permanent heat sources

[Gordrenn Higgler]

Looking for something that would be useful for heating a castle
Since there's no spell that works with permanency for creating a heat source, I was hoping there might be something that could be created with Polymorph Any Object that would work and have a permanent duration

Only other thing I could see as a sure fire way is turning a wall of iron into wood and using it for firewood :)

[Bakenellan]

Wall of fire can be made permanent.

[Gisher]

If you don't mind switching them out every 8 hours, 3 campfire beads will keep your fireplace operating 24/7.

[Mysterious Stranger]

You could try calling a fire elemental and just keeping it around. Lesser planar ally or lesser planar binding may work.

If you want to keep warm then hallow with a endure element as the fixed spell will work. It only covers a 40 foot radius so you may need more than one. The nice thing about this is it works for both heat and cold. It does need to be renewed every year though so is not really permanent.

[Franko a]

I've thought heat metal and water would work.