Wood fireplaces come in several types: open masonry, inserts, stoves, and built-in units for new homes. They are classified as either EPA certified for efficient heating or decorative for ambiance only. Technologies include regular, catalytic, non-catalytic, and hybrid combustion, each offering varying levels of efficiency and emissions. High-end models are typically large hybrid units, while inserts are more affordable. Rebates may be available for upgrading to cleaner-burning models.