Electric vs Gas Dryer Cost Calculator

Introduction: why the cheaper dryer depends on your own two utility rates

An electric dryer and a gas dryer do the same physical job. Both tumble damp fabric through heated air until the water evaporates and leaves with the exhaust. The difference is only in where the heat comes from, and that single difference is enough to swing the running cost by a factor of three in one town and by almost nothing in another. A vented electric dryer converts kilowatt-hours into heat inside the drum at essentially one hundred percent efficiency, but you pay retail electricity prices for every one of them. A gas dryer buys its heat far more cheaply per unit of energy, then throws part of that advantage away up the vent along with hot combustion products, and it still draws household electricity for the drum motor, the blower, the controls and the igniter.

Because both effects are real and pull in opposite directions, no general rule survives contact with an actual utility bill. This calculator therefore refuses to guess. It asks for your loads per week, the energy each machine uses per load in the unit that machine is billed in, your electricity price, your gas price, and the extra amount the gas option would cost to buy and install. From those seven numbers it produces monthly and annual operating cost for each machine, the cost of a single load, the size of the gap, and the number of months the gas installation would need before it pays for itself. Everything is an estimate for learning and budgeting, not professional appliance or energy advice.

How to use the electric vs gas dryer cost calculator

Work down the form in order. Start with laundry loads dried per week. The default of 5.4 is not arbitrary: it is the figure the United States Environmental Protection Agency uses when it reports certified dryer energy, equal to 283 cycles a year. Count only loads that actually go into a dryer, not loads that are hung to dry.

Next fill in the per-load energy. Electric dryer energy per load is in kilowatt-hours. Gas dryer gas per load is in therms, and gas dryer electricity per load is the separate kilowatt-hour draw that a gas machine still puts on your electric bill. If you have the yellow EnergyGuide label or the appliance manual, use the manufacturer figures divided by the label's assumed 283 cycles a year; that is always better than a national average. If you do not have the label, leave the defaults, which are derived below from the federal minimum efficiency standard.

Then enter your two rates. Take electricity price straight off your power bill as dollars per kilowatt-hour, ideally the all-in figure including delivery charges rather than the headline supply rate. Take gas price as dollars per therm. If your gas bill is written in hundreds of cubic feet (Ccf), one Ccf is close to one therm for most pipeline gas, so the numbers are near enough for a first pass. Finally, extra upfront cost of the gas option is how much more the gas route costs before you dry a single load: the appliance price difference plus any gas line run, shutoff valve, flexible connector and vent work. Enter zero if both hookups already exist.

Press Calculate dryer cost. The result panel shows monthly and yearly cost for both machines, cost per load, which one is cheaper, and the payback period on the gas premium. Reset to defaults restores every field, and Copy result puts the output on your clipboard once a calculation has run. The address bar also updates with your inputs, so the link can be bookmarked or shared.

Formula for monthly and yearly dryer operating cost

Let $L$ be loads dried per week, $E$ the kilowatt-hours an electric load uses, $G$ the therms a gas load burns, $K_g$ the kilowatt-hours a gas load still draws from the electric supply, $P_e$ the electricity price in dollars per kilowatt-hour and $P_g$ the gas price in dollars per therm. Loads per year are $N_y=52L$ and loads per month are $N_m=\frac{52L}{12}$, which is the familiar 4.333 weeks per month written without rounding.

The monthly cost of the electric machine is

Formula: C_e = N_m ⁢ E ⁢ P_e

$$C_e=N_{m}E{P}_e$$

and the monthly cost of the gas machine adds both fuels together, because a gas dryer appears on two bills:

Formula: C_g = N_m ⁢(G ⁢ P_g + K_g ⁢ P_e)

$$C_g=N_m(G{P}_g+K_g{P}_e)$$

Yearly cost is twelve times the monthly figure, and cost per load is simply the bracketed term itself. The monthly saving that gas delivers is $S=C_e-C_g$, which is negative whenever gas is the more expensive fuel at your rates.

