What size AC for El Dorado, AR? 3.5 tons for 2,000 sq ft

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

3.5 tons central AC or heat pump, about 41,300 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 581 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 El Dorado Goodwin Field (8.7 mi away). Jul is the hottest month, averaging a high of 93.6°F and a low of 71.3°F, with about 88 days a year at 90°F or more. That gives a design temperature of 101°F against 75°F inside.

What it costs to run

About 3,366 kWh a year at SEER2 14.3, or roughly $462 at Arkansas's average residential rate of 13.74¢ per kWh. Cooling runs 7 months of the year here.

What drives the load in El Dorado

Of the 41,300 BTU/hr, 18,720 comes through walls, roof and windows on a 101°F afternoon (45%), 13,000 is sun on the house (31%), 2,120 is four people and their appliances, and 7,400 is moisture the coil has to wring out of El Dorado'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 33,840 BTU/hr before the moisture allowance.

Other house sizes in El Dorado

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 El Dorado

Jul alone uses 24% of the year's cooling energy. The unit runs the equivalent of 1,166 hours a year at full output.

El Dorado against nearby cities

Of 39 Arkansas cities here, El Dorado has the 6th highest cooling load. The range runs from Harrison at 33,100 BTU/hr to Fort Smith at 44,000.

Where El Dorado's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is El Dorado Goodwin Field, 8.7 miles from the center of El Dorado at 256 ft above sea level. That is close enough that the station's summers are El Dorado's summers.

No other city in this set uses El Dorado Goodwin Field, so this sizing is El Dorado's alone.

The sun over El Dorado in late July

At 33.22°N, the noon sun on 21 July stands 77.2° above the horizon over El Dorado and the day runs 13 h 53 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.

16,657 people live in El Dorado, the 27th largest of the 39 Arkansas cities sized on this site. Coordinates used: 33.2190, -92.6641.

El Dorado AC sizing questions