When a cold front drops Miami from the 80s to the 40s or 50s, switch your thermostat from cool to heat early, expect a short burning dust smell, and avoid emergency heat unless the heat pump fails. Seal drafts at doors and windows with weatherstripping and caulk. A heating check typically costs $90 to $200.
| Task | DIY cost | Professional cost |
|---|---|---|
| Heating check or service call | Not a DIY job | $90 to $200 |
| Replace air filter | $10 to $40 | Usually part of a service visit |
| Heat strip or sequencer repair | Not a DIY job | $200 to $600 |
| Weatherstrip and door sweep, per door | $15 to $50 | $75 to $150 |
| Caulk windows and gaps | $5 to $10 per tube | $150 to $400 for a home |
How do you switch your AC to heat in Miami?
Most Miami homes heat with the same system that cools them: either a heat pump, which reverses the AC to move heat indoors, or electric heat strips inside the air handler. Because these systems sit in cooling mode for most of the year, the first switch deserves a little care.
- Replace the air filter before the front arrives. A dusty filter makes the burning smell worse and strains the system.
- Set the thermostat to Heat, not Emergency Heat, and pick a moderate temperature such as 68 to 70 degrees.
- Run it in the afternoon, while it is still mild, so any dust burns off before you need real heat.
- Open a window for 15 to 30 minutes if the dusty smell lingers.
- Listen and feel. Warm air should reach the vents within a few minutes.
Heat pump or heat strips: which do you have?
Check the outdoor unit while the heat is on. If the fan is running and the unit is working, you have a heat pump, which moves heat from outside air into the house and is the cheaper way to stay warm. If the outdoor unit sits still while warm air comes out inside, your system relies on electric heat strips in the air handler, which work well but use more electricity per hour.
Many Miami heat pumps also use strips as backup on the coldest nights, so seeing both run for a short time is normal. Either way, a cold front lasting two or three days rarely adds much to a monthly bill if you keep the thermostat around 68 to 70 degrees and close the drafts described below.
What is normal and what is not
| Normal on the first run | Shut it off and call for service |
|---|---|
| Dusty burning smell that fades in 30 minutes | Sharp electrical or melting plastic smell |
| Outdoor unit steaming briefly in defrost | Breaker tripping when heat starts |
| Air a little cooler than a furnace would blow | Cold air only after 15 minutes on Heat |
| A click when the system switches modes | Grinding, banging or burning smell that grows |
Heat pumps blow air that feels warm rather than hot, often around 85 to 95 degrees at the vent. That is normal. What is not normal is cold air on Heat, which often points to a reversing valve, thermostat or wiring problem. Our guide to heating tune up costs explains what a seasonal check covers.
Why do Miami homes feel so cold during a front?
Miami homes are built to shed heat, not hold it. Concrete block walls with little insulation, terrazzo and tile floors, sliding glass doors to the patio and older jalousie windows in neighborhoods like Little Havana, Coral Gables and Miami Springs all let warmth slip out fast. Tile floors feel icy underfoot, and gaps that let in humid air all summer become cold drafts overnight.
Salt air also wears down weatherstripping and window seals faster than in inland cities, so seals that looked fine two years ago may be cracked now. Our guide to protecting your home from salt and humidity covers the year round side of this.
How do you seal drafts before a cold front?
You can handle most draft sealing in an hour or two with $30 to $80 in supplies from a hardware store. Focus on the biggest leaks first:
- Exterior doors: replace flattened weatherstripping and add a door sweep if you can see daylight under the door.
- Sliding glass doors: clean the track, check the pile weatherstrip along the edges, and lock the door, which pulls the panels tighter.
- Windows: run a bead of caulk where frames meet the wall outside, and use removable rope caulk on older jalousie or single pane windows.
- Outlets on exterior walls: add foam gaskets behind cover plates.
- Attic hatch: add weatherstripping around the edge and a layer of foam board on top.
If you would rather hand it off, a handyman can typically weatherstrip and caulk an average home for $150 to $400, which is often a single visit.
Fronts usually pass within two or three days, so you do not need permanent upgrades to get through them. Still, if every winter brings the same cold rooms and drafty sliders, consider replacing worn weatherstripping for good or upgrading old jalousie windows when you next update for hurricane season. Those changes help with summer cooling bills as well.
What else should you protect when a front hits?
- Bring in or cover tropical plants such as orchids, crotons and hibiscus when lows dip under about 45 degrees.
- Bring pets inside overnight; many Miami pets are not used to the cold.
- Check the pool heat pump if you plan to swim, and run the pump as usual.
- Use space heaters only plugged directly into the wall, with three feet of clearance.
- Test smoke and carbon monoxide alarms before running any heat source.
Fronts are also a good moment to think about your thermostat. A smart thermostat can switch modes on schedule and keep you from accidentally running emergency heat; our smart thermostat installation guide walks through the options. And since the same equipment cools your home for the other 50 weeks of the year, pair a heat check with your spring AC tune up.
If the heat will not come on or something smells wrong, see your upfront price and book your HVAC service on House Fly. Your payment is held until the job is done.
Frequently asked questions
Why does my heater smell like burning in Miami?
Because Miami heaters sit unused for most of the year, dust settles on the electric heat strips. The first time they warm up, that dust burns off and smells like something is scorching. It should fade within 15 to 30 minutes. If the smell is sharp, electrical or lasts longer, shut the system off and call for service.
Should I use emergency heat on my thermostat?
Usually not. Emergency heat runs only the electric strips and skips the heat pump, which can cost two to three times as much to operate. In Miami, a working heat pump can handle typical cold fronts on its own. Use emergency heat only if the heat pump has failed and you are waiting on a repair.
How much does it cost to have my heat checked in Miami?
A heating check or service call in South Florida typically costs $90 to $200. If a heat strip, sequencer or capacitor needs replacing, repairs commonly run $200 to $600. Booking a check in late fall, before the first front, usually means more open appointments than the morning after a cold night.
How do I find drafts in my house?
On a cool, windy evening, hold a lit incense stick or a strip of tissue near door edges, window frames, outlets on exterior walls and attic hatches. If the smoke or tissue moves, air is leaking. Daylight showing around a closed door is another clear sign that weatherstripping needs replacing.
Are space heaters safe to use in Miami homes?
They can be if used carefully. Plug them directly into a wall outlet, never an extension cord, keep three feet of clear space around them, choose a model with tip over and overheat shutoff, and turn them off when you leave the room or go to sleep.
