Top 10 furnace repair services in Buffalo Grove, IL

Porch Pro Headshot C R Mechanical Svc
Furnace Repair
Serves Buffalo Grove, Illinois
CR Mechanical Services provides Comfort Solutions to fit your needs. from All Major manufacture Heating and Cooling Equipment Service, Repairs and Replacements to whole house Insulation solutions. kitchen and bathroom fixture Rejuvenation's. Water Removal and Distributions Systems design & Installa...Read more about C R Mechanical Svc
CR Mechanical Services provides Comfort Solutions to fit your needs. from All Major manufacture Heating and Cooling Equipment Service, Repairs and Replacements to whole house Insulation solutions. kitchen and bathroom fixture Rejuvenation's. Water Removal and Distributions Systems design & Installa...Read more about C R Mechanical Svc
Porch Pro Headshot Midwest Comfort Heating & Cooling
Furnace Repair
Serves Buffalo Grove, Illinois
(249)
Midwest Comfort is a family-owned and operated business that offers you and your family the ultimate in peace of mind, ensuring that your equipment operates safely and efficiently. We pride ourselves in building trusting relationships with our customers through exceptional service and savings. We ma...Read more about Midwest Comfort Heating & Cooling
Midwest Comfort is a family-owned and operated business that offers you and your family the ultimate in peace of mind, ensuring that your equipment operates safely and efficiently. We pride ourselves in building trusting relationships with our customers through exceptional service and savings. We ma...Read more about Midwest Comfort Heating & Cooling
Porch Pro Headshot Robinson Heating & Cooling
Furnace Repair
Serves Buffalo Grove, Illinois
(98)
Robinson Heating & Cooling has been serving the northern Lake County and southeastern Kenosha areas since 1962. In 1987, David Brown, the current president, purchased Robinson Heating & Cooling and has operated and served as President to this day. With a longstanding history of reliability and quali...Read more about Robinson Heating & Cooling
Robinson Heating & Cooling has been serving the northern Lake County and southeastern Kenosha areas since 1962. In 1987, David Brown, the current president, purchased Robinson Heating & Cooling and has operated and served as President to this day. With a longstanding history of reliability and quali...Read more about Robinson Heating & Cooling
Porch Pro Headshot Humble Heating & Air
Furnace Repair
Serves Buffalo Grove, Illinois
(82)
Welcome to Humble! It's hard to be HUMBLE...with us it's a way of life! We service all makes and models. Furnace and air-conditioner installations, repair and maintenance. We install humidifiers, air cleaners,set back thermostats, HEPA systems, UV lights and boilers.
Welcome to Humble! It's hard to be HUMBLE...with us it's a way of life! We service all makes and models. Furnace and air-conditioner installations, repair and maintenance. We install humidifiers, air cleaners,set back thermostats, HEPA systems, UV lights and boilers.
Porch Pro Headshot everything mechanical heating and cooling
Furnace Repair
Serves Buffalo Grove, Illinois
(70)
Heating and cooling ventilation, services and installation and sales. Goodman Furnace and Air Conditioner Dealer. Installation of Humidifiers and Thermostats and Air Purifiers.
Heating and cooling ventilation, services and installation and sales. Goodman Furnace and Air Conditioner Dealer. Installation of Humidifiers and Thermostats and Air Purifiers.
Porch Pro Headshot D's Air & Heating, Inc.
Furnace Repair
Serves Buffalo Grove, Illinois
(73)
Commitment, Dedication, Professionalism, Experience, Is Our Goal. Comfort Specialist You Can Depend On! Don't "FREEZE" Call D's...For All Your Heating, Ventilation And Air Conditioning Needs. A family owned and operated business here to deliver customer satisfaction in the heating, air con...Read more about D's Air & Heating, Inc.
Commitment, Dedication, Professionalism, Experience, Is Our Goal. Comfort Specialist You Can Depend On! Don't "FREEZE" Call D's...For All Your Heating, Ventilation And Air Conditioning Needs. A family owned and operated business here to deliver customer satisfaction in the heating, air con...Read more about D's Air & Heating, Inc.
Porch Pro Headshot Loud Brothers, Inc.
Furnace Repair
Serves Buffalo Grove, Illinois
(22)
Loud Brothers, Inc. provides the most comprehensive and affordable home HVAC services in the Chicagoland area. Our technicians install and service a wide variety of heating and cooling systems, including industry leading brands like Carrier. We realize that every family and home have specific needs...Read more about Loud Brothers, Inc.
Loud Brothers, Inc. provides the most comprehensive and affordable home HVAC services in the Chicagoland area. Our technicians install and service a wide variety of heating and cooling systems, including industry leading brands like Carrier. We realize that every family and home have specific needs...Read more about Loud Brothers, Inc.
Porch Pro Headshot Northfield Heating and Air LLC
Furnace Repair
Serves Buffalo Grove, Illinois
(6)
With more than 22 years of experience and efficient HVAC services, Northfield Heating and Air is the right company for all your heating and cooling system needs like ventilation systems and internet interfaces. Our reliable staff has remained the same for the last 8 years so you'll always receive pr...Read more about Northfield Heating and Air LLC
With more than 22 years of experience and efficient HVAC services, Northfield Heating and Air is the right company for all your heating and cooling system needs like ventilation systems and internet interfaces. Our reliable staff has remained the same for the last 8 years so you'll always receive pr...Read more about Northfield Heating and Air LLC
Porch Pro Headshot Murray HVAC  Inc.
Furnace Repair
Serves Buffalo Grove, Illinois
(28)
Murray HVAC, Inc. is a family owned and operated business that has been servicing the North Shore of Chicago since 1948. We are committed to Honesty, Quality and Service, which means you'll get it done right the first time and at a fair price. We are experts at solving comfort issues and we speciali...Read more about Murray HVAC Inc.
Murray HVAC, Inc. is a family owned and operated business that has been servicing the North Shore of Chicago since 1948. We are committed to Honesty, Quality and Service, which means you'll get it done right the first time and at a fair price. We are experts at solving comfort issues and we speciali...Read more about Murray HVAC Inc.
Porch Pro Headshot On Call Properties
Furnace Repair
Serves Buffalo Grove, Illinois
(7)
On Call Properties your best source for any of your emergency flood repair needs. With skilled and licensed flood and mold remediators, On Call Properties will get your home back to normal in no time flat. We are also accredited with the better business bureau.
On Call Properties your best source for any of your emergency flood repair needs. With skilled and licensed flood and mold remediators, On Call Properties will get your home back to normal in no time flat. We are also accredited with the better business bureau.

