(Written for the roommate who commutes 45 minutes to an office every day, only to come home to a $200 electricity bill because the AC has been running non-stop since 9 AM.)
The standard roommate agreement for utilities is almost always a 50/50 split. It's clean, it's easy, and for decades, it was perfectly fair. But the shift to remote work has fundamentally broken the 50/50 utility model.
If Roommate A works from home five days a week, and Roommate B commutes to an office, their usage of the apartment is no longer equal. Roommate A is consuming eight to ten extra hours of electricity, heating, air conditioning, and water every single weekday. Over a month, that "WFH utility gap" adds up to a significant amount of money.
If you're the commuting roommate, you might feel like you're subsidizing your roommate's home office. If you're the WFH roommate, you might feel defensive about being nickel-and-dimed in your own home. Here is how to navigate the conversation and find a fair mathematical split.
The Hidden Costs of Working From Home
Before negotiating a split, it's important to understand what is actually driving the utility bill up. It's not the laptop charger. Charging a MacBook costs mere pennies a month. The real culprits of the WFH utility spike are climate control and baseboard usage:
- Heating and AC: The largest driver of energy costs. A commuting household can turn down the heat or AC during the 9-to-5 window. A WFH household must run climate control all day.
- Water usage: Extra toilet flushes, making coffee at home, and running the dishwasher more frequently.
- Lighting and Monitors: While less expensive than AC, running multiple large monitors and overhead lights for 40 hours a week contributes to the baseline cost.
Depending on the season and your location, a full-time WFH schedule can increase a household's utility bills by 15% to 30% compared to an empty apartment.
How to Calculate a Fair WFH Split
There are three ways to adjust the utility split without making it overly complicated or resorting to petty calculations.
1. The 60/40 Ratio (The Easiest Method)
If you don't want to dig into historical data, the simplest solution is a slight ratio adjustment. Instead of a 50/50 split, shift the utilities to a 60/40 or 65/35 split in favor of the commuting roommate. This acknowledges the extra usage without requiring a spreadsheet. If the electric bill is $100, the WFH roommate pays $60, and the commuting roommate pays $40.
2. The "Historical Baseline" Method (The Most Accurate)
If you have lived in the apartment during a time when both of you commuted, you can use those old bills as a baseline. For example, if your average summer electric bill used to be $80, and now with one person working from home it is $130, the $50 increase is directly attributable to the WFH setup. The commuting roommate pays $40 (half the baseline), and the WFH roommate pays $90 (half the baseline + the full WFH overage).
3. The Internet Caveat
Internet bills are flat-rate. Whether you use 10GB or 1000GB, the bill is the same. Therefore, the internet should almost always remain a 50/50 split. However, if the WFH roommate insisted on upgrading to a more expensive, high-speed business tier specifically for their Zoom calls, they should pay 100% of the difference between the standard tier and the upgraded tier.
How to Have the Conversation
Money conversations between roommates can quickly feel like personal attacks. The key is to frame the discussion around the math, not the person's lifestyle.
Don't say: "You're home all day blasting the AC and my bill is huge. You need to pay more."
Do say: "Hey, I noticed our electric bill has gone up quite a bit during the weekdays since you started working from home full-time. Since I'm at the office most of the day, do you think we could adjust the split to 60/40 to reflect the daytime usage?"
Most reasonable people will recognize the fairness in this request. It's a logistical adjustment, not a punishment for working remotely.
Automating the New Split
Once you agree on a new ratio (like 60/40 for electricity and 50/50 for internet), the last thing you want to do is manually calculate those percentages every month. Doing manual math on a napkin every time a bill arrives is how resentment starts creeping back in.
Use a shared expense tracker where you can set default split weights. You input the $150 electric bill, the app automatically assigns 60% to the WFH roommate and 40% to you, and it keeps a running total of the balance. No calculators, no monthly negotiations. Just fair, transparent math that keeps the peace in your shared home.