What size AC for Meridian, MS? 4 tons for 2,000 sq ft

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

4 tons central AC or heat pump, about 43,100 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.6 tons. This is one of the climates the chart was written for.

If a contractor quotes you more than 4 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 557 square feet in this climate. For a single room, size by the room: 21.5 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Meridian Key Field (5 mi away). Jul is the hottest month, averaging a high of 93.3°F and a low of 72°F, with about 86 days a year at 90°F or more. That gives a design temperature of 100°F against 75°F inside.

What it costs to run

About 3,892 kWh a year at SEER2 14.3, or roughly $586 at Mississippi's average residential rate of 15.06¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in Meridian

Of the 43,100 BTU/hr, 18,000 comes through walls, roof and windows on a 100°F afternoon (42%), 13,000 is sun on the house (30%), 2,120 is four people and their appliances, and 9,900 is moisture the coil has to wring out of Meridian's summer air (23%).

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 33,120 BTU/hr before the moisture allowance.

Other house sizes in Meridian

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 3,200 BTU/hr; a 350 sq ft living room needs about 7,500 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 12,900 BTU/hr.

Month by month in Meridian

Jul alone uses 22% of the year's cooling energy. The unit runs the equivalent of 1,293 hours a year at full output.

Meridian against nearby cities

Of 41 Mississippi cities here, Meridian has the 2nd highest cooling load. The range runs from Brookhaven at 36,900 BTU/hr to Columbus at 44,000.

Where Meridian's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Meridian Key Field, 5 miles from the center of Meridian at 289 ft above sea level. That is close enough that the station's summers are Meridian's summers.

No other city in this set uses Meridian Key Field, so this sizing is Meridian's alone.

The sun over Meridian in late July

At 32.38°N, the noon sun on 21 July stands 78.0° above the horizon over Meridian and the day runs 13 h 49 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.

33,549 people live in Meridian, the 8th largest of the 41 Mississippi cities sized on this site. Coordinates used: 32.3842, -88.6894.

Meridian AC sizing questions