Summer is a great time for projects. Especially when they’re outdoors. What could be better this summer than an eco-friendly outdoor shower? Easy to build, easy on the environment, and when your girlfriend uses it…it’s easy on the eyes.
Project: Outdoor Solar Shower
Project Time: One day.
Energy Saved: Medium to high.
Ease of Use: Medium; must be refilled to heat.
Maintenance Level: Medium.
Skill Levels: Carpentry: Basic. Plumbing: Basic.
Materials: Water tank, plumbing fittings, wood, nails, hose bibb.
Tools: Flat or Phillips-head screwdriver, adjustable wrench, hammer, nails.
For many years, prior to moving to Durham, our only summertime shower was a solar shower, and after running through a few leaky off-the-shelf models that either didn’t heat up or dripped all the hot water out before we could use it, we found that the temporary solution of leaving a hose in the sun was just as effective, although sometimes the water would get too hot and the supply was very limited!
The best possible solar shower is one you make yourself: a small black container or water tank that sits in the sun, above your head on a wood or metal stand, and has a high-quality hose bibb or boiler drain valve that turns on and off securely, to which you can attach either a showerhead or a handheld sprayer.
There are also a lot of basic prefab models on the market; the most common is a 5-gallon thick-gauge plastic bag (either black or with a clear front and black back) that you hang in the sun, with a dangling small-diameter hose with a rudimentary closing clip or valve.
Siting the shower. There are three things you need to think about when siting a solar shower: first, privacy; second, water access; and third, sunshine. The most annoying thing about premanufactured solar showers is that you often have to take them down from the spot where they are hanging to fill them up, and then you have to struggle with a large heavy bag of water in the rehanging. If you can designate a spot for the shower and make it easy to get water into the container (usually with a hose, or even better via rainwater catchment), your solar shower will see a lot more use. It is hard to generalize about the amount of sunshine solar shower tanks need. If you live in Arizona, you might prefer that your water stays in the shade to provide relief on 100-degree days. If you live in Vermont, you’ll need at least four hours of direct sun on the tank to get it up to an enjoyable temperature. We found that in North Carolina, the water from the ground averages about 55 degrees, and it takes three hours in the sun for the water to reach a decent shower temperature. We can happily use a solar outdoor shower from May to September.
(Outdoor solar showers are fun and investigating and, best of all, can provide carbon-free hot water.)
The tank and stand. We built a basic wooden stand for our previous cob house’s solar shower (we don’t currently have a solar shower, as our water is already heated by the sun and our current house is on a corner lot with an alley in back, making privacy harder to come by). Our first solar shower consisted of four posts (4 × 4s) and a flat plywood top. The diagram in figure 6.3 shows another possibility, with brackets tied into house wall studs holding up the platform. Make sure that shower water drains away from the house foundation rather than toward it. Water is heavy, about 8 pounds per gallon, so depending on the size tank you want to use, the stand has to be of sufficient sturdiness to support the weight (see “Building a Horizontal Trellis for Shading” in chapter 10 of the book for information on attaching brackets).
If you oversize the tank, it will take much longer to heat up. Each outdoor showerer should use under 10 gallons of water, with 5 gallons often sufficient. The common 55-gallon rain-barrel-size tank is too large and would not heat up sufficiently. A 30-gallon or smaller tank is about right, depending on household size, showering frequency, and available sunlight. A black 5-gallon bucket can be a cheap solution for individual use. The more surface area the tank has relative to water, the faster it will heat up. The tank should either be black or be painted black, and it will need both a hose bibb (boiler drain) for the shower and a cap or cover that can be removed so you can fill the tank (see “Rain Barrel” in chapter 8 of the book for advice on inserting a hose bibb into a tank). If you rescue an old tank, make sure it didn’t contain something caustic or toxic in a previous life.
Building a solar outdoor shower is a good place to put your creativity to use. You might be able to fill the tank with rainwater overflow from your gutters. You could build an elaborate showering platform with built-in hooks and shelves and tiled walls. If you plumb the tank into the existing house water lines, refilling it will be a breeze. Just because you live in a city doesn’t mean you can’t have an outdoor shower. Nearly every home at the beach has an outdoor shower, and we’ve seen plenty of inner-city outdoor showers tucked away in the backyard behind simple board-and-batten walls. Just invest in a good bathrobe and you’ll have no trouble.