Sunward Solar Hot Water

What seems common (and counter-intuitive?) with renewable energy "packages" is, they are always expensive.  You can almost always do better sourcing the individual components yourself.  (I guess you are paying a "convenience" premium for "packages")   Second, these are flat-plate collectors.  I don't recommend them, especially if you live anywhere there is less the 98% sunny skies.  They suffer from two problems which reduce their efficiency.  First problem, the flat glass front.  Almost every photo on their website reflects the problem, literally!!!  Notice the glare on the panels.  That is reflected light that never gets collected.  It's not bad if the sun is directly in front of the panel, but as angle increases, energy absorption decreases exponentially.  Second problem, the collector itself.  It's just black tubing under glass.  The problem occurs when a cloud or any form of shadow reduces light input.  Heat energy of the fluid being pumped through the panels is actually radiated back out of the panel.  There are supposed coatings to help reduce this from happening, but it can't be avoided.  Essentially, when a cloud passes by, you go negative production.

I strongly recommend evacuated tube collectors.  They suffer neither of the problems of flat-plate collectors, as they are able to collect energy at an angle as efficiently as if directly forward, and being that they are vaccuum tubes, heat energy can't be released back when shaded. (that, and the fact that the fluid never enters the collector tubes to start with)  Efficiency all around is higher. Though be warned!  Fluid MUST be continuously circulated though evacuated tube collectors while exposed to sunlight. Due to the nature of their design, stagnation temperatures can exceed 400F.

The rest of their system is basically the same as my own I'm putting together.  So parts and costs.  What do you need and what is it going to cost?  Well, this is a breakdown of what I have.

• 2 - American Solar Works ASW-52B collectors. (old model no longer available)  I paid $650 each through a Craigslist ad placed by importer/distributor.
• 2 - El-SID 10PV 10 watt, 3.3 GPM direct solar, magnetically driven circulator pumps.  I paid $200 each
• 1 - 50 watt polycrystalline solar panel (used, brand unknown)  I paid  $254 shipped off Ebay
• 7 - Weksler 152FC 40F - 260F  1/2"NPT thermometers.  (Bought new on Ebay for $25.50 shipped.  So low the seller didn't want to sell them until I pressured him to complete the sale)

And, what I still need:

• 1 - ART-TEC  DTC-1 Solar powered temperature differential controller (costs $110 w/ sensors)
• 1 - liquid to liquid heat exchanger. (I haven't chosen one yet, but probably a flat plate <$100)
• 1 - expansion tank (<$50)
• 1 - pressure relief valve (<$10)
• 2 - 80 gallon water tanks (can be simple storage tanks or water heaters.  Way cheaper option than solar storage tanks with built in exchanger) Price?  Probably around $450 ea, versus a solar storage tank w/ internal heat exchanger at $1500+ each. 
• Pipe and fittings.  (I'll probably use copper pipe salvaged from my previous job for non-potable portions of the system)