Plug-In Solar AKA Balcony Solar
Why are we hearing so much about “balcony solar” or “plug-in solar” lately? In May, the Colorado legislature passed HB 26-1007. This article expands on the September newsletter article on the same topic. Plug-in solar is addressed and allows for solar systems up to 1920 watts (about four 480 watt panels) to be installed without utility permission or typical electrician installation. The law also limits the restrictions that landlords and HOA’s can place on these energy saving systems. These systems are relatively small producers and work differently from solar battery generators.
Instead of charging a battery with a couple of solar panels, a microinverter converts solar to alternating current and plugs directly into an outlet at the home. That power is fed through that circuit to the whole house or apartment. The microinverter that provides the AC power to the house is isolated in the case of a power outage so it shuts down. (Known as anti-islanding.) The panels that would provide the full wattage allowed by the law can be quite large for a typical balcony-a 440 watt panel is about 67.8 x 44.6in.
The plug-in system is a kit that includes panels, the microinverter, and the plug to a household outlet. Kits typically are 400-800 watts. A comparison of readily available kits shows the pros and cons of various offers.https://whydidmybillspike.com/blog/best-balcony-solar-kits-2026/
The best installation practice is to use an outlet that is dedicated so other uses can’t overload it. However outside outlets are often on their own circuit that is protected by a Ground Fault Circuit Interrupt (GFCI) against moisture and the elements, and they don’t share a lot of extra load. A circuit breaker cannot see the load that is coming in from the outlet side so it is theoretically possible to overload the wiring on that circuit with the solar input. That is why a dedicated circuit is the safest. A circuit level power meter could be installed to relay that information to a smart switch in the power box to essentially turn off the outlet if it is over-powered. But that is typically more complex than an apartment dweller is comfortable with. There is however, a new standard that addresses this issue.
The new law requires inverters to be smaller than 391 watts power outage and UL certified. There are two UL certification types that would apply to inverters, the older standard is UL-1791 and the newer is UL-3700 specifically for plug-in solar systems. Enphase is a well-known brand that meets the former standard along with several others. They would need to be re-manufactured to include a 120 volt plug. The Hoymiles HiFlow Pro LV 120V 360W Microinverter meets the new UL certification in the low wattage category. The APsystems EZ1-LV-NA 140219 can be software limited to meet the state limit. Both can be plugged directly into a 120 volt circuit.
But this new standard was just issued in December of 2025 so it is early. More systems will soon be on the market. The newer standard eliminates the overpower issue on a circuit as well as providing anti-islanding thus stopping all production if the grid goes out.
What can a householder expect from a small solar system? The power is only delivered during the day and excess power is not compensated by net metering agreements. The most benefit is for power use during the sunny hours of the day. Such daytime power uses would be refrigerators and freezers, electronics that are not on shut offs, electronic clocks, wired fire alarms, and time delayed washers and dishwashers. Even air conditioners and heat pumps would use some of the extra power since it powers the entire panel.
Systems will deliver more sun power in the summer than in winter. In Colorado where there are typically 6 hours of full sun in summer, users can expect close to maximum output from panels that are in full sun and tilted about 40 degrees. A 400 watt system might deliver up to 2 kWh on a sunny day or about 60 kWh per month. That is limited by cloud cover and smoke in the atmosphere. Winter sun is not as powerful. An apartment of 1200 sq ft uses about 600 kwh a month. That means a payback of one tenth of that monthly usage in summer, less in winter. The kWh cost is only part of the utility bill. Service fees and taxes are added. Still the payback time for these smaller solar systems is shorter that large system, within five to six years.
However, if there is space, a 1920 watt system is legal in Colorado as of Jan 1, 2027. That would come at additional expense of course. NAZ Solar explains the components and offers larger kits. A 1740 Watt kit with a ballast ground mount is under $2000.
These plug-in systems are great for renters or those who don’t want to invest in a roof-top or rack mounted system. Larger systems are more practical for saving energy and contributing to the cost of electricity but they are more expensive and require home ownership, insurance, an installer and agreements with the utility. That makes balcony solar big news for Colorado!
Further reading:
Is Plug-in Solar Legal in Colorado (2026) https://plugrule.com/states/colorado/
What Is UL 3700 Certification for Plug-In Solar? https://simplepluginsolar.com/learn/what-is-ul-3700
Balcony Solar Has Arrived https://www.brightsaver.org/blog