On 5/28/2017 7:22 PM, trader_4 wrote:
On Sunday, May 28, 2017 at 5:14:05 PM UTC-4, Vld5491 wrote:
replying to trader_4, Vld5491 wrote:
We decided to upgrade from 3t to 4t because we have a townhouse with 1708
sqft.

3 tons should be plenty for 1700 so ft.


I have 2100 sq. ft. and cool it with 2 1/2 ton. Of course, conditions
vary and the contractor should have run the manual J calculations.
http://www.loadcalc.net/
http://www.wikihow.com/Calculate-BTU...g_Capacity_sub


We had to close 3 registers/vents to get out 3 bedrooms to get to
comfortable level.

Probably because something is wrong with the system, design, etc.



Plus the contractor says in every 400 sq ft requires 1
tonage.

That contractor is an idiot. Following that logic, a 2500 so ft house needs 6 tons? A 3000 so ft needs 7+ tons? You can do a manual J calculation which factors in size, insulation,windows, exposure, climate to get a correct number. That's why you have a system that is short cycling.


Agree on the idiot part.. Looks like the OP will have a cold muggy
summer.