Possible Clues:

• Floor of a fireplace
• Fireplace, something cold or warm, then hot
• Hard world where things can get very hot
• Home centre close to hospital
• Symbol of home planet attached to horoscope's heading
• Hydrogen planet that could be considered home!
• Open fire on what is 16 down at first
• Home, metonymically
• Fireplace area
• Part of home that's the central part, and hot