Do I Need to Do Anything to My Furnace Before Switching to AC?

Should I Turn My Furnace Off Completely? No.
Your furnace still runs the blower motor during cooling season. It helps circulate air throughout your home.
Do not:

• Shut off furnace power
• Flip furnace breaker
• Close supply vents

What Should I Do Before Cooling Season?
1. Replace the Air FilterYour furnace filter works year-round — including during AC season.
2. Check Humidity LevelsMinnesota winters are dry. Spring humidity rises quickly.
Ideal indoor humidity:

• 30–50%

If humidity climbs too fast, your AC may feel less effective.

Should I Close Vents in Unused Rooms? No.
Closing vents increases pressure in the duct system and can reduce efficiency.

What About My Humidifier?
If you have a whole-home humidifier:

• Turn it off
• Shut water supply valve
• Set control to summer mode

Leaving it on can create excess indoor moisture.

How Do I Know My System Is Ready? Ask:

• Is airflow strong?
• Does thermostat respond correctly?
• Does outdoor unit start smoothly?
• Is there unusual noise?

If yes — you’re ready for spring.