What size AC for Fountain, CO? 2.5 tons for 2,000 sq ft

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

2.5 tons central AC or heat pump, about 28,800 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 46% 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 2.5 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 834 square feet in this climate. For a single room, size by the room: 14.4 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Colorado Springs Municipal Airport (8.3 mi away). Jul is the hottest month, averaging a high of 86.5°F and a low of 58.2°F, with about 23 days a year at 90°F or more. That gives a design temperature of 91°F against 75°F inside.

What it costs to run

About 793 kWh a year at SEER2 14.3, or roughly $133 at Colorado's average residential rate of 16.8¢ per kWh. Cooling runs 4 months of the year here.

What drives the load in Fountain

Of the 28,800 BTU/hr, 11,520 comes through walls, roof and windows on a 91°F afternoon (40%), 13,000 is sun on the house (45%), 2,120 is four people and their appliances, and 2,100 is moisture the coil has to wring out of Fountain's summer air (7%).

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 26,640 BTU/hr before the moisture allowance.

Other house sizes in Fountain

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,200 BTU/hr; a 350 sq ft living room needs about 5,000 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 8,600 BTU/hr.

Month by month in Fountain

Jul alone uses 39% of the year's cooling energy. The unit runs the equivalent of 394 hours a year at full output.

Fountain against nearby cities

Of 53 Colorado cities here, Fountain has the 47th highest cooling load. The range runs from Boulder at 15,700 BTU/hr to Grand Junction at 36,500.

Where Fountain's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Colorado Springs Municipal Airport, 8.3 miles from the center of Fountain at 6,182 ft above sea level. That is close enough that the station's summers are Fountain's summers.

1 other city uses the same station and get the same climate inputs. The closest to Fountain: Colorado Springs (13 mi away, 5.6 mi from the station). Fountain is farther from the station than 1 of them.

The sun over Fountain in late July

At 38.69°N, the noon sun on 21 July stands 71.7° above the horizon over Fountain and the day runs 14 h 19 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.

29,457 people live in Fountain, the 28th largest of the 53 Colorado cities sized on this site. Coordinates used: 38.6890, -104.6806.

Fountain AC sizing questions