What size AC for Greeley, CO? 3 tons for 2,000 sq ft

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

3 tons central AC or heat pump, about 34,200 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 23% 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 701 square feet in this climate. For a single room, size by the room: 17.1 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Greeley Unc (3.9 mi away). Jul is the hottest month, averaging a high of 91.7°F and a low of 59.3°F, with about 58 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 1,168 kWh a year at SEER2 14.3, or roughly $196 at Colorado's average residential rate of 16.8¢ per kWh. Cooling runs 4 months of the year here.

What drives the load in Greeley

Of the 34,200 BTU/hr, 16,560 comes through walls, roof and windows on a 98°F afternoon (48%), 13,000 is sun on the house (38%), 2,120 is four people and their appliances, and 2,500 is moisture the coil has to wring out of Greeley's summer air (7%).

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 Greeley

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,600 BTU/hr; a 350 sq ft living room needs about 6,000 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 10,300 BTU/hr.

Month by month in Greeley

Jul alone uses 37% of the year's cooling energy. The unit runs the equivalent of 488 hours a year at full output.

Greeley against nearby cities

Of 53 Colorado cities here, Greeley has the 4th highest cooling load. The range runs from Boulder at 15,700 BTU/hr to Grand Junction at 36,500.

Where Greeley's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Greeley Unc, 3.9 miles from the center of Greeley at 4,715 ft above sea level. That is close enough that the station's summers are Greeley's summers.

1 other city uses the same station and get the same climate inputs. The closest to Greeley: Evans (5 mi away, 4.4 mi from the station). Greeley sits closer to the station than any of them, so its numbers are the best measured of the group.

The sun over Greeley in late July

At 40.41°N, the noon sun on 21 July stands 70.0° above the horizon over Greeley and the day runs 14 h 28 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.

114,363 people live in Greeley, the 9th largest of the 53 Colorado cities sized on this site. Coordinates used: 40.4140, -104.7710.

Greeley AC sizing questions