What size AC for Provo, UT? 3.5 tons for 2,000 sq ft

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

3.5 tons central AC or heat pump, about 37,300 BTU/hr of load

Here the 20 BTU per square foot chart lands close: 3.5 tons against a load of 3.1 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 643 square feet in this climate. For a single room, size by the room: 18.7 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Provo Byu (0.3 mi away). Jul is the hottest month, averaging a high of 95.2°F and a low of 62.3°F, with about 74 days a year at 90°F or more. That gives a design temperature of 102°F against 75°F inside.

What it costs to run

About 1,572 kWh a year at SEER2 14.3, or roughly $207 at Utah's average residential rate of 13.19¢ per kWh. Cooling runs 5 months of the year here.

What drives the load in Provo

Of the 37,300 BTU/hr, 19,440 comes through walls, roof and windows on a 102°F afternoon (52%), 13,000 is sun on the house (35%), 2,120 is four people and their appliances, and 2,800 is moisture the coil has to wring out of Provo's summer air (8%).

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 34,560 BTU/hr before the moisture allowance.

Other house sizes in Provo

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,800 BTU/hr; a 350 sq ft living room needs about 6,500 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 11,200 BTU/hr.

Month by month in Provo

Jul alone uses 35% of the year's cooling energy. The unit runs the equivalent of 602 hours a year at full output.

Provo against nearby cities

Of 67 Utah cities here, Provo has the 28th highest cooling load. The range runs from Heber at 30,700 BTU/hr to St. George at 49,200.

Where Provo's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Provo Byu, 0.3 miles from the center of Provo at 4,570 ft above sea level. That is close enough that the station's summers are Provo's summers.

1 other city uses the same station and get the same climate inputs. The closest to Provo: Springville (6 mi away, 5.9 mi from the station). Provo sits closer to the station than any of them, so its numbers are the best measured of the group.

The sun over Provo in late July

At 40.25°N, the noon sun on 21 July stands 70.2° above the horizon over Provo and the day runs 14 h 27 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.

115,479 people live in Provo, the 4th largest of the 67 Utah cities sized on this site. Coordinates used: 40.2453, -111.6451.

Provo AC sizing questions