What size AC for Patchogue, NY? 2.5 tons for 2,000 sq ft

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

2.5 tons central AC or heat pump, about 27,300 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 54% 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 878 square feet in this climate. For a single room, size by the room: 13.7 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Islip-Li Macarthur Airport (4.8 mi away). Jul is the hottest month, averaging a high of 82.8°F and a low of 67.3°F, with about 8 days a year at 90°F or more. That gives a design temperature of 87°F against 75°F inside.

What it costs to run

About 1,230 kWh a year at SEER2 14.3, or roughly $360 at New York's average residential rate of 29.26¢ per kWh. Cooling runs 4 months of the year here.

What drives the load in Patchogue

Of the 27,300 BTU/hr, 8,640 comes through walls, roof and windows on a 87°F afternoon (32%), 13,000 is sun on the house (48%), 2,120 is four people and their appliances, and 3,600 is moisture the coil has to wring out of Patchogue's summer air (13%).

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 23,760 BTU/hr before the moisture allowance.

Other house sizes in Patchogue

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,100 BTU/hr; a 350 sq ft living room needs about 4,800 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 8,200 BTU/hr.

Month by month in Patchogue

Jul alone uses 35% of the year's cooling energy. The unit runs the equivalent of 644 hours a year at full output.

Patchogue against nearby cities

Of 90 New York cities here, Patchogue has the 39th highest cooling load. The range runs from Gloversville at 20,200 BTU/hr to Spring Valley at 33,400.

Where Patchogue's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Islip-Li Macarthur Airport, 4.8 miles from the center of Patchogue at 83 ft above sea level. That is close enough that the station's summers are Patchogue's summers.

1 other city uses the same station and get the same climate inputs. The closest to Patchogue: Lake Grove (8 mi away, 4.5 mi from the station). Patchogue is farther from the station than 1 of them.

The sun over Patchogue in late July

At 40.76°N, the noon sun on 21 July stands 69.6° above the horizon over Patchogue and the day runs 14 h 30 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.

12,447 people live in Patchogue, the 67th largest of the 90 New York cities sized on this site. Coordinates used: 40.7637, -73.0198.

Patchogue AC sizing questions