Formula for the payback period on a gas installation

If the gas option costs $U$ dollars more to buy and install, the simple payback period in months is

Formula: T = U / (C_e − C_g), C_e − C_g > 0

$$T=\frac{U}{C_e-C_g},C_e-C_g>0$$

The condition on the right matters. When gas does not save money the denominator is zero or negative, the quotient is undefined or meaningless, and the calculator reports that there is no crossover rather than printing an infinity. This is undiscounted simple payback: it ignores the time value of money, future rate changes and any repair difference between the two machines.

Formula for energy per load from the combined energy factor

The federal test procedure rates dryers with a combined energy factor, $\mathrm{CEF}$, in pounds of clothes dried per kilowatt-hour of total energy, gas included at the standard conversion of $3412$ British thermal units per kilowatt-hour. If the standard test load weighs $W_d$ pounds bone dry, then the total energy of one reference cycle is

Formula: E_cyc = W_d / CEF

$$E_{\mathrm{cyc}}=\frac{W_d}{\mathrm{CEF}}$$

To convert a gas dryer's kilowatt-hour-equivalent heat into therms, use the fact that one therm is exactly $100000$ British thermal units, so $1\text{kWh}=0.03412\text{therm}$. Finally, because nearly all dryer energy goes into evaporating water, the energy of a load scales with the water it carries. With bone-dry weight $W$, incoming remaining moisture content $R_0$ and final moisture $R_f$, the water to remove is $w=W\frac{R_0-R_f}{100}$, and cycle energy is well approximated by a small fixed term plus a term proportional to $w$.

Worked example: 5.4 loads a week at reference energy and typical rates

Take the defaults. Loads per year are $52\times 5.4=280.8$, so loads per month are 23.4. The electric machine uses 2.27 kWh a load at 17 cents, giving $23.4\times 2.27\times 0.17=9.03$ dollars a month, or $108.36 a year, or 38.6 cents a load. The gas machine burns 0.083 therms at $1.30 and 0.12 kWh at 17 cents, so one load costs $0.083\times 1.30+0.12\times 0.17=0.128$ dollars, which is $3.00 a month and $36.03 a year. Gas saves about $6.03 a month, so a $300 gas premium pays back in $300÷6.03\approx 50$ months, a little over four years.

Changing one rate at a time shows which lever moves the answer. The table below keeps 5.4 loads a week and the same per-load energy, and varies only the prices.

The last row is the important one. It is a perfectly ordinary combination in a hydro-heavy region with imported gas, and in that case the gas dryer both costs more to install and costs more to run. That is why the calculator prints an explicit no-crossover message instead of a number.

Reference figures behind the default per-load energy values

The defaults are not a marketing average. They come from the federal uniform test method for clothes dryers, which dries a standard-size test load weighing 8.45 pounds bone dry from 57.5 percent remaining moisture content down to about 2 percent, and from the minimum efficiency a new dryer is allowed to have. Dividing the test load by the minimum combined energy factor gives the reference cycle energy, and splitting the gas machine's total into a burner share and an electric share gives the two gas inputs on the form.

Two sanity checks are worth doing. First, 4.69 pounds of water needs roughly 4,690 British thermal units of latent heat, about 1.37 kWh, so an electric dryer that spends 2.27 kWh is running near 60 percent overall efficiency once vent losses, drum heating and motor draw are counted. Second, older field studies such as the Lawrence Berkeley National Laboratory Home Energy Saver model report considerably higher figures, around 3.8 kWh and 0.22 therms per load, because they describe the larger, wetter loads and less efficient machines that were common when the underlying utility data was collected. If your household runs full, heavy loads out of a slow-spinning washer, the field numbers may fit you better than the test-procedure numbers, and the form accepts either.

