Manual J Load Calculation
The industry-standard method (ACCA Manual J) for calculating a home's heating and cooling loads based on climate, insulation, windows, orientation, occupancy, and other factors.
Why It Matters
Proper sizing is critical for heat pumps. Oversized systems short-cycle (reducing efficiency and comfort); undersized systems can't keep up on extreme days. A Manual J calculation prevents both.
Related Terms
Heat Pump
An efficient HVAC system that transfers heat rather than generating it, providing both heating and cooling. Air-source heat pumps are most common; ground-source (geothermal) are most efficient.
Variable-Speed Compressor
A compressor that can modulate its speed continuously (using an inverter-driven motor) rather than cycling fully on and off. This allows the system to match output precisely to demand.