Are PV panels easy to maintain and clean?

Solar panels are very low maintenance as they have no moving parts.
The only regular maintenance which one must perform is cleaning as a clean panel enables better generation.

One must only use water  to ensure no damage occurs.

Bolts fixing the panels to the frame should also be checked from time to time.


Are PV panels guaranteed?

On panels, the manufacturers generally propose guarantees on productivity of between 20 and 25 years. On the inverters, the guarantee varies depending on the brand; between 5 and 7 years is standard.


Are solar power systems efficient?

Yes. Solar cells today have a high efficiency which is continually increasing. The efficiency varies between models due to the technology being used, however 8 pv panels are typically enough for a family of 3 people with average consumption.


Can I install a PV system elsewhere than on a roof?

There are no limits for the location of a PV system; beyond roofs, some of the most common places used to implement PV systems are, for example facades, which offer huge possibilities for architectural integration and visibility; sunshades; canopies; greenhouses; carports; the ground, especially for large scale installations.


Do PV panels lose efficiency each year?

In general, the panels lose very little output over time, at least during the first few years of use. Output decline is usually seen around 20 to 25 years after first installation and is estimated at a ratio of +/-20 %. However, for common financial calculations (pay-back) an average loss of 1% per annum is usually taken into consideration.


Doesn't PV technology need bright sunshine to work properly?

A PV system needs daylight to work, not direct sunlight. If a panel is exposed to artificial light, it will also produce electricity. However the electrical output of a PV cell is dependent on the intensity of the light to which it is exposed. Therefore if a panel is facing the midday sun on a clear day, then will produce its maximum output electricity (Watt peak = maximum power). You can therefore say that PV cells tend to generate more electricity on bright days than when skies are overcast. Nevertheless, photovoltaic systems do not need to be in direct sunlight to work, so even on overcast days a PV cell will be generating some electricity.


How much electricity does a PV system produce?

It depends on several conditions. Orientation of the system (south), system inclination (what is the inclination of the roof), irradiance value at the location and last but not least, the weather. The following value can be assumed as a rough planning aid: 1600 kWh per year for each kWp of installed power.


What feed in tariff(FIT) will I receive ?

The feed in tariff you will receive depends on whether you have applied for the €2300 grant or not.

If you apply and quality for the grant you will benefit for an FIT of 16.5 cents per unit generated, this rate applies for 6 years.
If you do not apply for the grant you will benefit for an FIT of 15.5 cents per unit generated, however this rate applies for 20 years.


What if there is a Problem with the System?

If a photovoltaic element no longer produces electricity or, under identical conditions, produces much less electricity than before, contact us immediately so that we may dispatch a technician to evaluate and fix the issue as soon as possible.


What is the lifespan of a PV system?

PV systems are currently considered to have at least a 25-year lifespan. PV panels are covered with a long term performance guarantee (usually 10 years with less than 10% decrease and 20 years with less than 20%) by most manufacturers. Guarantees for electronic components such as inverters can also be extended for several years beyond standard terms.


Why should I use a PV System?

Today’s PV systems integrate easily with your home’s existing electrical system. They produce clean energy, no air pollution, no greenhouse gas emissions and they can greatly reduce, or even eliminate, your electricity bills. Photovoltaic power systems can now be integrated into the fabric of a building, combining energy production with other functions of a building’s external structure. Roof tiles, windows, facades, canopies and skylights can all be used to support PV technology and this combination of functions can lead to substantial cost savings A well designed and an installed PV system is often considered a beneficial feature of a house and can increase the value of the property.


