Larson’s sidelite storm panels cut energy loss by up to 60% — a claim that actually means something when you’re heating a Montana home through January. These aren’t decorative trim pieces. They’re purpose-built storm panels that seal the weakest link in most entry door systems: those drafty sidelites that look great in summer and leak heat all winter.
The L703 vs L705 Decision
The choice between Larson’s two sidelite panel models comes down to glass technology and frame sizing.
The L703 is the entry-level clear glass panel, available in 11-7/8” and 13-7/8” widths at the standard 81” height. It’s straightforward protection — 1/8-inch tempered safety glass in an aluminum frame that blocks drafts without breaking the budget.
The L705 is the premium/decorative version with optional Low-E glass, sized at 12” and 14” widths. That Low-E coating matters more than most homeowners realize. It’s not just about UV protection for your flooring — it’s about reflecting radiant heat back where it belongs. In winter, that means keeping heat inside. In summer, it means rejecting solar gain.
| Model | Width Options | Glass Type | Best For |
|---|---|---|---|
| L703 | 11-7/8”, 13-7/8” | Clear tempered | Basic draft protection |
| L705 | 12”, 14” | Clear or Low-E | Maximum energy efficiency |
Both models share the same 81-inch standard height with custom sizes available for non-standard openings up to 96 inches using the included adjustable bottom expander.
Installation That Actually Works for Homeowners
The overlap mount design for quick DIY setup is what separates these from contractor-only products. No removing your existing sidelite. No complicated frame modifications. You’re looking at a genuine afternoon project.
The process breaks down to four steps:
- Position the storm panel over the exterior sidelite opening
- Drill pilot holes and secure with provided mounting screws
- Attach screw-cap covers to hide hardware
- Install the bottom expander if a gap exists at the sill
The panel is built with an overlap margin (approx. 1/2 inch), which forgives minor measurement errors — critical for DIY success. And when summer comes? They’re exterior-removable via mounting screws and screw-cap covers. No interior trim work to mess with.
Why Sidelites Matter More Than You Think
Entry doors get all the weatherization attention, but sidelites are where the real energy loss happens. They’re typically single-pane or at best low-quality insulated glass. No weatherstripping. Minimal frame insulation. In a Montana winter, they’re basically decorative heat leaks.
General brand rating (Larson) is 4.1/5 stars; specific sidelite panels are noted for their niche utility but are less frequently reviewed individually. Makes sense — these aren’t glamour products. They’re problem solvers for a specific issue most homeowners don’t think about until they get their heating bill.
The included components tell you Larson understands the installation reality: tempered glass sash, aluminum frame components, mounting hardware, screw-cap covers, and that adjustable bottom expander. Everything ships in one box. No trips back to the store for missing brackets.
The Verdict on Value
Sidelite panels are focused purely on the side windows, whereas storm doors protect the main opening; they are often used together. If you’ve already invested in a quality storm door but still feel drafts, check your sidelites. They’re probably the culprit.
Skip these if your sidelites are already double-pane Low-E units in good condition. But for the majority of homes with original or builder-grade sidelites, Larson’s panels offer measurable improvement without the cost and disruption of full window replacement. That 60% energy loss reduction pays for itself through lower heating bills — usually within two Montana winters.
The 10-year warranty covers manufacturing defects in materials and workmanship for the glass sash and frame. Standard coverage, nothing exceptional, but it shows Larson stands behind the product for the long haul.
Frequently Asked Questions
Q: Can I install these panels on interior sidelites? A: No. These are designed for exterior mounting only. The overlap design and mounting system require exterior installation to function properly.
Q: Do the panels work with decorative glass sidelites? A: Yes. Since they mount over your existing sidelites, decorative glass remains visible through the clear storm panel. The Low-E option (L705) provides UV protection to help preserve decorative glass finishes.
Q: How much energy will these panels actually save? A: Depends entirely on your current sidelites, local energy rates, and heating habits. The 60% reduction claim refers to air infiltration through the sidelite opening, not your total heating bill. Figure one to three winter heating seasons to recoup the investment in most Montana climates.
Q: Can these panels handle Montana’s temperature swings? A: The aluminum frame and tempered glass construction handles extreme temperature cycling without issue. The mounting system allows for thermal expansion and contraction. These materials are proven in much harsher commercial applications.
Q: Why choose L705 over L703 if I don’t need Low-E? A: The L705 offers slightly different width options (12” and 14” vs 11-7/8” and 13-7/8”). If your sidelites match those dimensions exactly, go with the model that fits. Otherwise, the L703 delivers the same draft protection for less.
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