Solar Hot Water FAQ

Solar PV System FAQ


Why would I want a solar hot water system?
  • Reduce your utility bill and save money!
  • Contribute to our country’s shift to clean, renewable energy
  • Reduce the amount of pollution created by burning fossil fuels
How does a solar hot water system work?
A Solar Hot Water (SHW) system consists of solar collectors that are installed on the roof of a structure and capture energy from the sun which is used to heat water. Effective in almost any climate, these systems can provide up to 80% of a property’s hot water needs for showering, laundry, cooking, pool heating or other processes that utilize hot water. See the details and diagram on our Solar Hot Water page.
How much does it cost to install a solar hot water system?
Prices will vary depending on where you live and what your demand for hot water is. A typical residential system costs approximately $6,500 while commercial systems can range from $10,000 to over $200,000 depending on the hot water demands of the property.
How long until I break even?
The break-even period is the amount of time it takes for your savings to equal the amount of your investment. The break-even period for solar water systems is 1 to 5 years depending on the following factors:

  • How much hot water you use (the more you use, the more you save and the quicker you break even)
  • The cost of your system,
  • The cost of energy you are currently using (offsetting higher energy costs speeds up your break-even time), and
  • The available Federal, State and utility incentives which reduce the amount of your investment and lower your time to break even.
Is a SHW system a smart investment?
YES! Your solar hot water system is an investment that will provide a significant Return on Investment as well as increase the value of your property. The value of a home should increase by at least the amount of the system while commercial properties should increase by at least 50% of the system cost based on the application of a cap rate to the utility savings produced by the system…
How should the collectors be installed to ensure optimum performance?
Solar hot water collectors should be oriented geographically to maximize the amount of daily and seasonal solar energy that they receive. In general, the optimum orientation for a solar collector in the northern hemisphere is true south. However, recent studies have shown that, depending on your location and collector tilt, your collector can face up to 90o east or west of true south without significantly decreasing its performance. You’ll also want to consider factors such as roof orientation, local landscape features that could potentially shade the collectors, and local weather conditions as these factors may affect your collector’s optimal orientation. In most areas, the collectors will be mounted on the roof at a predetermined angle in order to maximize the system’s output.
What is the difference between a passive system and an active system?
In a passive solar hot water system, the system has no pumps or motors and is designed on basic principals of physics — hot water rises and cold water falls. Therefore, through that basic principal, water circulates through the system to provide hot water for the property. In an active system, a circulating pump is utilized to pump water through the system.

How long does it take to install a system?
It typically takes only one day to install a residential solar hot water system. Depending on the size and complexity of the system, commercial solar hot water systems typically take 5-7 business days to install and would cause minimal interruption to the property’s operations.
Are there any rebates?
Yes, there are Federal, State and Utility incentives offered for the purchase of a solar hot water system. The state and utility incentives vary by location, so please contact us to identify available incentives for you! Below is a brief description of credits available:

  • Federal Tax Credit — 30% off of the total installed cost of the solar hot water system. Business can elect to receive this as a cash grant in 2009 and 2010.
  • State Tax Credits — these vary by location and can range from 0% to up to 55% of the cost of a solar hot water system. A sample of state incentives are as follows:

    • Arizona — 10%
    • California — Up to 55% (proposed incentive based on system output)
    • Hawaii — 35%
  • Utility Rebates — Various utilities offer additional rebates toward the purchase of a solar hot water system. These can be as much as 60% of the cost of the system.
What if there is no sun to heat the water?
Although solar hot water systems work in both sunny and overcast conditions, under periods of prolonged cloud cover, the system may not produce enough hot water that the property demands. Therefore, we advise our customers to keep their conventional electric or natural gas heater in place to be used as a back up system which can be utilized at night or during periods of prolonged clouds.

How hot does the water get?
Our systems will usually heat water to 130 to 150 degrees.
How large of a storage tank do I need?
This is a matter of your hot water use and the size of the solar hot water system. For most residences, an 80 or 120 gallon tank is sufficient. For commercial systems, we assess your hot water usage and proposed system size to design a system that utilizes optimal storage.
How do Solar Hot Water systems compare with an on demand water heater?
There are three costs which should be analyzed when making this comparison:

  • The purchase price
  • The cost of operating the system
  • Maintenance costs

Although a solar hot water system costs more than an on-demand system, a SHW system costs virtually nothing to operate. Thus over the long run, you should save significantly more by employing a SHW system versus an on-demand system. In addition, a SHW system should last longer and require less maintenance than an on-demand system.

