Question 285120
250*2 for the winter=$500 for the winter.
But what does the fireplace insert cost including purchase delivery, installation and maintenance?
You work backwards starting with what you know and working towards the amount saved.

5*120=600 hours
33,000*600=bTU's per hour=19,000,000 btu's
190*100,000
190 therms*.70 per therm
$133
500-133=367 saved

Solar energy is cheap but the initial cost is very high. Is it he same with the insert?