh. Cooling runs 5 months of the year here.

What drives the load in Seymour

Of the 29,000 BTU/hr, 10,080 comes through walls, roof and windows on a 89°F afternoon (35%), 13,000 is sun on the house (45%), 2,120 is four people and their appliances, and 3,800 is moisture the coil has to wring out of Seymour's summer air (13%).

Sun is the biggest share here, more than heat through the walls, so shading west windows and a light roof cut the size you need more than extra insulation would. Sensible heat totals 25,200 BTU/hr before the moisture allowance.

Other house sizes in Seymour

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,200 BTU/hr; a 350 sq ft living room needs about 5,100 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 8,700 BTU/hr.

Month by month in Seymour

Jul alone uses 30% of the year's cooling energy. The unit runs the equivalent of 672 hours a year at full output.

Seymour against nearby cities

Of 88 Indiana cities here, Seymour has the 54th highest cooling load. The range runs from Auburn at 24,100 BTU/hr to Jasper at 36,400.

Where Seymour's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Seymour 1 Wsw, 1 miles from the center of Seymour at 567 ft above sea level. That is close enough that the station's summers are Seymour's summers.

No other city in this set uses Seymour 1 Wsw, so this sizing is Seymour's alone.

The sun over Seymour in late July

At 38.95°N, the noon sun on 21 July stands 71.5° above the horizon over Seymour and the day runs 14 h 20 min from sunrise to sunset. A lower noon sun puts more of the day's heat on east and west walls than on the roof, which is why shading west glass pays off here. Shorter days give the house a longer night to shed the day's heat.

22,524 people live in Seymour, the 45th largest of the 88 Indiana cities sized on this site. Coordinates used: 38.9468, -85.8892.

Seymour AC sizing questions