Specifications & Testing Data
| Frame material | Acrylic or glass roof collector, highly reflective aluminum rigid tube (or flexible ducting), frosted acrylic ceiling diffuser |
|---|---|
| Design pressure (DP) rating | Tested to NAFS (AAMA/WDMA/CSA 101/I.S.2/A440); rigid tubes carry a 20-year tube warranty |
| AAMA performance class | Tubular daylighting device — no NFRC U-factor is published for the complete unit; VELUX offers an insulating Energy Kit for the diffuser |
| Glass options | Acrylic dome (pitched or low-profile), Flat tempered glass collector (TLR), Impact dome, Fire-resistant diamond-wire glass (TZR series), Frosted, Prismatic, Micro Fresnel or Triple Wave diffusers |
| Available styles | TMR 010/014 rigid, pitched dome, TGR 010/014/022 rigid, low-profile dome, TMF 014 flexible, pitched dome, TGF 014/022 flexible, low-profile dome, TLR 014 rigid, flat glass, TCR 014 rigid, curb-mount for 0–60° |
What the Sun Tunnel Actually Is
Strip away the branding and a Sun Tunnel is three parts: a clear collector on the roof, a reflective tube through the attic, and a diffuser in the ceiling that looks like a 15-inch recessed light. Sunlight bounces down the tube and spreads across the room. There is no light shaft to frame, no drywall to hang, and — because the tube slips between existing rafters or truss chords — no structural change to the roof.
VELUX builds the tube two ways. The rigid models (TMR and TGR) use polished aluminum sections that VELUX rates at 99.99% reflectivity, snapped together without screws. The flexible models (TMF and TGF) use a bendable duct for attics where something is in the way. The letters tell you the flashing: M models carry a pitched, angled flashing that tilts the dome toward the sky, gathering more light through the day and on north-facing roofs; G models carry a low-profile flashing that lies parallel to the shingles for a quieter roofline.
Two diameters cover residential work: 10-inch (TMR/TGR 010, ceiling opening 11¼") and 14-inch (ceiling opening 15¼"); a 22-inch TGR exists for large rooms. Three specialty rigid units round out the line: the TLR 014 with a flat tempered-glass collector for HOAs that prohibit domes, the TCR 014 on a one-piece metal curb for flat and low-slope roofs (0–60°), and the fire-rated TZR family with diamond-wire glass for wildland-interface lots.
The Numbers That Matter
Standard-pitch Sun Tunnels flash to roofs from 14° to 60° (3:12 to 20:12); the TCR curb model goes flat. Each kit ships with a starting length of tube — 4 feet in the rigid models, 8 feet in the flexible ones — and VELUX publishes a maximum recommended run for each:
| Model | Tube | Diameter | Tube in kit | Max recommended run |
|---|---|---|---|---|
| TMR / TGR 010 | Rigid | 10" | 4 ft | 20 ft |
| TMR / TGR 014 | Rigid | 14" | 4 ft | 30 ft |
| TGR 022 | Rigid | 22" | 4 ft | 40 ft |
| TMF 014 | Flexible | 14" | 8 ft | 8 ft |
| TGF 014 / 022 | Flexible | 14" / 22" | 8 ft | 8 ft / 12 ft |
| TLR 014 (flat glass) | Rigid | 14" | 4 ft | 30 ft |
| TCR 014 (curb) | Rigid | 14" | 4 ft | 30 ft |
The roof-deck rough opening for a 14-inch unit is 14½" x 18" — it fits between rafters or trusses at either 16" or 24" centers without cutting a member. Additional rigid sections (ZTR) and adjustable elbows extend or steer the run.
There is no whole-unit NFRC U-factor to compare here the way there is for a glass skylight; these are tubular daylighting devices, tested to the NAFS standard for air and water, and VELUX offers an insulating Energy Kit at the diffuser for homeowners who want to tighten the ceiling plane further. The rigid tube carries its own 20-year warranty.
Two accessories matter in practice. The Solar Night Light sits inside a rigid tube and charges from the daylight coming down it, giving a soft moon-level glow after dark — a hallway or bath never needs the switch for a midnight trip. The electric light kit (ZTL) puts a standard fixture in the tube so the same ceiling opening serves day and night.
