Add an “artificial skylight” to any room for $50! Bring natural-ish sunlight to any room. Even works for renters and apartment dwellers!

Background:

Skylights (or light pipes) are a great way to get natural sunlight indoors.

Unfortunately, installation is moderately complicated and is infeasible for renters and high-rise dwellers.

Also, skylights only provide light during the daytime (unsurprisingly).

Proposal:

Thanks to LED lighting, it is possible to create a convincing “artificial skylight” (Figure 1) for 50 American dollars (~4 hours of of 2021 minimum wage).

Fig. 1: The final result: depending on your perspective, it’s either a HIGH CLASS bespoke lighting solution, OR it’s a trash can with a light bulb inside (and a monitor arm VESA mount on the outside).

The actual application of this light looks surprisingly convincing: in a dark environment, relatively little wattage is required to simulate sunlight.

Fig. 2: Totally acceptable results: there’s a “fake skylight” at the top of these stairs in this view taken at midnight. The bulb used here is a 3300 lumen (5000 kelvin color temperature) LED

The motivation for this DYI “skylight” is cost: commercial versions of this system are substantially nicer—and 1000x more expensive (Figure 3).

Fig. 3: Above: this 2021 Google search result displays an estimate of nearly $70,000 for a professionally-installed system. Still, these state-of-the-art “skylights” look extremely convincing in these videos.

Materials / Build Process:

For prototyping, it’s easy to use a cardboard box (instead of a high-class trash can) with dimensions at least 8″ x 10″ x 20” (it’s also OK if it’s bigger in any dimension). From the outside, this will look like Figure 4.

Fig. 4: The cardboard box prototype exterior (see Fig. 5 for the interior).
Fig. 5: …and like this on the inside. See the following list of components.

The specific items in Figure 5:

  • A: Extension cord (~$5.00).
  • B: Light socket to wall outlet adapter (screw the light bulb into this, then plug it into the extension cord) (~$5.00).
  • C: A 3000+ lumen directional floodlight (~$30.00).
    • This means a ~30 Watt LED (or “≥250 Watt incandescent-equivalent”) bulb.
    • I did not get good results from “corn cob”-style LED bulbs. The widely-spread-out LEDs create a weird and irregular final image.
  • D: A cheap plastic magnifying sheet / “Fresnel lens” (~$10). This will be the “light” from the viewer’s perspective, so try to make it at least 8 x 10 inches!
    • I cut a hole in the front of the box, then used Scotch tape to attach the lens. Quality workmanship!

I had to move the light bulb back and forth a bit until I found a good focus distance.

Note about burning your house down:

Don’t! Surprisingly, these bulbs are passively cooled (i.e. there’s no fan). A 30W LED should normally not get especially hot, but you should double check this.

Fig. 6: The result from just this 3000-lumen light is very convincing to the not-especially-nitpicky consumer. This could definitely be a photo of a room illuminated by an actual skylight!

Fig. 7: For a truly regal solution, use a VESA mount monitor arm to attach the skylight-box high up on a wall.

Conclusion:

This skylight has turned out to be extremely pleasant in practice! It’s especially convincing if there is still some external light (e.g in the late afternoon / twilight hours).

Psychologically speaking, it’s almost like getting two extra hours of full sunlight every day!

PROS: Only 1% as expensive as a professional “artificial skylight” solution!

CONS: Might also only look 1% as good as a professional “artificial skylight” solution!