Frequently asked questions about heating & furnace repair companies

Your furnace should be cleaned every year or every two years at the most. A yearly furnace cleaning can catch small problems and fix them before they become serious repairs. It's like how changing the oil in your car may prevent a breakdown in the future. You should plan to have your furnace cleaned before you need it in the winter. Most people leave this to the last minute, and HVAC companies become very busy as the temperature drops.

Some indicators that your furnace needs to be cleaned:

  • The temperature is inconsistent from room to room.
  • Your furnace is struggling to maintain the temperature you set.
  • The furnace produces no heat at all.
  • You have a higher than expected energy bill after turning it on.
  • You smell rubber, smoke, or oil when you turn it on. (It's normal to smell dust).
  • Your furnace flame is any color but blue, which can indicate an imbalance in the gasses.
  • It makes a loud bang, howling, or whistling sound. This points to clogged air filters, dirty burners, or a restricted fuel supply.

Some people consider cleaning the furnace in the spring rather than in the fall. The best practice is to vacuum the furnace out in the spring, then do your annual maintenance in the late summer or fall.

Regular furnace maintenance can extend your furnace’s life by years and prevent some costly repairs. Regular furnace maintenance involves taking apart essential components, inspecting and cleaning them, then reassembling them for use. These components include your furnace filter, blower, burners, and flame sensors.

You can tackle a lot of this work on your own. It may take a few hours to familiarize yourself with the tools and equipment if it's your first time maintaining your furnace. Once you know the drill, furnace maintenance shouldn’t take more than a couple of hours. Start by shutting off the furnace's electrical power and fuel supply. Once that’s done, the combustion chamber can be accessed, vacuumed out, and inspected for holes. If you find any holes, patch them with foil tape.

Next, thoroughly clean the blower compartment. This will remove dirt and debris. Like with the combustion chamber, you or a professional need to inspect for any holes. Don’t forget to replace the air filter. You may be able to upgrade the air filter so it protects against mildew, pollen, and other airborne allergens. If you have an oil furnace, you’ll also want to replace the oil filter. This should be done annually. Finally, oil the machine bearings, taking care not to over-lubricate them.

