What Should I Set My Thermostat to in a Minnesota Winter?
68–70°F while you're home and awake, lower at night, never below 55°F when you're away. What setbacks save, how heat pumps differ, how to avoid wet windows.
Read the guideHeating Guides
Furnaces, boilers and everything that keeps a Minnesota house warm from October to April.
A Minnesota furnace runs from October into May, and most of the calls we take in January come down to a handful of parts: the igniter, the flame sensor, the pressure switch, the inducer motor, a clogged filter or a frozen vent pipe. These guides walk through what each symptom usually means, what you can safely check yourself, and when to shut the system off and call.
They also cover the bigger decisions: when a furnace is worth repairing, what a replacement costs, how 80% and 96–98% AFUE furnaces differ, and whether a boiler or radiant floor makes sense in an older house. For hands-on help, see furnace repair or furnace replacement.
What Does the Blinking Light on My Furnace Mean?
The blinking light on a furnace is a fault code from the control board. How to read it safely, what common codes mean, and when a reset is fine or not.
Read the guideHow Long Does a Furnace Replacement Take?
A straight furnace swap is usually done in one day. Venting changes, a chimney liner, gas line or duct work, and the permit inspection add time. What to expect.
Read the guideWhat Is an Orphaned Water Heater, and Why Can a New Furnace Mean a Chimney Liner?
An orphaned water heater is left alone in a chimney sized for two appliances after a 90%+ furnace goes in. Why it drafts poorly, the CO risk and the fixes.
Read the guideWhy Is My Thermostat Screen Blank, and Is the Furnace or AC Still Working?
A blank thermostat screen usually means lost power: dead batteries, a tripped furnace switch, a blown board fuse or a condensate switch. What to check first.
Read the guideWhat Is a Manual J Load Calculation, and Why Should an HVAC Quote Include One?
A Manual J load calculation works out how much heating and cooling your house needs. What goes into it, why the old nameplate oversizes and what to ask.
Read the guideWhat Size Furnace Do I Need for a Minnesota House?
Furnace size comes from a Manual J heat loss at a -15°F design day, not square feet. Input vs output BTU, AFUE, why old furnaces run big and what to ask for.
Read the guideWhat Does a Boiler Expansion Tank Do, and How Do You Know It's Failing?
A boiler expansion tank absorbs water that swells as it heats. How it works, what the pressure gauge tells you, and why a dripping relief valve is the clue.
Read the guideWhat Is a Communicating HVAC System, and Is It Worth It in Minnesota?
A communicating HVAC system uses a two-way data link between thermostat, furnace and outdoor unit. What it does, what it locks you into, and when it pays.
Read the guideWhat Is a Furnace Inducer Motor, and What Are the Signs It's Failing?
The inducer motor is the small fan that starts first and pushes exhaust out the vent. Noises and codes of a failing one, repair vs replace, and cost.
Read the guideWhat Does a Furnace Pressure Switch Do, and Why Does It Keep Tripping?
A furnace pressure switch proves the inducer is venting exhaust before the gas can open. Why it trips in a Minnesota winter, what you can check, and the cost.
Read the guideWhat Does It Mean When a Furnace Is Red-Tagged?
A red tag means a technician or the gas utility found your furnace unsafe and shut it off. Common reasons, what not to do, and how to get a second opinion.
Read the guideWhat Is Static Pressure in HVAC, and Why Does It Matter?
Static pressure is the resistance your furnace blower pushes against in the ducts and filter. Why it matters for a new furnace or AC, symptoms and fixes.
Read the guideCan a Furnace Leak Carbon Monoxide? How It Happens and What to Do
Yes. How a gas furnace leaks carbon monoxide, the symptoms MDH lists, Minnesota's CO alarm law, what to do when the alarm sounds and what a red tag means.
Read the guideWhy Is My Furnace Leaking Water? Find the Source, Then Fix It
Water around your furnace? Find the source by where and when it drips: condensate trap, pump, frozen line, humidifier or AC coil, and what can't wait.
Read the guideFurnace Noises: What Each Sound Means and When to Shut It Off
Bang at startup, squeal, scrape, rattle, hum, click, whistle or a rumble after shutoff: what each furnace noise means and whether it's safe to keep running.
