Ghost loads: the hidden amps that fail heat pump installs
Every electrical panel has two stories. The paper story — what the load calculation, the permits, and the breaker labels say is connected. And the real story — what actually draws current when winter arrives. A ghost load is anything living in the second story but missing from the first: real equipment, pulling real amps, invisible in every document anyone will use to decide whether your panel can take a heat pump.
Where ghost loads come from
Almost never from bad intent. They accumulate the way houses accumulate — owner by owner, project by project:
The weekend addition
A previous owner finished the basement and ran two baseboard heaters off a spare breaker. No permit, no updated load calc — 3,000 W that exists nowhere on paper.
The inherited hot tub
Wired in properly, even permitted — but the panel schedule was never updated, and the load calc from the last service change predates it entirely.
The mislabeled breaker
"Garage" turns out to feed a 240 V workshop heater. Labels rot faster than wiring does.
The forgotten well pump or MUA unit
Equipment that runs rarely enough to be invisible in daily life, and large enough to matter enormously at design conditions.
Each one is harmless on its own. The problem arrives the day someone sizes a new load — a heat pump, an EV charger — against a load list that pretends these do not exist.
Why the math cannot forgive a missing load
The electrical codes are generous about loads they know about. Both the US and Canadian optional methods apply demand factors — NEC 220.82 counts general loads above the first tier at only 40%; CEC Rule 8-200 counts a dryer at 25% when a range is present — because you never run everything at once.
But a demand factor can only discount a number that was entered. A ghost load is not under-counted at 40% — it is counted at exactly zero. The calculation is then internally perfect and externally wrong, and every decision downstream of it inherits the error: the "your panel is fine" reassurance, the quote, the breaker that holds all summer and trips in January.
Field note:the worst ghost load we've encountered was a commercial make-up air unit drawing 129 amps that appeared in no load calculation for 11 years — on a 200 A service. The residential version is smaller, but the shape is identical: one missing line, and everyone downstream trusted the total.
The heat pump connection
Ghost loads stayed harmless for decades because panels had slack. A gas-heated home with a 100 A service might use a third of it. Electrification spends that slack: a heat pump adds 15–30 A, backup heat strips can add 40 A more at design temperature, a Level 2 EV charger another 30–50 A. Suddenly the difference between the paper story and the real story is the difference between PASS and FAIL.
This cuts both ways, and this is the part most homeowners miss: sometimes the ghost works in your favor. If the "load" everyone assumes — that old 10 kW electric furnace still listed from 1985 — was actually removed when gas came in, your panel has more room than the paperwork suggests. The only way to know which side of the ledger your home is on is to run the calculation with a current, complete load list.
Run your real numbers
The free check walks you through every load category and runs the NEC 220.82 / CEC 8-200 math on your actual home. Two minutes, no signup.
Check My Panel Free →Frequently asked questions
How do I find ghost loads in my own home?
Walk the house, not the panel. Open the breaker panel door and read the labels, then go room to room looking for anything electric that heats, cools, pumps, or charges: baseboard heaters, in-floor heat thermostats, a hot tub, a well pump, a workshop subpanel, a kiln, block heater outlets. Anything that heats or moves water is a suspect. If it draws serious power and no breaker label mentions it, it may also be missing from any load calculation done on your home.
Are ghost loads dangerous?
The load itself is usually fine — it is on a breaker, and the breaker protects the wire. The danger is in decisions made from incomplete math: a service sized on a load list missing 4,000 W of baseboard heat can end up chronically running past its continuous rating once a heat pump is added, tripping the main on the coldest nights — exactly when you need heat most.
Is standby power a ghost load?
No. Standby (phantom/vampire) power is the few watts your TV and chargers sip when idle — an energy-cost nuisance, irrelevant to panel sizing. A ghost load is hundreds to thousands of watts of real equipment that was never written down. Different problem, different order of magnitude.
Will the free calculator catch my ghost loads?
It makes you catch them. The calculator walks you through every load category — including the ones people forget — and runs the code math on what you enter. The result is only as complete as your list, which is exactly the point: the discipline of listing every load is what a proper calculation forces, and what a guess never does.
Next: Do you actually need a panel upgrade for a heat pump? · Heat pump costs and rebates: HeatPumpLocator.com