Buyer's Guide: Questions you may ask to suppliers or installers of your Solar Power System


Buyer's questions about sizing and design of solar power systems

- For maximum efficiency, solar panels should be mounted on a south facing roof (in the north hemisphere) or on a north south roof (in southern hemisphere countries) at an around 30° angle with the horizontal. Does the proposed solution correspond to those principles? Why not?

- Is the system mounted away from shadows? Why not?

- What are the impacts of the installing on the building structure? None?

- Will the system be configured according to all the manufacturer’s specifications?

See also, for information on solar systems sizing: Solar Systems Sizing


Buyer's questions in the case of solar hot water systems:

- Is the solution an active system (with circulating pumps and controls) or a passive (without circulating pumps and controls)? Why?

- Typical solar collectors require a flat mounting area of around 3 m2 for each collector. Most installations require one to two solar collectors. Is the solution proposed within these parameters? Why not?

Buyer's questions in the case of PV systems:

- Is the proposed solution a stand-alone system or a grid-connected system? Why?


Buyer's Guide questions on Solar Power Equipment

- Do all the materials conform to manufacturer’s specifications?

- Are the solar panels and other equipment certified by a quality label?

- What is the average performance of the system in terms of wattage (in the case of the PV systems) or hot heating or acclimatization (in the case of Solar Heater Collectors)?

- Are fixing and flashing components for the panels provided?

- Is the system capable of resisting to overheating, freezing or powerful pressures?

In the case of hot water systems:

- Does the system come with a storage tank (for cloudy days and times of increased demand) and additional outlet and inlet connecting to and from the collector? Why not?

- Is the proposed system appropriate to local climate? Does the system involve the non-freezing fluids and heat exchangers (common on cold climates)? Why not?

- Is the system regulated to bring the hot water to 140ºF/60 °C at least once daily?

In the case of PV systems:

- The solution includes the modules (set of panels), the inverter, the batteries (in the case of a stand-alone system), a solar power monitor and an electric meter?


Buyer's Guide questions on Costs and payment of the installation and the solar panels

- What elements are covered by the quote? Is there additional costs? Is labour costs covered?

- What is the average annual savings under average conditions?

- What are the financing options or payment terms? Is there any rebates or finance incentives by local or federal authorities?


Buyer's Guide questions on Quotes and prices of the solar power systems

- In today's USA market the average price of an active solar hot water system is around $2,500-$4,000 per home, for a production of about 80 to 100 gallons of hot water per day. A passive system will cost about $1,000 to $2,000 installed (with a lower capacity of hot water production). Is the quote within this range? Why not?

- In today's USA market, the price of a PV system is often comprised in the range $13,000-$20,000 per home, without rebates and tax incentives (that may cut the price substantially). Is the quote within it? Why not? See for more details on prices: Prices Pv Photovoltaic and Prices of Solar Heating Water Systems. See Rebates, taxes and financial incentives for solar energy

Buyer's Guide questions on Installation of the solar power systems

- How long will the installation take?

- Will any part of the installation be sub-contracted?

- Is the installer recognized by the manufacturer? Does the installer belong to professional associations?

- What is the experience and accreditation of the installer?

- Which local references can dealer and installer provide?

- Which are the services offered by the supplier: delivery, installation, commissioning, after sales services?

- Who will ultimately be responsible for what segments of work?


Buyer's Guide questions on After-sales services offered by the dealer of the power solar system

- What are the manufacturer’s (or supplier’s) warranties for the various components of the solar system?

- What warranties are provided for the installation?

- Is an annual service contract available from the supplier?

- Does the dealer provide emergency services?


Searching suppliers and retailers of solar systems?
Try the boxes above. Eventually, add your local zone (Alabama, Australia, whatever...) 

Note: some questions of this list came from A Buyers’ Guide to
Solar Water Heaters from the Sustainable Energy Ireland


See also:
Basics of solar systems
Domestic Solar Hot Water Systems
Solar Electricity: Photovoltaic PV Systems
Pros and Cons of Solar Energy Panels
Costs and payback of Solar Energy
Solar Panels Technology
Quotes and the buying process
Market and Prices of Solar Hot Water Systems
Market and Prices of Solar PV Electricity
Manufacturers of Solar Power Systems




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