Key Takeaways
- Florida's humid sub-tropical climate demands focusing on thermal envelope air-sealing and solar heat gain reduction first.
- Cool roofing materials with high Solar Reflectance Index (SRI) reduce roof surface temperatures from 150°F+ down to under 100°F.
- Unvented attics using open-cell or closed-cell spray foam on roof sheathing bring HVAC ductwork inside the conditioned space, eliminating 20%–30% duct losses.
- Right-sized variable-speed HVAC units provide essential dehumidification—oversized systems cool too fast without removing moisture, causing mold risks.
Building an energy-efficient structure in Florida requires a completely different approach than in northern heating climates. In Central Florida, our primary adversary is radiant solar heat gain combined with intense outdoor relative humidity. Designing an energy-efficient residential home or commercial building means combining building-envelope science with precision mechanical engineering.
1. The Roof as the First Line of Defense: Cool Roofs & Radiant Barriers
During summer, a dark asphalt shingle roof in Orlando easily reaches 150°F to 175°F. That heat radiates directly into attic insulation and seeps down through the ceiling drywall:
- High-SRI Metal & Tile: Standing seam metal roofs with Kynar 500 reflective pigment finishes reflect up to 70% of solar radiation back into the atmosphere.
- Commercial TPO Membranes: Brilliant white thermoplastic polyolefin (TPO) single-ply roof membranes keep commercial low-slope buildings dramatically cooler, significantly reducing commercial chiller loads.
- Radiant Barrier Sheathing: OSB roof sheathing backed with an aluminum foil radiant barrier reflects up to 97% of radiant heat before it enters the attic space.
2. Unvented Spray-Foam Attics: The Conditioned Space Revolution
In traditional Florida construction, attics are vented with soffit and ridge vents, meaning attic air temperature matches the 130°F+ outdoor heat index. When flexible air conditioning ducts run through a 130°F attic, heat penetrates the ductwork, forcing the AC to work 25% harder.
By sealing off exterior vents and spraying 5.5 to 7 inches of open-cell spray foam directly to the underside of the roof decking, the attic becomes an insulated, "conditioned" space. Attic temperatures stay within 8–10 degrees of your home's thermostat, protecting air handlers, water heaters, and storage items from extreme thermal fatigue.
3. Precision HVAC Sizing: Manual J & Dehumidification
A common error in Florida construction is oversizing air conditioning tonnage. An oversized 5-ton system cooling a 2,200 sq. ft. home will drop the air temperature in 8 minutes and shut off. Because it short-cycles, it fails to run long enough across the evaporator coil to extract moisture from the air, leaving the indoor air feeling clammy, sticky, and ripe for mold growth.
We mandate ACCA Manual J (heating/cooling load calculation), Manual S (equipment selection), and Manual D (duct design) calculations. Installing variable-speed inverter-driven heat pumps (16 to 20+ SEER2) allows the system to ramp down to 30% capacity, running continuously at whisper-quiet levels to maintain a crisp 45%–50% indoor relative humidity.
New Edge Construction builds to the latest Florida Energy Conservation Code, integrating high-performance building techniques that lower utility bills, enhance indoor air quality, and deliver lasting structural comfort.