Gas fireplaces: For gas fireplaces with a standing pilot light (one that's on all the time), make sure your pilot is serviced regularly. Fireplaces with no pilot light, or that are on only while something is burning, can be serviced less often. "All unvented gas fireplaces and gas logs built in the last two decades have had an Oxygen Depletion Sensor pilot," says Parks. "This should be cleaned every year to keep the system from becoming more sensitive and causing annoying shutdowns." A can of compressed air can be used to clean out the pilot orifice (the opening where the gas comes out). If your system is 5 or more years old, you may need to call a specialist.