What size AC for Jasper, IN? 3 tons for 2,000 sq ft

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

3 tons central AC or heat pump, about 36,400 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 15% 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 3 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 659 square feet in this climate. For a single room, size by the room: 18.2 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Patoka Lake (13.2 mi away). Jul is the hottest month, averaging a high of 91.7°F and a low of 67.2°F, with about 73 days a year at 90°F or more. That gives a design temperature of 98°F against 75°F inside.

What it costs to run

About 2,136 kWh a year at SEER2 14.3, or roughly $364 at Indiana's average residential rate of 17.04¢ per kWh. Cooling runs 5 months of the year here.

What drives the load in Jasper

Of the 36,400 BTU/hr, 16,560 comes through walls, roof and windows on a 98°F afternoon (45%), 13,000 is sun on the house (36%), 2,120 is four people and their appliances, and 4,800 is moisture the coil has to wring out of Jasper's summer air (13%).

Heat through the shell is the biggest share here, so insulation and air sealing cut the size you need more than shading would. Sensible heat totals 31,680 BTU/hr before the moisture allowance.

Other house sizes in Jasper

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,700 BTU/hr; a 350 sq ft living room needs about 6,400 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 10,900 BTU/hr.

Month by month in Jasper

Jul alone uses 29% of the year's cooling energy. The unit runs the equivalent of 839 hours a year at full output.

Jasper against nearby cities

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

Where Jasper's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Patoka Lake, 13.2 miles from the center of Jasper at 561 ft above sea level. That is close enough that the station's summers are Jasper's summers.

No other city in this set uses Patoka Lake, so this sizing is Jasper's alone.

The sun over Jasper in late July

At 38.39°N, the noon sun on 21 July stands 72.0° above the horizon over Jasper and the day runs 14 h 17 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.

16,967 people live in Jasper, the 53rd largest of the 88 Indiana cities sized on this site. Coordinates used: 38.3932, -86.9406.

Jasper AC sizing questions