Solar Water Heater

[cityimrov]

I was reading an article about how popular they are in China and they are pretty cheap, only around $200 for something basic to something a bit over $1000 for something more complex.    

I'm thinking about getting one.  Has anyone installed one of these solar water heaters in their house yet?  How was it?  Does it provide consistent hot water?  How much did it cost you guys?  I'm guessing installation is going to be where they charge the big bucks.

[Jason]

Many systems can be installed yourself if you're pretty handy.  I don't have one personally but know some people who do and work with them quite regularly in my line of work.  IMO, they are the most practical form of "green evergy" that exists today and do work very well in Florida.  They are essentially a system that uses the sun to heat up an internal liquid that is piped down to a heat exchanger inside the house that is used to heat the incoming water feeding your existing water heater.  The heating elements in the heater are then only used when the tank temperature drops low enough to be needed (at night or during really cold days).

[Dog Walker]

We have had one for five years.

What Jason is describing is a "closed loop" system.  It is the most efficient and most expensive of the solar water heaters.  If there are more than two or three people in a household, they are the way to go.  Cost $3000-$4000 installed (a/o five years ago).  JEA will refund $800 of the cost.

Since there are only two of us (the dogs don't bathe much)  we have an "open loop" system which is the simplest and cheapest system.  The water is heated and stored in the solar panel which is directly connected to the water supply.  That heated water is then pulled into a regular electric water heater when hot water is used from a tap.  The electric water heater will bring the water up to usable temperature if it isn't hot enough.

In practice, we turn the electric water heater on in November and turn it off in March.  In the summer months the water coming out of the collector on the roof runs 180 degrees +!  The system cost us $2100 after the JEA rebate.

Solar water heaters are the biggest "bang-for-the-buck" you can get and the logical first step in going solar.  Water heating accounts for 25-30% of your electric bill unless you have teenagers when it can account for 80%!  

[Jason]

Thanks for breaking it down a bit more, DW.   Do you have trouble with hard freezes with your system?

[Ernest Street]

I have seen a home made one in Arlington with black garden hose coiled back and forth on a roof.

[Doctor_K]

Since there are only two of us (the dogs don't bathe much)  we have an "open loop" system which is the simplest and cheapest system.  The water is heated and stored in the solar panel which is directly connected to the water supply.  That heated water is then pulled into a regular electric water heater when hot water is used from a tap.  The electric water heater will bring the water up to usable temperature if it isn't hot enough.

In practice, we turn the electric water heater on in November and turn it off in March.  In the summer months the water coming out of the collector on the roof runs 180 degrees +!  The system cost us $2100 after the JEA rebate.

So you get scalded and 1st-degree burns in the shower for a minute and a half before the water turns cold? 

[Dog Walker]

Thanks for breaking it down a bit more, DW.   Do you have trouble with hard freezes with your system?

Not in our climate.  40 gallons of hot water in an insulated box takes days of no sunshine and below freezing temperatures to even begin to freeze and that would also presume that no water was used in the meantime.  I think they use open loop systems like mine as far north as Atlanta.  Up North they have to use the closed loop systems such as Jason described to prevent freezing.

The black plastic hose on the roof is usually indication of a swimming pool heater where you aren't trying to heat water for washing, but to take the chill off of a swimming pool.  If you have a pool, the various solar pool warmers are real money savers.

[Dog Walker]

Since there are only two of us (the dogs don't bathe much)  we have an "open loop" system which is the simplest and cheapest system.  The water is heated and stored in the solar panel which is directly connected to the water supply.  That heated water is then pulled into a regular electric water heater when hot water is used from a tap.  The electric water heater will bring the water up to usable temperature if it isn't hot enough.

In practice, we turn the electric water heater on in November and turn it off in March.  In the summer months the water coming out of the collector on the roof runs 180 degrees +!  The system cost us $2100 after the JEA rebate.

So you get scalded and 1st-degree burns in the shower for a minute and a half before the water turns cold? 

No, the forty gallon water heater between you and the forty gallons of 180 degree water on the roof tempers the incoming water to a less dangerous heat.  There is also a "tempering" valve between the collector and the tank that will mix cold water with the incoming 180 degree water to take it down to whatever you have it set for.  We set ours at 140 degrees, but I would set it lower if we had children in the house.  Our electric heater is set at 110 degrees.

Your concern is one of the reasons to get a system professionally installed rather than trying to do it yourself.

[Doctor_K]

Since there are only two of us (the dogs don't bathe much)  we have an "open loop" system which is the simplest and cheapest system.  The water is heated and stored in the solar panel which is directly connected to the water supply.  That heated water is then pulled into a regular electric water heater when hot water is used from a tap.  The electric water heater will bring the water up to usable temperature if it isn't hot enough.

In practice, we turn the electric water heater on in November and turn it off in March.  In the summer months the water coming out of the collector on the roof runs 180 degrees +!  The system cost us $2100 after the JEA rebate.

So you get scalded and 1st-degree burns in the shower for a minute and a half before the water turns cold? 

No, the forty gallon water heater between you and the forty gallons of 180 degree water on the roof tempers the incoming water to a less dangerous heat.  There is also a "tempering" valve between the collector and the tank that will mix cold water with the incoming 180 degree water to take it down to whatever you have it set for.  We set ours at 140 degrees, but I would set it lower if we had children in the house.  Our electric heater is set at 110 degrees.

Your concern is one of the reasons to get a system professionally installed rather than trying to do it yourself.

I was being about 90% facetious, but was still curious - thanks so much for enlightening me.

[Dog Walker]

No problem!  I am a huge fan of solar power and even have 5K watts of solar panels on the roof, too.

I got enthusiastic about solar hot water as a kid in Atlantic Beach where several of the houses in our neighborhood had awnings over their windows that were actually homemade, open-loop, solar hot water collectors and that was in the early '50's.  Nothing new about this stuff and in Florida it just makes sense.

A commercially installed, open loop system will pay for itself in 3-4 years.  Pretty good investment.

[Doctor_K]

One other question - do multiple floors affect the open loop system's usefulness/efficiency?  If I've got a solar panel for an open loop system on my roof and that's three stories above my garage, does (pipe) distance matter much?

[Jason]

It shouldn't matter as long as the pipe is insulated.  Very cheap and easy to do.

[Sigma]

You can also use these with the tankless water heaters, correct?

[Jason]

I wouldn't think the benefit would be as great with tankless water heaters but it should work.  Being able to store the hot water so that it is ready to use during the night time and cold weather is where the greatest savings will come from.  Without the storage, hot water is "on-demand" and will be using the electric heat when the solar panels aren't producing.

[cityimrov]

Are there any special precautions you need to take during high winds?  Is there wind ratings for these things? 

I read there is benefits with a tankless water heater.  The water from the solar can just be stored in an ordinary tank and then connected to a tankless water heater.  I hear it's somewhat more cost effective during those very cold winter days.