What does emergency heat actually do?
Emergency heat turns the heat pump's outdoor unit off and runs only the backup heat source, either electric strips or a furnace. It makes warm air but does so inefficiently, so it is meant as a short term bridge until a technician can repair the heat pump.
The setting is manual. Auxiliary heat, by contrast, comes on automatically when the system needs help, and you do not need to select anything for it.
Because the heat pump is bypassed, the system does not have its normal efficiency. A long stretch on emergency heat shows up on the electric bill.
Check the thermostat first. A screen set to Cool or Off, a dead battery, or a setting stuck on Emergency can all look like a failed heat pump when they are not.
Should I use emergency heat when it is cold outside?
No, cold weather alone is not a reason to use emergency heat. The system adds auxiliary heat automatically when it needs it. Selecting emergency heat for comfort just runs the expensive backup all the time and does not make the home warmer in a meaningful way.
Many people switch it on because the vents feel cooler than a furnace. Heat pumps deliver gentler air, and that is normal when the system is working.
In the West Valley, winter lows are mild. If your heat pump struggles at those temperatures, something is wrong with the equipment and it needs a diagnosis.
Replace a dirty air filter before calling. Restricted airflow can make a healthy heat pump act weak and can lead to coil icing.
What are the signs my heat pump has failed?
Signs of a failed heat pump include an outdoor unit that does not run, blowing cool air in heat mode, heavy ice on the outdoor coil, a breaker that trips, or strange noises. Any of these means switching to emergency heat only as a temporary step while you call a technician.
Look at the outdoor unit from a safe distance. A fan that is not spinning, a thick coating of ice or debris around it are useful details to report.
Frost during winter mornings is normal because the unit defrosts itself. A solid block of ice that remains is not.
Keep notes on when the problem started, what the outdoor unit looked like and what the thermostat displayed. That information speeds up the technician's diagnosis.
When should I turn the system off and call for help?
Turn the system off and call for help if you see sparks, smell burning, hear loud grinding or banging from the outdoor unit, or a breaker keeps tripping. These are safety signs, so do not keep running the system on emergency heat to stay warm.
Electric heat strips draw a lot of power, and failing components can overheat. A hot smell on first use after a long off period can be dust burning off briefly, but a lingering smell is not.
Reset a tripped breaker once at most. If it trips again, leave it off and call a licensed electrician or technician, then use safe temporary heating while you wait. Vortech's licensed AC technicians and electricians can diagnose a failing heat pump and the electrical side of the backup heat.
More questions: Heat Pumps in Arizona: 12 Questions Homeowners Ask