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Heliatos Solar Water Heating Kits Frequently Asked Questions

FAQs About Solar Water Heating Kits

Why have a Solar Water Heater?

Heating water is a huge portion of your electric and/or gas bill (often it can be as high as 40% of your bill!). Heating water with the sun is a time-tested and efficient way to heat water. It eliminates waste and saves you money. The Heliatos Solar Water Heating System is affordable and easy to install.

What is a Heliatos Solar Water Heater?

Our systems are unique, and inexpensive, no need for an extra tank. Here's how it works:
Cold water will be pumped out of your water heater and then through the solar water heating panels where it is heated by the sun. The pump's electricity is provided by a photovoltaic solar panel, so it's completely off the grid. Free hot water!

Where Do I put my panels?

Anywhere there is sun throughout the day. They look great on your roof or next to the house/RV/cabin.

What are the Panels made of?

The front of the panel is twinwall polycarbonate glazing , the same material used for airplane windows, robust and lightweight. The sides are thick aluminum and the backing is aluminum sheeting. Out unique design inside (patent pending), provides ample heat but is so lightweight anyone can carry these to a roof or install them on a boat or RV!!

What about Water Pressure?

If you have low water pressure you know you can't have a tankless water heater. Our system works with any water pressure!

How do I connect to my Existing Water Heater?

We manufacture a simple fitting called the "Bottom Feed Connector" which connects the Heliatos Solar Water Heater System to your existing water heater. It only takes minutes. No soldering or other difficult operations!

What happens at Dark?

First you use the water that was heated by the sun during the day. Then if you need more hot water then your gas or electric will kick in.

What powers the motor? Is it purely PV or is there inside electrical?

The pump is powered purely by the PV panel. It is specially designed for this purpose. This way the flow rate generated by the pump is proportional to the heat input into the heating panels.

Does the panel come with wiring?

Kits include wire, mounting tabs for the PV panel, and wire nuts

What are the recommended number of panels for my tank?

The recommended panel number depends on where you live. For Florida we recommend 1 panel for every 10 gallons of water heater capacity. If you have a good south facing site for the array that is also very close to the water heater (15 ft or less) you can also go with one panel for every 12 gallons of water heater capacity.

What temperature can the kits get the water up to (i.e. peak temperature and average temperature)?

The peak temperature depends primarily on the quality of the insulation on the pipes and water heater as well as how close the panel array is to the water heater. Typical values for Florida are 150 to 170 degrees. With normal usage on a suitably sized tank the average for Florida should be around 130 in the summer and 120 in the winter.

Are any permits needed to install the system?

What permits are required depends on the local building regulations. These vary from town to town. The customer should consult with the local building department.

What type of tubing is used? Does it come with the kit?

You can use 1/2" copper, CPVC, or PEX tubing. It does not come with the kit.

Does the solar panel provide enough heat without needing to turn on the breaker?

With a properly sized system and normal usage most people in Florida can turn off the breakers in early May and have to turn them on for backup in November. From November through May electricity usage is still reduced, but having the breaker on assures that you have hot water always even during longer periods of cloudiness.

Is there an orientation to the panels - supply lower left and return upper left?

supply - lower left, return - upper left
supply - lower right, return - upper right
supply - lower left, return - upper right
supply - lower right, return - upper left
These will work equally well. What will not work is if supply and return are both on the upper or both on the lower.

Is there a more efficient or more professional way to tie it into the hot water storage tank other than with the valve? If so, how can we do this?

There are two ways to connect a solar water heater. The top connection is the way it was always done in the past, except in Florida where some plumbers started to use the bottom connection like the one we provide. The bottom connection using the bottom feed connector is more efficient and more reliable.

Are the products eligible for the 30% federal tax credit plus state incentives?

Our products do not have SRCC rating which is required in most States (but not all) for the state rebates. Our understanding is that the Federal rebate is available if you have a state rebate, but this is not solid tax information. So in short the answer depends on the state and we suggest the customer consult a tax professional before claiming any rebates.

Could your kits work well with a tankless water heater?

