ThermoSeal Draft Blocking Cellular Shades

Even the most insulating cellular shade is limited by the air gaps around its edges. ThermoSeal Draft Blocking Shades address this vulnerability with a complete perimeter sealing system that transforms your window into a true thermal barrier. Aluminum side channels mount to the window jambs, capturing the shade edges and blocking air infiltration. A magnetic bottom bar adheres to a metal strip on the sill, sealing the lower edge. An optional top seal closes the gap above the headrail. When fully deployed, the shade creates an airtight enclosure that dramatically reduces drafts and heat loss. Independent testing confirms up to 50% reduction in air infiltration compared to standard inside-mount cellular shades. Available in 1⅛-inch single-cell and double-cell configurations, with light-filtering, room-darkening, and blackout opacities. Custom‑sized to your exact window dimensions, with motorized operation recommended. Stop drafts. Start saving.

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Side Channels with Brush Seals

ThermoSeal side channels are fabricated from 1.2 mm aluminum and custom‑cut to the exact drop of your shade. They mount to the window jambs (inside mount) or wall (outside mount) and feature a U‑shaped channel lined with nylon brush pile. As the shade glides within the channel, the brush pile compresses against the fabric edges, dramatically reducing air infiltration. Independent testing (ASTM E283) confirms an 85% reduction in air leakage at the sides.

Magnetic Bottom Bar Seal

A continuous flexible magnetic strip is embedded in the bottom bar, paired with a ferrous strip adhered to the sill. When the shade is lowered, the magnets engage with a clean, audible click, compressing the brush pile and creating an airtight bottom seal. This eliminates the drafts that typically flow beneath the bottom rail. For sills that cannot accept adhesive, a weighted drop‑seal is available.

Top Seal Options

Even with side channels and a bottom seal, air can leak over the headrail. Our optional top seal is a flexible PVC extrusion that mounts to the top of the window frame and compresses against the headrail, closing the final gap. It is available in matching colors and remains virtually invisible once installed.

Double‑Cell Construction for Maximum Insulation

ThermoSeal shades are offered in 1⅛‑inch double‑cell construction, providing two layers of trapped air for exceptional thermal resistance (R‑5.2). Combined with the perimeter sealing system, these shades approach the insulating performance of a low‑E storm window—without altering the exterior appearance of your home.

Motorization Recommended

Because the sealing system adds weight and requires precise alignment for airtight performance, ThermoSeal shades are recommended with motorized operation. Our high‑torque motors are calibrated to overcome brush‑seal resistance and magnetic breakaway force. Both long‑life battery (3–5 years) and hardwired options are available.

Energy Savings Payback

ThermoSeal shades typically pay for themselves in 3–7 years through reduced heating and cooling costs, depending on climate, window type, and local energy rates. They are especially effective on older, single‑pane windows. An energy‑savings calculator is available on our website to estimate your payback period.

Ideal for Historic Homes & Drafty Windows

ThermoSeal shades are an excellent solution for historic homes where window replacement is impractical or prohibited. They deliver modern energy efficiency without altering the building’s exterior or requiring permanent modifications to the window frame.