What size AC for Tuscaloosa, AL? 3.5 tons for 2,000 sq ft

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

3.5 tons central AC or heat pump, about 39,500 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.3 tons. This is one of the climates the chart was written for.

If a contractor quotes you more than 3.5 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 607 square feet in this climate. For a single room, size by the room: 19.8 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Northport 2 S (3.9 mi away). Jul is the hottest month, averaging a high of 92.2°F and a low of 71.2°F, with about 89 days a year at 90°F or more. That gives a design temperature of 99°F against 75°F inside.

What it costs to run

About 3,260 kWh a year at SEER2 14.3, or roughly $538 at Alabama's average residential rate of 16.51¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in Tuscaloosa

Of the 39,500 BTU/hr, 17,280 comes through walls, roof and windows on a 99°F afternoon (44%), 13,000 is sun on the house (33%), 2,120 is four people and their appliances, and 7,100 is moisture the coil has to wring out of Tuscaloosa's summer air (18%).

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 32,400 BTU/hr before the moisture allowance.

Other house sizes in Tuscaloosa

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 3,000 BTU/hr; a 350 sq ft living room needs about 6,900 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 11,900 BTU/hr.

Month by month in Tuscaloosa

Jul alone uses 23% of the year's cooling energy. The unit runs the equivalent of 1,180 hours a year at full output.

Tuscaloosa against nearby cities

Of 66 Alabama cities here, Tuscaloosa has the 24th highest cooling load. The range runs from Boaz at 30,600 BTU/hr to Montgomery at 44,000.

Where Tuscaloosa's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Northport 2 S, 3.9 miles from the center of Tuscaloosa at 150 ft above sea level. That is close enough that the station's summers are Tuscaloosa's summers.

1 other city uses the same station and get the same climate inputs. The closest to Tuscaloosa: Northport (4 mi away, 3.1 mi from the station). Tuscaloosa is farther from the station than 1 of them.

The sun over Tuscaloosa in late July

At 33.23°N, the noon sun on 21 July stands 77.2° above the horizon over Tuscaloosa and the day runs 13 h 53 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.

114,288 people live in Tuscaloosa, the 5th largest of the 66 Alabama cities sized on this site. Coordinates used: 33.2344, -87.5283.

Tuscaloosa AC sizing questions