Solar panel selection is often the first of a series of choices homeowners need to make when buying a new residential solar power system. What kind of solar inverter should you consider? Can you install solar panels without hiring a contractor? Are backup batteries worth the cost? Here’s how to navigate the final steps of your residential solar project.
A photovoltaic inverter is a crucial component of a residential solar setup. This device converts the direct current (DC) generated by solar panels, which fluctuates in intensity due to environmental effects, and converts it into 60 Hz alternating current (AC) that can power every electrical device in your home.
Most customers opt for what’s known as a string inverter, a hub to which DC energy from all your solar panels is sent for conversion. Because the panels are wired in a series, power output will only be as strong as the weakest panel in the array. This can pose a problem if your roof experiences excessive shading, or if debris is present that blocks or scatters sunlight.
Solar microinverters, an alternative to string inverters, mitigate this issue. Efficiency is increased as these small inverters are connected to the underside of every solar panel, forming a parallel circuit. This allows you to extract the maximum amount of power from each panel. Microinverters also enable panel-level monitoring. This service, which usually comes at an added cost, can help you pinpoint trouble spots or failures without having to inspect the entire array.
While the cost of microinverters is decreasing, string inverters are generally more affordable and easier to install (consumers often place string inverters in their garage). Inverters are complex devices that are more prone to failure than other elements in solar energy systems. Opting to use microinverters in a large solar setup where many will need to be installed on your roof theoretically increases the risk of reliability issues.
However, if a small array suits your needs, roof space is limited, or performance issues are a main concern, microinverters are worth considering. Some are designed to be connected to two or four panels at a time, which adds convenience. Solar panels with built-in inverters are also available.
As soon as you settle on a design for your residential solar energy system, you can get in touch with the appropriate parties to arrange for permits and approvals. At its core, the process involves two authorities.
First, unless you’re planning an off-grid installation, your local utility company will have you complete an interconnection permit to evaluate the safety of your proposed system. The form will require you to detail the size and capacity of your array, the make and model of all components, location of your utility meter and other aspects of your setup.
Concurrently, you’ll need to apply for another permit which is issued by the authority having jurisdiction over new construction in your area. The planning office will look to ensure that your roof can support the weight of the panels you’d like to install, which can be an issue with older homes. Consult with an engineer if you’re unsure, as a rejected permit will add significant delays to your project.
Solar permitting in the US is an unstandardized and time-consuming process, but a new initiative by the National Renewable Energy Laboratory is looking to change that with a digital solution. SolarAPP+ is an automated online permit processing platform that promises to ease the backlog faced by permitting offices and create an environment in which the solar power industry can thrive. If your local government has signed onto the platform, your application experience will be streamlined.
Homeowners looking to install solar panels on their property have three options when it comes to labor. The most expensive option is to enlist the services of a turnkey service provider who will handle every aspect of the installation for you, requiring little participation on your behalf. They can also handle all consultations and procedures related to permitting.
The least expensive option is to perform all the non-specialized tasks yourself. Some jurisdictions require certified workers to install residential solar power systems. If yours isn’t one of them, and you have an aptitude for large home renovation projects, you can consider a DIY solar panel installation. Be forewarned that racking and mounting rooftop solar panels, which weigh around 40 pounds each, is physically demanding work. It’s imperative to take safety precautions by always wearing a harness and using a voltmeter to avoid electrical shock during roof work. You will still need to liaise with a licensed electrician to make the final connections.
The middle-ground option involves enlisting the help of a contractor experienced in residential solar panel setup. With federal incentives covering the cost of such labor, the average contractor installation fee of $1 per watt becomes more manageable. Their work is also covered by a warranty, adding peace of mind. A contractor’s knowledge of building codes, roofing, electrical work and renovation best practices will ensure the project is completed properly and on time.
In some cases, adding a stationary battery to your home energy configuration makes sense. The battery would store excess energy captured by your solar panels, giving you the opportunity to be completely energy self-reliant. If you live in a rural area and are looking to implement an off-grid setup, consider this solution.
Net metering, an agreement that allows you to sell the excess energy you produce to your utility company in exchange for credits, may also factor into your decision. If your state doesn’t support net metering, drawing energy stored in a backup battery may be more cost-effective than using grid power at times when your solar panels cannot fully meet your energy needs. As large batteries cost as much as $10,000, you will need to determine whether this investment is worthwhile for you.
Electric vehicle owners should keep in mind that their car can double as a backup battery. When coupled with a bidirectional charger, an EV can power your home during the night, and potentially provide over 50 hours of power in the event of a blackout.
To calculate how much money solar panels can save you in the long run, check out our previous blog post.