What size AC for Fairfield, OH? 3 tons for 2,000 sq ft

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

3 tons central AC or heat pump, about 31,500 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 33% 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 763 square feet in this climate. For a single room, size by the room: 15.7 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Hamilton Butler County Regional Airport (2.4 mi away). Jul is the hottest month, averaging a high of 86.8°F and a low of 64.3°F, with about 28 days a year at 90°F or more. That gives a design temperature of 92°F against 75°F inside.

What it costs to run

About 1,482 kWh a year at SEER2 14.3, or roughly $279 at Ohio's average residential rate of 18.81¢ per kWh. Cooling runs 5 months of the year here.

What drives the load in Fairfield

Of the 31,500 BTU/hr, 12,240 comes through walls, roof and windows on a 92°F afternoon (39%), 13,000 is sun on the house (41%), 2,120 is four people and their appliances, and 4,100 is moisture the coil has to wring out of Fairfield'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 27,360 BTU/hr before the moisture allowance.

Other house sizes in Fairfield

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,400 BTU/hr; a 350 sq ft living room needs about 5,500 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 9,400 BTU/hr.

Month by month in Fairfield

Jul alone uses 31% of the year's cooling energy. The unit runs the equivalent of 674 hours a year at full output.

Fairfield against nearby cities

Of 176 Ohio cities here, Fairfield has the 2nd highest cooling load. The range runs from Conneaut at 24,100 BTU/hr to Hamilton at 31,500.

Where Fairfield's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Hamilton Butler County Regional Airport, 2.4 miles from the center of Fairfield at 606 ft above sea level. That is close enough that the station's summers are Fairfield's summers.

8 other cities use the same station and get the same climate inputs. The closest to Fairfield: Forest Park (3 mi away, 5.2 mi from the station), Hamilton (5 mi away, 3.3 mi from the station), Springdale (5 mi away, 5.4 mi from the station), Sharonville (8 mi away, 8.2 mi from the station), Trenton (11 mi away, 8.6 mi from the station). Fairfield sits closer to the station than any of them, so its numbers are the best measured of the group.

The sun over Fairfield in late July

At 39.33°N, the noon sun on 21 July stands 71.1° above the horizon over Fairfield and the day runs 14 h 22 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.

45,094 people live in Fairfield, the 26th largest of the 176 Ohio cities sized on this site. Coordinates used: 39.3314, -84.5427.

Fairfield AC sizing questions