Whole-House Dehumidifier Energy Payback Calculator

Calculate how much energy a whole-house dehumidifier saves—or adds—by reducing HVAC runtime and whether the upgrade pays back. Enter annual HVAC runtime, expected runtime reduction, your electric rate, and installed cost. Optionally adjust HVAC and dehumidifier power draws to reflect your equipment mix and review the net kWh impact, annual savings or added spend, and simple payback timeline.

Estimated hours your HVAC system operates each year across cooling seasons.
Percent of HVAC runtime you expect the dehumidifier to eliminate through improved humidity control.
All-in electricity cost per kilowatt-hour including delivery and riders.
Total installed cost including equipment, labour, electrical work, and permits.
Defaults to 3.5 kW if blank. Override with your system's average compressor and fan draw.
Defaults to 0.7 kW when left blank. Use the manufacturer's rated wattage for accuracy.

Model assumes steady power draws and runtime reductions. Verify equipment specifications, moisture loads, and rebate eligibility with HVAC professionals before purchasing.

Examples

  • 1,500 hours, 22% reduction, $0.18/kWh, $3,200 cost, 9.0 kW HVAC, 0.6 kW dehumidifier ⇒ Net savings are 2,772.00 kWh, worth $498.96 annually, yielding a 6.41-year payback.
  • 900 hours, 10% reduction, $0.12/kWh, $2,900 cost, defaults for power draws ⇒ Only 477.00 kWh are saved for $57.24 per year, stretching payback to 50.66 years.
  • 1,200 hours, 8% reduction, $0.15/kWh, $3,500 cost, 3.5 kW HVAC, 1.2 kW dehumidifier ⇒ Extra draw outweighs savings by 168.00 kWh, adding $25.20 per year and eliminating payback.

FAQ

How do utility rebates factor in?

Subtract rebates from the installed cost before running the calculation to shorten the payback timeline.

What if the dehumidifier increases HVAC efficiency?

Reduce the HVAC power draw input to model improved coil performance or use a higher runtime reduction percentage if humidity control allows higher thermostat setpoints.

Can I model seasonal differences?

Run the calculator for summer and shoulder seasons separately, then add the savings to approximate a full-year impact.

Why does the result sometimes show added energy use?

If the dehumidifier's wattage and runtime exceed the HVAC savings, the net kWh becomes negative. Revisit runtime reduction expectations or choose a more efficient unit.

How should I treat maintenance or filter costs?

Add any recurring maintenance expenses to the installed cost or subtract the annual amount from the calculated savings to get a net operating impact.

Additional Information

  • HVAC and dehumidifier draws represent average power while the equipment is running; adjust to match manufacturer specs.
  • Runtime reduction percentage converts to hours avoided and multiplies by HVAC load to estimate energy saved.
  • The dehumidifier's own consumption is subtracted so savings represent net impact on the utility bill—including the risk of higher usage.
  • Simple payback divides installed cost by annual savings and does not account for rebates or maintenance costs.
  • Negative savings indicate the dehumidifier uses more electricity than it saves, signalling the need to revisit assumptions.

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