How hand dryers vs paper towels is worked out
Hand dryers and paper towels are priced on different things, so the fair comparison is the net cost over the same 25 years and the same number of dries. The dryer side buys the machine and pays for the electricity: the energy per dry is the power in watts times the dry time in seconds divided by 3,600,000, which gives kilowatt-hours, and the cost per dry is the energy per dry times the electricity price. The annual cost is the dries a year times the cost per dry, the 25-year gross is the annual cost times 25, and the net is the gross plus the dryer price. The towel side pays per dry: the cost per dry is the towels per dry times the towel price, the annual cost is the dries a year times the cost per dry, and the 25-year net is the annual cost times 25, with no machine to buy. The net winner is the smaller net cost, and the gap between the two nets is how much the winner wins by.
At the defaults — 100 dries a day, 250 days a year, dryer 1,500 W, dry time 30 seconds, electricity $0.17/kWh, dryer $400.00, 2 towels per dry, towel $0.01 — the dryer energy per dry is 1,500 × 30 ÷ 3,600,000 = 0.0125 kWh, the dryer cost per dry is 0.0125 × $0.17 = $0.002125, the dries a year are 100 × 250 = 25,000, the dryer annual cost is 25,000 × $0.002125 = $53.13, the 25-year gross is $53.13 × 25 = $1,328.13, and the net is $1,328.13 + $400.00 = $1,728.13, or $69.13 a year. The towels cost per dry is 2 × $0.01 = $0.02, the annual cost is 25,000 × $0.02 = $500.00, and the 25-year net is $500.00 × 25 = $12,500.00 — so the hand dryers win net by $12,500.00 − $1,728.13 = $10,771.88.
| Case | Dryer net | Towels net | Net winner |
|---|
| 100 dries/day (default) | $1,728.13 | $12,500.00 | Hand dryers by $10,771.88 |
| 50 dries/day | $1,064.06 | $6,250.00 | Hand dryers by $5,185.94 |
| 200 dries/day | $3,056.25 | $25,000.00 | Hand dryers by $21,943.75 |
| Electricity $0.30/kWh | $2,743.75 | $12,500.00 | Hand dryers by $9,756.25 |
| Towel $0.005 | $1,728.13 | $6,250.00 | Hand dryers by $4,521.88 |
| Dry time 45 s | $2,392.19 | $12,500.00 | Hand dryers by $10,107.81 |
| Towels $0.001 each | $1,728.13 | $1,250.00 | Paper towels by $478.13 |
The worked example, line by line
Setup: 100 dries a day, 250 days a year, dryer 1,500 W, dry time 30 seconds, electricity $0.17/kWh, dryer $400.00, 2 towels per dry, towel $0.01.
Line 1 — the dries and the energy. 100 × 250 = 25,000 dries a year, and 1,500 × 30 ÷ 3,600,000 = 0.0125 kWh per dry, which is 25,000 × 0.0125 = 312.50 kWh a year, or 7,812.50 kWh over 25 years.
Line 2 — the dryer cost. 0.0125 × $0.17 = $0.002125 per dry, so 25,000 × $0.002125 = $53.13 a year, $53.13 × 25 = $1,328.13 over 25 years, and $1,328.13 + $400.00 = $1,728.13 net, or $69.13 a year.
Line 3 — the towel cost. 2 × $0.01 = $0.02 per dry, so 25,000 × $0.02 = $500.00 a year, and $500.00 × 25 = $12,500.00 net over 25 years.
Line 4 — the towels used. 25,000 × 2 = 50,000 towels a year, or 1,250,000 over 25 years, which at about 2 g each is about 100 kg a year, or 2,500 kg over 25 years.
Line 5 — the winner. $12,500.00 − $1,728.13 = $10,771.88 to the hand dryers. The dryer costs $69.13 a year net against $500.00 a year for towels.
Every branch, checked
50 dries a day: the dries a year fall to 12,500, the dryer annual cost falls to $26.56, the 25-year gross to $664.06, and the net to $1,064.06, while the towels cost $250.00 a year and $6,250.00 over 25 years — so the hand dryers win net by $5,185.94. A quiet washroom saves less in total, because there are fewer dries to save on, but the dryer still wins.
200 dries a day: the dries a year rise to 50,000, the dryer annual cost rises to $106.25, the 25-year gross to $2,656.25, and the net to $3,056.25, while the towels cost $1,000.00 a year and $25,000.00 over 25 years — so the hand dryers win net by $21,943.75. A busy washroom is where the dryer pays best, because every extra dry costs $0.002125 with the dryer against $0.02 with towels.
