What size AC for Clearwater, FL? 3.5 tons for 2,000 sq ft

What size AC a 2,000 sq ft house in Clearwater 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 St. Petersburg Clearwater International (7 mi away). Aug is the hottest month, averaging a high of 90.6°F and a low of 76.3°F, with about 94 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 5,814 kWh a year at SEER2 14.3, or roughly $891 at Florida's average residential rate of 15.32¢ per kWh. Cooling runs 12 months of the year here.

What drives the load in Clearwater

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 Clearwater'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 Clearwater

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 Clearwater

Aug alone uses 15% of the year's cooling energy. The unit runs the equivalent of 2,019 hours a year at full output.

Clearwater against nearby cities

Of 173 Florida cities here, Clearwater has the 77th highest cooling load. The range runs from Miami Shores at 36,500 BTU/hr to Plant City at 44,900.

Where Clearwater's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is St. Petersburg Clearwater International, 7 miles from the center of Clearwater at 0 ft above sea level. That is close enough that the station's summers are Clearwater's summers.

6 other cities use the same station and get the same climate inputs. The closest to Clearwater: Dunedin (4 mi away, 10.9 mi from the station), Safety Harbor (5 mi away, 6.5 mi from the station), Largo (5 mi away, 5.4 mi from the station), Oldsmar (8 mi away, 9.4 mi from the station), Pinellas Park (9 mi away, 4 mi from the station). Clearwater is farther from the station than 3 of them.

The sun over Clearwater in late July

At 27.98°N, the noon sun on 21 July stands 82.4° above the horizon over Clearwater and the day runs 13 h 31 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.

116,811 people live in Clearwater, the 20th largest of the 173 Florida cities sized on this site. Coordinates used: 27.9794, -82.7713.

Clearwater AC sizing questions