Zelenskiy, speaking in his nightly video address on Tuesday, also assessed how local authorities in Ukraine's cities were tackling the aftermath of massive Russian attacks, particularly in ensuring high-rise apartments had power and heating.
He again singled out for criticism officials in the capital Kyiv.
Zelenskiy said he held long discussions with the military's Commander-in-Chief, Oleksandr Syrskyi, the chief of the general staff, Andrii Hnatov, and Defence Minister Mykhailo Fedorov.
"Many changes are happening right now in the work of air defence," he said.
"In some regions, the way teams operate, interceptors, mobile fire units, the entire small air defence component is being practically rebuilt completely," Zelenskiy said.
"But this is only one element of defence that requires changes. Changes will happen."
The president has frequently pointed to improved air defences as critical to protecting cities from air attacks and has asked Kyiv's Western allies to provide more weaponry to knock out incoming missiles and drones.
Last week, with heating still not restored to hundreds of dwellings after air raids targeting energy infrastructure, he said defence lines in some areas were proving inefficient.
Energy Minister Denys Shmyhal, writing on Telegram after the daily meeting of officials on energy issues, said crews were working around the clock to restore heating in Kyiv, where night-time temperatures were set to hit minus 19C.
After meeting with the top brass, Zelenskiy said Kharkiv and Poltava regions in central and northeastern Ukraine were also having difficulties with electricity, as well as parts of Odesa region on the Black Sea.
He renewed criticism of decision-makers in Kyiv, where he has been at odds with Mayor Vitali Klitschko, as well as in his hometown of Kryvyi Rih and Okhtyrka near the Russian border.
"Every community leader and responsible service must pay real attention to what is happening with buildings, with networks," he said.
"We are monitoring at all levels and people will be held personally responsible."