If your furnace makes odd noises, you should hire a professional as soon as possible. There are a few other indicators that your furnace needs professional attention. Excessive soot could mean your burners need adjustment or that the heat exchanger needs replacing. If your flame is pale in color or irregular, this can indicate dirty burners or a cracked heat exchanger. This is a potential hazard and requires a professional to investigate. If your furnace is short-cycling (which means it only runs for a short period of time before shutting off), you may have a thermostat issue or an overheating exchanger. This also requires the expertise of a professional.

You should have your furnace serviced annually for the best results. Some people will wait every two years, though better maintenance schedules often mean fewer surprises. Most times, when a furnace stops providing heat without warning in the winter, the issue could have been solved with a maintenance call the season beforehand. Maintained furnaces run at their best efficiency, which helps your energy bill.

Furnace services can reveal carbon monoxide leaks, a health hazard that needs to be fixed immediately. If left untreated, carbon monoxide can lead to dizziness, nausea, headaches, and even death.

When hiring a professional, whether for annual maintenance or repairs, a quick search for “Furnace repair near me” will bring up several local companies to hire. Most states require HVAC companies to be licensed. They should also be fully insured and bonded. A great HVAC repair company will be transparent in what they do and what they charge, and they should be able to show documentation if requested. HVAC companies get quite busy as the temperature drops, so consider calling in the late summer and get ahead of the rush.

Your HVAC company should be able to give you an estimate of what repairs will cost. Oil and gas furnace repairs cost more than their electrical competitors, but their maintenance costs should be similar. If your furnace is over ten years old, you should prioritize annual maintenance. Most furnaces need to be replaced within ten to twenty years. Most furnace companies will advise that any serious repairs to an older furnace may not last long and that replacing your furnace would be the best option.

If your furnace is not producing heat, there are several components you should check. Start with the thermostat - is it switched to “heat”? What temperature does the thermostat say compared to the actual room temperature? Try setting the thermostat to five degrees higher and see if the furnace kicks on. Replace the battery and check the wiring for any breaks. Ensure there are no loose wires within the thermostat, and blow away any dust while you’re in there.

Check the fuse box and the power switch for the furnace and ensure that everything is switched on. Occasionally, a clogged filter can cause the furnace to shut off, so check your filters next. The gas line should be open, but may be switched off for whatever reason. If the drain hose is particularly dirty or the chimney flue is clogged, this could also be why your furnace doesn’t produce any heat. Clean them of dust and debris and try the furnace again. After that, check the heat vents and ducting. Clogs in those areas may also affect your furnace’s heat.

If you’ve tried all that and your furnace still isn’t turning on, it’s time to call a professional to get your furnace repaired. They’ll also run through these basic troubleshooting steps, then move on to the complex components and causes of failure within furnaces. If your furnace is older than fifteen years or breaks down regularly, you may want to consider replacing it. New models are more efficient, and repairs can be expensive in the long run.

If you’re looking to have your furnace serviced or tuned up, the cost will depend on the type. An electric furnace can cost between $70 to $130 for a tune-up. Gas furnace tune-ups can cost between $80 to $170, whereas oil furnaces can cost between $100 to $200. A tune-up involves an inspection of the flues and vents, air filters, ignitor switches, fan belts, blowers, motors, electrical components, the heat exchanger, the condensate drain, and testing the thermostat.

Some HVAC companies have two standards for maintenance calls. A basic maintenance call will include a cleaning and offer a diagnostics report. The advanced maintenance call will involve a full tune-up and cleaning of your furnace’s sensors. This can cost between $130 to $200, whereas the basic (or standard) may cost between $70 to $130.

Other factors may alter the cost of furnace maintenance. If you do this at a slower time of year for HVAC companies, you may pay less. Also, if you have several HVAC systems, you may be able to get a discount. You may be charged more if your HVAC system is hard to reach. Some HVAC companies offer a discount for a maintenance plan. Others may charge more if you haven’t serviced the furnace in over a year, as more work will be involved.

The cost to repair a furnace is much higher than the cost to maintain one. The average repair cost for a furnace is anywhere from $100 to $600, based on the issue. There's a hidden cost as well - if your furnace is under warranty and you neglected the annual maintenance, the furnace company may not honor the warranty.

