Why Is My Energy Bill So High This Winter?

The envelope shows up in late January and the number in it doesn't look like a number you've seen before. First thought for almost everybody: something is wrong with the furnace.

Occasionally that's true. Much more often the furnace is fine and the bill is telling you about something else entirely. You can figure out which one you've got in about ten minutes, without anybody coming to your house.

The catch is that you have to stop looking at the dollars.

Read the Usage, Not the Total

The dollar amount is the least useful thing on a utility bill. They fold together how much you used, what the rate was, how many days the billing period covered, and any fees or true-ups. Four variables in one number.

Find the usage instead. On the gas bill it's therms or CCF. On the electric side it's kilowatt-hours. Both utilities print a bar chart showing the last twelve or twenty-four months of usage, and that chart is the single most useful thing in the envelope.

Now compare this month's usage to the same month last year. Not to last month — heating usage swings wildly from November to January and that comparison tells you nothing.

Three possible answers:

Usage is flat, dollars are up. That's rates, plus possibly a longer billing period. Nothing is wrong with your equipment. Annoying, but not a repair.

Usage is up and the weather was clearly colder. Also normal. A January that runs eight degrees colder than the previous one will burn substantially more gas in an identical house. Weather explains more winter bill complaints than every other cause combined, and it's easy to underestimate because nobody remembers last February accurately.

Usage is up and the weather was comparable. Now you have something. Keep reading.

One more thing to rule out before you go further: if you're on budget billing, a big charge may be a true-up rather than a month's consumption. That's accounting, not heating.

The Causes, Roughly In Order

When usage genuinely jumped and weather doesn't explain it, this is the order I'd work.

Somebody changed the thermostat. Sounds too simple. It's the most common real cause I find. A teenager who's cold. A guest who bumped it. A schedule that got wiped by a power outage and reverted to holding one temperature around the clock — that one is sneaky, because nothing looks different on the display. A smart thermostat that lost its Wi-Fi and stopped following its schedule. Each degree you hold around the clock costs real money over a Michigan winter, and holding seventy-two all day instead of setting back while the house is empty is a significant number over three months. Go look at the schedule, not just the current setpoint. The fall settings post has the numbers.

Space heaters. This is the biggest single cause of an electric bill surprise, and people genuinely don't connect the two. A 1,500-watt heater running continuously is a substantial daily cost, and the households that call me about a shocking electric bill often have two or three of them going in rooms that never get warm. Worse, the reason those rooms are cold is usually a fixable duct or balance problem, so they're paying premium rates to work around something that could be repaired.

A heat pump on emergency heat. If you have a heat pump, check the thermostat for EM HEAT. That setting shuts the heat pump off entirely and runs on electric strips, which is the most expensive way to heat a house there is. People flip it during a cold snap thinking it means "extra heat" and then forget. Same with AUX coming on constantly in mild weather, which is a symptom rather than a setting — worth understanding the difference.

The filter and airflow. A restricted filter makes the furnace run longer to deliver the same heat, and in bad cases it trips the limit switch so the blower runs with the burners off. Pull it and look. Four dollars to rule out. Just don't expect it to account for a doubled bill. It's usually a contributor, not the whole story. Same family of problem if somebody put a very high-MERV filter in a one-inch slot.

Dry air. This one is indirect and it's real. Very dry air makes you feel colder at the same temperature because moisture evaporates off your skin faster. So people creep the thermostat up two or three degrees chasing comfort that isn't about temperature at all. Fixing the humidity often lets people back the heat down and feel better doing it.

The House, Not the Furnace

Duct leakage. Supply ducts running through an unheated crawlspace, an attic, or an uninsulated garage ceiling leak heat directly outside the conditioned space. In older homes with retrofitted ductwork, this can be a large number. Sealing accessible joints with mastic is cheap work with a real return.

The house itself. Attic insulation that's thin or has been compressed, an attic hatch with nothing on it, a rim joist that's bare wood, a door that's lost its weatherstripping. Nothing changed suddenly, but if you compare against a year when you had storm windows up and this year you didn't, it shows.

Something new in the house. A dehumidifier left running in the basement all winter, heat tape on a roof edge or a pipe, a second refrigerator in the garage struggling in the cold, an engine block heater, a hot tub. These are electric and they're easy to forget about.

A failing water heater. An electric unit with a stuck element or a leaking hot water line somewhere will quietly run up a bill. Gas water heaters can too if the thermostat has drifted.

Where the Equipment Comes In

The furnace itself. I put it last on purpose. Equipment losing efficiency does it slowly over many seasons, so it very rarely explains a year-over-year spike. What can cause a sudden change is a furnace that's overfiring, a cracked heat exchanger changing how it burns, a gas valve that's drifted, or a short cycling problem that has it burning at its least efficient point over and over. Those are real, they're findable with a combustion analyzer, and they're a service call.

What Actually Moves the Number

Once you know what you're dealing with, be realistic about what each fix is worth.

Air sealing and attic insulation. The biggest lever by a wide margin in most West Michigan houses, and it isn't HVAC work. Rim joist, attic penetrations, the hatch, then insulation depth. It pays back faster than anything else on this list and it makes the house more comfortable at the same time.

Thermostat discipline. A genuine setback overnight and while the house is empty is free and it's worth real money over a season. For a gas furnace, the old advice about holding one temperature is wrong. A cooler house loses heat more slowly, which is the whole reason it works.

Duct sealing. Cheap where the ducts are accessible, meaningful where they run through unconditioned space.

Fixing whatever made you buy the space heaters. A balance problem, a blocked return, a closed damper, a duct that was never properly connected. Solving it at the source is dramatically cheaper than running resistance heat all winter.

Equipment efficiency. Real but slow. Replacing a working furnace purely to chase savings rarely pencils out on its own. It makes sense when you're replacing anyway, not as a standalone investment.

A guy out in Jamestown called me a couple of winters ago convinced his four-year-old furnace was defective, because his gas usage was up around a third from the year before. I went out and put an analyzer on it. Furnace was burning beautifully, better numbers than most units I see. So we sat at the kitchen table and pulled up his usage history instead, and the pattern was obvious once it was side by side: the jump started in early November, not in the deep cold, and it never came back down. His wife had switched to working from home that fall. The house that used to sit at sixty-two for nine hours a day was now holding seventy all day, every day, five days a week.

Nothing was broken. I didn't charge him for a repair because there wasn't one. But he was genuinely relieved to have an answer, and they compromised on sixty-seven and a good sweater.

Most of these calls end somewhere like that. The bill is usually describing the house and the people in it, not the machine in the basement. Worth ruling the machine out — just not worth starting there.