Skylight Installation Cost 2026: $900–$2,500 Standard Fixed

Room-based recommendations: bathroom → venting skylight with moisture-resistant frame; kitchen → venting (heat and steam exhaust); bedroom → fixed (light without ventilation complexity, fewer failure points); living room over existing light well → fixed (no need to vent); dark interior space → tubular skylight (smallest roof penetration, fits between rafters). Roof-based constraints: pitched roofs over 14-degree slope → most standard skylight systems work well; low-pitch or flat roofs → require curb-mount skylights with special low-pitch flashing kits (+$200–$400); metal roofs → require metal roof-specific flashing kits. Minimum pitch for most standard skylights is 5/12 — check manufacturer specs before specifying.

A skylight providing 5% of floor area as glazing is the minimum for meaningful impact; 10% is the target for good daylighting. A 150 sq ft bedroom needs a 7.5–15 sq ft skylight (approximately 2.5×3 ft to 3×5 ft). Standard skylight sizes (Velux/FAKRO) include 14×46 in, 22×46 in, 30×46 in, 38×46 in — choose the nearest size above your calculated minimum. Multiple smaller skylights distribute light more evenly than one large skylight. Sizing too large creates glare and heat gain — triple-pane units with solar control glazing ($200–$400 upgrade) reduce summer heat gain significantly in sun-facing skylights.

Skylight installation is a roofing specialty — the critical work is flashing, not carpentry. Ask bidders: 'How many skylights have you installed in the past year?' and 'What flashing system do you use — integrated curb or step-flash-and-counter-flash?' Integrated factory flashing kits (Velux's EDL/EDW systems) are superior to site-built caulked flashing for pitched roofs. Also verify the contractor is using ICC (International code compliant) skylights — non-certified units sold online may not meet thermal or structural requirements. Check that any cutting of roof joists is accompanied by proper headers per the span table for the joist size.

When the skylight is over attic space above a finished ceiling, a light shaft (tunnel or splayed well) must be built to direct light to the room below. Splayed (angled) wells distribute light better than straight shafts — all four sides angled outward increases the light cone at ceiling level. Finish the well interior in white paint or drywall to maximize light reflection; a dark-painted well loses 30–50% of the light before it reaches the room. If the attic run is over 8 feet, a tubular skylight with a reflective tube is more efficient than a built light shaft for standard fixtures.

The roofing sealants and caulks used in skylight flashing degrade over 7–15 years. Most skylight leaks begin as a slow degradation of flashing sealant rather than sudden failure. Annual inspection: from the attic after heavy rain, check for any dampness around the skylight framing or light well. Exterior inspection: look for cracked caulk, lifting flashing edges, or debris accumulation in the skylight frame channel (clogs the drainage path and floods the sill). Budget $200–$400 per skylight for resealing at the 10-year mark; $400–$800 for reflashing at 15–20 years. Well-maintained skylights often last 25+ years without replacement.