VELUX ZTL Electric Light Kit

The ZTL Electric Light Kit transforms VELUX sun tunnels into 24/7 light sources by adding hardwired electric illumination capability. Designed to provide illumination at night or on dark days when natural daylight is not available, the kit retrofits into existing sun tunnel installations without major ceiling work.

The quick and easy installation retrofit design makes this kit particularly valuable for Montana contractors dealing with long winter nights and limited daylight hours. The kit installs in minutes (excluding electrical wiring to the switch), mounting inside the tunnel just above the diffuser where it remains hidden from view.

Installation Requirements and Compatibility

The ZTL kit retrofits all VELUX sun tunnel models including TGR, THR, TCR, TMR, TGF, TMF, TLR, TZR, TZRQ, and TSR. Compatible with both rigid and flexible Sun Tunnel tubes, the kit works across the full range of tunnel diameters from 10 inches to 22 inches.

Installation requires standard electrical work. The kit requires hardwiring to a standard 120V power source and connection to a wall switch for control. While the physical mounting takes minutes, the electrical wiring to the switch adds time depending on the run distance and complexity.

The installation process follows these steps:

• Disconnect power, remove diffuser, mount the kit above the diffuser location, wire to the electrical source, insert GU24 bulb (not included), replace diffuser

Electrical Specifications and Bulb Requirements

The kit’s electrical requirements vary by tunnel size, and contractors need to match bulb wattage carefully:

Tunnel Size	Bulb Wattage	Bulb Type
10-inch	9W - 13W CFL	Compact Fluorescent
14-inch	13W - 26W CFL	Compact Fluorescent
22-inch	Up to 26W CFL	Compact Fluorescent
10-inch (modern)	8W - 15W LED	LED recommended

All sizes require GU24 base bulbs — not standard Edison screw-base. This catches some contractors off guard. Some users find the GU24 bulb requirement slightly restrictive compared to standard Edison bases, but the restriction serves a critical purpose. Do not use incandescent bulbs due to heat accumulation risks.

The GU24 requirement prevents homeowners from installing high-wattage incandescent bulbs that could overheat in the confined tunnel space. For contractors, this means stocking GU24 CFL or LED bulbs specifically for these installations.

Professional Considerations

UL-listed components ensure code compliance across jurisdictions. The kit comes with VELUX’s standard 5-year warranty covering defects in manufacturing or materials, matching their accessory warranty period.

With an average rating of 4.4 stars across 32 reviews, field performance proves solid. Users appreciate the ability to use the sun tunnel as a standard light at night. The kit particularly suits residential spaces including bathrooms, closets, hallways, and basements, as well as commercial spaces like offices or retail areas requiring supplemental light.

For renovations, the kit allows adding light to existing Sun Tunnel installations without major ceiling work. This retrofit capability matters in Montana’s older housing stock where adding conventional ceiling fixtures might require extensive drywall and electrical work.

The kit does have limitations compared to VELUX’s solar-powered options. Unlike the ISL Solar Night Light that operates automatically with dusk-to-dawn sensors and requires no wiring, the ZTL needs hardwired electrical connections and manual switch control. The trade-off delivers constant, reliable power without depending on solar charging — critical during Montana’s overcast winter months.

Frequently Asked Questions

Q: What size bulbs can I use with the VELUX ZTL Electric Light Kit?

The VELUX ZTL requires GU24 base bulbs with wattage varying by tunnel size: 9-13W CFL for 10-inch tunnels, 13-26W CFL for 14-inch tunnels, and up to 26W CFL for 22-inch tunnels. Modern LED alternatives range from 8-15W, but incandescent bulbs are prohibited due to heat accumulation risks in the confined tunnel space.

Q: Will the VELUX ZTL kit work with my existing sun tunnel?

The VELUX ZTL Electric Light Kit is compatible with all VELUX sun tunnel models including TGR, THR, TCR, TMR, TGF, TMF, TLR, TZR, TZRQ, and TSR in 10-inch, 14-inch, and 22-inch diameters. The kit works with both rigid and flexible tunnel tubes and retrofits into existing installations without major ceiling modifications.

Q: Does the VELUX ZTL kit require professional electrical installation?

The VELUX ZTL kit requires hardwiring to a standard 120V AC power source and connection to a wall switch, which typically necessitates a licensed electrician. While the physical mounting takes just minutes and follows a simple six-step process, the electrical wiring must meet local code requirements for permanent fixtures.

Q: What’s included with the VELUX ZTL Electric Light Kit?

The VELUX ZTL kit includes light fixture mounting hardware, wiring harness, GU24 connector, and installation instructions. The kit does not include the GU24 bulb, wall switch, or external wiring from the electrical source to the tunnel — these must be purchased separately.

Q: How does the VELUX ZTL compare to their solar-powered lighting option?

The VELUX ZTL Electric Light Kit provides constant hardwired power controlled by a wall switch, while the ISL Solar Night Light operates automatically with dusk-to-dawn sensors using rechargeable batteries. The ZTL requires electrical wiring during installation but delivers reliable power year-round, whereas the ISL installs tool-free but depends on solar charging capability.

Q: What warranty coverage does VELUX provide for the ZTL kit?

VELUX covers the ZTL Electric Light Kit with their standard 5-year warranty for accessories and controls, protecting against defects in manufacturing or materials. All components are UL-listed for safety compliance, with the kit earning a 4.4-star average rating from 32 user reviews.