It would be, 1.000. Hope that helps :)
Answer:
=118.8 K= 154.2°C
Explanation:
COP_max of carnot heat pump= 
where T_H and T_C are temperatures of hot and cold reservoirs
Also COP=
in the question 
⇒
heat is added directly to be as efficient as via heat pump

and T_H= 24° C= 297 K

on calculating the above equation we get
=118.8 K
the outdoor temperature for efficient addition of heat to interior of home
=118.8 K= 154.2°C
Heat!!!!!!!!!!!!!!!!!!! sorry about the exclamation marks but it wont let me post in less it has more than 20 characteristics