A Heil heat strip system in Keystone that is driving your electric bill through the roof is usually not a mystery — it is an electrical staging problem. Heat strips are simple, honest equipment: coils of nichrome element wire that glow hot when current flows through them. They are staged on and off by sequencers so your system adds heat in steps instead of all at once. When a sequencer sticks, a contactor welds closed, or an element fails and the rest overwork to compensate, the strips run when they should not — and resistance heat is the most expensive heat your home can make. This page walks the staged-element chain the way we diagnose it: what fails, how we prove it, and when a strip repair stops being the right call.
How heat strips actually work
Electric heat strips live in the air handler and do one job: turn electricity into heat, directly. The key components:
- Nichrome elements. Coils of nickel-chromium wire that heat rapidly when energized. Each coil is a fixed amount of heat — your system’s capacity is the sum of its elements.
- Sequencers. Time-delay relays that bring elements on in stages, seconds apart, so the system ramps up instead of slamming the electrical panel with the full load at once.
- Contactors and relays. The heavy-duty switches that carry the actual current to the elements. They open and close every cycle, thousands of times a season.
- Breakers and wiring. High-amperage circuits feeding the air handler. Loose lugs, undersized wiring, or a tired breaker are failure points, not background details.
- Limit switches. Safety devices that cut power to the elements if airflow drops and temperatures climb too high.
Heil systems integrate this staging with Observer communicating controls, which coordinate when strips engage relative to the rest of the system. When every link is healthy, strips are a reliable, quiet backup. When one link fails, the bill is the first thing that tells you.
The three ways strips drive your bill up
High electric bills from a strip system almost always trace to one of three electrical faults:
- A stuck sequencer or welded contactor. The most common cause. The switching device fails closed, and one or more elements run continuously — even when the thermostat is satisfied. The house overheats slightly, the system short-cycles, and the meter spins.
- Failed staging. Elements that should come on in sequence all fire at once, or a failed element forces the remaining ones to run far longer to meet the call for heat. Either way, you pay for heat delivered inefficiently.
- Control and wiring faults. A thermostat or control fault calling for heat nonstop, or damaged wiring energizing a circuit it should not. These are the faults that make a strip problem look like something else entirely.
All three are provable with a meter in under an hour. None of them require guessing.
Electrical safety: when to cut power and call
Heat strips draw serious amperage, and electrical faults deserve respect. Cut power at the breaker and call us the same day if you notice any of these:
- A burning or hot-dust smell from the vents that does not clear after a few minutes of runtime.
- Scorch marks, melted insulation, or discolored wiring visible at the air handler.
- A breaker that trips repeatedly when the heat runs.
- Strips that stay glowing or the air stays hot long after the thermostat is satisfied.
Do not keep resetting a tripping breaker — it is doing its job. Repeated trips mean a fault that needs hands and a meter, not another reset.
What a proper heat-strip diagnosis includes
Our Keystone technicians diagnose strip systems electrically, link by link:
- Amperage draw per element. Each element should pull its rated current — a dead element reads zero, a failing one reads wrong.
- Sequencer timing. Verifying each stage engages and, critically, releases on schedule. A sequencer that never releases is the classic high-bill culprit.
- Contactor and relay inspection. Checking for pitted or welded contacts that fail to open.
- Breaker, lug, and wiring inspection. Tightening connections, checking for heat damage, and confirming the circuit is correctly sized for the load.
- Thermostat and control signals. Confirming the call for heat starts and stops when it should — including the Observer communicating control staging.
- Limit switch and airflow check. Restricted airflow from a clogged filter overheats elements and trips limits; we confirm the air path is clear.
The full sequence typically takes one to two hours depending on access. Our vans carry replacement elements, sequencers, and contactors matched to Heil equipment, and we offer same-day dispatch across Keystone — because a stuck strip wastes money every hour it runs.
Repair or replace: where the line sits
A failed sequencer, contactor, or individual element almost always means repair. These are component-level electrical fixes, and on an otherwise healthy air handler they restore normal bills at a fraction of replacement cost.
The conversation changes when the air handler itself is aging: brittle wiring throughout, a rusted cabinet, repeated electrical failures across multiple seasons, or elements no longer available for the unit. At that point, replacing the air handler — with new elements, sequencers, and controls — is the honest recommendation. We show you what failed, what it costs to fix, and what the equipment’s condition says about the next five years.
Whichever path you take, warranty-safe practice matters: uncertified work can void the manufacturer warranty on your Heil system, which is why we use genuine parts matched to your equipment.
Keeping Keystone heat strips healthy
Strip failures are electrical failures, and electrical failures are preventable:
- Keep filters clean. Restricted airflow is the number one cause of overheated elements and tripped limit switches.
- Annual electrical inspection. Connection lugs loosen with thermal cycling; a yearly torque check prevents the arcing that destroys sequencers and contactors.
- Do not ignore staging changes. If the heat feels different — slower to warm, running longer, or cycling oddly — the staging is telling you something before the bill does.
How long does a heat-strip diagnosis take in Keystone?
Usually one to two hours. We measure amperage draw per element, test sequencer timing, inspect contactors and wiring, and verify control signals. The exact time depends on air handler access and how many stages your system has.
Is it safe to keep running the heat with a suspected strip fault?
If you smell burning that does not clear, see scorch marks, or the breaker trips, cut power and call — do not keep running it. If the only symptom is a high bill with otherwise normal operation, it is safe to run until your appointment, but book soon: a stuck element wastes money every cycle.
Why did my electric bill spike so suddenly?
The most common reason is a sequencer or contactor stuck closed, running elements continuously. Resistance heat at full tilt, around the clock, shows up fast on a bill. The second most common is failed staging — all elements firing at once instead of in sequence.
My thermostat is satisfied but the air still feels hot — what is that?
That is the signature of a switching device that failed closed: the thermostat stopped calling for heat, but a welded contactor or stuck sequencer kept an element energized. It needs a technician, not a thermostat adjustment.
When should I replace the air handler instead of repairing the strips?
When the electrical system is failing in multiple places at once — brittle wiring, repeated sequencer or contactor failures, a deteriorated cabinet, or parts no longer available. A single failed element or sequencer on an otherwise sound air handler is a repair.
If your Keystone home’s electric bill has spiked and your Heil heat strips are the suspect, do not wait through another billing cycle. We offer same-day dispatch across Keystone with 24/7 emergency service, and our vans arrive equipped to test every element, sequencer, and contactor in one visit. Contact us today and get your bills back under control.