Habanero peppers vary in heat based on their type. The New Mexico State University Chile Pepper Institute has published a list of the top ten hottest peppers. The Chocolate Habanero ranks sixth, the Red Savina Habanero ranks seventh and the Orange Habanero comes in as ninth.
The spicy heat of chile peppers is measured on the Scoville Scale in Scoville Heat Units. To determine a chile pepper's heat, human tasters test chile samples repeatedly. The samples are diluted between tests, with each dilution comprising one Scoville Heat Unit. This process is repeated until the heat can no longer be perceived.