AUSTIN (KXAN) — Come Oct. 1, virtually all new homes and commercial buildings in Austin will need to be built “solar-ready.” That means they must have enough space on their roofs to add solar panels. The outside electrical box also has to be large enough to incorporate a circuit-breaker for future solar technology.

City Council approved the move Thursday night, with just Council Member Ellen Troxclair against the ordinance, but those in the building industry warn the requirement comes with a cost.

Donovan Davis, president and design architect for Danze and Davis Architects, appreciates solar panel savings. He says, “It knocks off $100-$200 a month off my bill.”

But Davis doubts whether the new requirement is worth the overall cost.

“Every regulation the city does just adds another layer of cost to what would be an affordable house otherwise,” he said, noting 15-20 years ago, “What used to cost maybe $75 for us to do a site plan in Austin now cost over $2,000 because of the amount of time it takes to do all those regulations that we do.”

Davis says the solar-ready requirement just adds to the list.

In what’s called an Affordability Impact Statement, the city notes the extra construction costs will hurt the production of affordable housing. A note in the document goes on to explain, “The potential financial benefits for consumers of a solar ready roof are difficult to quantify, would be on a longer term-scale, and only in cases where potential savings associated with the installation and use of solar panels were passed on to home buyers or renters.”

“it just adds time that we have to spend on it,” Davis explained, as an architect. “And that’s just me. There’s other people that that gets added in and so just more and more, just stacks up.”

The Sierra Club’s Lone Star Chapter says the new requirement just makes sense, in a statement, saying it will “lower costs for all new building owners and tenants who wish to add solar in the future, and also convince many designers and home builders to incorporate solar from the beginning.”

New homes larger than 800 square feet, multi-family buildings and commercial construction larger than 2,000-square feet will be required to identify areas where solar panels can be added. There are exceptions for heavily shaded buildings and those that install panels right away.

Austin is now the third city in the state to require this solar-ready construction, joining Houston and Lewisville. That said, Austin is the first city in the state with multi-family and commercial construction requirements.