Costs·7 min read
My bill went up after switching. What happened?
Usually one of five things, and four of them are fixable without touching the equipment.
Usually one of five things, and four of them are fixable without touching the equipment.
It's a common enough complaint that it's worth walking through systematically, because the equipment itself is rarely the actual cause.
The most common cause: a big jump in the electricity-to-gas price ratio in your specific area. A heat pump moves the cost of heating from the gas meter to the electric meter. If your utility's electric rate is high relative to gas, the fuel switch alone can raise the bill even though the equipment is more efficient, especially without generous rebates offsetting the higher upfront electric use. This is a real economic tradeoff, not a malfunction, and it's the one item on this list that equipment can't fix, only rate design or a dual-fuel setup can.
Backup strip heat running more than it should. If the heat pump is undersized, poorly commissioned, or the balance point is set too high in the thermostat's controls, expensive electric resistance heat kicks in far more often than the design intended. This alone can double a winter electric bill and is worth checking with a contractor, it's often a configuration fix, not a new-equipment fix.
A thermostat habit carried over from furnace days: setting the temperature back significantly at night or while away. With a furnace this saves energy because the furnace can rapidly reheat the house. With a heat pump, especially one with backup strip heat, a big setback can force the system into expensive backup heat mode to recover the temperature quickly, erasing the savings and then some. Heat pumps generally prefer a steady setpoint.
Air sealing and insulation that didn't change when the equipment did. A heat pump exposes duct leakage and envelope leaks more visibly on a bill than a furnace does, mostly because it's now running longer, steadier cycles instead of short furnace blasts, so any losses accumulate more consistently. If ducts run through an unconditioned attic or crawlspace, sealing them can matter as much as the equipment swap itself.
A genuinely undersized or mismatched system, running constantly and still not keeping up, so it's drawing power nonstop without effectively heating. This traces back to the sizing and quote issues covered elsewhere on this site, and the fix is a proper load calculation and, sometimes, an equipment correction under warranty.
