What size AC for Miami Shores, FL? 3 tons for 2,000 sq ft

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

3 tons central AC or heat pump, about 36,500 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 15% 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 657 square feet in this climate. For a single room, size by the room: 18.3 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Miami Beach (5 mi away). Aug is the hottest month, averaging a high of 88.1°F and a low of 78.1°F, with about 30 days a year at 90°F or more. That gives a design temperature of 93°F against 75°F inside.

What it costs to run

About 6,577 kWh a year at SEER2 14.3, or roughly $1,008 at Florida's average residential rate of 15.32¢ per kWh. Cooling runs 12 months of the year here.

What drives the load in Miami Shores

Of the 36,500 BTU/hr, 12,960 comes through walls, roof and windows on a 93°F afternoon (36%), 13,000 is sun on the house (36%), 2,120 is four people and their appliances, and 8,400 is moisture the coil has to wring out of Miami Shores's summer air (23%).

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 28,080 BTU/hr before the moisture allowance.

Other house sizes in Miami Shores

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,700 BTU/hr; a 350 sq ft living room needs about 6,400 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 11,000 BTU/hr.

Month by month in Miami Shores

Aug alone uses 13% of the year's cooling energy. The unit runs the equivalent of 2,576 hours a year at full output.

Miami Shores against nearby cities

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

Where Miami Shores's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Miami Beach, 5 miles from the center of Miami Shores at 8 ft above sea level. That is close enough that the station's summers are Miami Shores's summers.

3 other cities use the same station and get the same climate inputs. The closest to Miami Shores: North Miami (2 mi away, 6.9 mi from the station), Miami Beach (4 mi away, 1 mi from the station), Miami (7 mi away, 5.2 mi from the station). Miami Shores is farther from the station than 1 of them.

The sun over Miami Shores in late July

At 25.87°N, the noon sun on 21 July stands 84.5° above the horizon over Miami Shores 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.

11,917 people live in Miami Shores, the 160th largest of the 173 Florida cities sized on this site. Coordinates used: 25.8670, -80.1783.

Miami Shores AC sizing questions