As the evenings start to cool down here in the Pacific Northwest, it’s normal to start thinking about turning the heat back on. And if you’re a new ductless mini-split owner, you might be wondering, how exactly do I switch this thing from cooling to heating?
Good news: it’s easier than you might think!
We help homeowners with this transition every fall, and it’s one of those things that’s simple once you know the steps.
In this guide, we’ll walk you through exactly how to switch your system over, share some helpful tips to make sure everything runs smoothly, and explain what to do if things don’t go quite as planned.
Let’s get into it.
First Things First: What Your Mini-Split Actually Does
Your mini-split isn’t just an air conditioner. It’s a heat pump.
There’s a part inside called a reversing valve that changes the direction of the refrigerant, which is what allows your system to flip between cooling and heating. So when you switch modes, you’re basically telling the system which way to move the heat energy.
Step-by-Step: How to Switch from Cooling to Heating
Step 1: Change the Mode on Your Remote or Wall Controller
Grab your remote or use the wall-mounted controller and hit the MODE button. Each press will cycle through the options: Cool, Dry, Fan, and Heat. Look for the sun icon or the word HEAT. That’s the one you want.
Step 2: Set the Temperature Higher Than the Room Temperature
Once you’re in heating mode, make sure the temperature you set is higher than what the room currently is. If it’s 65 degrees in the room and your system is set to 63, it won’t turn on. Bump it up a few degrees to kick things off.
Step 3: Make Sure the System Has Power
This one’s easy to overlook. If the outdoor unit isn’t powered, or the batteries in your remote are dead, the system won’t respond. Check your breaker box or any outdoor disconnect switches to make sure everything’s on and running.
Step 4: Be Patient. It May Take a Few Minutes
When you first switch to heat mode, it might take a minute or two before warm air starts blowing. That’s totally normal. The system may be running a quick diagnostic or warming up the coils. Give it a little time.
Step 5: Check and Clean Your Filters
If your filters are dirty, your mini-split can’t breathe properly. That makes it harder to heat your space efficiently. Before the heating season gets into full swing, pop out those filters, give them a good cleaning, or replace them if needed.
Step 6: Make Sure Air Can Flow Freely
Double check that the vents on your indoor unit aren’t blocked and that nothing is piled up around the outdoor unit. Fallen leaves, snow, or debris can block airflow and reduce performance.
Step 7: Watch for Any Error Codes or Unusual Noises
Weird noises, flashing lights, or ice forming on the outdoor unit are all signs something might be off. If you notice anything out of the ordinary, it could point to a mechanical issue that needs a professional look.
Troubleshooting: What If It’s Still Not Heating?
Sometimes, even if you follow every step, your mini-split still doesn’t seem to be doing its job. Here are a few common culprits:
- Reversing Valve Trouble
If this part isn’t switching like it should, your system might stay stuck in cooling mode. This usually requires a technician to diagnose and fix. - Remote or Thermostat Issues
Old batteries, a malfunctioning remote, or even a temperature sensor issue can all prevent your system from switching to heat. - Low Refrigerant or System Leak
If the refrigerant is low (often due to a leak), your system may struggle to produce heat. This also requires professional service. - Outdoor Unit Is Iced Over
When temps drop really low, the outdoor unit can develop frost. Most systems go into a defrost mode automatically, but if yours doesn’t, it could mean the defrost sensor isn’t working properly.
Tips to Get Your System Winter-Ready
Here are a few simple things you can do to make sure your mini-split keeps you warm all season:
- Clean the filters regularly. Check them once a month.
- Keep the outdoor unit clear. Rake away leaves, clear out snow, and trim back any plants or bushes that get too close.
- Schedule a yearly tune-up. Having a qualified technician check refrigerant levels, sensors, and electrical components each year keeps things running smoothly.
- Don’t blast the heat. Setting your system to 80 degrees won’t warm your house faster. Aim for a steady, comfortable temperature. Your mini-split will work more efficiently that way.
Why This Matters in the Pacific Northwest
Here in the PNW, we get cool, wet winters and that damp chill can make it feel even colder than it really is. Ductless heat pumps are perfect for our climate because they pull heat energy from the air even when it’s pretty cold outside. Some models can even keep you warm down to 5°F or lower!
But with all that moisture in the air, it’s even more important to keep your system clean and running efficiently. A little maintenance now helps avoid bigger problems later, and you’ll stay more comfortable all season long.
Quick Pre-Heating Checklist
Here’s a handy list you can reference when the weather turns cold:
- Set system to HEAT mode (look for the sun icon)
- Temperature is set higher than room temp
- Power is on, including circuit breaker and disconnect
- Filters are cleaned or replaced
- Nothing is blocking airflow around indoor and outdoor units
- Warm air is coming after a few minutes
- No strange noises, flashing lights, or error codes
Need a Hand?
Switching from cooling to heating should be quick and easy, but if your system isn’t responding the way it should, or you want help making sure it’s running at its best, we’re here to help! At Alpine Ductless, we offer free estimates and friendly, local service to keep your home comfortable year-round.
We’ll make sure your mini-split is ready to keep you warm all winter long.