Furnaces make several different noises which indicate different problems. If your furnace is banging or booming when you turn it on, this likely indicates a delayed ignition. This can be attributed to a defective ignitor, a weak flame or pilot light, low gas pressure, or a burner malfunction. You should consult an HVAC professional for all these issues, as working with gas and fuel can be tricky.

Intermittent banging or booming is most likely caused by expanding and detracting ductwork. This doesn't necessarily need a fix, unless the noise is preventing you from sleeping at night. You’ll need to fortify the ductwork or replace it with round ductwork. Your furnace may make a dry squeal if any belts or bearings are worn. You can fix this yourself for relatively cheap, but a worn belt points to a lack of cleaning and maintenance. You may want to call a professional to inspect for other potential repairs that may be in your future.

If your furnace makes a high-pitched wail, it’s most likely an airflow problem. A dirty air filter and closed or blocked vents are your likely culprits. Rattling means a part is loose or your heat exchanger is cracked. If you hear the rattling right after you turn the furnace on, it's probably the heat exchanger. The rattling is likely the metal coils expanding. If you hear a constant humming, this is likely a motor problem for either the blower or the inducer. Humming sounds from your furnace requires a professional right away.

A furnace is a large machine. Like a car engine, if it’s making a noise that it shouldn’t, this is usually a warning sign before it breaks down entirely. Every time you use your furnace while it needs repairing, you risk damaging it further and racking up a higher repair bill.

Recent reviews for Buffalo Grove furnace repair services

22377

Terrible. Never going to use them again!! No follow up no calls to let me know when my unit would be in!!! He is so unprofessional !!! He Kevin even had the nerve to demand I move the mother duck hatching her newborns by the old a/c unit!!! It's illegal t...

