correct size unit

[nick varie]

We are trying to find the correct size unit for new construction of our guest house. The house is approximately 1600 sq feet under air. Two stories with only two windows on each floor. The first floor has ten foot ceilings. The second floor has 8 ft ceilings in the center for a span of about 12 feet going down to 4ft at the side walls. We would prefer to use one unit. We have been told 3.5 ton to 5 tons. Please help.
thanks.

[ngore22]

Ask your contractor to show you the Load Calculation they did to determine the size unit the house needed. They should have a load calculation based on manual J

[dash]

You can do your own Manual J load calculation on this site for a fee,click here; http://hvaccomputer.com/talkref.asp


Your HVAC contractor should do it,but many can't or won't.

Equally important are Manuals S ,to select equipment size,and Manual D to size the ducts.

All the Manuals are from http://www.acca.org

[dan sw fl]

Originally posted by nick varie

The house is approximately 1600 sq feet under air.

Two stories with only two windows on each floor.

The first floor has ten foot ceilings.
The second floor has 8 ft ceilings in the center for a span of about 12 feet going down to 4ft at the side walls. We would prefer to use one unit.

We have been told 3.5 ton to 5 tons. Please help.

< ~ 3 Tons & ~ 1,200 CFM might be appropriate if you do not live in AZ or TX ,,,
and more likely 2.5 ton and 1,000 CFM for northern U.S.
or if ducts & house are well sealed

Location ?
Ceiling Insulation R-30 ?

Outside Design Temp 94' F ?
Inside Temp desired 76'F with < 50% R.H.

4 windows = < 70 Sq. Ft total