Should I Turn On Emergency Heat?

When It Makes Sense

• Good fit: Outdoor temperatures have dropped well below the heat pump’s balance point (often around 30‑40°F/‑1‑4°C) and the home is struggling to stay warm, making supplemental heating necessary.
• Good fit: The heat pump displays a fault code or stops functioning altogether, and you need immediate warmth while a technician is scheduled.

When You Should Avoid It

• Warning sign: Outside temperatures are only mildly cold and the heat pump is operating normally; using emergency heat will dramatically increase electricity or gas usage.
• Warning sign: The thermostat has been set to emergency heat for more than a day or two, suggesting the underlying issue is being ignored.

Pros and Cons

Pros

• Provides rapid, reliable heat when the primary heat‑pump system cannot meet demand, protecting indoor comfort and preventing frozen pipes.
• Allows you to maintain a safe indoor temperature while waiting for professional service, buying you time without a complete loss of heat.

Cons

• Consumes significantly more energy than normal heat‑pump operation, leading to higher utility bills.
• Can conceal mechanical problems in the heat‑pump system, delaying necessary repairs and potentially causing more expensive damage.

Decision Checklist

• Is the outdoor temperature below the heat‑pump’s balance point or has the unit stopped providing heat?
• Do you have a clear plan to diagnose and repair the primary system within a short timeframe?
• Have you calculated the expected increase in energy cost and confirmed it fits your budget?

Alternatives to Consider

If emergency heat is not ideal, you can supplement warmth with portable electric space heaters, add extra insulation or curtains, or use a programmable thermostat to lower the setpoint temporarily. In milder cold, a reverse‑cycle heat pump may still be efficient, and a professional service call can resolve underlying faults without relying on the high‑energy backup.

Final Recommendation

Turn on emergency heat only when the primary heating system cannot keep the home comfortable due to extreme cold or a clear malfunction, and plan to revert to normal operation as soon as the issue is fixed. Always weigh the immediate comfort benefit against the steep rise in energy cost, and consult an HVAC technician if the problem persists beyond a short period.