Why washer spin speed is the largest lever on dryer running cost

Every model above is dominated by one term: the water in the load. A washer removes water mechanically. Spinning at 1,400 rpm rather than 800 rpm can leave twenty to thirty percent less moisture in the fabric, and the extra spin costs only a few hundredths of a kilowatt-hour because the drum is already turning. The dryer, by contrast, removes water thermally at roughly 0.45 kWh per pound of water for an electric machine. Dropping a nine-pound load from 70 percent remaining moisture to 45 percent takes 2.25 pounds of water out before the dryer starts, which is worth about one kilowatt-hour of drying energy for perhaps 0.03 kWh of extra spin: a thirty-to-one return.

The second lever is cycle selection. A moisture-sensing automatic cycle stops when the clothes are dry. A timed cycle keeps heating to the end of the dial whether or not the load is finished, and habitually overdries by ten to twenty percent, which is both wasted money and the main cause of fabric wear. A low-heat cycle is gentler and slightly kinder to clothes, but it runs the drum and blower much longer, so its total energy is usually a little higher rather than lower. The Dryer Derby game further down the page lets you pull all three levers under time pressure and watch the two meters respond.

Limitations and assumptions you should know before trusting the number

This calculator is a steady-state operating-cost model and nothing more. It assumes every load is the same size and the same wetness, that your weekly laundry rhythm is stable, and that your rates hold for the whole period. It does not model the fixed monthly customer charge on a gas account, which can wipe out the savings entirely for a household whose only gas appliance is the dryer. It does not model tiered, seasonal or time-of-use electricity rates, standby power between cycles, or the electricity a heat pump dryer saves by recycling its own exhaust heat. It ignores purchase price beyond the single upfront-difference field, and it ignores maintenance, repairs, vent cleaning and the shorter expected life of some designs.

The payback figure is undiscounted, so it is optimistic in real terms: three hundred dollars saved five years from now is worth less than three hundred dollars today. The energy defaults describe a machine that just meets the current federal minimum; a certified efficient model will beat them, and a twenty-year-old machine will not. Emissions are outside the model entirely, and the ranking on carbon can differ from the ranking on cost depending on how your grid is generated. Treat the output as a structured estimate for learning and budgeting, and confirm anything expensive with your own bills and a qualified installer.

Dryer Derby: the game version of the same arithmetic

The interactive panel below the form runs the identical energy model in real time. Loads arrive in a basket with a fabric type and a bone-dry weight; you choose a washer spin speed, a dryer cycle and a machine, and the chosen drum tumbles until the water is gone while its meter fills in kilowatt-hours or therms. Scoring compares the cost you actually incurred with the cheapest fabric-safe choice available for that load, so a high score means you understood the model, not that you were lucky. The payback horizon bar at the foot of the stage takes your average per-load gas saving, multiplies it by the loads per year from the form, and shows where the gas premium would break even against a typical thirteen-year appliance life. The game reads the rates and the premium from the calculator inputs but never writes to them, so you can change a rate mid-season and watch the crossover move.

Sources for the dryer energy, unit and efficiency figures

The test load weight of 8.45 pounds bone dry, the 57.5 percent initial and roughly 2 percent final remaining moisture content, the combined energy factor definition in pounds per kilowatt-hour and the 3,412 British thermal units per kilowatt-hour gas conversion all come from 10 CFR part 430 subpart B, appendix D2, the U.S. Department of Energy uniform test method for measuring the energy consumption of clothes dryers. The minimum combined energy factors of 3.73 lb/kWh for a standard vented electric dryer and 3.30 lb/kWh for a standard gas dryer are set in 10 CFR 430.32, energy and water conservation standards and their compliance dates. The therm as exactly 100,000 British thermal units and the 3,412 Btu heat content of a kilowatt-hour are published by the U.S. Energy Information Administration, Energy units and calculators explained. The 283 cycles a year, equal to 5.4 loads a week, used as the default laundry volume is the reporting basis in the U.S. EPA ENERGY STAR clothes dryers program. The higher field-study per-load figures of 3.8 kWh and 0.22 therms are from the Lawrence Berkeley National Laboratory Home Energy Saver drying energy documentation.

Frequently asked questions about electric and gas dryer running costs