How to Split the Electric Bill Fairly With Roommates

It’s June, your roommate has the AC at 64, you’ve been at work all day, and the electric bill just hit $312. Now they want to Venmo request you exactly half. You stare at the ceiling.

If you’re trying to figure out how to split the electric bill fairly with roommates when usage is wildly uneven, the honest answer is: a 50/50 split only works when habits are roughly equal. When one person runs the AC like a meat locker or leaves space heaters on overnight, you need a method that adjusts for that. There are four that actually work.

What is the fairest way to split an electric bill between roommates?

The fairest way to split an electric bill is to use a weighted split based on usage habits, not a flat 50/50. If both roommates use power the same amount, split evenly. If one person controls the thermostat or has high-draw devices, they cover a larger share — usually 60/40 or 70/30 — proportional to who’s driving the bill.

Method 1: Flat split (only if usage is even)

If you both leave for work at the same time, both sleep with the AC at the same temp, and neither of you has a gaming rig running 18 hours a day, just split it down the middle. Don’t overcomplicate it. This is the default for a reason — it’s easy and it’s fair when habits match.

The second usage diverges, this method stops being fair. That’s where it falls apart.

Method 2: Weighted split based on who’s home

If one roommate works from home and the other is gone 50 hours a week, the WFH person is using way more power. Lights, monitor, fridge opens, coffee machine, AC running all day in an empty-but-occupied apartment.

A common weighted split: 60/40 or 65/35 in favor of the person who’s gone more. Sit down once, agree on the split, write it in your roommate agreement, done. You’re not nickel-and-diming each room — you’re recognizing that one person’s habits drive the meter harder.

Method 3: Thermostat-based split

This is the move when the disagreement is specifically about climate. One person wants the AC at 78, the other wants 68. Cooling each extra degree below ~74 in summer raises your bill noticeably, so the person setting the temp pays for the gap.

How it works: agree on a “neutral” temp (say, 74°F in summer, 68°F in winter). Whoever wants it colder or warmer pays the marginal cost. You can ballpark this — every degree below the neutral temp adds roughly 6-8% to the cooling portion of the bill. So if AC accounts for 60% of a $300 summer bill ($180), and roommate A wants 70°F instead of 74°F, that’s 4 degrees × 7% × $180 = ~$50 extra they cover.

You don’t need to be exact. You need to be in the right ballpark and consistent.

Method 4: Pay your own room

Some apartments let you submeter or estimate by room. Less common, but if you’re in a house with separate HVAC zones or window units, each person pays for what their unit pulls. Most renters can’t do this — but if you can, it eliminates the argument entirely.

How do you handle space heaters and gaming PCs?

These are bill killers and they’re almost always one person’s problem. A 1500W space heater run 8 hours a day adds about $40-60/month to the bill in most US markets. A gaming PC pulling 600W under load for 6 hours adds $20-30/month.

Two options: the person who owns the device pays for the estimated extra draw on top of their share, or you agree to a flat “device surcharge” — say, $25/month — added to their portion. The point isn’t to be petty. It’s that one person’s hobby shouldn’t quietly become the other person’s bill.

If you’re also trying to sort out the rest of the utilities — water, gas, internet — there’s a fuller breakdown in how to split utility bills with roommates.

How homies handles it

homies. lets you set custom split ratios per bill — not just 50/50. You log the electric bill, set the weight (say, 65/35 because your roommate WFHs), and everyone sees exactly what they owe with a paper trail. Adjustments are visible to everyone, so nobody can claim they didn’t agree to the split later. The AI mediator also helps you draft the conversation about uneven AC use if you’re dreading bringing it up.

rooming, minus the drama. Join the waitlist at joinhomies.app.