What size AC for Del Rio, TX? 4 tons for 2,000 sq ft

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

4 tons central AC or heat pump, about 51,500 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, which falls short here. On a design day the unit runs flat out and the house still drifts above 75°F by late afternoon.

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 466 square feet in this climate. For a single room, size by the room: 25.7 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Del Rio International Airport (2.7 mi away). Aug is the hottest month, averaging a high of 101°F and a low of 78.8°F, with about 141 days a year at 90°F or more. That gives a design temperature of 109°F against 75°F inside.

What it costs to run

About 6,650 kWh a year at SEER2 14.3, or roughly $1,066 at Texas's average residential rate of 16.03¢ per kWh. Cooling runs 9 months of the year here.

What drives the load in Del Rio

Of the 51,500 BTU/hr, 24,480 comes through walls, roof and windows on a 109°F afternoon (48%), 13,000 is sun on the house (25%), 2,120 is four people and their appliances, and 11,900 is moisture the coil has to wring out of Del Rio'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 39,600 BTU/hr before the moisture allowance.

Other house sizes in Del Rio

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 3,900 BTU/hr; a 350 sq ft living room needs about 9,000 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 15,400 BTU/hr.

Month by month in Del Rio

Aug alone uses 18% of the year's cooling energy. The unit runs the equivalent of 1,847 hours a year at full output.

Del Rio against nearby cities

Of 252 Texas cities here, Del Rio has the 2nd highest cooling load. The range runs from Levelland at 37,300 BTU/hr to Laredo at 51,500.

Where Del Rio's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Del Rio International Airport, 2.7 miles from the center of Del Rio at 1,003 ft above sea level. That is close enough that the station's summers are Del Rio's summers.

No other city in this set uses Del Rio International Airport, so this sizing is Del Rio's alone.

The sun over Del Rio in late July

At 29.37°N, the noon sun on 21 July stands 81.0° above the horizon over Del Rio and the day runs 13 h 37 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.

34,678 people live in Del Rio, the 107th largest of the 252 Texas cities sized on this site. Coordinates used: 29.3730, -100.8819.

Del Rio AC sizing questions