What size AC for Chicago Heights, IL? 2.5 tons for 2,000 sq ft

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

2.5 tons central AC or heat pump, about 26,400 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 59% 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 908 square feet in this climate. For a single room, size by the room: 13.2 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Park Forest (2.6 mi away). Jul is the hottest month, averaging a high of 83.9°F and a low of 63.8°F, with about 16 days a year at 90°F or more. That gives a design temperature of 88°F against 75°F inside.

What it costs to run

About 1,121 kWh a year at SEER2 14.3, or roughly $216 at Illinois's average residential rate of 19.23¢ per kWh. Cooling runs 5 months of the year here.

What drives the load in Chicago Heights

Of the 26,400 BTU/hr, 9,360 comes through walls, roof and windows on a 88°F afternoon (35%), 13,000 is sun on the house (49%), 2,120 is four people and their appliances, and 2,000 is moisture the coil has to wring out of Chicago Heights's summer air (8%).

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 24,480 BTU/hr before the moisture allowance.

Other house sizes in Chicago Heights

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,000 BTU/hr; a 350 sq ft living room needs about 4,600 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 7,900 BTU/hr.

Month by month in Chicago Heights

Jul alone uses 32% of the year's cooling energy. The unit runs the equivalent of 606 hours a year at full output.

Chicago Heights against nearby cities

Of 225 Illinois cities here, Chicago Heights has the 192nd highest cooling load. The range runs from Fox Lake at 24,900 BTU/hr to Granite City at 36,000.

Where Chicago Heights's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Park Forest, 2.6 miles from the center of Chicago Heights at 710 ft above sea level. That is close enough that the station's summers are Chicago Heights's summers.

3 other cities use the same station and get the same climate inputs. The closest to Chicago Heights: Park Forest (3 mi away, 1 mi from the station), Matteson (6 mi away, 3.5 mi from the station), Richton Park (6 mi away, 3.4 mi from the station). Chicago Heights is farther from the station than 1 of them.

The sun over Chicago Heights in late July

At 41.51°N, the noon sun on 21 July stands 68.9° above the horizon over Chicago Heights and the day runs 14 h 34 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. Long days mean the house keeps gaining heat into the evening, well after the outdoor peak.

26,533 people live in Chicago Heights, the 84th largest of the 225 Illinois cities sized on this site. Coordinates used: 41.5107, -87.6341.

Chicago Heights AC sizing questions