Solving Heat Transfer Equations for Rtot: Understanding Units and Formulas

[stunner5000pt]

Homework Statement

Consider a room in a house that has composite walls with some heat resistance R(tot). The total cross sectional area of the walls in 35 m^2. During winter, the temp outside is -5 deg C. Inside there is an electric heater emitting heat at a rate of 400 W so the room temperature is constant at 18 deg C. The room is occupied by 2 people each emitting 80 W each. What is the heat resistance of the walls in W?

Relevant Equations

$$\frac{dQ}{dt} = \frac{T_{out} - T_{in}}{R_{tot}}$$

I believe that just using the equation above should yield the following:

R_{tot} = \frac{18 -(-5)}{400 + 2(80)} = 0.041

but the units don't seem to match up... The units of the above answer are in K / W.

Is there a different formula i should be using?

Your help is appreciated!

 

[Lnewqban]

Homework Statement:: Consider a room in a house that has composite walls with some heat resistance R(tot). The total cross sectional area of the walls in 35 m^2. During winter, the temp outside is -5 deg C. Inside there is an electric heater emitting heat at a rate of 400 W so the room temperature is constant at 18 deg C. The room is occupied by 2 people each emitting 80 W each. What is the heat resistance of the walls in W?

Your relevant equation is missing the total area of the walls of the room.
Also, the question seems to be mixing rate of heat transfer (watts) and R-value of the composite walls.

Please, see:
https://www.engineeringtoolbox.com/overall-heat-transfer-coefficient-d_434.html

 

[haruspex]

the question seems to be mixing rate of heat transfer (watts) and R-value of the composite walls.

Yes, it should ask for $Km^2/W$.