Heat Pump Dryer Savings Calculator

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Table of contents

• How to use
• Common mistakes
• Definitions
• Methodology
• Limitations & assumptions
• Sources

kWh per load: Kilowatt-hours used to dry one load. This is the main energy input for each dryer.

Electricity price: The cost you pay for each kWh of electricity, including per-kWh delivery charges if they apply.

Extra price before rebates: How much more the heat pump dryer costs than the conventional electric dryer before incentives. A negative value means it costs less.

Rebate or incentive: A dollar amount that reduces the extra upfront price for the heat pump dryer.

Simple payback: Extra price after rebates divided by yearly energy bill savings. It ignores loan interest, inflation, and the time value of money.

CO2 rate: Pounds of carbon dioxide linked to each kWh of electricity. Local rates vary by power grid and power source.

Mistake: Entering watts or yearly kWh in Heat pump dryer energy use instead of kWh per load.
Fix: Convert the spec to kWh per load, or use the product's listed per-cycle energy number if available.

Mistake: Using a low supply-only rate for Electricity price and leaving out per-kWh delivery charges.
Fix: Use the all-in $ per kWh from your bill when those charges change with usage.

Mistake: Putting the full heat pump dryer price in Extra price before rebates .
Fix: Enter only the price difference between the heat pump dryer and the conventional dryer you would buy or keep.

Mistake: Entering a negative Rebate or incentive to model fees or taxes.
Fix: Keep the rebate at zero or more; add extra fees to Extra price before rebates instead.

Mistake: Treating Rebate-adjusted payback time as a full ownership cost forecast.
Fix: Read it as simple payback from energy savings only, then consider repairs, dryer life, and resale separately.

• The comparison is for a heat pump electric dryer versus a conventional electric dryer. It does not model gas dryer fuel costs.
• Both dryers are assumed to handle the same Laundry loads per week.
• Energy use per load can change with load size, fabric type, washer spin speed, sensor settings, vent condition for vented dryers, and user habits.
• The calculation uses a single Electricity price. It does not model time-of-use prices, demand charges, or seasonal rate changes.
• Rebate-adjusted payback time is simple payback only. It does not include repairs, maintenance, financing, taxes, installation, dryer lifespan, or discounting future savings.
• The CO2 rate is user-entered and can differ by utility, region, season, and time of day, so Yearly CO2 avoided is an estimate.
• Rebates may have eligibility rules, application deadlines, income limits, or product requirements that are not checked by this calculator.

How the savings are calculated

The calculator first turns weekly laundry use into yearly loads, then calculates yearly electricity use and cost for each dryer. ENERGY STAR and DOE materials describe clothes dryer energy use and efficient dryer comparisons as energy-use questions, but the calculator uses the specific kWh per load numbers you enter instead of assuming a fixed product rating [1][4].

annual_loads = loads_per_week * 52

heat_pump_annual_kwh = heat_pump_kwh_per_load * annual_loads

conventional_annual_kwh = conventional_kwh_per_load * annual_loads

heat_pump_annual_cost = heat_pump_annual_kwh * electricity_rate

conventional_annual_cost = conventional_annual_kwh * electricity_rate

annual_energy_cost_savings = conventional_annual_cost - heat_pump_annual_cost

Payback and impact formulas

The upfront comparison uses only the extra price of the heat pump dryer, reduced by the rebate you enter. Signed results are kept, so a negative extra price after rebates means incentives more than cover the price difference.

net_extra_price_after_rebate = extra_upfront_cost - rebate_amount

annual_kwh_saved = conventional_annual_kwh - heat_pump_annual_kwh

annual_co2_avoided_lb = annual_kwh_saved * co2_rate_lb_per_kwh

Payback is shown only when yearly energy bill savings are positive. If the extra price after rebates is zero or less and savings are positive, the calculator shows 0 years because there is no remaining extra price to recover from energy savings.

payback_years_after_rebate = net_extra_price_after_rebate / annual_energy_cost_savings

Mini-example

If the heat pump dryer uses 1.5 kWh per load, the conventional dryer uses 3.5 kWh per load, you dry 5 loads per week, and electricity costs $0.17 per kWh, yearly loads are 260. The heat pump dryer uses 390 kWh per year and costs $66.30 per year. The conventional dryer uses 910 kWh per year and costs $154.70 per year, so yearly energy bill savings are $88.40. With a $400 extra price and no rebate, simple payback is $400 divided by $88.40, or about 4.52 years. With a CO2 rate of 0.8 lb per kWh, yearly CO2 avoided is 520 kWh times 0.8, or 416 lb CO2 per year.