Top Reasons to Upgrade Existing Solar Power Systems

Why would anyone ever upgrade an existing solar power system? After all, most homeowners and businesses are sold on the promise of making a one-time clean energy investment, with nothing to worry about over the 25+ years of their panels’ warrantied lifetimes.

And it’s an appealing pitch – one that is largely steeped in the truth.

Solar photovoltaic (PV) panels are incredibly resilient and impact-resistant (which is precisely why they ship with multi-decade warranties). And this durability can further be enhanced through routine preventive maintenance.

So then why go through the trouble and expense of upgrading an existing solar system if your current one already works?

Let’s explore.

Why Expand or Upgrade Existing Solar Power Systems?

There are actually many compelling reasons to upgrade an existing solar installation. Below are three of the most popular.

1. Maintenance and Servicing

This category might technically count as “repairs” more than a traditional “upgrade.” But whenever a component in the PV system fails or starts to underperform, it’s necessary to replace that part to continue generating solar power and utility bill savings.

Residential roof showing six solar panels in a smaller system.

The panels themselves may be warrantied for 25 years, but solar modules are not the only components in a standard residential or commercial PV system:

  • Inverters and batteries both ship with much shorter warranties (five to 15 years on average).
  • The wires, nuts, fasteners, and bolts in the system usually have no warranty protection at all.
  • Don’t forget the balance of system components like fuses, circuit breakers, junction boxes, and combiner boxes – each with their own warranty guidelines.

Any and all of the above can break. And when that happens, you’ll need to upgrade the original components with newer hardware.

2. Increased Utility Bill Savings

For many solar customers, the goal is to save money on their utility bills by generating more clean energy on-site. And they accomplish this by expanding their existing PV system or replacing older components with newer alternatives.

Adding more panels is probably the most popular expansion technique. In addition to increased savings, this approach also helps to reduce your carbon footprint. However, adding batteries, solar monitoring, or electric vehicle (EV) charging all qualify as upgrades as well.

3. More Power Generation

A well-design solar PV system should be correctly sized to cover the owner’s needs – plus a little extra slack just in case. However, it’s difficult to budget one’s energy requirements far into the future. And many solar customers end up needing to add more capacity as their power consumption requirements increase over time due to the addition of new family members or power-hungry appliances (like electric vehicles).

Moreover, rising utility prices might prompt you to add more solar capacity. The same is true of falling panel prices or the introduction of new incentives or subsidies.

And remember that adding panels isn’t the only way to get more power out of your system. For example, many older solar installations automatically shut down and stop sending power into the grid whenever there’s an outage. Known as “islanding,” this safety feature is to protect utility technicians as they try to repair downed power lines. However, many newer PV installations now come with anti-islanding technology that allows your panels to continue feeding electricity into your home or business – even if the rest of the grid goes down.

Multiple solar arrays on a residential roof

These are just some of the potential reasons why homeowners and business owners expand their systems. But there’s another category of solar customers – those who aggregate distributed energy resources like PV panels, batteries, and EV’s and sell this power on “spot” energy markets. However, the Federal Energy Regulatory Commission (FERC) will soon allow aggregators to compete on wholesale energy markets. When this happens, many aggregators will expand or upgrade their existing capacity in order to maximize their profits.

What Does It Take: Upgrade an Existing Solar Power System?

Solar PV systems are customized from the ground up. And this means expanding or upgrading them is an even more specialized task since technicians must work around existing hardware (and sometimes existing software as well – in the case of solar monitoring).

Depending on the system, this can make things either easier or more complex. For example:

  • If the current inverter can safely accommodate more solar panels, there’s no need to install a new one.
  • If the current roof needs structural reinforcement to support more PV modules, upgrading becomes a lot more involved.

When adding or replacing components, it is also important that the amperage, voltage, and current are properly balanced – both at the component level and systemwide. Adding more panels, for example, might give you more theoretical power. But you won’t be able to use that extra electricity if your inverter isn’t rated for that many modules. Similarly, installing an oversized battery might be overkill if you already consume most of the daytime solar electricity your panels generate.

In addition, all upgrades should meet the legal and technical requirements of local regulators, equipment manufacturers, and your utility provider (if the PV system is grid-connected).

Advantages and Benefits of Upgrading an Existing Solar Panel

The decision to go solar is a very personal choice. And the same is true of expanding an existing PV installation, with most system owners ultimately moving forward for the reasons outlined earlier – i.e. maintenance, savings, energy security, and profit maximization (in the case of aggregators).

But because upgrading isn’t free, one must balance the projected cost of expanding against the perceived benefit. For example:

  • Repairing a broken or underperforming system is an investment that nearly always pays for itself.
  • Upgrading to boost utility bill savings is something you can forecast prior to commissioning any expansions.
  • Energy security is difficult to price since every customer is different. But if having a baby or adding an electric vehicle increases your utility bills, it becomes easier to run a cost/benefit analysis.
  • As an aggregator, it makes sense to add as much new solar capacity as they can reasonably sell (at a profit).