Where It Fits in Idaho — and Where It Doesn't
The Sun Tunnel was made for the 1990s and 2000s ranch and split-level. Those plans put a windowless hall down the spine of the house, a master bath with a fan and no window, and a walk-in closet you dress in by 60-watt bulb. Roof trusses at 24" centers, a four-to-six-foot attic, and asphalt shingles on a 5:12 or 6:12 pitch — that is a textbook rigid 14-inch install. We cut the roof opening, set the flashing under the shingles, drop the tube, cut the ceiling and mount the diffuser. A single unit is a half-day job, and we regularly set two or three in one morning.
Interior laundry rooms, pantries, stairwells and the dark end of an L-shaped kitchen are the other steady customers. North-facing roofs are fine — the pitched TMR flashing is designed to gather light from all directions.
Where the tunnel is not the answer: when the homeowner wants to see sky, or a room bigger than a family room. A tunnel delivers light, not a view, and it will not exhaust summer heat the way a venting skylight does. A vaulted great room or a kitchen where the daylight is the architecture wants a fixed FS or venting Fresh Air skylight with a proper shaft. And a two-story home where the target room sits under another floor is usually a no — the run is too long or there is no attic path at all.
Warranty and Service, Locally
VELUX covers Sun Tunnel skylights and their flashing for 10 years against defects, with a 20-year warranty on the rigid tube itself. VELUX's 10-year installation warranty is written around its deck- and curb-mounted glass skylights installed with VELUX flashing kits; Sun Tunnels carry the product warranty rather than that installation warranty, so we tell homeowners that plainly at the quote rather than blurring the two.
That said, 46 years of putting holes in Treasure Valley roofs has taught us how to flash a tube so it never becomes a service call. Every Sun Tunnel is installed by Wood Windows Inc employees out of Garden City, and if a dome ever crazes or a diffuser gasket fails, you call the shop that installed it.
Want to know if your hallway has a straight shot to the roof? Request a quote on this page or call (208) 376-2200 and we will look in the attic.
Frequently Asked Questions
Rigid or flexible Sun Tunnel — which should I choose?
Rigid whenever the tube can run reasonably straight. The rigid aluminum tube is far more reflective than flexible ducting, so it delivers noticeably brighter, whiter light, and it can run up to 20 feet in the 10-inch size and 30 feet in the 14-inch size. Flexible tunnels (TMF, TGF) are capped at about 8 feet and exist for the attic where a truss web, duct, or chimney sits directly in the path. In most Treasure Valley ranch homes with a 3–6 foot attic, rigid is the answer.
How much light does a 14-inch Sun Tunnel put out compared to a 10-inch?
The 14-inch tube has roughly twice the cross-section of the 10-inch, and on a sunny Idaho afternoon it lights a space in the 150–300 square foot range — a kitchen or family room. The 10-inch is sized for hallways, closets, powder rooms and laundry rooms up to roughly 150 square feet. Longer tunnels lose some light on every bounce, so we upsize to 14 inches whenever the run gets past eight feet.
What is the difference between a Sun Tunnel and a fixed skylight?
A fixed skylight is a framed opening with a drywalled light shaft — you see sky, and you can sit under it. A Sun Tunnel is a reflective tube that ends in a ceiling diffuser the size of a recessed light — you get daylight, not a view. The tunnel needs no framing changes and installs in a morning; a skylight shaft is a carpentry project. For a hallway or bath, the tunnel wins on cost and speed. For a kitchen where the daylight is the design feature, see our fixed skylight page.
What does a VELUX Sun Tunnel cost installed?
Roughly $800–$1,500 installed for a standard 10- or 14-inch rigid unit in a single-story home with a normal attic run, including flashing and the ceiling trim ring. Extra tube sections, a tile roof, a two-story run, or the solar night light add to that. Full pricing detail is in our skylight installation cost guide.
Sources & Testing Data
Last reviewed 2026-09-10 by Wood Windows Inc — (208) 376-2200