Heat calculation

[preetnep]

Can someone  help.
I have a room of 30ft x 30ft. R values of material are 20,10,5. Outdoor temp is 80 f and indoor is 100' . How much heat has to be removed from room.

As per my understanding
Q=a.u.delta t
= 90 × .03 × 20
=54.
Is it btu h ?

[walker]

whats the height of the wall?

[preetnep]

It doesn't say height of wall . It's one of practice questions for 313D exam

[walker]

well first off a= L x W, in your case would be 30 x 30 = 900 not 90 as you've put in your equation.

[preetnep]

Yes . It should be 900.
I don't have answer so I want to know if it's the right way to calculate btuh or I m missing some thing.

U is 1/R
Where R = r1+r2+r3

[walker]

then you're looking at removing 540btu