A vent-free gas fireplace operates without a chimney, flue or vent, so you can install one just about anywhere. They burn natural or propane gas, and most models require no electricity. Choose from vent-free gas fireplaces, stoves, fireplace inserts and gas logs. Modern vent-free gas fireplaces: are inexpensive and have low operating costs are 99 percent energy efficient and provide warmth during power outages are Design-Certified to the latest national safety standards (ANSI Z21.11.2) do not exceed 40,000 Btu/hr of heat output and are a source of pleasure for years to come. Pro - Flexible Installations Con - NYS recommends 4hrs per day