Note though that the sulfur smell from hot water in Iceland is only a thing in certain areas in Reykjavik, and perhaps some locations around the island.
This is due to the hot water in those regions literally being pumped out of the ground and into homes, and on a completely separate plumbing system. Majority of other areas use heat exchangers with pristine cold water, thus no smell nor taste is transferred.
So if you are staying in any other municipality in the capitol, you can use the hot water in cooking directly without boiling cold water. It's the same.
This is due to the hot water in those regions literally being pumped out of the ground and into homes, and on a completely separate plumbing system. Majority of other areas use heat exchangers with pristine cold water, thus no smell nor taste is transferred.
So if you are staying in any other municipality in the capitol, you can use the hot water in cooking directly without boiling cold water. It's the same.