What size AC for Opa-locka, FL? 3.5 tons for 2,000 sq ft

What size AC a 2,000 sq ft house in Opa-locka needs

3.5 tons central AC or heat pump, about 41,200 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.4 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 583 square feet in this climate. For a single room, size by the room: 20.6 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Miami Opa Locka Airport (1.9 mi away). Aug is the hottest month, averaging a high of 91.1°F and a low of 76.8°F, with about 100 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 7,059 kWh a year at SEER2 14.3, or roughly $1,081 at Florida's average residential rate of 15.32¢ per kWh. Cooling runs 12 months of the year here.

What drives the load in Opa-locka

Of the 41,200 BTU/hr, 16,560 comes through walls, roof and windows on a 98°F afternoon (40%), 13,000 is sun on the house (32%), 2,120 is four people and their appliances, and 9,500 is moisture the coil has to wring out of Opa-locka'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 31,680 BTU/hr before the moisture allowance.

Other house sizes in Opa-locka

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 3,100 BTU/hr; a 350 sq ft living room needs about 7,200 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 12,400 BTU/hr.

Month by month in Opa-locka

Aug alone uses 13% of the year's cooling energy. The unit runs the equivalent of 2,451 hours a year at full output.

Opa-locka against nearby cities

Of 173 Florida cities here, Opa-locka has the 100th highest cooling load. The range runs from Miami Shores at 36,500 BTU/hr to Plant City at 44,900.

Where Opa-locka's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Miami Opa Locka Airport, 1.9 miles from the center of Opa-locka at 4 ft above sea level. That is close enough that the station's summers are Opa-locka's summers.

4 other cities use the same station and get the same climate inputs. The closest to Opa-locka: Hialeah (4 mi away, 3.1 mi from the station), Miami Lakes (4 mi away, 2.3 mi from the station), Hialeah Gardens (6 mi away, 4.9 mi from the station), Miramar (7 mi away, 5.5 mi from the station). Opa-locka sits closer to the station than any of them, so its numbers are the best measured of the group.

The sun over Opa-locka in late July

At 25.90°N, the noon sun on 21 July stands 84.5° above the horizon over Opa-locka and the day runs 13 h 23 min from sunrise to sunset. With the sun that close to overhead, the roof takes most of the heat at midday and the west wall takes the rest after 3 pm. Shorter days give the house a longer night to shed the day's heat.

16,507 people live in Opa-locka, the 141st largest of the 173 Florida cities sized on this site. Coordinates used: 25.9000, -80.2552.

Opa-locka AC sizing questions