We usually cook twice a day, five days a week, the usage for previous months were at most 20ccf until November, it rocketed up to 120ccf and increased continuously to 216ccf. Is it because of the weather? But the usage is so high, and once I googled for that usage, we need to cook at least 10 hours each day! It is impossible, and we even left for vacation for 10 days during Jan, and the usage still got higher. The heat and hot water in our apt are from electricity. That usage is really confusing. The supplier is Philadelphia Gas Works. Looking forward to help. Thanks!