A thermal break is a polyamide strip embedded inside an aluminum frame to physically separate the exterior aluminum from the interior aluminum. Aluminum conducts heat aggressively. Polyamide does not. The strip stops the heat transfer at the frame and lets the glass package do its job.
Most architectural systems we sell use a 24mm polyamide 6.6 strip. The longer the strip, the better the thermal performance. AAMA reports U-values from 0.22 with thermally broken frames and dual-pane low-E argon-filled glass. Without the thermal break, even the best glass package tops out around 0.45.
Thermal breaks pay for themselves in two scenarios: cold-climate installs where heating bills are the dominant cost, and any climate where the building has a high glass-to-wall ratio. For a Miami beach house with full-height glass walls, the thermal break is what stops condensation from running down the interior aluminum on humid mornings.
The pricing premium is typically 15 to 25 percent over a standard non-thermally-broken aluminum frame. For a high-end residential project, that delta is recovered in HVAC equipment downsizing alone.
