Need some advice regarding utilities. My electricity usage is extremely high without aircon! How to solve this? Or rather how to find out where is the root cause for causing this drain?

Has your billed usage been high all along or was it a recent surge?

Some possible reasons:

1. Work from home = more usage

2. Meter readings (see Shaun's answer)

3. Identify the appliances which use the most energy (e.g. fridge, heater) and check their efficiency. If they are rather old, there is a chance that they aren't operating as efficiently

1. Do verify if the meter readings are estimates based on the load profile or actual usage figures first. If your readings are accurate or taken every two months, the usage should be accurate.

2. You might consider getting an advanced meter installed at your own costs if SP is not installing in your area first. It should help with identifying the usage pattern.

https://www.ema.gov.sg/Metering_Options.aspx

3. If not, probably can get those socket power meters or smart plugs to track your electrical appliances power consumption.

4. Otherwise, switch off all sockets for electrical appliances whenever not in use, see if your lights and water heaters are efficient etc and monitor for a few months.