One grand lavatory for cool house (5)

I believe the answer is:

igloo

I'm a little stuck... Click here to teach me more about this clue!

'cool house' is the definition.
'igloo' can be an answer for 'house' (I've seen this before). I'm unsure of the 'cool' bit.

'one grand lavatory' is the wordplay.
'one' becomes 'I' (Roman numeral).
'grand' becomes 'g' (G is short for grand as in a thousand).
'lavatory' becomes 'loo' (loo is a kind of lavatory).
'i'+'g'+'loo'='IGLOO'

'for' is the link.

Can you help me to learn more?

(Other definitions for igloo that I've seen before include "home in the cold" , "Icy home for Eskimo" , "basic dwelling" , "Inuit hut" , "series of chilly blocks" .)

I've seen this clue in The Telegraph.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.