Cheat sheet: Four simple products to cool homes naturally

(i) Crack sealant: Heat-resistant caulk can close off gaps in walls that let in hot air. 

(ii) Blackout curtains: Thermal-lined cloth provides an insulating layer on windows.

(iii) Reflective foil: Sheets of reflective material reduce absorption of heat on roofs. 

(iv) Draft stoppers: Block out warm air by placing "door snakes" along openings.