If you’re in the tropics or near-tropics for the summer, you know that sunlight streaming through every window — hatch, port, or whatever you call it — just adds to the heat inside the boat.
Catamarans, trawlers and some newer monohulls are the worst, with large non-opening windows. They offer gorgeous views from inside the boat, but can raise inside temperatures considerably.
And so, the first thing most boat owners do is to make (or have made) snap-on exterior shade panels with a fabric such as Phifertex or Phifertex Plus. Both of these block a fair amount of the light (70-90%) but still let you see out a bit. Our boat came with one for the saloon windshield, and I made another for the large window in our cabin.
They snap on, which is helpful for the one that the helm looks through (we take it off before getting underway — it’s part of our “Before Moving Boat” checklist), and they do a great job nine months of the year.
But, we’ve learned, they are woefully inadequate during the summer. Enough sunlight comes through that the window gets uncomfortably hot to touch!
We looked at all sorts of possible solutions and ended up going for the 5-minute, less than $20 solution. We bought a roll of Reflectix (bubble wrap with foil on both faces) and cut it to the size of the windows and slid it under the snap-on shades. I simply cut out little places where the snaps are so that the Reflectix can be the full size of the window.
My technique was simple — I cut the pieces roughly to size, put them in place (on our boat, it was easiest to set them against the bottom snaps), made the cutouts for the snaps on that side (on ours, the bottom), slid the Reflectix into its “final” spot, trimmed up the other sides and cut the holes for the rest of the snaps, then snapped the fabric covers back into place. Two done in about 5 minutes.
It has made a big difference in the temperature inside the boat. Temps inside the boat used to be about 10 degrees (Fahrenheit) hotter than outside “in the shade” temperatures; now they are about the same. 90° in the boat is a lot more tolerable than 100º!
We got the idea from another boat that was going on the hard for hurricane season, but it works just as well if you’re living on the boat.
NOTE: Putting the Reflectix on the inside of the boat is a bad idea we’ve learned — the heat will build up between the window and the Reflectix and can damage the window. Putting it on the outside, on the other hand, helps to protect the window.
When we get ready to get underway, we always remove the snap-on shade over the windshield anyway and put it back in place once we’re anchored or at a dock. With the Reflectix in place, we simply roll the Reflectix up with the shade to get underway and put them on together at the end of the trip. It takes no more time.
We had seen various ways to make pockets in the shade cloths for the Reflectix or to otherwise attach the Reflectix either to the boat or the shade. We have found it totally unnecessary.
Yes, with the Reflectix in place we lose the view and so don’t use it during the cooler months. The pieces are easy to store under a mattress during the winter and we’ve found that even in tropical sun and rain, they last two to three years. They didn’t disintegrate; the foil just slowly wore away so that light started coming through. Exact longevity will depend on how much of the year you use them and how intense the sun and rain are.
A couple weeks ago I had to replace one and walked over to the Home Depot in Marathon, Florida (it’s a couple blocks from Boot Key Harbor, making it very convenient for cruisers). I figured with all the part-year residents leaving homes and boats here, Reflectix would be a popular item. Discovered that they don’t carry it or anything similar in stock at this store (only their larger stores do). Turns out that no local store carries it. Okay, off to Amazon (seems to me that there’s a business opportunity here for a local entrepreneur):
Reflectix comes in a bunch of different sizes, so you’ll have to do some rough measuring to figure out what width and length roll will work best for you. It also comes in “tabbed” for stapling in home construction; this generally isn’t needed for making sun shades but can easily be cut off if that’s all you can get.
P.S. If you have large “glass” hatches, look at Outland Hatch Covers to insulate (and also protect) them. Read my post here.