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The following post was written by Eric Sandeen and can be seen on his blog here.

There are a lot of silly DIY solar scams out there, but here’s the real deal.

Consider:

• An average electric dryer run uses about 3.3 kWh of electricty
• An average home might run 150 dryer loads per year
• This equates to roughly 500 kWh per year for drying clothes

Let’s say you wanted to “go green” for your laundry drying needs by “going solar.”  How much solar PV would it take to dry this much laundry?  According to the PV Watts website,  a 500W (0.5 kW) PV system would yield about 612 kWh in a year here in Minnesota.  That’s a bit more than the dryer is taking, but panels are commonly 230W these days, so let’s round down to a 460W system, and say it’d net somewhere around 500 kWh in very round numbers.

Hm, or you could just not use your dryer, and hang your clothes outside!  How much might that save vs a solar setup?

Ok, you can’t hang up clothes in a Minnesota winter.  So let’s cut the potential in half – 250kWh/year of clothesdrying in the summer, and this would take about a 230W solar array to compensate.  Let’s say $8/watt for a solar install – really, for a small job like this it’d be more, but again, round numbers – this leads to about $2000 for a panel, inverter,  installation, and hookup.

Or – you could spend about $20 on a couple of retractable clotheslines, and have the same net effect, plus the zen-like serenity attained by taking a little time out to do a simple task like this outdoors.  $20 for the equivalent utility of 230W of solar … at $0.09 per watt!

(This really is a fine example of why any good solar installer will tell you to do everything you can to conserve first – it’s much, much cheaper!)