The answer is no. ALL solar water heaters have to have a tank, not just ours. We use the existing tank, but others use separate tanks or tanks built into the panel. What does work great is a solar water heater with a tank feeding water into a tankless. If you have a modern tankless this means that the solar will do most of the heating and the tankless will just top it off.

What is the lifetime of the system and what is the performance degradation?

Solar thermal panels are different from PV panels in that they do not have a predictable degradation mechanism based on material physics. Therefore a prediction of the life of a panel is not really possible. However here are a few pieces of information that may be helpful.

The frame and mechanical components of the panels are thick architectural grade aluminum. Therefore the lifetime of these parts will be in the many decades range. The water or heat transfer liquid are contained in copper tubing therefore the lifetime is comparable to copper plumbing. There is considerable uncertainty in this as a lot depends on the characteristics of the water. With glycol as the heat transfer liquid the lifetime of this component should again be in the many decades range.

The coating of the absorber plate is the component that determines the efficiency and performance. Unlike PV panels which rely on semiconductor physics this component relies on simply the ability to absorb light (remain black). We do not have any lifetime data on this component, but in our original test samples (8 years old) there is no appreciable degradation of absorption.

Finally the glazing is polycarbonate. This component is guaranteed not to yellow for 10 years by the manufacturer, meaning that no reduction in transmittance is to be expected for this time. After that a gradual drop in transmittance will bring about a reduction in performance. Unfortunately there is no solid data on this reduction, but we estimate it to be of the order of 3% per year.

The remainder of the system consists largely of standard plumbing parts so the lifetime is equivalent to the average residential plumbing system.

The PV panel to power the pump has the durability characteristics of crystalline silicon photovoltaics, however since this component's power generation efficiency has almost no effect on the thermal performance of the system this factor is not important.

You said use a shutoff valve on heater top and bottom.What runs the valves, pressure elec. and are the valves in the kit?

The kit comes with a "bottom feed connector" that has the appropriate shutoff valves. If you use a different way to connect the solar heater to the water heater you will have to supply the shutoff valves. These will be manually operated standard ball valves. Their purpose is to allow you to close off the system if needed.

What’s the difference between the ez-connect ez-37 panels and the sw-38 ? I live in  South Florida.

The panels are identical in size and performance. The EZ-37 internal fluid dynamics have been designed to enable you to connect more than 4 in a single string. The SW-38 costs less and is internally simpler and more robust but you can only connect up to 4 in series. For small installations (up to 4 panels) the SW-38 is the better choice, but if you need more than 4 you have to go with the EZ-37.

Do you need an expansion tank for the installation?

This kit assumes that your existing system has an appropriate provision for expansion. It is designed to connect to an existing water heater and as far as expansion is concerned it doesn't really matter if the heat comes from electricity or the sun, so if your system is properly set up for electric heat it should also work fine with solar heat.

Unfortunately many installations count on the fact that with electric or gas heat the water does not get very hot and so they simply ignore thermal expansion. So if your system has a provision for expansion already you will not need to install an expansion tank, but if not you should install one whether you put in solar or not.

Do you leave your existing hot water heater on?

You can leave it on or turn it off depending on your needs and the amount of sun you are getting. Most people who have a properly sized system turn the existing energy source (electric or gas) off during the summer. In winter they turn it on in case there is a longer period of cloudiness. If you have it on whenever there is sun you end up using solar energy, but when there isn't sufficient sun you still have hot water supplied by the standard source.

Can this system be installed on the roof of a 2 story home with the tank in the garage?

Yes, the height difference does not matter. However please be aware that both pipes going to and from the panel must be well insulated all the way between the tank and the panels.

Anyone knows if we need a permit from the city to install this system?

It depends on the city. In most jurisdictions you have to have a permit. There are only very few where you do not. Please check with your building department to see if permits are required.

Do the panels drain the water when the pump turns off? I live in ME so I want to know there is no risk of residual water freezing.

This system will not automatically drain the water so unless you actively drain it yourself before a freeze it will be damaged. For a freeze protected system we suggest the "GH" version of this system. None of our kits are for "drainback" systems which is the kind that drains the panels when the pump goes off.

