Which is better – for saving money, for the environment?

When comparing gas vs electric dryers, you first have to ask yourself whether you’re considering the right issue. If you’re trying to cut your energy use on laundry, your clothes dryer is probably not the best place to start – instead, you should first look at your clothes washer.

The main factors to consider for a washer are how much water it uses (especially hot water) and how fast it can spin the laundry at the end of the cycle. The faster the spin cycle, the less water is left in the clothes for the dryer to handle. That means that a relatively inefficient dryer can use less energy drying a load of laundry from a high-efficiency front-loading washer, than a super-efficient dryer would use drying a load of laundry from a lower-efficiency top-loading washer.

But assuming you’ve already done what you can on the clothes washer side, and you really want to know the answer to the gas vs electric dryers debate, let’s consider some of the key issues regarding financial cost and environmental issues.

Pricing of gas vs electric dryers

When comparing gas vs electric dryers for price, there is not a lot of difference, at least in Canada, where gas dryers are more commonly used than in the US – but you’ll have less selection for gas dryers. For instance, checking the Sears Canada website I find about half as many gas vs electric dryers (29 vs 57) and an average price of $746 for electric dryers vs $846 for gas dryers, or typically about $100 more. The price difference is mainly because there are a large number of very cheap electric dryers at the bottom end; top prices for gas vs electric dryers are about the same, around $1500.

But remember, sticker price is not the same as total cost of ownership. In general, gas dryers are much less expensive to operate, because natural gas is a better heating source than electricity. The consumer cost for one hundred cubic feet of natural gas (1 CCF)  has ranged between $1.40 and $1.20 between 2006 and 2010 (with the cost falling over time). One CCF of natural gas produces 99,800 BTU of thermal energy, which means that 100,000 BTU costs about $1.20. The consumer cost for one kilowatt of electricity as of December 2009 was 10.93 cents per kilowatt hour, and one kilowatt hour produces 3,414 BTU of thermal energy, or about $3.20 for 100,000 BTU. So in terms of operating costs for gas vs electric dryers, the gas dryers come out at around 37% of the operating cost of an electric dryer.

What about from an environmental perspective?

Almost all the heat created by burning natural gas in your gas dryer goes towards heating the clothes and evaporating the water. The same is true of the electrical heat produced in an electric dryer. The problem is that, in the case of the electric dryer, if the electricity was produced with fossil fuels such as burning natural gas or coal or oil, only about 30-35% of the original heat in the fossil fuel gets converted into electricity (because of thermodynamic inefficiencies governed by the Carnot fuel cycle) and a further 3-7% is lost in transmission from the power plant to your house, so an electric dryer whose power is supplied from fossil fuels is only about 25-30% efficient. That partly explains why with gas vs electric dryers the former are less expensive to operate. And it partly explains why, in the US at least where a large percentage of electricity is generated from coal, gas dryers are also more environmentally friendly than electric dryers.

Add to this the fact that burning coal produces more CO2 per therm of heat than natural gas, and a gas dryer is actually responsible for only about 1/5 the amount of CO2 of an electric dryer where the electricity comes from coal. How do we determine this?

  1. Burning coal to generate electricity releases 2.117 lbs of CO2 per kwh produced. Burning natural gas to produce electricity releases 1.314 lbs of CO2 per kwh produced. (These are average figures for US production from the Energy Information Administration, part of the DOE.) That means the CO2 emissions ratio for gas vs electric dryers is 1.314 / 2.117 or 62%, per unit of fossil fuel burned.
  2. Assuming for argument’s sake that 80% of the heat from natural gas in a gas dryer is used to heat the clothes (and about 25% of the fossil fuel coal heat in the case of the electric dryer, as explained above), we can multiply that 62% by (0.25 / 0.8) or 31%, which gives us about 19%.

So my guidance, if you get your electricity from coal, is to go with a natural gas dryer instead of an electric dryer, as you’ll cut your CO2 emissions.

On the other hand, if you buy your electricity from a green electricity supplier, then from an environmental perspective I would recommend an electric dryer because green electricity doesn’t produce any CO2 emisssions, which is better than any gas dryer is likely to do (unless you have a biogas digester for your kitchen waste or your composting toilet!).

The catch with drying clothes with green electricity is that green electricity is typically 50% to 100% more expensive than ‘dirty’ or grey electricity (the kind produced by coal-fired plants or gas generators) so that price comparison, where a gas dryer costs about 37% as much to operate as an electric dryer, gets even better for gas vs electric dryers: a gas dryer would cost only 19% to 25% of the cost of an electric dryer that uses green electricity!

Performance of gas vs electric dryers

There shouldn’t be any difference in the performance of gas vs electric dryers – they both dry clothes using the same technique of applying heat and airflow in a tumble dryer. The electricity used to move the tumbler is negligible. I measured my gas dryer and a fully dryer cycle took about half a kilowatt hour of electricity. (In an electric dryer almost all the electricity is used for heat, not the tumbling.)

Best tips for saving on clothes dryers

As I mentioned at the outset, the best way to save on drying your clothes is to make sure the clothes are as dry as possible before they go into the dryer, whether you have a gas dryer or an electric one. You can do that by switching from a top-loadingto a front-loading washer; buying an extra spinner that extracts water from clothes at high speed rotation after the clothes are washed; or, best of all, hanging your clothes up on a line or laundry rack, either outside or in your basement or laundry room, and using the dryer just to finish off the drying or fluff them (as line-dried laundry sometimes can get stiff – my bathroom towels often feel like boards after I line dry them!).

And avoid gimicks like dryer balls – they just don’t work, as I explain in my dryer balls review.

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