I'm speaking of my solar hot water project, that's been on hold for a month and a half because of other very important duties around here...yesterday, all was done and I attacked the solar water project, determined to finish it...and I did....

Typically, I manage my KWH usage around the electric hot water heater, as it is the biggest abuser of power...I needed a way to drop that abuse...I bought three Heliatos solar hot water panels, installed them on the roof, and proceeded to figure how to get the water up there and back..simple heavy duty garden hoses (big $$$) was the answer....

The plan for the electric water heater, to conserve power, is to run it every other day, as there is just 2 of us in the house and the tank's hot water lasts for those two days, yesterday, after morning showers and dishes washed, the tank was cold...I completed the solar heater about 9:30 a.m, just as the sun was coming around from the far east towards south...when I have a cold tank, the electric will run at 4.7 kwh for 40 to 50 minutes, usually clocking around 4 kwh on the EM100B power meter...yesterday,I started the solar panel powered pump and the water began circulating thru the solar hot water panels...

The clouds were not my best friend yesterday, but all in all, I got about a 90% sun day...as I reached my scheduled shut off time, the cold water line to the panels was actually warm and the hot line to the tank was hot...at 4:30 p.m., I shut down the pump and threw the switch to heat the water electrically....

Now, at 9:30 a.m. this was a cold tank, I should have run the electric power, at the least, 40 minutes to get full hot water....it ran 14.02 minutes (on a digital stop watch) and the EM100B showed ONE kwh!!!

The excitement was unbelievable, I FINALLY found a way to REALLY, "kill the dragon"...

I have the "Dale Marshall Special" d.c. timer on the power line from the solar panels to run the pump, set at, on at 10 a.m., off at 4 p.m., I'm hoping, with some luck, I will rarely us the power companies power to heat the tank from now on, well, at least for the next 3 months, until Old Man Winter raises his ugly head

Here's some pics...


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I just love the smell of success in the morning.

Hillbilly Gene


Wonderful---great looking.

Really happy it's paying off.

HVAC distributers have insulation that will fit the 3/8" copper pipe,conserv heat.

just a idea,

rich in southern Va.

Have you considered a thermal switch instead of a timer? That way the pump will only run when the set temp is reached. This will make life a little easier. And as already stated insulation will improve the performance 

I also have a great working DIY hot water system.  I put a little snap thermostat inline to my 12 volt pump. At 100F the circut closes. It keeps the water from circulating while it is colder than the water at the bottom of the tank.

Hello Bill,


Not pretty... you are correct....... It is BEAUTIFUL !!!!


I don't have much to say about your system because you are always asking questions that I just can't answer and have to leave it to the more advanced members.


But man your system continues to inspire me to advance my own situation. The attic fan started it for me. That is just awesome and now this. I can see me "borrowing" some more of your ideas as I move forward.


Thank you for posting the pictures and for staying active on the forum... your system truely is inspiring.




I have considered this on many occasions, I was wondering if you can share where you purchased your water panels and the cost for them. I am an HVAC guy by trade so I have considered building my own out or 3/4" refrigeration copper but with the cost of that stuff now I have to do an analysis of the purchase/build scenario before I just jump right in!


As far as the waterlines are concerned:

If you decide to later "pretty them up" I have an excellent solution for you to research. In my area the guys who are installing the outdoor wood water furnaces are using a product which has 1/2 or 3/4" pex inside insulated flexible pipe. A quick search for insulated pex pipe brought up some ebay results which will give you some great ideas. This is going to be my route for piping. This could work with your current water system as well I think.


What part of the world do you live in? Do you have a drainback system for cold weather or do yo have to worry about freezing temps? I have to worry alot about freezing temps which is another reason I have not started my project. I am renting and just can't do some things. I want a drainback system but can't mount it on the roof so I may have to wait. I am thinking about incorporating a passive tank into the system as a sort of "boost" and for extra capacity...so many ideas not enough money!  :)


I really would like a link to he solar attic fan, that sounds like something I would enjoy reading!


