Choosing and using an inspection flashlight
The flashlight is the tool inspectors use most and think about least. A few specifications and techniques make a real difference to what you see.
Specs that matter
- Lumens is total light output. Bigger isn't always better: a very bright flood washes out detail and glares off white surfaces in tight spaces.
- Candela (beam intensity / throw) is how far the light reaches. You want throw for roof surfaces from the ground, the far end of an attic, or the back of a long crawlspace.
- Color rendering (CRI) describes how true colors look under the light. A high-CRI light (often listed as 90+) makes it easier to tell water staining from dirt, rust from paint, and scorching from shadow.
- Beam control: a light that switches between a focused spot and a wide flood covers both attics and electrical panels.
- Power: rechargeable lights with common cells (18650 or 21700) are standard; carry a spare cell or a charged second light.
Why carry two
A headlamp keeps both hands free on ladders, in attics and when removing panel covers. A handheld light lets you control the angle. Many inspectors carry both, which also means a dead battery never ends the job early in a crawlspace.
Raking light
Hold the light almost parallel to a surface rather than pointing it straight on. Shadows exaggerate texture, which reveals:
- Hairline cracks in drywall, plaster and foundations
- Bowing, waves or deflection in walls, ceilings and floors
- Patched areas and fresh paint over repairs
- Delamination and blistering on siding or roofing
Safety
- Use a light with a non-conductive body or keep it clear of exposed conductors when looking into an open panel.
- Secure handheld lights with a lanyard on roofs and ladders.
- Very bright lights can dazzle occupants, drivers or yourself off reflective surfaces; dim them for close work.