You get into your car, turn the knob, brace for warmth, and get…refrigerated air. Augh. Before you assume the worst, though, take a breath. Most heater failures fall into a short, familiar list for mechanics, and many are far less dramatic than a full dashboard teardown (no guarantees, though).

Here are the seven most common “no heat” culprits, what the fixes look like, and what they typically cost today. And while I spent many years at the front counter of a full-service car repair facility, it’s been a few years. I’m using RepairPal national average estimates here.

1. The engine hasn’t warmed up yet

I have to start with the obvious: If you only drive a mile or two at a time, especially in deep winter, your engine may never reach operating temperature. That means no heat.

Fix: Let the car warm up longer (depending on your location and the outdoor temp, I’d give it up to 10 minutes)

Cost: Free! (The best price in automotive repair…)

2. A bad blend door actuator

Blend door actuators control whether air goes through the heater core (that’s a little radiator-looking component inside your dash) or bypasses it. There are usually several in every car’s dash. Each switches directions based on your preferred heat settings. When a blend door fails, you may get cold air, heat on only one side, or clicking behind the dash.

Fix: Replace the failed actuator

Estimated cost: $446 to $583 installed, depending on the car and dash access

3. Low coolant level

Your heating system relies on hot engine coolant. If levels are low, there’s not enough heat to share. Low coolant usually means a leak. It’s a closed system, so the fluid is draining out somewhere.

Fix: Top off coolant, locate and repair leak(s)

Estimated cost: $120 to $350 for diagnostics and simple repairs (hose clamp, for example). Expect “more” if a major hose or “much, much more” if a radiator is involved (think $700 to $1,400)

4. Air trapped in the cooling system

After a coolant service, air pockets can block flow to the heater core. The result is lukewarm or nonexistent heat.

Fix: Properly bleed the cooling system.

Estimated cost: $75 to $200 if you’re a DIYer taking it to a local mechanic. But this should be free if this is something you paid for that wasn’t done “right” the first time, like after a routine coolant drain and fill or other repair.

5. A faulty thermostat

A thermostat stuck in the open position keeps coolant flowing constantly, preventing the engine from warming up. The temperature gauge staying low (think well under the halfway mark) is a classic clue.

Fix: Thermostat replacement (usually includes a coolant flush/drain and refill)

Estimated cost: $567 to $657

6. A bad heater core

This one’s basically the worst-case scenario. The heater core is a small radiator buried deep behind the dashboard. When it clogs or leaks, heat disappears. Foggy windows or a sweet smell inside the cabin are warning signs.

Fix: Heater core replacement

Estimated cost: $1,322 to $1,845. Labor is the villain here

7. Blower motor problems

No airflow at all usually points to the blower motor, resistor, fuse, or relay. Sometimes it’s minor. Sometimes the motor is done.

Fix: Electrical diagnosis or blower motor replacement

Estimated cost: $363 to $444 for the blower motor (the most expensive part in its circuit)

When your car’s heat stops working, don’t assume catastrophe

These are everyday jobs for mechanics, and most fixes are straightforward. With the right diagnosis, you’ll be back to warm fingers and defrosted windshields before winter gets any worse.