Guide
Heating Fuel Cost Comparison
Gas, oil, propane, electric, and heat pump on one yardstick.
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Worked examples for HVAC sizing and costs.
Parameter tables plus hand calculations you can reproduce: bills, rates, solar, EV charging, commercial demand, and power factor.
Guide
Replace or Repair: The HVAC Decision Guide
The 5,000 rule, lifespan, and refrigerant phaseouts.
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AC Sizing Guide: Tons, BTU, and Manual J
Rules of thumb screen candidates; Manual J and Manual S pick the winner.
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Furnace Sizing Guide: BTU and AFUE
Output covers the load; input is what you buy. AFUE connects them.
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Heat Pump Guide: Sizing for Cold Climates
COP, HSPF2, balance point, and dual-fuel switchover explained.
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SEER2 Efficiency Guide
SEER2, EER2, HSPF2, and what upgrades actually pay back.
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Ductwork Basics: CFM, Velocity, and Manual D
Velocity, friction rate, and Manual D in plain terms.
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Superheat and Subcooling Guide
Charge by numbers, not by feel. EPA 608 applies.
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