Lighting guide · Updated August 21, 2026
A room-by-room LED upgrade plan that prioritizes payback
Replace the highest-use bulbs first, avoid compatibility mistakes and buy the right number of multipacks.
Start with an inventory
Walk the home after dark and list fixture location, bulb count, existing wattage, base, shape and estimated daily use. Photograph unusual bulbs and labels so you can compare them while shopping.
Mark dimmed, enclosed, wet-location and specialty fixtures. Those constraints matter more than saving a few cents per bulb.
Rank by annual energy
A porch lamp operating all night or a busy kitchen fixture can use far more annual energy than a higher-wattage lamp in a rarely opened storage area. Rank projects using watts multiplied by hours, not watts alone.
Replace a small high-use group first and verify brightness and color. Then use the results to standardize the next purchase instead of opening several incompatible multipacks.
Calculate complete project cost
Pack size creates leftover bulbs and affects real project cost. Divide the number of bulbs required by the pack size and round up before calculating total purchase cost.
Compare that cost with annual electricity savings to estimate simple payback. Keep spare matching lamps labeled by room so replacements preserve a consistent appearance.
Sources and editorial note
Kill The Watt uses primary government and program sources for technical reference points. Product compatibility, incentives and prices can change; verify them before purchase.