when should you use emergency heat
You should only use emergency heat when there’s an actual problem with your heat pump or when it can’t safely run as normal, not just because it’s really cold outside.
What “emergency heat” really is
Emergency heat (often labeled EM Heat) is a backup heat source your thermostat can switch to when the heat pump can’t do its job.
Instead of pulling heat from outside air, it usually uses electric heat strips or a backup gas/oil furnace, which is much more expensive to run.
Think of it like the spare tire in your car: it’s there to get you safely to the repair shop, not for everyday driving.
When you should use emergency heat
Use the emergency heat setting in situations like:
- Your heat pump stops working or won’t turn on at all.
- The outdoor unit is visibly damaged (branch fell on it, fan bent, etc.).
- The outdoor unit is a solid block of ice and will not defrost on its own.
- The system is clearly malfunctioning (tripping breakers, loud grinding, burning smell) and you’ve turned the heat pump off for safety.
- In rare, extreme icing conditions where running the compressor could damage it (e.g., freezing rain building up on fan blades).
In all of these cases, you:
- Turn off regular heat/heat‑pump mode.
- Manually switch thermostat to EM Heat.
- Call an HVAC technician and only use EM Heat until repairs are done.
When you should NOT use emergency heat
Avoid turning on emergency heat in these situations:
- It’s just very cold outside, but the system still runs and eventually reaches set temperature.
- You want “extra” heat because it seems slower than a gas furnace—that’s normal for heat pumps.
- You see “AUX” heat on the thermostat; that is usually automatic backup, not manual EM Heat, and doesn’t mean you should flip the emergency setting.
Most modern systems will automatically turn on auxiliary heat when needed in extreme cold or during defrost cycles, so you don’t need to manually choose EM Heat for that.
Why emergency heat is risky for your wallet
Emergency heat can keep you safe and warm, but it’s usually much more expensive:
- Electric strip heat can use several times more energy than the heat pump.
- Running it for days instead of hours can cause a huge spike in your power bill.
- Using EM Heat constantly instead of fixing the underlying issue can stress other parts of the system and lead to more repairs.
So the rule of thumb: short-term use only, during a real emergency, while you’re arranging service.
Simple checklist: “Should I turn on EM Heat?”
If you’re unsure, run through this quick mental checklist:
- Is the outdoor unit damaged, iced solid, or clearly malfunctioning?
- Yes → You can switch to EM Heat and schedule repair.
* No → Go to step 2.
- Is the system still heating the home, even if slowly, without scary noises or smells?
- Yes → Leave EM Heat off; let the heat pump and automatic auxiliary heat do their job.
* No → You may use EM Heat temporarily and call a pro.
- Have you already been on EM Heat for more than a day or two?
- Yes → Time to get the system properly diagnosed; EM Heat is not meant as a long-term solution.
Mini “forum-style” note and SEO bits
If you were reading a current forum thread about “when should you use emergency heat,” the top replies would almost all say something like:
Only flip that switch when the heat pump is broken, iced over, or could be damaged by running—otherwise let the system handle cold weather on its own.
Right now, people are especially curious about this in recent cold snaps and ice storms, so you’ll see “latest news” posts and local utility advisories reminding homeowners not to use emergency heat as their main winter setting because of cost and grid load.
| Situation | Use Emergency Heat? | Reason |
|---|---|---|
| Heat pump broken or won’t start | Yes, temporarily | Keeps home warm while you wait for repair. | [5][7][9][1]
| Outdoor unit badly iced and not defrosting | Yes, temporarily | Prevents damage to compressor and still provides heat. | [7][9][1][5]
| Extreme cold but system still heating | No | Aux heat will kick in automatically if needed. | [4][9][5]
| Want faster or “hotter” heat | No | EM Heat is costly and not meant for comfort-only use. | [3][4][7]
| Freezing rain icing fan blades, risk of damage | Sometimes | Can use EM Heat to avoid running the outdoor unit until ice melts. | [9][7]