How much do the collectors weigh?
Weight should not be a concern when deciding whether to purchase a solar hot water system. At approximately 3 pounds per square foot, these collectors should not create any load problems for your roof. For commercial systems where a large number of collectors may be installed, we hire a structural engineer to ensure that the roof/structure can hold the weight of the system (this has never been an issue).
When should we recommend using a Solar Powered Pump?
Anytime our customers prefer utilizing Solar Power over Energy created by fossil fuels, we offer the option.
What type of Photovoltaic Panels do you use?
We use SolarWorld 230 watt, made in the USA, photovoltaic cells for the majority of our installations.
Do the solar panels need to be mounted on my roof?
Panels are often mounted on the roof, but can also be mounted on the ground. Ground mounts are great if the house is shaded, or if dormers or other obstructions limit available space on the roof.
Do the panels need to face south?
South is best, but panels installed facing east or west still generate a very high percentage of possible power. It is usually more effective (and more attractive) to install the panels in the same plane as the roof direction, rather than build an awkward mount to angle them.
Are the panels fragile?
No. While the panels are made of tempered glass, it is quite strong. They pass hail tests, and are regularly installed in Arctic and Antarctic conditions.
How much solar electric power do I need to power my home?
Each home is different, and the amount of electricity you use is very dependent upon your lifestyle, how your home was built, and your appliances. As part of our services, we work with you to reduce your electrical consumption in easy ways.
How much power does the system produce?
Systems come in all sizes, and produce as much or as little power as required. Many systems produce a portion of the home’s required power, leaving room for additional conservation or generation in the future.
How long will the system last?
The solar panels have a 25-year power warranty from the manufacturer. This is longer than almost anything else you can buy. The rest of the system has a 5-year warranty in most areas. Inverters can have warranties up to 10 years.
What happens when the utility has a power outage?
Most systems we sell are “clean power” systems, without batteries. These systems do not generate power when the utility is out, even if it is sunny. If backup power is desired, a battery system can be added. This increases the complexity and cost. Most people find that what they want is Clean Power, and find that the very occasional outage does not bother them, so they do not purchase the battery option.
Do I need batteries with the system?
Batteries are only required if you want backup power when the utility is out of service. Without batteries, the system has no way to store power, and for safety reasons cannot produce power without the utility in operation.
What is Net Metering?
Net Metering is the regulatory ability to get credit for electricity you generate with solar energy and send backwards through your utility meter. Exact provisions vary with each state, but the effect is to allow you to generate excess power during the day, and use it at night, without needing batteries.
Do I need to install a new roof before the solar panels are installed?
Solar panels will last many years (over 25). Because of this, we want the roof to be in decent condition, as it does not make sense to remove and reinstall the panels after only a few years. However, after the panels are in place, they will greatly reduce the wear on the roof by blocking ultraviolet rays, keeping most snow and ice off the roof, and keeping anything from hitting the roof. Most installations do not require a new roof prior to PV installation.
What happens if the panels are shaded?
PV panels should be installed in areas where they get significant shade-free sun every day. Even small amounts of shade can significantly reduce the output. Our designs and installations also seek to minimize the impact of any shade issues through selection of the proper equipment and good engineering.
Do I need to clean the panels periodically?
Most of our customers do not clean their panels. In most areas of the country, there is sufficient rain to clean the panels. However, if you are in a dusty area (very near a busy dirt road, very urban area, etc.) you may see a performance gain from cleaning the panels monthly. If necessary, a hose stream is usually sufficient for cleaning. Do not walk on or over the panels to clean them. Do not use metal, hard, or abrasive methods for cleaning. Do not spray water on the panels when they are very hot.
Are there financial incentives for buying solar electricity?
There are many incentives for purchasing solar. Some common incentives include:

  • Clean electric generation
  • Stable electric cost
  • Backup power for utility outage
  • Fight climate change / global warming
  • Take care of my children’s world
  • Create secure electricity supply
  • Political statement for a renewable energy future
  • Strongly dislike buying electricity from the utility
  • Feeling of empowerment
  • Remote site with no electric service
  • Sending electricity back to the utility (net metering) is cool
  • Solar energy just makes sense
  • Higher resale value for my property
If I sell my property, what effect does PV have on the sale price?
Energy conservation and renewable generation adds value to a home. Surveys have shown that for every $1,000.00 saved per year, $20,000.00 is added to a home’s value. Solar energy can be one of the best home improvement investments you make.
How long does it take to install a PV system?
Typical residential systems take from 2 to 5 days to install. Systems mounted on the ground and systems with batteries are more complex, and may take longer. Most of this time is spent outside your house, so there is little disturbance to you. Commercial systems take several weeks to over a month to install, depending upon size and type of installation.
How does the solar power get stored?
In a Clean Power, non-battery system, power is not stored. It is either used immediately in the house, or sent backwards through the meter, creating a credit. If storage is needed, large batteries and other equipment are added to the system.