For Energy Auditors & Utility Partners
A Verified Solution for the Audit Report.
The mail slot is a documented air leakage point with no previously verified solution. The Brass-Seal is one of the first mail slot products independently tested under ASTM E283. Now your customers have somewhere to go.
Auditors Flag It.
Now There Is a Fix.
Energy auditors and BPI-certified contractors consistently identify the mail slot as a significant infiltration point during blower door tests. Until now, no independently tested, specification-grade product existed to address it. Recommendations stopped at "consider sealing" with no verified product to reference.
The Brass-Seal changes that. It is one of the first mail slots tested under ASTM E283 by Intertek - the same standard applied to windows and doors. The Intertek ASTM E283 Report (No. T4376.01-301-44-R1) is available upon request at info@blockouttheair.com for inclusion in audit documentation.
E283
| Configuration | Test | Result | Allowable Max | Status |
|---|---|---|---|---|
| Interior (standalone) | Air Infiltration · 75 Pa | 0.6 L/s/m² (0.12 cfm/ft²) | 1.5 L/s/m² (0.3 cfm/ft²) | PASS |
| Interior (standalone) | Air Exfiltration · 75 Pa | 0.3 L/s/m² (0.06 cfm/ft²) | 1.5 L/s/m² (0.3 cfm/ft²) | PASS |
| Exterior (standalone) | Air Infiltration · 75 Pa | 1.0 L/s/m² (0.20 cfm/ft²) | 1.5 L/s/m² (0.3 cfm/ft²) | PASS |
| Exterior (standalone) | Air Exfiltration · 75 Pa | 0.6 L/s/m² (0.11 cfm/ft²) | 1.5 L/s/m² (0.3 cfm/ft²) | PASS |
| Paired System | Air Infiltration · 75 Pa | 1.0 L/s/m² (0.20 cfm/ft²) | 1.5 L/s/m² (0.3 cfm/ft²) | PASS |
| Paired System | Air Exfiltration · 75 Pa | 0.6 L/s/m² (0.11 cfm/ft²) | 1.5 L/s/m² (0.3 cfm/ft²) | PASS |
Intertek Building & Construction · Report No. T4376.01-301-44-R1 · April 2026 · Test pressure: 75 Pa (1.57 psf) · Full report available upon request at info@blockouttheair.com
How It Works for Utility Programs.
BOTA works with utility energy efficiency program managers to place the Brass-Seal on auditor recommendation lists. When an auditor flags the mail slot, the customer receives a BOTA reference and a direct link to the savings calculator. The estimate is pre-formatted for rebate submission.
No maintenance. No ongoing cost. Fully compatible with existing door hardware. Available in two sizes to fit the full range of residential mail slot cutouts.
Start the Conversation- ASTM E283 Verified - Full Intertek report available upon request at info@blockouttheair.com. Formatted for audit documentation.
- Two Configurations - Brass-Seal Exterior for full replacement. Brass-Seal Interior for retrofit without altering existing exterior hardware. Interior also completes the paired system alongside the Brass-Seal Exterior.
- Two Sizes - Letter (8.00" × 2.25") and Magazine (11.375" × 2.50"). Covers the majority of residential mail slot cutouts.
- No Maintenance Required - No ongoing cost, no electricity. The EPDM gaskets and polyurea-lined cavity provide a continuous seal once installed.
- Historic Properties - Brass-Seal Interior preserves existing exterior hardware for historic and landmark properties.
The BOTA savings estimate PDF - generated from Intertek ASTM E283 results and matched to local utility rates - includes the Intertek report number and regional energy data source.
A one-page product sheet for homeowners. Covers construction, verified performance, configurations, sizing, finishes, and pricing. Ready to share or print.
Download PDFAdd It to Your
Recommendation List.
If you conduct residential energy audits or blower door tests and regularly flag mail slots as leakage points, BOTA gives you a specific, verified product to recommend. The savings calculator produces a formatted PDF estimate your customers can use immediately.
Built to Last.
Built to Perform.
Every component of the Brass-Seal system is specified for longevity and verified performance. When you recommend the Brass-Seal, here is what your customers are getting.
01
Forged Brass Construction
Solid forged brass throughout. Not plated, not cast. Forging compresses the grain structure of the brass, producing a material that is denser, stronger, and more resistant to wear and corrosion than cast alternatives. A material choice that communicates permanence and rewards close attention over years of use.
02
Brass-Seal Exterior Closure
A heat-resistant magnetic closure maintains consistent compression against the acoustic-lined cavity gasket with each delivery. Engineered for high-temperature performance, retaining approximately 90% pull strength at 212°F. Relevant to direct sun exposure on dark or south-facing doors.
03
Brass-Seal Interior Closure
A calibrated closure mechanism designed to allow mail to pass easily while returning to a precise, sealed position after each delivery. A continuous perimeter gasket seals the hardware to the door face on the interior, completing the seal across the full thickness of the door.
04
Acoustic Polyurea Lining
A custom-blended polyurea acoustic cavity gasket is featured in both the Brass-Seal Exterior and Brass-Seal Interior. It absorbs impact and reduces sound transmission in both directions, softening the passage of exterior noise into the home.
05
EPDM Perimeter Gasket
A continuous EPDM perimeter gasket is attached to the rear face of each slot assembly. It seals the hardware to the door face across the full perimeter, eliminating hidden air gaps at the hardware-to-door interface. No installation thought required - it is factory-attached and compresses uniformly when the unit is fastened.
06
PVD Finish
Physical Vapor Deposition bonded to solid forged brass at the molecular level. Not a surface coating. Engineered to hold appearance over the life of the hardware without peeling, flaking, or oxidizing. Available in Satin Brass, Satin Nickel, and Satin Black. All visible components - including screws and hinge pins - finished to match.
Full product detail at blockouttheair.com/brass-seal
Utility & Energy Program Inquiries
We are actively building relationships with utility energy efficiency programs in the Philadelphia region and nationally. If you manage an energy audit or rebate program and want to discuss placing the Brass-Seal on your recommendation list, we want to hear from you.
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