Read the guideHow Long Does a Furnace Last in Minnesota?
How long a furnace lasts in Minnesota: sourced 15–20 year figures, why long winters add wear, signs it's near the end, and how to decide repair or replace.
Read the guideBest Furnace Brands for Minnesota Winters (2026)
Furnace brands for a Minnesota winter by tier: Carrier, Trane, Lennox, Rheem, Goodman and Amana lines, plus what matters more at -20°F than the badge.
Read the guideCarrier vs Trane vs Lennox: Which to Buy in Minnesota
Carrier vs Trane vs Lennox for Minnesota homes: tiers, modulating furnaces, variable-speed AC, cold-climate heat pumps, controls, parts and warranties.
Read the guideFrozen Condensate Line on a High-Efficiency Furnace
Furnace quit in a cold snap and the drain line froze? How it trips the pressure switch, how to thaw it safely, and fixes that keep it from freezing again.
Read the guideNo Heat in a Minnesota Winter: What to Check Before You Call
Furnace out on a cold night? What to check in order, what the blinking light means, how to keep pipes safe while you wait, and when to stop and call.
Read the guideOutdoor Wood Boiler vs Gas Furnace in Minnesota: The Real Trade-Offs
Is an outdoor wood boiler cheaper than a gas furnace in Minnesota? Fuel math per million BTU, daily labor, smoke rules, freeze risk and backup heat.
Read the guideOil to Natural Gas Conversion in Minnesota: Steps, Costs and Gotchas
Converting an oil furnace or boiler to gas in Minnesota: typical national costs, getting gas to the house, venting, the oil tank, hot water and rebates.
Read the guideThe Quietest Furnaces for Minnesota Homes, and Why the Ducts Matter as Much
The quietest gas furnaces from Lennox, Carrier and Trane, the features that really cut noise, and the duct fixes that quiet any furnace in a Minnesota home.
Read the guideGas Line Installation for a Furnace, Garage Heater or Range: Cost and Sizing
What a gas line for a furnace, garage heater or range typically costs nationally, how pipe is sized to the BTU load, and the permit and pressure-test steps.
Read the guideFurnace Repair in Prescott, WI: What Local Homeowners Should Know
Furnace repair in Prescott, WI and nearby Pierce County towns: common no-heat causes, propane quirks, Wisconsin programs, and our $79 trip charge.
Read the guideFurnace Short Cycling: Time the Cycle, Then Find the Cause
A furnace that turns on and off too often tells you what's wrong by how long it runs. How to time a cycle, and what seconds, minutes and frequent cycles mean.
Read the guideBryant Evolution vs Legacy Furnaces: What the Extra Money Buys
Bryant's Evolution 987M modulates; Legacy furnaces are single-stage. What that means in a Minnesota winter, how warranties compare, and where Preferred fits.
Read the guideCracked Heat Exchanger: Symptoms, How It's Confirmed and What to Ask For
Signs of a cracked furnace heat exchanger, how a technician confirms one, what to ask for if your furnace is red-tagged, and when to repair or replace it.
Read the guideBoiler Banging, Kettling or Gurgling: What Each Noise Means
Kettling, banging, gurgling or a grinding pump: what each boiler noise means in a hot-water or steam system, what you can safely check and when to call.
Read the guideFurnace Limit Switch Tripping? What It Does and What to Check First
Why a furnace high-limit switch keeps tripping, a symptom-to-cause table, the checks to do yourself, the order a technician follows, and what the fix costs.
Read the guideGarage Heaters for a Minnesota Winter: Forced Air, Infrared, Electric or Mini-Split
Forced-air unit heater, infrared tube, electric or mini-split? How to pick a garage heater for a Minnesota winter, what installs cost and the venting rules.
Read the guideLennox Furnaces Compared: Merit vs Elite vs Dave Lennox Signature
How to decode a Lennox furnace model number, what really separates Merit, Elite and Dave Lennox Signature, and which one fits a Minnesota house and budget.
Read the guideRadiant Floor Heat vs Baseboard in Minnesota: Comfort, Water Temperature and Cost
Radiant floor or hydronic baseboard for a Minnesota basement, addition or remodel: comfort, water temperature, boiler efficiency and what a retrofit involves.