Electricity $0.30/kWh: the dryer cost per dry rises to 0.0125 × $0.30 = $0.00375, the annual cost to $93.75, the 25-year gross to $2,343.75, and the net to $2,743.75, while the towels stay $12,500.00 — so the hand dryers win net by $9,756.25. Dear electricity narrows the gap, because the electricity is the whole of the dryer running cost, but at $0.30 the dryer still wins: the towels only win above the break-even price of $1.55/kWh.
Towel $0.005: the towels cost per dry falls to 2 × $0.005 = $0.01, the annual cost to $250.00, and the 25-year net to $6,250.00, while the dryer net stays $1,728.13 — so the hand dryers win net by $4,521.88. Half-price towels halve the towel bill, but they do not flip the answer: the towels only win below the break-even price of $0.0014 each.
Dry time 45 s: the energy per dry rises to 1,500 × 45 ÷ 3,600,000 = 0.01875 kWh, the cost per dry to $0.0031875, the annual cost to $79.69, the 25-year gross to $1,992.19, and the net to $2,392.19, while the towels stay $12,500.00 — so the hand dryers win net by $10,107.81. A slow dryer costs more to run, but it still wins by more than $10,000.00.
Extra — towels $0.001 each: the towels cost per dry falls to 2 × $0.001 = $0.002, the annual cost to $50.00, and the 25-year net to $1,250.00, while the dryer net stays $1,728.13 — so the paper towels win net by $478.13. Towels this cheap flip the answer: the towel price is the one input that can turn the whole comparison around, because every dry pays it.
Reverse — the break-evens: the towels tie the dryer if they cost $0.0014 each — $1,728.13 ÷ 1,250,000 towels over 25 years. The electricity ties the towels if it costs $1.55 a kilowatt-hour — ($12,500.00 − $400.00) ÷ 7,812.50 kWh. And the usage ties at 3.58 dries a day — $400.00 ÷ $111.72 of saving per dry per day over 25 years: below 3.58 dries a day the towels win, because the dryer is spread over too few dries.
What the defaults assume
The model assumes the same number of dries every day for 25 years, the same electricity price, and the same towel price, with one dryer that lasts the whole 25 years. It assumes every dry takes the full dry time at the full power, and that every dry takes the towels per dry entered. It leaves out the cost of the washroom, the plumbing, the bin and the cleaning, the cost of the electricity for the lights, and the cost of the dryer’s maintenance — and it leaves out the hygiene and the comfort of each option, which are not priced here. The towel waste is about 2 g per towel, so 50,000 towels a year is about 100 kg. Rounding convention: money is rounded to cents, energy to 2 decimals, and all figures are computed from unrounded values, rounded only for display.
Output · formula · meaning
| Output | Formula | What it means |
|---|
| Dryer cost per dry | power × time ÷ 3,600,000 × $/kWh | $0.0021. |
| Towels cost per dry | towels per dry × towel price | $0.0200. |
| Dryer annual | dries/yr × dryer cost/dry | $53.13. |
| Dryer gross (25 yr) | dryer annual × 25 | $1,328.13. |
| Dryer net (25 yr) | dryer gross + dryer price | $1,728.13. |
| Dryer net/yr | dryer net ÷ 25 | $69.13. |
| Towels annual | dries/yr × towels cost/dry | $500.00. |
| Towels net (25 yr) | towels annual × 25 | $12,500.00. |
| Net winner | dryer net − towels net | Hand dryers win by $10,771.88. |
| Dryer energy/yr | dries/yr × kWh/dry | 312.50 kWh. |
| Dryer energy (25 yr) | energy/yr × 25 | 7,812.50 kWh. |
| Towels/yr | dries/yr × towels per dry | 50,000. |
| Towels (25 yr) | towels/yr × 25 | 1,250,000. |
| Towel waste/yr | towels/yr × 2 g | 100 kg. |
| Towel waste (25 yr) | waste/yr × 25 | 2,500 kg. |
| 50 dries/day | same model, 50 dries | Dryer net $1,064.06, towels net $6,250.00, Hand dryers win by $5,185.94. |
| 200 dries/day | same model, 200 dries | Dryer net $3,056.25, towels net $25,000.00, Hand dryers win by $21,943.75. |
| Electricity $0.30/kWh | same model, $0.30/kWh | Cost/dry $0.00375, annual $93.75, 25-yr $2,343.75, net $2,743.75, Hand dryers win by $9,756.25. |
| Towel $0.005 | same model, towel $0.005 | Cost/dry $0.01, annual $250.00, 25-yr $6,250.00, Hand dryers win by $4,521.88. |
| Dry time 45 s | same model, 45 s | Energy 0.01875 kWh/dry, cost/dry $0.0031875, annual $79.69, 25-yr $1,992.19, net $2,392.19, Hand dryers win by $10,107.81. |
| Towels $0.001 each | same model, towel $0.001 | Cost/dry , annual , 25-yr , . |
| Reverse: break-even towel price | dryer net ÷ towels over 25 yr | $0.0014 each. |
| Reverse: break-even electricity | (towels net − dryer price) ÷ kWh over 25 yr | $1.55/kWh. |
| Reverse: break-even usage | dryer price ÷ saving per dry per day | 3.58 dries/day. |
Who uses this
- The office manager fitting out a washroom: they learn a dryer costs $1,728.13 net over 25 years against $12,500.00 for towels — so they know the dryer saves $10,771.88, and they know it costs $69.13 a year net against $500.00 a year for towels.
