Willis Carrier developed the first mechanical refrigeration system in 1903. It took another 50 years before window air conditioners became popular in homes and businesses. Hot and humid climates, such as those in the southeast, were by necessity the first to widely adopt air conditioning. By the 1970s, air conditioning was standard and the industry matured to one in which system maintenance and upgrades were the bread and butter for industry professionals.

The PV industry has a similar path. Bell Labs developed the modern solar cell in 1954. 50 years later rooftop PV was becoming popular in certain U.S. markets. Because of high electric rates, California and Hawaii were at the forefront of PV adoption.

By 2019, California hit a million rooftop PV systems in 2019, and solar is now standard on new California homes. Those intrepid early adopters of rooftop solar are now upgrading their 10- and 20-year old systems with new inverters, as well as adding battery storage. Solar-plus-storage systems are going into millions more buildings around the U.S.

How do these HVAC industry experiences foreshadow developments in the PV industry? Here are a few likely outcomes:

The solar industry will evolve from component brands to system brands. This evolution will become even more important as battery systems become standard. With ample module and battery cell manufacturing capacity, not all system components must be manufactured by the system brand. SunPower was ahead of the pack in this regard, integrating its panels with OEM inverters, all installed by their branded dealer network — perhaps so far ahead of the pack that they recently decided to divest their module brand.

New installations in all market segments will be on a tear for the next 20+ years as all buildings with decent solar potential will have PV on their rooftops. Unlike the HVAC industry – which relied on enhanced comfort to drive sales – PV systems provide both economic and valuable environmental benefits. Except for temporary incentive and policy blips, the fundamental economics for solar generation in all markets will drive long term installation growth.

Inverter, monitoring, battery and configuration support will be an increasing part of every established PV contractor’s business. Customers will select contractors based on their reputation supporting existing customers. Since ongoing maintenance is rarely priced into the cost of a new installation, maintenance on existing systems is likely to be expensive.

Equipment branding will be a key differentiator for solar-plus-battery systems. Just as Carrier, Trane and Lenox dominate HVAC system brands, profitable solar equipment manufacturers will need to invest in their brands on both a financial and technology basis.

Batteries and home energy system integration will become a core competency of solar contractors. Accordingly, their skill set will extend to indoor electrical and communications wiring, home network integration, app-based configuration, and remote software updates as equipment and electric rates change.

I believe it is most likely that inverters will be the home energy hub, rather than the other two largest home energy consumers – HVAC systems and cars. Since inverters will control both generation and storage, they will essentially act as a traffic cop to direct power flows among appliances depending on electric rates, grid conditions (or lack thereof), and appliance energy needs/surpluses.

Finally, software, communications and cybersecurity will be among the most important components of solar-plus-storage systems. Great solar cell, inverter or battery technology will not be usable by installers and customers without a complete suite of secure and easy-to-use software.

Willis Carrier probably never imagined the ubiquitous growth of refrigeration and air conditioning, just as the inventors of solar cells never imagined the ubiquity of PV systems. The solar-plus-storage industry is destined to be a key part of virtually every building in the U.S. From a growth perspective, we haven’t seen anything yet.