Advantages of the solar water heater

The direct advantages of having a solar water heater are:

a. Up to 80% savings on your water heating bills. There is a reduced amount of electricity or other fossil fuels (gas, electricity, etc) needed to heat your water. The solar-heated hot water can be used directly (showers, baths, laundry, kitchen);

b. To pre-heat domestic water prior to switching to the conventional heating system (running on fossil fuels). This reduces the energy used by your conventional heater as the water is already pre warmed.

c. Durability. By being made of stainless steel, the boiler will last around 10-15 years depending on how regularly it is serviced;

d. The solar water heating system requires very little maintenance (see maintenance);

e. Because thermo-dynamics circulate the thermal fluids in the closed circuit, no electrical pump is needed for the system to work, reducing the possibility of leakage, system failure (if the pump stops for any reason) and expenses (for the pump and electricity used to run it).



Do I need a separate plumbing system for the solar water heater?

There is NO need for a separate plumbing system for a solar water heater. Your installation technician will be able to guide you during this process; the only plumbing necessary will be to connect the cold water inflow to the boiler to the main water supply line, and the hot water outflow from the boiler to the hot water pipes in your home (remember to insulate them). The closed-circuit pipes are provided with the solar water system and run independently from your home’s water pipes.


Does it make any noise?

Absolutely no noise whatsoever. The system works by natural movement of the fluid in the closed circuit into the boiler and back to the panel; it does not require any electrical pump. It may require a pump if the boiler is placed behind or below the panel, in which case that would be the only “noise” the system might produce. Do NOT use a stainless pump.


For how long does the warranty/guarantee last?

The panels and boiler have 5-year warranty covering both the interior and exterior of the system, however the glass in the panels is excluded from this. We recommend insuring the solar water heater both for damages to it and for any risk of damage to third parties.


For how long does the water keep hot?

The water in the boiler will keep hot for several hours; the length of time depends on a number of factors:

a. Size of the boiler (water volume): A larger boiler will retain heat longer;

b. Air temperature: The colder the ambient temperature, the faster the loss of heat from the boiler and pipes.

c. Initial water temperature: The warmer the water prior to non-sunny periods, the longer it will retain its heat.

d. Thickness of the insulation: The thicker it is, the longer the water stays hot. In addition, the pipes both outside and inside the building, must be insulated;

e. Usage: If a lot of water is used whilst the the sun is shining, then fresh, cold water flows into boiler and cools down any existing hot water in the tank.

f. Insulation: Thicker insulation will result in reduced heat-loss from the boiler.


For how many years does the system last?

When installed and maintained properly, a stainless steel solar water heating system can last between 10- 15 years.


How does it work when there is no sunlight?

When there is no sunlight, there are 2 options:

a. Because the boiler is insulated with a 5cm thick polyurethane insulation, the sanitary water inside the boiler stays hot for several hours, and as such you can continue using it even at night or on a cloudy day. This thermal inertia depends on many factors such as the initial temperature of the water in the boiler; outside air temperature; usage. For this reason, it is best to install a larger boiler when possible in order to use the water mass to retain more heat during non-sunny periods;

b. Inside the boiler there is back-up electrical resistance from the thermostat that heats or keeps the water hot when the sun is unable to heat the water.


How does the solar water heater work?

The sun’s rays hit the solar panel and transfer the thermal energy to the panel’s copper surface (the absorber); this heat is then transferred to the fluid (a mixture of distilled water and glycol) running inside the copper tubes which in turn heats the domestic water inside the boiler.

There are 2 different fluid circulating systems:

a. Natural circulation; when heated, the fluid becomes less dense and lighter and ascends towards to top of the collector into the closed circuit chamber in the boiler. Once inside the boiler’s closed circuit, the heat is transferred into the sanitary water you use in your home; during this process (ceding thermal energy into the sanitary water), the fluid becomes colder and denser and therefore descends to the bottom of the closed circuit chamber in the boiler channeling it to the bottom of the collector. At this point the process restarts; there is no need for any pump as long as the boiler is located above the panel/s. This process runs by itself generated by the heat of the sun;

b. Forced circulation: instead of the fluid flowing by itself following the laws of thermodynamics, the fluid is forced through the panels and the closed circuit by a small electric pump. An electronic control system ensures that the fluid circulates keeping the temperature in the panel is higher than that in the boiler. Forced circulation is used when the boiler is installed below the panel/s.


