How spacing changes the look
At 12 inches, C9 bulbs sit close enough that from the street they read as a nearly continuous line. This is the fullest look and suits houses viewed from close range, detailed architecture and displays where brightness matters. At 15 inches, the line is still clearly defined but individual bulbs are easier to pick out. It is a very common roofline choice and uses a fifth fewer bulbs than 12 inch spacing. At 24 inches, bulbs are distinct points, which suits very long runs, fence lines, large commercial buildings seen from far away and budgets that need to cover a lot of footage.
Bulbs per 100 feet
| Spacing | Sockets per 100 ft | Bulb cost per 100 ft (500 case price) | Spool, listed price |
|---|---|---|---|
| 12 in | 100 | $63.80 | $275.00 |
| 15 in | 80 | $51.04 | $240.00 |
| 24 in | 50 | $31.90 | $289.00 |
Bulb costs above use the C9 LED bulb 500 case at $319.00, or $0.64 per bulb. Buying in 25 packs at $19.95 works out to $0.80 per bulb, so for small jobs the per-100-foot figure is a little higher. Clips follow the same count as sockets, one per socket.
Picking a spacing by situation
| Situation | Suggested spacing | Why |
|---|---|---|
| Single-story home, viewed from the sidewalk | 12 in | Close viewing distance shows gaps at wider spacing |
| Typical two-story roofline | 12 or 15 in | 15 in gives a defined line with fewer bulbs |
| Long ranch roofline or large lot | 15 in | Good coverage per bulb, still reads as a line |
| Commercial building or fence seen from a road | 15 or 24 in | Distance hides spacing; fewer bulbs over long footage |
| Walkway stakes | Match the roof or wider | Stakes are usually set every one to two feet |
Keep spacing consistent across a house
Mixing spacings on the same visual plane is noticeable. If the main roof is 12 inch, the garage roof next to it should be too. Different spacing is fine for separate features, such as a ridge line above the main eave or stakes along the walk. Buying all wire from one spool also keeps the socket positions predictable when a run wraps a corner.
Corners, peaks and ends
Because sockets are fixed on the wire, a run does not always end exactly at a corner. Installers handle this by starting each run at a visible anchor point, such as a peak or a corner, and letting the tail end fall where it will at the less visible end. If a socket lands right at a sharp corner, shift the run an inch or two rather than bending the socket hard around the edge. Because socket wire is live at every socket, put a bulb in every socket on a run; if a stretch should stay dark, end the run and bridge the gap with plain lamp cord instead.
Spacing in the prebuilt kits
Prebuilt kits are sold in both 12 and 15 inch spacing. For example, the 250 ft kit with 12 in spacing is listed at $435.00 and the 500 ft kit with 15 in spacing at $823.12. Each kit bundles bulbs, clips, stakes and plugs sized to its spool, so the spacing decision also decides which kit to choose.
Spools in every spacing. Christmas Light Supplier lists 1,000 ft C9 socket wire spools in 12, 15 and 24 inch spacing. Christmas Light Supplier ships every order free, the same day it is placed, with no order minimum and no added fees.