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Heat Streamer FAQ

How do I assemble it? 

Check out the assembly instructions here.

How does it work?

The infrared rays from the sun are absorbed by the reflective copper, aluminum, and steel coatings on the inside of the tube. The heat is trapped inside the double-walled vacuum inside, causing it to heat up very quickly. The copper manifold inside the tubes heats cold water from one end and pumps it out the other end, heating up to 5 gallons of water from room temperature to above hot tub temp in four hours.

What are the solar tubes made out of?

The Heat Streamer is constructed with borosilicate glass vacuum tubes, with a copper pipe manifold and aluminum frame.

How much does it heat, and how fast?

The Heat Streamer heats 5 gallons of water from room temperature (68 F, 20 C) to the average temperature of a hot shower (105 F, 40.5 C) in 3 hours. The array transfers solar power to water flowing inside at a rate of 165 watts.

What’s inside the tube?

Inside the tubes are highly reflective steel, aluminum, and copper coating, which provides infrared insulation. One tube holds 1 liter of fluid.

What can I heat with it?

The heat streamer is highly versatile. Previous customers have used the heat streamer to heat hot tubs, as supplemental water heaters, a heating supplement for greenhouses, heater for a garage, hot water for sink/showers, and off-grid homes. You can also connect more than one heat streamer for greater effect!

Are they freeze-resistant?

Yes. See more info here.

How fast should it be flowing?

There isn’t necessarily a benefit to flowing water quickly through the array, in terms of collecting heat. A flow rate of even five gallons per hour is sufficient to “cool off” the insides of the glass tubes and harvest the incoming solar heat.

How do I install it?

The heat streamer comes with a detailed installation document.

Is the water potable i.e. can I drink it?

Bare Tubes: We get this question quite a bit, and it is a good one to ask. As the solar tubes aren’t primarily designed to be used with potable water, there hasn’t been a lot of testing on the safety of using them for drinking water. The only thing coming into contact with the water is glass, but the glass has not been food safety tested.

Heat Streamer: The inner layers do come in contact with the copper pipe, which is safe to run water through, and the water is totally isolated from the glass.

Will it heat my pool?

This one is tricky. Technically, yes it will, but since the Heat Streamer is relatively small, one wouldn’t be enough to make a big enough impact on a 7,500 gallon pool. Multiple Heat Streamers would make a much bigger impact when heating a pool.

What else do I need in order to install the Heat Streamer/10 Solar Tubes?

This is definitely a choose-your-own-adventure situation, but since we get this question a lot we’ve listed a few materials necessary on here so your installation will be easier.

Heat Streamer

12V Brushless DC Pump (available on eBay)

Insulation for intake and output hose lines (easily found at any hardware store)

10 Solar Tubes

PVC Piping rated to withstand 200F

Water-proof epoxy

Solar Hot Water Systems, Quick Facts and Practical Set Up

Active Systems (Heat Streamer): Use a small pump to move water between the collectors and the tank. Unobtrusive, lightweight, can use an existing tank.

Passive/Thermosyphon Systems (10 Solar Tubes): The storage tank sits above the collectors, cold water sinks into the collectors, while warm water rises unassisted from the collectors into the tank. Space-saving, easy to maintain since it has no moving parts.

  1. Collectors (whatever collects the sun’s rays) should face true North in a shade-free environment.
  2. The ideal inclination is the angle of latitude plus 5 to 10 degrees. Seattle’s latitude is 47.5 Degrees N, so an ideal angle would be around 55 degrees.
    1. If your collectors face E or W, the lower the inclination is better.
  3. Insulating tubes is a great way to protect against freezing, as is a temperature controlled pump.
    1. A temperature control valve also works to protect against pressure buildup/overheating.
    2. Outside temperatures don’t reduce energy in light. If it’s sunny, there will be heat.
  4. A storage tank does not need to be massive, especially for the heat streamer. 5-10 Gallon storage tanks work well for it, and if you have more than one heat streamer you can go up in size.
  5. Think of the tube acting like a thermos. The vacuum keeps heat inside it for a long time, whereas a flat plate would cool off quickly. Ex: If you filled a glass and a thermos with hot water and put them in the freezer, the water in the glass would get cold while the water in the thermos would stay hot. This is because the vacuum in the thermos keeps heat in.


Using red dye to capture the effect of a solar thermosiphon system.