Context. The narrow-line Seyfert 1 galaxy IRAS 17020+4544 is one of the few known sources to exhibit a multiphase outflow in the highly ionized and molecular phases consistent with active galactic nucleus (AGN) feedback operating in the “energy-conserving” regime.

Aims. We aim to characterize the properties of the ionized warm ionized gas in IRAS 17020+4544 using new optical integral-field spectroscopic (IFS) data, and to assess the presence of outflowing ionized gas and its connection with the other gas phases and its role in the AGN feedback.

Methods. We analyzed new optical seeing-limited IFS observations obtained with MEGARA at the Gran Telescopio Canarias in both low- (R ∼ 6000; LR) and medium-resolution (R ∼ 12 000; MR) modes. We modeled the Hα and [OIII]λ5007 emission lines using multi-Gaussian fitting to characterize in detail the ionized gas kinematics, particularly that of the ionized outflow, in order to derive its energetics and compare it with those of the X-ray and molecular phases. Diagnostic diagrams (WHAN, WHaD, and BPT) were used to investigate the dominant ionization mechanism.

Results. We identify a fast ionized outflow traced by both Hα and [OIII] emission lines, with similar extensions (R_out ∼ 1 kpc and ∼0.5 kpc, respectively) and velocities (v_out ∼ 1460 and 1240 km s⁻¹, respectively). A slower ionized outflow (v_out ∼ 450 km s⁻¹) is also detected in the secondary component of the [OIII] line. The fast outflow follows an energy-conserving regime in both Hα and the [OIII] lines (from the LR setup), while the slower outflow follows a “momentum-driven” regime. The ionized outflows are enclosed within the molecular outflow detected with NOEMA (R_CO = 2.8 ± 0.3 kpc), and the large momentum boosts derived in both phases suggest efficient AGN feedback, likely dominated by radiatively driven winds (quasar-mode) rather than kinetic (jet-driven) processes. Ionization diagnostics indicate that the outflow is primarily AGN-driven, although a contribution from star-formation-driven excitation cannot be ruled out, and some contribution from shocks cannot be excluded on smaller scales.

Conclusions. Our results support a scenario in which the multiphase outflow in IRAS17020+4544 is AGN-driven and energy-conserving in the different (i.e., highly ionized, warm ionized, and molecular) phases, efficiently coupling the AGN energy to the host galaxy’s interstellar medium. The molecular outflow appears to be the dominant phase, while the ionized phase contributes less to the mass budget and feedback efficiency.