If placed on a the roof, what is the maximum pitch these can be installed at?

The panels can be installed at any pitch, but to get optimum results they have to be pointing at the sun as closely as possible. Most pitched roofs in the continental US are pitched "close enough" to point the panels in the right direction.

Can this be used with a tankless water heater?

All solar water heaters need to have a tank because the energy from the sun comes in an even stream all day and therefore needs to be stored. To use this with a tankless heater you will need to install a small water heater as a pre-heat tank. The electric connections to the water heater need not be connected, it would simply be used as a tank. The solar water heater would be connected to the tank in the usual way. The input to the tank would be from the city water and the output would go to the tankless heater and from there to the tap.

You will need to make sure that your tankless heater has a proportional controller. Most older tankless heaters are pressure operated so they will go on no matter how hot the input water is. With this type of tankless heater a solar pre-heat will have no benefit at all.

The newer tankless heaters sense the temperature of the input water. If it is already hot they will not go on, and some even can adjust the internal heating rate so that the output is always at the desired temperature. For this type of tankless heater the solar water heater works by reducing the gas or electricity used. With proper system sizing the tankless will never have to go on unless it has been cloudy for a while or if there is a lot of usage early in the morning.

Can a frame be constructed to mount the collectors at ground-level?

Yes you can mount these on a frame on the ground. The optimum year round tilt would be equal to your latitude pointing due south. To optimize for winter you would tilt them by an additional 20 degrees and for optimal summer performance you would reduce the tilt by 20 degrees.

I live in the desert; 115 degrees is common. How is the Temp regulated in this system? I do not want my HW heater PT valve gushing.

In most areas overheating is prevented by sizing the array properly. If the array is not too large you will not get overheating. However in the desert this is a challenge because if you size the array for the summer it will not be sufficient in the winter, but if you size for the winter your PT valve will have to go to work. We can supply a temperature limit switch for the pump on request and free of charge. This will cut off the pump and prevent the system from getting any hotter. We have them in stock for a 180 degree limit, but can get other settings on request.

What is the flow rate of this pump (kit#077.0050)?

The nominal flow rate of the TopsFlo TD5 is 5 gpm. The actual flow rate in a system will be lower depending on the overall flow resistance of the piping and the array. A typical 4 panel EZ system will have peak flow rates around 3 gpm.

At what temp is the water in solar panels before the pump kicks on?

These systems are not controlled with the legacy on off type controllers so there is no fixed panel temperature or temperature differential at which the system comes on. The pump is specifically designed to connect directly to a PV panel so that the flow rate is proportional to the amount of incident sunshine. It so happens that the heat added to the water in the panels is also proportional to the incident sunshine so the system always operates at the optimal heat transfer rate.

Approx how many gallons does each panel contain?

These panels are not batch heaters so they are not meant to contain a lot of water. The EZ-37 panel contains 10.5 ounces of water.

Are these panels elevated to allow rain water to flow under them?

The way these are mounted is up to the user. They can be mounted directly on a surface such as the roof, but can also be mounted above. Unlike PV panels they do not need an air gap for cooling, but if there is one that is fine as they contain very efficient insulation.

I am interested in the Healiatos solar water heater for a house in North Florida. It rarely freezes, there, but it sometimes does. I would be interested in trying to arrange a drainback system for such occasions, rather than a glycol system (I am familiar with glycol systems b/c I have one in Colorado). Have you ever set up the Heliatos EZ-Connect with a drainback tank?

We have never been successful at setting up a drain-back with our system because of the pump. You need a more powerful pump for drain-back in most cases. So with our system you either have to drain (my recommendation for places where it rarely freezes) or go with glycol.

Control for over-heating as a Florida summer gets quite hot. Do you rely solely on the T/P valve on the water heater for this situation, or do you have another control for this. Seems like this would be a problem even with a glycol system as well. 

