Ahh yes, the burning question on everybody's mind. There is not a set answer because of a few factors. Each installation is site specific, meaning the location of the panels and the consumer hot water requirement changes with just about every installation. That being said, a good estimate on a 3-4 person home using 2 collectors, a new 80 gallon tank with the SolVelox installed could run $5,000 to $6,000 depending on the installation. Make sure you check with your local dealer for more detailed installation prices. But when you take into account the government tax credit programs (up to $3,400 with both federal and NC state) and the fact that you will get around a 25-30% return on your investment each year through energy savings, I doesn't take that long at all to see the money going back into you pocket for years to come.

The payback will vary with each installation. It depends on a properly sized system, and the amount of hot water used compared to the home's energy bill. But lest use a retrofit application for an example. If the amount for the installation of a solar hot water system cost $7,000, then you would get a federal tax credit of 30% ($2,100) and a NC tax credit of $1,400. That brings the cost down to $3,500, and lets say in this example that the homeowner was going to have to replace the old water heater anyway, and his quote for that was $1,000 for a new 50 gallon electric/gas. That would make a $2,500 difference between a solar water system and a standard electric/gas change out. The big difference is this, where the standard electric is going to cost the homeower every month, the solar water system will save around 30%. If the average monthly energy bill is $165 x 30% = $49.50 savings times 12 months = $594.00 per year. If you divide the $2,500 it cost extra to install by the $594 yearly savings, the system will have paid for itself in 4 years! Just think, after that you are putting that $594 back into your pocket, instead of having an electric/gas water heater to pay for. For the next ten years your investment returns to you $5,490.00.

                       total cost - $7,000.00
                      tax credits - $3,500.00
          cost of standard heater - $1,000.00
                                  = $2,500.00
               50 months @ $49.50 = $2,475.00  PAID FOR BY SAVINGS
for the next ten years you pocket - $5,490.00

The number of collectors depend on two things. One, the number of people using water in the home dictates the gallons of hot water needed per day (a good average is 15-25 gallons a day per person). Panel sizing per person is around 13-16 square feet of panel suface area. For example, a household with two people needs about 32 square feet of panel surface area which translates into one 4' x 8' panel (4' x 8' panel = 32 square feet). Two, the panels need to be facing due south and at an angle of around 40 degrees for best performance. If the home has a sligthly lower roof pitch or if the roof faces just off of south, it usually is not a noticeable difference in performance, but if it is a concern, the addition of an extra panel can be used.

Instantaneous water heaters only replace about 15-25% of the energy used by a conventional water heater while solar water systems replace 70-90%. An article by Consumer Reports states that the tankless heater savings can add up to some $50 per year compared with conventional heaters. But even at that rate, it will take more than 25 years for an average household to recoup the extra $1,300 or so those units cost to buy, install, and maintain.

Currently, there is tremendous interest in solar energy in the United States with apparently a lot more interest in solar electricity than in solar heating. How do the two technologies compare? Typically, installers will talk about BTUs when they talk about solar heating systems. That is unfortunate. The general public doesn’t understand a BTU nor do they care to. They are billed in kilowatt hours or therms or gallons for their energy so why do they want to go back to high school chemistry to learn a new item that has no bearing on their daily life? While the two types of solar energy generate their energy in different ways there is a very simple way to compare the two systems. Both solar heating and solar electric systems can be talked about in terms of their peak energy produced. Solar electric systems are marketed by their peak energy production or the amount of energy produced under ideal circumstances. When a solar electric system is installed it is sized, installed, and quoted based on this peak number. A typical residential installation might run from 2 to 5 KW. In residential applications a solar electric system might run $7 - $10 per watt installed. So, a 4 KW solar electric system would cost $28,000 - $40,000 installed (before any incentives). How does solar heating compare? A solar heating system can (and should) be talked about in the same way in terms of peak energy. A standard system with 2 4’x8’ panels a peak output of 4.1 KW. This same system would typically install for between $5000 - $7,000. A huge difference. The next time you are talking to a potential customer let them know that you can install their 4 KW solar energy system for under $10,000 and let’s see if we can get some of the solar electric people to sit up and take notice.

Compared at watts installed - a solar electric system costs between $7 - $10/ watt installed. A solar energy heating system is typically installed for $1.20 - $2.20 /watt installed. When you look at the system having an expected life of 25 years that means you are selling clean renewable solar energy for $0.06 - $0.10 /kwh. Not a bad deal. And you get to own your power generation rather than leasing it from the power company.

Yes you can! The SolVelox can handle in excess of 240,000 BTUs per solar day making it well suitable for space heating needs. You could use a radiant style heat such as a floor in your master bath, or used a forced air system by sliding a hot water coil into your existing HVAC system. This would also qualify you for an additional NC tax credit for a total of up to $3,500. With any type of space heating application there are addtional design components to keep in mind - added collectors to handle the hot water load, a larger tank or multiple tanks for added storage , controls/valves to direct the hot water to the coils, and added installation cost.

This will always vary with the demand load of the home, but on average one could see around a 25% savings on their bill with hot water only, and up to 50% with addtional space heating.

The Collectors should face as close to direct South as possible and have tilt angle of approx. 40 degrees for the best performance. If the direction or angle are just sligthly off, you should not see a drop in performance. But if it is still a concern, the addition of an extra panel usually can compensate for the difference.

Glycol

A glycol system is a closed-loop, active solar system. It uses a pressurized solar loop with food grade propylene glycol as the heat transfer fluid. The glycol system is very versatile, great for ground mounted systems or other situations where the pipe runs can not sloped the requisite amount for a drainback system. A glycol system needs to be sized carefully to avoid excessive overheating. The heat transfer fluid must be changed every 3-5 years.

Glycol diagram

Drainback

A drainback system is a closed-loop, active solar system not to be confused with a draindown system. The solar loop uses distilled water as its heat transfer fluid and it is a non-pressurize loop. A drainback tank is installed on the return side of the solar loop so that when the system does not run, the water collects in the tanks leaving the collectors empty and so removing dangers from freezing. A drainback system requires very careful installation. Each collector and pipe run must be sloped a least 1/4 inch per foot of run. If the installer avoids any horizontal runs or sags in the pipe where water can pool or back up, a drainback system can provide years of fool proof freeze protection and high efficiency with little to no maintenance.

drainback diagram

If the tank is at least a 50 gallon electric with enough ports, then yes you can. But remember that with a well designed system you will be able to store much more water, so a larger tank or an additional tank is recommended. Usually with a reftrofit application the current tank already has some age on it, so upgrading to a larger tank is well worth the money to get the performance you will need.

That depends on the type of system and the harshness of the water supply. With a Glycol system you will need to replace the fluid in the panels about every 5 years to maintain the performance and longevity of the piping. With a Drainback system, the only thing is to check the sight glass on the side of the 10 gallon drainback tank to ensure proper water level. As with any water supply that is considered "hard" water, scaling may occur, and you will have to drain the system to remove the deposits from hindering the heat exchanger. Luckily the SolVelox comes with accessible water cut-offs to easily clean the system.

It will provide on averge about 80% of your hot water needs. There will be cloudy days, for example, that will hinder the performance of the system. With the electric water heater tanks, the top element remains connected to provide the system with a back-up heat source when conditions arise. This also brings up the fact of storage, the bigger the tank, the more hot water you store.