- Leslie Kamin
45337

Affordable prices, very knowledgeable,will recommend to family and friends

- Earlene Bozovsky

All Heating & Furnace Repair Companies in Buffalo Grove, IL

Porch Pro Headshot Omega Heating
Furnace Repair
Serves Buffalo Grove, Illinois
At Omega Heating and Air, we believe every client deserves high-quality equipment at affordable prices with reasonable finance options. . Our goal is to provide each and every client with comfortable heating and cooling at a price they can afford, so we will work with you to craft a solution that wi...Read more about Omega Heating
At Omega Heating and Air, we believe every client deserves high-quality equipment at affordable prices with reasonable finance options. . Our goal is to provide each and every client with comfortable heating and cooling at a price they can afford, so we will work with you to craft a solution that wi...Read more about Omega Heating
Porch Pro Headshot Britannia Home Services
Furnace Repair
Serves Buffalo Grove, Illinois
Britannia Home Services recognizes that you have a choice in where and how you spend your home improvement dollars. That is why we exist. we provide prompt, professional and courteous service, always....Our goal is to provide you with fair pricing in exchange for professional quality work. You will ...Read more about Britannia Home Services
Britannia Home Services recognizes that you have a choice in where and how you spend your home improvement dollars. That is why we exist. we provide prompt, professional and courteous service, always....Our goal is to provide you with fair pricing in exchange for professional quality work. You will ...Read more about Britannia Home Services
Porch Pro Headshot DUCTZ of Chicago
Furnace Repair
Serves Buffalo Grove, Illinois
(16)
If you're looking for quality air duct cleaning services, turn to DUCTZ. We are the trusted name in air duct and HVAC cleaning because we utilize industry-leading methods, advanced technology, and effective techniques. Our team of highly trained professionals has the knowledge and insight to tackle ...Read more about DUCTZ of Chicago
If you're looking for quality air duct cleaning services, turn to DUCTZ. We are the trusted name in air duct and HVAC cleaning because we utilize industry-leading methods, advanced technology, and effective techniques. Our team of highly trained professionals has the knowledge and insight to tackle ...Read more about DUCTZ of Chicago
Porch Pro Headshot Ultra Lux Construction
Furnace Repair
Serves Buffalo Grove, Illinois
(26)
Experienced 5 star Residential and Commercial Real Estate Developer and General Contractor for all you remodeling needs in Chicago and suburbs. Licensed, bonded and insured.
Experienced 5 star Residential and Commercial Real Estate Developer and General Contractor for all you remodeling needs in Chicago and suburbs. Licensed, bonded and insured.
Porch Pro Headshot A & C Heating & Cooling
Furnace Repair
Serves Buffalo Grove, Illinois
A & C Heating & Cooling offers HVAC services to the Chicagoland area including northwest Indiana and southwest Wisconsin. Call us today!
A & C Heating & Cooling offers HVAC services to the Chicagoland area including northwest Indiana and southwest Wisconsin. Call us today!
Porch Pro Headshot Ahr Ozon Inc
Furnace Repair
Serves Buffalo Grove, Illinois
Ozone, Inc. specializes in heating, cooling, plumbing, refrigeration, remodeling, and much more! Our HVAC contractor began his illustrious career as a handyman and remodeling expert. He has the experience and expertise to build your imagination!, Our HVAC contractor offers cost-effective heating and...Read more about Ahr Ozon Inc
Ozone, Inc. specializes in heating, cooling, plumbing, refrigeration, remodeling, and much more! Our HVAC contractor began his illustrious career as a handyman and remodeling expert. He has the experience and expertise to build your imagination!, Our HVAC contractor offers cost-effective heating and...Read more about Ahr Ozon Inc
Porch Pro Headshot Air Blue Htg & Cooling Inc
Furnace Repair
Serves Buffalo Grove, Illinois
Air Blue Heating & Cooling, Inc. is full service heating and cooling company staffed by experienced, trained, and courteous professionals. We serve you with over 30 years of HVAC field experience. We pride ourselves on excellent customer service, and will make sure that your every HVAC need and requ...Read more about Air Blue Htg & Cooling Inc
Air Blue Heating & Cooling, Inc. is full service heating and cooling company staffed by experienced, trained, and courteous professionals. We serve you with over 30 years of HVAC field experience. We pride ourselves on excellent customer service, and will make sure that your every HVAC need and requ...Read more about Air Blue Htg & Cooling Inc
Porch Pro Headshot Service Pros HVAC and Appliance Repair
Furnace Repair
Serves Buffalo Grove, Illinois
Contact Us-24/7 About Us Our Services Heating Heat Pumps Boiler Boiler Repair Boiler Replacement Boiler Tune-up Boiler Installation Experts Underfloor Heating Hydronic Heating Furnace Repair Furnace Repair Furnace Replacement Furnace InstallationFurnace Tune-up Furnace Cleaning Air Conditioning Air ...Read more about Service Pros HVAC and Appliance Repair
Contact Us-24/7 About Us Our Services Heating Heat Pumps Boiler Boiler Repair Boiler Replacement Boiler Tune-up Boiler Installation Experts Underfloor Heating Hydronic Heating Furnace Repair Furnace Repair Furnace Replacement Furnace InstallationFurnace Tune-up Furnace Cleaning Air Conditioning Air ...Read more about Service Pros HVAC and Appliance Repair