How efficient is the solar water heater?

85% when heating sanitary water and up to 40% when used for pre-heating household water.


How long does it take to install a solar water-heating system?

A technician can usually install a solar water heater in a few hours on a flat roof. It may take longer if specific conditions have to be taken into account such as installing the system on a fragile roof or the need for additional supporting structures. In these circumstances, we will be able to give you the best advice. It might be necessary to call a plumber and an electrician to complete the installation.


How many years does the solar water heating system take to pay for itself?

This depends on how many hours of sun your panels are exposed to annually, and other factors such as air temperature, dust on the glass etc.

On average, a solar water heating system will pay for itself after a 4-5 year period (a shorter period for larger installations, for example at hotels or swimming pools), after which it is all net gain apart from the minor yearly maintenance costs. Please ask us for detailed information about this.


How much CO2 will my solar water heating system produce?

Zero emissions when the water-heating system is running entirely on solar power; reduced emissions when any electrical backup is deployed. Emissions are reduced because the water is not as cold as if it was coming from the supply pipe.


How much space do I need?

This depends on the size of the solar water heater system you require. A family of 4 would need a boiler of at least a 200-litre capacity and a panel area of about 4m². This might change depending on your latitude (the further away from tropical latitudes you are, the larger surface area you will need). On average a solar water heating system uses around 4m² of roof space.


Is there any available grant scheme, tax reduction, contribution on installation costs, reduced loan?

Most countries, local governments, city halls and/or banks are giving grants, subsidies, cheaper loans, tax rebates or other form of financial help to buy and/or install alternative energy solutions; please ask us about what’s available locally. Solar water heating systems are classified as an alternative energy solution.

See our Government Grants page for the latest information.


What do I have to use inside the panel/s?

Inside the closed circuit of the panel, you are advised to use a mixture of biodegradable glycol and distilled water. There are a number of products available on the market, either in pure form or premixed.

Water from the domestic water-supply goes into the boiler. Do not use the solar water heater for any other type of liquid.


What if my roof is in the shade or not facing the sun?

Unfortunately if your solar system doesn’t face the sun, it cannot produce hot water. Your solar system must face the position of the sun at 12:00 midday, In Malta this means that it has to face south.



What is the best orientation and inclination?

Your  technician will know in which direction and at what angle to point the panel/s.

The further North or South you go from the Equator, the higher the panel’s angle needs to be. As a general rule, solar thermal panels are raised from a horizontal position of an amount of degrees equal to the latitude plus 10.


What is the difference between a stainless steel and a glass lined boiler?

Stainless steel boilers do not have any internal coating; it is plain marine grade stainless steel which will not rust on contact with water.

Glass lined boilers are made of steel or other materials and have a “coating” of glass. Because these expand and contract at different ratios during heating and cooling, sooner or later the glass will crack and water will have contact with the metal casing, rusting it and further cracking the structure. Stainless steel boilers last longer.



What is the difference between vacuum-tube and flat-panel solar units?

Vacuum-tube solar water panels, during the summer, perform the same as any flat surface panel; during winter there is slightly better performance due to their ability to better insulate the fluid from the outside air temperature.

These types of panels are used primarily in colder countries where there is a risk of freezing temperatures during winter months. In countries with no risk of frost, the difference is almost negligible.



What maintenance is involved?

A solar water heating system requires little maintenance:

a. Cleaning of the panel glass at the beginning of the sunny season and when needed if there is a build-up of pollutants (dust, leaves, grease, …).

b. Changing of the internal anode every year is essential to keep your solar water heater performing.

c. Checking (and filling if needed) the closed circuit fluid, this is best undertaken the beginning of the sunny season;

d. Checking (and substituting when needed) the insulation of the water and fluid pipes;

e. For the closed circuit fluid, use distilled water and approved glycol only. Do not use any other fluid mixture because this will shorten the product’s life span.