What size bug zapper do I need for my yard?

Coverage claims scale with bulb wattage. Across the listings, a 15W/half-acre unit suits a small patio, a 40W unit is rated to roughly 1 acre, and 80W–120W models claim 1.5 to 2 acres. Reviewers and community posts note that a single unit rarely 'clears' a large property, and some run two units on opposite sides of a patio for best coverage.