Cold house with one good lavatory (5)
I believe the answer is:
igloo
'cold house' is the definition.
'igloo' can be an answer for 'house' (I've seen this before). I'm not sure about the 'cold' bit.
'with one good lavatory' is the wordplay.
'with' means one lot of letters go next to another.
'one' becomes 'i' (Roman numeral).
'good' becomes 'g' (abbreviation).
'lavatory' becomes 'loo' (loo is a kind of lavatory).
'i'+'g' is 'ig'.
'ig'+'loo'='IGLOO'
Can you help me to learn more?
(Other definitions for igloo that I've seen before include "Inuit ice house" , "Traditional Inuit house" , "native dwelling" , "Inuit residence" , "Home made of blocks of snow" .)