Question about thermodynamics (heat loss)

[vande060]

Homework Statement

Suppose that you own a poorly insulated small house, with outside walls l = 0.25m thick, total outer wall plus roof
surface area 210m^2 (about 1992 ft^2) and your walls have a thermal conductivity of 1.3 W/m·K (limestone). Calculate
how much power your air conditioner will require to keep your house at 293K when the outside temperature is 308K.

Homework Equations

maybe dQ/dt = ak(dT/dx)

The Attempt at a Solution

i think

(1.3)(210)(15/.25) = 16380 W

but what do you think? have i made errors?

 

[blacknovember]

This is a classic 'Carnot refridgerator' problem...

EDIT: Maybe this will help.

http://www.ohio.edu/people/piccard/phys202/carnot/carnot.html

Find an expression for the heat leakage first(through the walls).