Most Florida homes heat with a heat pump outside and electric heat strips inside the air handler as backup. When the heat pump can’t do its job, the strips carry the load, and many thermostats flag that by showing emergency heat.
“The customer can tell by looking at their thermostat. It will say emergency heat activated, or emergency heat will show on the thermostat. That tells the customer something’s wrong.”
Jason Healy, Operations Manager
What you might notice
| What you notice | What it usually means | What to do |
|---|---|---|
| “Emergency heat” on the thermostat and you didn’t set it | Problem | The heat pump isn’t heating. Call. |
| Some heat, but not what you’re used to | Maybe | Possible sticking reversing valve. Have it checked. |
| Heat strips seem to run all the time | Problem | The backup is doing the heat pump’s job. Call. |
| You switched to Emergency Heat yourself | Normal | That’s the backup running as intended. |
Why the reversing valve sticks in Florida
The reversing valve is the part that flips your heat pump between cooling and heating. Here, it spends most of the year in cooling mode.
“All it is is a spring-loaded valve. In Florida, a lot of people very rarely run their heat pumps in the winter because they don’t need that much heat. After sitting all that time in cooling mode, when it goes to switch over to heat, that cylinder and spring tries to move and sometimes it’ll stick.”
Jason Healy
It may stick only partway, so you get some heat. Then the heat strips kick on to make up the difference, and the house just doesn’t feel the way it normally does.
What to do tonight
Let the backup heat work
If the house is warming, your heat strips are keeping you comfortable. You’re safe for the night.
Check the outdoor unit
If it isn’t running at all, switch the thermostat to Emergency Heat yourself so the strips run on their own.
Call and choose your visit
If the strips are keeping you warm, you can book a daytime visit the next day, when there’s daylight for a deeper diagnosis. Need someone tonight? We generally have a technician at your door in under two hours.
How we fix it
“Sometimes it’s an easy fix. You can simply tap it and we can break it loose. Sometimes it sticks all together and we have to put in for a warranty replacement part.”
Jason Healy
If a warranty part is needed, our parts and warranty team files the claim first thing in the morning, and our parts runners get it to your technician as quickly as possible. Your heat strips keep the house warm in the meantime.
Call us if
- Emergency heat shows and you didn’t set it
- Your heat strips seem to run constantly
- The outdoor unit won’t run in heat mode
- The house isn’t warming even on emergency heat
How to prevent it
Routine maintenance is the answer. Members of our maintenance plan get a visit at the start of winter, when your technician runs the system through heat mode, including the switchover, before the first cold front.
“Routine maintenance is the key. We set those up once at the beginning of winter and once at the beginning of summer, so we can test the system, run it through all its operations, and make sure it’s running correctly.”
Jason Healy
Not sure whether it’s emergency heat or AUX heat you’re seeing? Read AUX heat vs. emergency heat, or start with our 6-step heating checklist.
Emergency heat on?
Flat $129 diagnostic. Serving Volusia County since 1976.
Frequently asked questions
Why did my thermostat switch to emergency heat by itself?
Your heat pump stopped heating properly, so the system is relying on its backup electric heat strips. A sticking reversing valve is a common cause in Florida after months of cooling.
Is it safe to run emergency heat?
Yes. Emergency heat runs your electric heat strips, which are sized to heat your home. It uses more electricity than the heat pump, so have the system checked soon.
Can I fix a stuck reversing valve myself?
No. It’s a refrigerant-side part that needs a technician. Sometimes it can be freed on the spot; sometimes it needs a warranty replacement.
How do I prevent the reversing valve from sticking?
Have your system maintained at the start of winter, so it’s tested in heat mode before you need it.