Porch Pro Headshot Libertyville Unique Indoor Comfort, Inc.
Furnace Repair
Serves Buffalo Grove, Illinois
For more than 40 years, the reliable heating and air conditioning products provided by the courteous staff of Unique Indoor Comfort have kept homes and businesses comfortable all year long. More than 20,000 customers in Lake County, North Shore and Chicago neighborhoods and Southeastern Wisconsin de...Read more about Libertyville Unique Indoor Comfort, Inc.
For more than 40 years, the reliable heating and air conditioning products provided by the courteous staff of Unique Indoor Comfort have kept homes and businesses comfortable all year long. More than 20,000 customers in Lake County, North Shore and Chicago neighborhoods and Southeastern Wisconsin de...Read more about Libertyville Unique Indoor Comfort, Inc.
Porch Pro Headshot A Custom Heating & Air Condit Longing
Furnace Repair
Serves Buffalo Grove, Illinois
We specialize in residential HVAC work. All furnaces,Boilers, A/C systems, Humidifiers, Indoor air quality, Unico/Space pac systems, and Air balancing( making your heating and cooling more efficient and fixes uneven temps). We have been in business on the north west side of Chicago for over 21 year...Read more about A Custom Heating & Air Condit Longing
We specialize in residential HVAC work. All furnaces,Boilers, A/C systems, Humidifiers, Indoor air quality, Unico/Space pac systems, and Air balancing( making your heating and cooling more efficient and fixes uneven temps). We have been in business on the north west side of Chicago for over 21 year...Read more about A Custom Heating & Air Condit Longing
Porch Pro Headshot Elite Appliance 847-581-2880
Furnace Repair
Serves Buffalo Grove, Illinois
We are family appliance repair business serving the Chicagoland area and most suburbs. We have over 20 years of experience with major brand appliances (GE, Whirlpool, Amana, Bosch, Maytag, Kitchen Aid) including high end (Sub Zero, Viking, Dacor, Miele, Marvel, Thermador). Our Technicians will diagn...Read more about Elite Appliance 847-581-2880
We are family appliance repair business serving the Chicagoland area and most suburbs. We have over 20 years of experience with major brand appliances (GE, Whirlpool, Amana, Bosch, Maytag, Kitchen Aid) including high end (Sub Zero, Viking, Dacor, Miele, Marvel, Thermador). Our Technicians will diagn...Read more about Elite Appliance 847-581-2880
Porch Pro Headshot The Appliance King, Inc.
Furnace Repair
Serves Buffalo Grove, Illinois
The Appliance King in Chicago, we provide in home appliance repair service including Washing Machine, Washer, Dryer, Dishwasher, Oven, Stove, Cooktop, Range, Freezer, Refrigerator, Ice Maker, Garbage Disposal, Food Disposal Repair. We Service Almost All Major Appliance Brands, Makes and Models inclu...Read more about The Appliance King, Inc.
The Appliance King in Chicago, we provide in home appliance repair service including Washing Machine, Washer, Dryer, Dishwasher, Oven, Stove, Cooktop, Range, Freezer, Refrigerator, Ice Maker, Garbage Disposal, Food Disposal Repair. We Service Almost All Major Appliance Brands, Makes and Models inclu...Read more about The Appliance King, Inc.
Porch Pro Headshot Air Quality Analysts
Furnace Repair
Serves Buffalo Grove, Illinois
(22)
Air Quality Analysts, located in Arlington Hts, is an HVAC contractor. They offer gas pipe installation, air duct cleaning, and air conditioning maintenance.
Air Quality Analysts, located in Arlington Hts, is an HVAC contractor. They offer gas pipe installation, air duct cleaning, and air conditioning maintenance.
Porch Pro Headshot ServPro of Elks Grove/Itasca/Roselle/Palatine/Rolling Meadows
Furnace Repair
Serves Buffalo Grove, Illinois
ServPro of Elks Grove/Itasca/Roselle/Palatine/Rolling Meadows, based in Elk Grove Village, is an HVAC company that was founded in 2000. They offer gas appliance connection, water line installation and more. The United States Environmental Protection Agency has accredited ServPro of Elks Grove/Itasca...Read more about ServPro of Elks Grove/Itasca/Roselle/Palatine/Rolling Meadows
ServPro of Elks Grove/Itasca/Roselle/Palatine/Rolling Meadows, based in Elk Grove Village, is an HVAC company that was founded in 2000. They offer gas appliance connection, water line installation and more. The United States Environmental Protection Agency has accredited ServPro of Elks Grove/Itasca...Read more about ServPro of Elks Grove/Itasca/Roselle/Palatine/Rolling Meadows

Latest projects near Buffalo Grove

Recent projects booked on Porch
Lake Zurich 60047
Furnace Repair
Start Date
Within a month
Furnace fuel source
I'm not sure
Furnace problems
humidifier leak
When problems started
I'm not sure
Furnace age
I'm not sure
Buffalo Grove 60089
Furnace Repair
Start Date
Within a month
Furnace fuel source
Natural gas
Furnace problems
System keeps cycling on and off
When problems started
Less than one week ago
Furnace age
Less than 5 years old
Long Grove 60047
Furnace Repair
Start Date
Within 48 hours
Type of project
Repair, maintenance or cleaning
Repair, maintenance or cleaning project
Heating and cooling system repair
Item to repair
Furnace
Furnace fuel source
I'm not sure
Furnace problems
new home owner, house has been sitting for a few years
When problems started
I'm not sure
Furnace age
5-10 years old
Vernon Hills 60061
Furnace Repair
Start Date
Within 48 hours
Item to repair
Furnace
Furnace fuel source
Natural gas
Furnace problems
It won't turn on or off
When problems started
Less than one week ago
Furnace age
10-15 years old