Introduction: Heat Your Pool With Solar Lily Pads

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There's no doubt that a Solar blanket can really help to heat your pool. They turn your pool into a greenhouse, letting sunlight in, trapping the heat inside. They also significantly reduce heat by evaporation, and also to a limited extent prevent heat loss by emission. Studies have reported that with 6 hours of sunlight, a good solar blanket can heat your pool by 10-15F (6-8C). https://blog.intheswim.com/how-effective-are-solar...

However, despite their ability to heat your pool for free, many people are reluctant to use them because of the safety risk. If a child or a pet jumps into a pool with a solar blanket cover still on, they can get wrapped in the blanket or can slip under it, and can drown.

Instead of covering your pool with a solar blanket, these solar lily pads are a safer alternative that reduces the risk of harm. By having lots of smaller floating pads instead of one large blanket, anyone falling in the pool will slip between the gaps, and similarly can surface between the pads, or move it out of the way. Only 80% of the pool is actually covered, but it still really makes a difference, and that 20% gap is adding safety.

Note, nothing can completely remove the risk of harm around a pool. This is designed to make it "safer", but not "100% safe".

Supplies

  • Hula hoops. You need enough to almost cover the pool. I have an 8m x 4m pool, so I bought 32 90cm hoops (i.e. 8 x 4). Why not 1m hoops? Because you are going to need some wiggle room or it will be a nightmare to get the hoops in the water. I used these.
  • Enough solar blanket to cover your pool. I used the SolGuard GeoBubble from here.
  • 6mm x 10mm Fir tree car trim panel clips - at least 6 per hoop (I actually could only find 6mmx14mm and had to trim the ends off them all). I found some on eBay.
  • Some fiberboard to make a template - at least 90cm x 45cm

Tools

  • Drill with 6mm bit (to match the fir tree clip diameter)
  • Stanley Knife
  • String
  • Sharpie
  • Jigsaw

Step 1: What You Are Aiming For

Here's a picture of what you are aiming for to give you an idea of the end result. We are cutting the solar blanket into circles, and fastening it to the hula hoop.

Step 2: Cutting Your Solar Blanket

To cut the solar blanket, you're going to need a template. I tried first of all with just using a knife on a piece of string, like a compass. It didn't work - horribly messy edges. So, find a piece of fiberboard or similar, and make a template. Make it about 3cm larger in diameter than your hoops - you're going to need it to go over the edges or the fasteners will be too fragile. Get a sharpie and a piece of string, and draw a nice circle on the board (or a semi-circle if, like me, you don't have a big enough piece. Then get out a jigsaw and cut the template out.

Next, start cutting circles. Put your template down and cut around it with a Stanley knife, or other heavy-duty knife. I did it on the lawn so that I was able to easily kneel on it all and cut without fear of damaging whatever was underneath. Don't leave too big a gap between the circles or you won't have enough material.

Step 3: Build the Hoops

Once you've cut your first circle (not the last - let's make sure it fits when you've only cut one), lay it on top of the hula hoop, bubble side up. Hopefully it's going to just go over the edge all the way round. Get your drill and drill a hole through the bubble cover and the hoop together. Pop a clip in, and then start drilling more holes. Drill one and clip one hole at a time. If you try to do more, it's pretty much guaranteed to move between holes and won't line up.

If the hoop squashes as you put the clip in, get a pair of grips to squash the hoop horizontally and push the clip in then. Once you have 6 clips it should all be sturdy. If you can get a good price on the clips, put 12 in - it will be easier to move the hoops in the water later on.

Assuming the first hoop was all perfectly sized, cut out the remaining circles and get clipping.

Step 4: Throw Them in the Water

Once it's all done, throw those hoops in the water, bubble side down. They'll increase the heat in your pool for free.

I did a test to see how much - I measured two similar days - one day with the hoops in the water. The water went up 2.5C with the hoops on (and the heat pump on). The next day was the same starting water temperature and the same air temperature. I left my solid slats cover on, which is more insulating against heat loss, but doesn't have any solar gain. The pool temperature went up 1.5C, again with my heat pump on. So the 1C heat rise is not the amazing 5-8C rise that is seen in some places, but I figure it will save me money over one season, and it will be better for the environment too.