Blog - Air Comfort Heating & Air Conditioning
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.
Why Your AC Might Not Work After a Long Minnesota Winter
Why Won’t My AC Turn On in Spring?
Common causes:
1. Tripped Breaker
Outdoor units share electrical circuits that may trip over winter.
Check:
Main panel
AC disconnect box
2. Thermostat Still on Heat
Sounds simple — but it happens constantly.
Make sure:
Mode is set to COOL
Temperature is set below current room temp
3. Dirty Air Filter
A clogged filter can restrict airflow and prevent startup.
Replace filter before first cooling cycle.
4. Outdoor Unit Damage
Minnesota winters bring:
Snow buildup
Ice
Rodent nesting
Debris
Inspect for visible damage or chewed wiring.
Is It Normal for My AC to Sound Loud the First Time? Yes — briefly.
Fans and compressors may sound louder after months of sitting. However:
Grinding
Buzzing
Clicking repeatedly
Those require inspection.
How Long Should It Take My House to Cool Down?
If outdoor temps are mild (60–70°F), cooling should happen within 15–30 minutes.
If it’s hot:
Expect gradual cooling
AC lowers temperature 15–20 degrees from outside temp
Example:
If it’s 85°F outside, your system may struggle to reach 65°F quickly.
Prevent Spring AC Failure
Test system before peak season
Keep outdoor unit clear
Schedule annual service
Most emergency AC repairs happen in late May when everyone turns systems on at once.
When Should Minnesota Homeowners Switch From Heat to AC?
When Is It Safe to Switch From Heat to Air Conditioning?
For most Minnesota homeowners, the switch from furnace to air conditioning happens sometime between late March and early May. But the real answer depends on outdoor temperatures — not the calendar.
You can safely switch to AC when:
Daytime temps are consistently above 60°F
Overnight temperatures stay above 40°F
There’s no risk of hard freeze
Running your AC when it’s too cold outside can damage the system. Air conditioners are designed to operate in warmer weather. If outdoor temperatures drop below 60°F, pressure inside the system can become unbalanced.
Can I Just Turn the Thermostat From Heat to Cool?
Yes — but do it correctly.
Steps:
Set the thermostat to OFF
Wait 3–5 minutes
Switch from HEAT to COOL
Set your desired temperature
This prevents short cycling and protects your equipment.
Do I Need AC Maintenance Before Turning It On?
Yes — especially in Minnesota where systems sit unused for 5–6 months.
Before first use:
Replace furnace filter
Clear debris from outdoor unit
Check thermostat batteries
Schedule spring tune-up
Most “first hot day” breakdowns happen because systems weren’t tested early.
What If My AC Smells Musty When I Turn It On? That’s common.
After months of inactivity, dust and condensation can cause:
Mild burning smell (dust on components)
Musty odor (moisture buildup)
If smell lasts more than 30 minutes, have it inspected.
Minnesota Spring Weather Reality
Minnesota weather is unpredictable. You may switch back to heat briefly in April. That’s normal. Modern systems are built for this — just avoid switching back and forth multiple times per day.
Heater Zoning — What It Is and Why It Matters
If some rooms in your home feel like a sauna while others feel like an icebox, heater zoning may be the missing link. Zoning allows different areas of your home to be heated independently instead of relying on a single thermostat.
In a zoned system, dampers inside the ductwork open and close based on demand from multiple thermostats. This means upstairs bedrooms, basements, additions, or sunrooms can each get the heat they actually need.
Zoning matters most in:
Multi-level homes
Houses with additions
Homes with large window exposure
Older homes with uneven insulation
For Minnesota winters, zoning can improve comfort while reducing wasted energy. Instead of overheating the entire house, you heat only the spaces being used — a smarter approach during long heating seasons.
Tiny Things That Add $200 to Your Heating Bill
Heating bills don’t usually spike because of one big mistake — they creep up due to dozens of small ones.
A dirty air filter can increase energy use by forcing your furnace to work harder. Drafty doors and windows leak warm air nonstop, especially during windy Minnesota nights. Closing vents in unused rooms may seem smart, but it often disrupts airflow and lowers efficiency.
Even thermostat habits matter. Constantly adjusting the temperature or cranking the heat to recover from big setbacks uses more energy than steady settings.
Individually, these issues seem minor. Together, they can easily add $200 or more to your winter heating costs. Awareness is the first step to stopping the leak — financially and literally.
How COVID & Flu Season Impacts Indoor Air Quality
When COVID, flu, and respiratory illnesses circulate, people spend more time indoors — exactly when homes are sealed tight for winter. That combination makes indoor air quality more important than ever.
Viruses and bacteria spread more easily in dry, stagnant air. Low humidity can dry out nasal passages, weakening your body’s natural defenses. At the same time, limited ventilation allows airborne particles to linger longer.
HVAC systems play a major role here. Upgraded filtration, balanced humidity, and controlled ventilation help dilute airborne contaminants and improve overall air freshness. While HVAC systems aren’t a cure, they can support healthier indoor environments.
Simple habits like regular filter changes and maintaining consistent humidity can make a noticeable difference during peak illness season.
Gas Furnace Safety Checks Every Owner Should Know
Gas furnaces are reliable workhorses in Minnesota winters, but safety should never be assumed. Every homeowner should be familiar with a few basic checks that help prevent dangerous situations.
Start with carbon monoxide awareness. If you don’t already have CO detectors on every level of your home, winter is the time to add them. A cracked heat exchanger or blocked vent can allow dangerous gases to build up without warning.
Next, take a look at your exhaust and intake pipes outside. Snow, ice, or even animal nests can block airflow, forcing the furnace to shut down or operate unsafely. Keeping these clear during heavy snowfalls is critical.
Pay attention to unusual smells or sounds. A strong gas odor, persistent rattling, or delayed ignition are signs something isn’t right. While some noises are normal, anything new or intense should be investigated.
Routine professional inspections combined with homeowner awareness are the best defense. Gas heat is safe — when it’s maintained properly.
DIY vs Pro: When to Call an HVAC Tech
Change filters? DIY. Adjust a thermostat? DIY. Replace a heat exchanger or test a gas valve? That’s a pro job. DIY saves money — but only if you stay safe. Don’t risk carbon monoxide leaks or electrical hazards. When in doubt, YouTube less, call more.
How to Read Your Furnace’s Error Codes
That blinking red light isn’t Morse code — it’s a diagnostic. Most furnaces have a panel or sticker explaining what each blink pattern means. Common codes point to ignition failure, dirty filters, or limit switch trips. Look it up in your manual or online. But if it keeps blinking after a reset, call in the pros.
How Often Your Heating System Really Needs Maintenance
Once a year — that’s the magic number. Every furnace or heat pump needs an annual checkup to stay efficient and safe. Fall is ideal, but if you missed it, winter is still better than never. Maintenance includes cleaning burners, testing safety controls, inspecting heat exchangers, and checking airflow. It’s cheaper than a mid-storm emergency call.