Solar Panel Addition

When upgrading an existing PV installation, the solar panels themselves are the most likely component to be replaced (although this will change as batteries and electric vehicles gain in popularity.

While it’s possible to mix and match PV modules of different wattages (or from different manufacturers), this is not considered best practice since this approach requires more setup and testing. It’s often easier, cheaper, and faster to replicate the original panels as much as possible.

Inverter Replacements and Upgrades

Solar inverters are another common “upgrade” contender. They have shorter lifetimes than PV modules, which means most system owners will have to replace their own inverters at some point over the next 25+ years.

In addition, if other components are added elsewhere in the system, you might need a newer inverter to handle the extra load.

Are You Using an Old Solar Inverter?

If so, that might be okay. Solar inverters come with ratings that clearly outline how much energy they can safely handle. And this means any experienced installer or solar technician can tell you how many additional panels you can add. If you’re over that threshold, you may need to upgrade your inverter.

Why Should You Upgrade Your Inverter?

PV panels get all the glory. But your inverter is what makes that solar power used in your home or business. That’s because PV panels generate direct current (DC) electricity – while most appliances rely on alternating current (AC) power.

The inverter is responsible for making this conversion:

  • If your own inverter allows you to use all of the energy your panels generate, then keep it.
  • If it’s not up to the task, upgrading your inverter could deliver significant financial and environmental savings.

Innovation is another reason to replace a perfectly working solar inverter.

Your current one might have the right rating but rely on outdated technology. String inverters, for example, work in a similar fashion to older Christmas lights. A broken panel or partial shading can negatively impact the entire system.

By contrast, microinverters treat each panel independently, which allows you to generate and use more solar power even if a single module in the system is underperforming due to cracks or shading.

Replacing a Failed Solar Panel

We’ve already discussed adding PV modules to an existing system. However, it’s far more common to replace a broken solar panel.

Damaged solar panel

Even though the technology is incredibly resilient, things like falling debris, extreme temperature changes, or the inevitable march of time are all things that can damage PV panels before their warranty coverage ends:

  • Defects and internal malfunctions are normally covered under these warranty policies.
  • Cracks, shoddy installation workmanship, and damage from external causes aren’t usually covered.

Either way, repairing or replacing that panel is the only way to restore your PV system’s former output.

Factors to Consider When You Upgrade an Existing Solar Power System

If you decide to expand or upgrade your existing PV installation, here are 4 important things to consider.

1. Energy Needs

You probably budgeted your energy needs as best you could when installing your initial PV system. But the world is changing fast, and our energy requirements keep going up as we buy more gadgets and electrify more of our lives.

Making energy efficiency improvements within your home or business can help reduce some of this consumption. And you won’t need as many panels when upgrading. Even still, installing more capacity than you need can be a wise investment. This doesn’t always mean adding extra panels. For example, you can upgrade an existing solar system with more storage. Doing so allows you to power more of your nighttime activities with the solar power in your batteries (instead of buying that electricity from the utility).

2. Spatial Constraints

You need sufficient space to install or expand whatever you’re upgrading:

  • Most PV systems are rooftop installations. But if you don’t have enough real estate to add more modules, ground-mounted systems or solar carports may be an option.
  • Inverters and batteries usually go in the garage or electrical room. But many newer models of both types of components are weather-resistant and can be safely installed outdoors.
  • Adding electric vehicle charging requires having sufficient clearance in the garage (or municipal permission if installing on the street).

3. Compatibility

Another key consideration involves making sure all the components are correctly sized and configured to work with the other components in the system. This balancing act is tricky enough when installing a new installation the first time around. But it becomes significantly harder when working with legacy hardware installed by someone else.

4. Moving Your PV System

Having to move an installation isn’t something most solar customers have to think about – at least not in the very beginning. However, there is a very real possibility you may change properties over the next 25 years.

Fortunately, removing an existing PV system and installing it at a new location is doable. And in fact, some homeowners and business owners do precisely that – while also adding newer or more powerful components along the way.

However, many solar customers choose to leave the PV system in place for the next owner. That’s because solar-enabled homes often sell for more. According to the National Renewable Energy Laboratory (NREL), every $1 in annual utility bill savings from your solar panel can increase the resale value of your home by as much as $20. Better still, the U.S. Department of Energy reports that solar homes also spend less time on the market.

If the property value increase is enough to finance an entirely new PV system out-of-pocket, this represents the ultimate upgrade.


There are many reasons to upgrade an existing solar installation – even one that works perfectly well. If the return on investment is attractive enough, moving forward may be the right option for you.

If you’re looking to increase returns, savings, or energy security, trading an existing solar system for an upgrade isn’t the only option. It may be possible to get more out of your PV installation without spending a fortune upfront.

To discover how be sure to read our comprehensive guide on Solar PV System Maintenance.