This is an appliance that is used seasonally. If you use your fireplace for only three months of the year, you would enter "3" in the first field and select "months/year" in the second field. The monthly and yearly cost will be automatically calculated for you.
Please note: For the selection "months/year", our calculation is based on the assumption that the average usage is 20 hours per month. If you want to figure out a more accurate estimate, please select a different option such as hours/day, hours/week, or hours/month. This will give you the monthly cost and you can multiply it by the number of months that you will be using this appliance to get the yearly cost.