As far as overheating there are two safeguards against it. One is that the pump shuts itself off at 180 degrees. So once the system gets that hot the heat transfer from the panels to the tank stops until things have cooled down again. The second is that for a properly sized system in Florida it is not really likely to overheat. While it feels very hot there the system temperature does not depend on humidity, only actual temperature and it rarely goes over 100 degrees there. The overheating issue is more likely in places like Arizona where the actual temperatures can be around 120 degrees.

Do the SW-38 panels hook to the existing water heater?

We sell SW-38 based kits that connect to the water heater the same way that the EZ-37 based kits you have been selling do. The SW-38 panels cost less and are more robust, but you can only connect up to 4 in series in a single array. This is why we only sell the SW-38 based kits up to 4 panels. I'm thinking about changing this so you can have more than 4 SW-38 panels connected in a single array because as I said the SW-38 are in many ways superior to the EZ-37. The performance is identical though.

I am interested in your solar hot water kits; can I plumb it to be additional swimming pool heating in the summer and then plumb it/them into my hot water heater? What are the dimensions of the 10W PV panel?

The panels can be used to heat any water though the effort of connecting the system to a pool is hardly ever worth it. The system is designed to heat small amounts of water (water heater up to 120 gallons) to a high temperature. Pools are usually very large compared to water heaters so using a "solar pool heater" is much more effective and costs a lot less. Also pool water is frequently very chlorinated. The copper in solar panels can withstand the chlorine except if the pH of the water is not well controlled near neutral. 

I need to serve a house with one kitchen (no dishwasher)  and two bathrooms.  There may be up to four people in the house. How big a tank and system do you think we need?  This is located in Vieques PR. It is very hot and tropical year round with daily sunshine.  Does it make sense to have a small tank (12 gal) with perhaps four or more panels?

For the tank I would recommend a 40 gallon tank because they are least expensive and the capacity would mean that nights are bridged more easily than a smaller tank. In Puerto Rico 4 panels would be a good match for the 40 gallon tank. If they can get the panels very close to the tank 3 might do and if it is over 30 ft each way they might need to add a panel. They will have to insulate both lines all the way in spite of it being hot and tropical.

What does "Please Note - Will NOT work with Marathon Non Metallic (Plastic) Water Heaters" mean on the GH Kit product page?

Marathon is a brand of water heater that is actually made of plastic. All other water heaters are made of steel. As long as it doesn't say "Marathon" on the brand name he should be fine. Incidentally the Marathon heaters are excellent because plastic will never corrode and they have superior insulation also. They are made of a special plastic that is heat resistant and will not impart an odor on the water either. The drain is different, which is why our standard kits don't work.

Why does the cold weather kit have a expansion tank and heat exchanger and the regular kit doesn't?

The GH kits use a closed loop filled with glycol (included), so to account for the expansion the expansion tank is needed and to transfer the heat from the closed glycol loop to the water in the water heater the heat exchanger is needed. The standard kits just circulate the water from the water heater through the panels directly so those two components are unnecessary. The only drawback of the simpler systems is that since there is water in the panels if it gets cold at night the water might freeze and damage the panels.

How far can You place a panel of the GH freeze protection kit from the water heater on the roof?

The closer the panels to the water heater the better. If it is more than about 50' you will have to have one additional panel to make up for the losses. 25' is good.

Does the system turn off automatically if it gets hot or reaches a certain temperature?

The pump shuts off at 180 degrees so the system can't get hotter than that.

It freezes only a few days out of the year. Does It still need to get the freeze protected kit?

The standard system will be damaged by any freezing. My personal preference when I lived in a place like that was to drain the system before predicted freezes. As long as it only happens once or twice a year I thought it was better to go that way than to have the more expensive and complex freeze protected system. Others don't want to have to think about it so they would have to have the freeze protected system even if it freezes only once a year.

Do I need to insulate the pipes from the water heater to the panels even though I live in Houston?

All pipes HAVE to be insulated. Even in a hot place like Houston.

Can I manually set the temperature when to shut off?

The pump shutoff at 180 degrees is a safety feature and is not user selectable. If you want to shut it off at lower temperatures you would have to use a thermo switch.

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