Read the guideFurnace Burning Smell in a Minneapolis Home: What Each Smell Means
Dust, hot plastic, rotten eggs or exhaust: what each furnace smell means, which mean shut it off now, and the basement causes we find in Minneapolis homes.
Read the guideFrozen Furnace Vent Pipe? How to Clear It Safely in a Minnesota Winter
Furnace quit in a cold snap? How to tell if the PVC intake or exhaust is iced or drifted shut, clear it without cracking the pipe, and keep it from recurring.
Read the guidePropane Heating Costs for Rural Homes Around the Twin Cities: How to Figure Yours and Cut Them
How to work out what propane heat really costs per delivered BTU, compare it with gas and heat pumps, and cut gallons with the right furnace and fill plan.
Read the guideTrane or Carrier Furnace? A Minnesota Buying Guide for Your Replacement
Trane or Carrier furnace? How the lineups match tier by tier, warranty registration windows, what to check on both quotes and what a Minnesota install adds.
Read the guideBoiler vs Furnace: Which Fits Your Saint Paul Home?
Keep the boiler or switch to a furnace? How Saint Paul radiator homes and postwar houses decide, what each costs to replace, and how to add AC without ducts.
Read the guideFurnace Blowing Cold Air: What to Check, in Order
Cold air from the vents with the heat on? The order a technician checks: fan setting, burners, limit trips, flame sensor, vents, gas supply and ductwork.
Read the guide96% vs 98% AFUE Furnace: Is the Upgrade Worth It in Minnesota?
What AFUE measures, the gas math from 80% to 96% to 98% using your own bill, and what a 98% furnace really buys you in a cold Minnesota house.
Read the guideFurnace Won't Ignite: Find Where the Startup Stops
Furnace clicking but not lighting? Follow the startup sequence a technician uses: thermostat, power, inducer, pressure switch, igniter, gas and flame sensor.
Read the guideHeating questions
What warranty comes with a repair?
Completed repairs come with a written 1-year parts-and-labor warranty. If a part we installed fails within that year, we come back and fix it without charging you for the part or the labor. Keep the invoice somewhere you can find it, since it lists what was done and when, and that makes a warranty call quick.
What warranty comes with a new install?
Our installs carry a 2-year labor warranty from us, on top of the manufacturer's parts warranty. Many manufacturers require you to register new equipment online, often within 60 days of installation, to get their longer parts warranty, so check the current registration terms for your brand and don't let that window slip. Keep the model and serial numbers with your paperwork.
Should I repair my furnace or replace it?
Age and the type of failure decide most of these. We'd usually repair a 9-year-old furnace with a bad inducer motor, and usually recommend replacing a 22-year-old furnace with a cracked heat exchanger. In between, weigh the repair price against the furnace's age and how often it has needed work. Replacement price ranges are in our furnace cost guide.
Do you work on my brand of furnace or air conditioner?
Yes. We service every major brand: furnaces and air conditioners from Carrier, Trane, Lennox, Goodman, Rheem, York and the rest, mini-splits from Mitsubishi, Daikin, Fujitsu and LG, boilers from Weil-McLain, Burnham, Navien and others, and thermostats and air quality equipment. Many brands share a parent company and parts. The brands page has a page for each one; if yours isn't there, call and ask.
What does it mean if my furnace was red-tagged?
A red tag means a technician or the gas utility found the furnace unsafe to run and shut off its gas. The usual reasons are a cracked heat exchanger, carbon monoxide spilling into the house, or a venting problem. Don't turn it back on. Have the problem confirmed and fixed, or replace the furnace if the heat exchanger is cracked. Our heat exchanger guide covers the warning signs.
Can you recharge my old R-22 air conditioner?
Sometimes, but it's rarely a good deal. R-22 production and import ended January 1, 2020, so the only refrigerant available is reclaimed or stockpiled, and it's expensive. If the system is leaking, you'll be paying for it again next summer. On an older R-22 unit with a leak, replacement usually makes more sense. Our R-22 guide walks through the options.
Contact Us
Heat out? AC quit? Call or send a request.