You've got a lot to learn about electricity usage.
Your computer and space heater do _not_ use 2500 watts 24/7.
A typical space heater uses 600, 900, or 1500 watts, and doesn't run all the time (you hear that periodic clicking? that's the heater turning on and off as it reaches whatever you set its crappy thermostat to).
A typical computer at idle uses a couple hundred watts. Under full gaming load, it _may_ reach 800 _if_ you have a ridiculously powerful rig and are playing the latest games at full settings.
Your refrigerator does not run 24/7. Its compressor kicks in as needed to maintain an acceptable temperature range. While running, it eats a few hundred watts.
Your router and cable box eat only a couple dozen watts at most. Your television perhaps 200 watts, and only when it's on.
Your air conditioner's fan may be on at all times, but its compressor is not, and the compressor is what eats most of the power.
Do not confuse something being plugged in or having a lit LED or making noise with it using its full, rated power. In particular, do _not_ confuse having something like a 1000-watt power supply in your computer with "my computer uses 1000 watts". It doesn't.