What size AC for Barnstable Town, MA? 2 tons for 2,000 sq ft

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

2 tons central AC or heat pump, about 25,700 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 64% 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 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 935 square feet in this climate. For a single room, size by the room: 12.8 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Hyannis Barnstable Municipal Airport (4.6 mi away). Jul is the hottest month, averaging a high of 80.8°F and a low of 64.8°F, with about 2 days a year at 90°F or more. That gives a design temperature of 85°F against 75°F inside.

What it costs to run

About 878 kWh a year at SEER2 14.3, or roughly $265 at Massachusetts's average residential rate of 30.19¢ per kWh. Cooling runs 4 months of the year here.

What drives the load in Barnstable Town

Of the 25,700 BTU/hr, 7,200 comes through walls, roof and windows on a 85°F afternoon (28%), 13,000 is sun on the house (51%), 2,120 is four people and their appliances, and 3,300 is moisture the coil has to wring out of Barnstable Town'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 22,320 BTU/hr before the moisture allowance.

Other house sizes in Barnstable Town

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 1,900 BTU/hr; a 350 sq ft living room needs about 4,500 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 7,700 BTU/hr.

Month by month in Barnstable Town

Jul alone uses 39% of the year's cooling energy. The unit runs the equivalent of 489 hours a year at full output.

Barnstable Town against nearby cities

Of 58 Massachusetts cities here, Barnstable Town has the 43rd highest cooling load. The range runs from Pittsfield at 22,600 BTU/hr to Framingham at 28,000.

Where Barnstable Town's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Hyannis Barnstable Municipal Airport, 4.6 miles from the center of Barnstable Town at 37 ft above sea level. That is close enough that the station's summers are Barnstable Town's summers.

No other city in this set uses Hyannis Barnstable Municipal Airport, so this sizing is Barnstable Town's alone.

The sun over Barnstable Town in late July

At 41.66°N, the noon sun on 21 July stands 68.7° above the horizon over Barnstable Town and the day runs 14 h 35 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. Long days mean the house keeps gaining heat into the evening, well after the outdoor peak.

49,831 people live in Barnstable Town, the 26th largest of the 58 Massachusetts cities sized on this site. Coordinates used: 41.6615, -70.3570.

Barnstable Town AC sizing questions