Find the coldest point
Check temperature before the room warms, especially near windows, exterior walls, or drafty doors. Daytime readings alone can miss an overnight dip.
A heater is not mandatory in every home, but it may help when the room regularly falls outside your chosen range. Use an aquarium-rated device and verify it with a separate thermometer.
Prevent abrupt recovery
Keep the aquarium away from direct heater vents and avoid turning the thermostat sharply up for the tank's sake. Match water-change temperature to the aquarium.
Test the heater and its placement regularly. If power fails, use a gradual, safe warming plan rather than adding hot water directly.
For your own tank
Check the tank during the coldest hours and after the heater cycles. A separate thermometer helps catch a stuck thermostat. Keep the heater away from direct contact with plants and follow its instructions before lowering water for maintenance.
Use these as general hobby references. Test your aquarium and confirm product guidance before making changes.