Great to see someone actually "getting it done"!






I got lucky and bought a used 4x10 panel with a 10w PV panel to power a 12v pump.  I modified a 50g new hot water heater so the cold water feed goes into the drain hole at the bottom of the tank and a TEE put there is the cold water feed to the pump=>panel=> and back into where the cold water is designed to go into the tank.  I'm using the red pex pipe good to 200F. We might get a few freezes here in central florida. I deal with them by powering the pump with a 12v power supply so it circulates the tank water through the panel to keep it above freezing.  When I first put the system in.  Yeah it worked great but at night, the laws of physics would kick in and a convection flow would start so the hot tank water would rise up into the panel and radiate away all the heat gain overnight. After a few modification tries, I put in a one way valve that stopped this.  I also put in the same pressure/temp relief valve that you find at the top of a hot water heater at the highest point of the hot water panel to take any air out of the system that might build up.  Yesterday my tank hit 160F.  It's just too hot.  If I had any kids or old people in the house I would have to put in a tempering valve that wouldn't allow it past a certain temp.

Alot of questions and thank you for the nice replys....let me see if I can answer some stuff in one post, let's see...

The panels are from heliatos.com, a company in California, and I think they went for $150 a panel, but a quick look at their site will give you up to date prices...

The delivery system, yes, garden hose was not my first choice, but I also live in an apartment and the need to disassemble the whole thing, including the PV stuff, was necessary, not that I'm going anywhere, but I had to leave the option open...

This will be a summer only use project, I can't even imagine having to deal with water on the roof when it gets well below zero here at times during the winter, this also encompasses the need for a flexible delivery system, come fall, I just roll up the hoses inside the apartment, blow air thru the panels and let them cook in the sun for a few days to dry the water in the panels and I'm winterized...

Insulating the delivery lines...this all comes down to how far do I need to go...aside from the cost of the water panels, hoses, solar driven pump and solar panels, the system is free, every day the sun is out, I pay less money to the power company which reflexs payback to the cost of the system, even if it's only a 6 month system, one has to understand, 4 kwh for 15 days a month really adds up...

And finally, slightly off topic, the solar attic vent fan was built "out of my head", the 2 d.c. fans came from eBay, the 5 watt panel and wood and sealer came from Lowe's, saw, screw, cut, seal, mount it and DA-DA, attic vent fan, and the difference in the apartment with it and solar screens on the south windows, no need for air conditioning, a cheap, easy way to keep us cool (of course the window fan uses power, but not like that a.c. unit)...

So as I go with this new project, I will be monitoring and maybe tweeking, I'll let ya all know how it goes.....

Just ran the elecricity to heat the water tank after 2 days with no power from the power company...at 2:55 a.m....typical 2 day, heavy hot water usage, which was the scenario this run, it normally runs for 45 minutes...

9 minutes, 30 seconds...the top element didn't even come on! That calculates to .783 kwh...

....damn, this is just frigin' incredible...

I'm sitting here thinking about you guys suggestions...the one that concerns me is "the law of physics" comment, I can easily see that scenario happening here, although the whole system is pressurized and the solar hot water system is connected to my same pressurized electric tank, also pressurized. so would the feed to the panels happen in a pressurized system?

Maybe I should just look into a one way valve...what do you all think?

My system is also pressurized and it happened in mine and others that I saw while doing research on the solution. I don't know your plumbing routes.  My panel/pump is in it's own loop off the modified hot water heater so water usage in the house overnight has no effect.  The best system design to fix this would be to have your panel below your tank. The folks that do this don't even need a pump in the system.  Convection currents set up during the day and the collected heat rises into the tank and it stays there at night. Are you losing your heat at night?  I first tried putting in heat traps which are a big up and down zig zag in the plumbing but this didn't work at all.  The one way valve was the fix.


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