What you are experiencing are night sweats — essentially hot flashes that happen during sleep. The AC helps with the ambient room temperature, but it does not address what is happening inside your body.

Falling oestrogen levels disrupt the hypothalamus, the part of the brain that regulates body temperature. The hypothalamus misreads your body temperature as too high and triggers a heat-release response — blood vessels near the skin dilate, you flush, and you sweat heavily to cool down. This can happen several times a night, and it happens regardless of how cold the room is.

Practical things that help in the short term: layered cotton bedding that you can kick off easily, a small fan directed at your face, and avoiding spicy food, alcohol, and caffeine in the hours before bed — all of which can trigger or worsen flashes.

For severe or frequent night sweats that are disrupting your sleep meaningfully, these measures manage the symptoms without treating the cause. HRT — particularly transdermal oestrogen (patch or gel) — is the most effective treatment because it directly addresses the oestrogen withdrawal driving the hypothalamic misfiring. It typically reduces night sweats by 50–90% depending on dose. Speak to a gynaecologist about your options. You should not have to lose sleep every night.