- The small business with a quiet washroom: they learn at 50 dries a day the dryer still wins, by $5,185.94 — $1,064.06 against $6,250.00 — so they know the dryer pays even at half the traffic, and they check the break-even usage of 3.58 dries a day before they decide.
- The facilities manager buying towels in bulk: they learn towels at $0.005 each still lose, by $4,521.88 — $6,250.00 against $1,728.13 — so they know cheap towels narrow the gap but do not flip it, and they check the towel price against the break-even of $0.0014 each.
- The sustainability lead counting waste: they learn the washroom uses 50,000 towels a year, about 100 kg, or 1,250,000 towels and 2,500 kg over 25 years — so they know the dryer wipes out the whole waste stream, and they weigh that against the dryer’s 312.50 kWh a year of electricity.
Accuracy & limitations
The math is exact for the numbers you enter: the energy per dry is the power times the dry time divided by 3,600,000, the cost per dry is the energy per dry times the electricity price, the dryer net is the 25-year electricity plus the dryer price, and the towels net is the dries a year times the towels cost per dry times 25. What the model cannot do is measure your washroom for you: count the dries for a week, and check the electricity price on the bill and the towel price on the invoice. It leaves out the bin, the cleaning, the plumbing, and the dryer’s maintenance, and it assumes one dryer lasts 25 years, which is a long life for a machine that runs every day. It assumes every dry takes the full dry time at full power. For the same comparison by laundry, see paper towels vs cloth towels; for the same comparison by transport, see car vs bike commuting calculator.
Cite this calculatorBright Side Kit. “Hand Dryers vs Paper Towels: 25-Year Cost Calculator.” brightoolbox.com, 2026. Method: energy per dry = power (W) × dry time (s) ÷ 3,600,000 kWh; dryer cost per dry = energy per dry × electricity $/kWh; dries per year = dries per day × days per year; dryer annual = dries per year × dryer cost per dry; dryer gross = dryer annual × 25; dryer net = dryer gross + dryer price; dryer net per year = dryer net ÷ 25; towels cost per dry = towels per dry × towel price; towels annual = dries per year × towels cost per dry; towels net = towels annual × 25; net winner = smaller net; towels per year = dries per year × towels per dry; towel waste = towels × 2 g; break-even towel price = dryer net ÷ towels over 25 years; break-even electricity = (towels net − dryer price) ÷ kWh over 25 years; break-even usage = dryer price ÷ saving per dry per day over 25 years. Defaults: 100 dries/day, 250 days/yr, 1,500 W, 30 s, $0.17/kWh, $400.00 dryer, 2 towels/dry, $0.01/towel → dryer energy 0.0125 kWh/dry, cost/dry $0.002125, annual $53.13, 25-yr gross $1,328.13, net $1,728.13, $69.13/yr; towels cost/dry $0.02, annual $500.00, 25-yr net $12,500.00; hand dryers win by $10,771.88; energy 312.50 kWh/yr, 7,812.50 kWh over 25 yr; towels 50,000/yr, 1,250,000 over 25 yr, about 100 kg/yr, 2,500 kg over 25 yr; 50 dries/day → dryer net $1,064.06, towels $6,250.00, hand dryers win by $5,185.94; 200 dries/day → dryer net $3,056.25, towels $25,000.00, hand dryers win by $21,943.75; electricity $0.30/kWh → cost/dry $0.00375, annual $93.75, 25-yr $2,343.75, net $2,743.75, hand dryers win by $9,756.25; towel $0.005 → cost/dry $0.01, annual $250.00, 25-yr $6,250.00, hand dryers win by $4,521.88; dry time 45 s → energy 0.01875 kWh/dry, cost/dry $0.0031875, annual $79.69, 25-yr $1,992.19, net $2,392.19, hand dryers win by $10,107.81; towels $0.001 each → cost/dry $0.002, annual $50.00, 25-yr $1,250.00, paper towels win by $478.13; break-even towel price $0.0014 each; break-even electricity $1.55/kWh; break-even usage 3.58 dries/day. Bright Side Kit. "Hand Dryers vs Paper Towels: 25-Year Cost Calculator." https://brightoolbox.com/hand-dryers-vs-paper-towels/ Accessed October 25, 2026.
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