What size AC for Oakland, TN? 3.5 tons for 2,000 sq ft

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

3.5 tons central AC or heat pump, about 38,700 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.2 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 621 square feet in this climate. For a single room, size by the room: 19.3 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Collierville (12.5 mi away). Jul is the hottest month, averaging a high of 91.4°F and a low of 70.3°F, with about 63 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 2,800 kWh a year at SEER2 14.3, or roughly $386 at Tennessee's average residential rate of 13.8¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in Oakland

Of the 38,700 BTU/hr, 16,560 comes through walls, roof and windows on a 98°F afternoon (43%), 13,000 is sun on the house (34%), 2,120 is four people and their appliances, and 7,000 is moisture the coil has to wring out of Oakland'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 31,680 BTU/hr before the moisture allowance.

Other house sizes in Oakland

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,900 BTU/hr; a 350 sq ft living room needs about 6,800 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 11,600 BTU/hr.

Month by month in Oakland

Jul alone uses 26% of the year's cooling energy. The unit runs the equivalent of 1,036 hours a year at full output.

Oakland against nearby cities

Of 65 Tennessee cities here, Oakland has the 8th highest cooling load. The range runs from Crossville at 27,300 BTU/hr to Memphis at 41,200.

Where Oakland's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Collierville, 12.5 miles from the center of Oakland at 300 ft above sea level. That is close enough that the station's summers are Oakland's summers.

No other city in this set uses Collierville, so this sizing is Oakland's alone.

The sun over Oakland in late July

At 35.23°N, the noon sun on 21 July stands 75.2° above the horizon over Oakland and the day runs 14 h 02 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.

10,769 people live in Oakland, the 60th largest of the 65 Tennessee cities sized on this site. Coordinates used: 35.2261, -89.5382.

Oakland AC sizing questions