Top 10 furnace repair services in Scottsdale, AZ

Porch Pro Headshot AZ Perfect Comfort
Furnace Repair
Serves Scottsdale, Arizona
Phoenix residents know that having an effective cooling system is absolutely required to stay comfortable throughout the year, and while the climate makes for a short heating season, it's still important to have a way to keep warm in the winter as well. We at AZ Perfect Comfort are proud to serve th...Read more about AZ Perfect Comfort
100% response rate
Phoenix residents know that having an effective cooling system is absolutely required to stay comfortable throughout the year, and while the climate makes for a short heating season, it's still important to have a way to keep warm in the winter as well. We at AZ Perfect Comfort are proud to serve th...Read more about AZ Perfect Comfort
Porch Pro Headshot A/C Experts Cooling & Heating
Furnace Repair
Serves Scottsdale, Arizona
Air Conditioning Experts (A/C Experts) was started over 20 years ago with the vision that we would offer good quality service at a fair price. We are not the cheapest in the Valley and we are far from the most expensive. We are however EXPERTS when it comes to cooling and heating your home or busine...Read more about A/C Experts Cooling & Heating
100% response rate
Air Conditioning Experts (A/C Experts) was started over 20 years ago with the vision that we would offer good quality service at a fair price. We are not the cheapest in the Valley and we are far from the most expensive. We are however EXPERTS when it comes to cooling and heating your home or busine...Read more about A/C Experts Cooling & Heating
Porch Pro Headshot Alaskan home services
Furnace Repair
Serves Scottsdale, Arizona
(6,390)
Family owned and Trusted service since 1976 with offices in Phoenix,Az and Tucson,Az. Proud winner of 2013 Rheem Dealer of the year and 2014 Rheem dealer of the year. All our technicians are Crimeshield background checked and have N.A.T.E certification.
Family owned and Trusted service since 1976 with offices in Phoenix,Az and Tucson,Az. Proud winner of 2013 Rheem Dealer of the year and 2014 Rheem dealer of the year. All our technicians are Crimeshield background checked and have N.A.T.E certification.
Porch Pro Headshot Penguin Air & Home Services
Furnace Repair
Serves Scottsdale, Arizona
(2,551)
Penguin Air & Home Services is a residential A/C, Heating and Plumbing company. We specialize in installation of central air systems. We also provide emergency service and maintenance on all brands. We also provide residential plumbing service. We install water heaters and whole house water condit...Read more about Penguin Air & Home Services
Penguin Air & Home Services is a residential A/C, Heating and Plumbing company. We specialize in installation of central air systems. We also provide emergency service and maintenance on all brands. We also provide residential plumbing service. We install water heaters and whole house water condit...Read more about Penguin Air & Home Services
Porch Pro Headshot Just Better Air Conditioning and Heating
Furnace Repair
Serves Scottsdale, Arizona
(673)
We are an Air Conditioning and Heating company serving the Phoenix Metro area. We specialize in Repair, Maintenance and Installation of all brands makes and models of heating and cooling equipment. Our mission is to provide superior service at reasonable prices - without high pressure sales tactics...Read more about Just Better Air Conditioning and Heating
We are an Air Conditioning and Heating company serving the Phoenix Metro area. We specialize in Repair, Maintenance and Installation of all brands makes and models of heating and cooling equipment. Our mission is to provide superior service at reasonable prices - without high pressure sales tactics...Read more about Just Better Air Conditioning and Heating
Porch Pro Headshot Anthony James Air Conditioning
Furnace Repair
Serves Scottsdale, Arizona
(622)
Porch Pro Headshot Simply The Best Heating & Cooling
Furnace Repair
Serves Scottsdale, Arizona
(238)
About Us Simply the Best Heating & Cooling in Gilbert, AZ Air Conditioning Repair GilbertWhether you're looking to repair, replace or maintain your cooling and heating system, Simply the Best Heating & Cooling will help you maintain your home comfort! Simply the Best Heating & Cooling is an expert,...Read more about Simply The Best Heating & Cooling
About Us Simply the Best Heating & Cooling in Gilbert, AZ Air Conditioning Repair GilbertWhether you're looking to repair, replace or maintain your cooling and heating system, Simply the Best Heating & Cooling will help you maintain your home comfort! Simply the Best Heating & Cooling is an expert,...Read more about Simply The Best Heating & Cooling
Porch Pro Headshot Adams Refrigeration Co.
Furnace Repair
Serves Scottsdale, Arizona
(126)
With more than 65 years in the heating and cooling business, Adams Refrigeration is dedicated to providing the best possible service for you and your family. You can count on us to provide you with a system and solution that fits your family's unique needs and since we've installed many systems in t...Read more about Adams Refrigeration Co.
With more than 65 years in the heating and cooling business, Adams Refrigeration is dedicated to providing the best possible service for you and your family. You can count on us to provide you with a system and solution that fits your family's unique needs and since we've installed many systems in t...Read more about Adams Refrigeration Co.
Porch Pro Headshot Sun Devil Heating and Cooling
Furnace Repair
Serves Scottsdale, Arizona
(197)
We are a family owned and operated company. Serving the valley for over a decade with exceptional reviews and an A+ rating with the BBB.
We are a family owned and operated company. Serving the valley for over a decade with exceptional reviews and an A+ rating with the BBB.
Porch Pro Headshot Peterson Air Care & Home Services
Furnace Repair
Serves Scottsdale, Arizona
(155)
Family owned and operated HVAC Contractor specializing in Residential HVAC Repair, Replacement and Indoor Air Quality. We work daily with local homeowners and residential or multi family property management companies to create the best service and value in the Greater Phoenix Valley. Our goal is t...Read more about Peterson Air Care & Home Services
Family owned and operated HVAC Contractor specializing in Residential HVAC Repair, Replacement and Indoor Air Quality. We work daily with local homeowners and residential or multi family property management companies to create the best service and value in the Greater Phoenix Valley. Our goal is t...Read more about Peterson Air Care & Home Services

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 Scottsdale furnace repair services

23103

Extremely professional, very courteous.

- Jeremy Tamayo
289215

NO BUSINESS ETHICS. AVOID. I bought a Groupon for an A/C tune-up, which was falsely advertised. I was given a diagnostic instead of a tune-up and nothing was tuned-up. I called the company and was told that “tune-up” means “diagnostic”, even though the wo...

- Tim Winer
8378

had one of the bigger companys come out, due to my vents blowing cold air out in december, they told me my compressor failed and i had to with a new unit. I called simply the best for a second Opinion , jesse got to my home with in a hour, and found one ...

- jim ducan
8221

Perfect experience. AC unit quit working and called their answering service at night and Steve called back in less than 3 min saying he could come in an hour to fix it since we had children including a 6 week old baby in the Arizona heat!! We had already ...

- Nick J
5723

Clean, Trustworthy, Honest, quick, background checked, quality work, fair priced, and polite. I had one of my a/c units not functioning, I contacted simply the best at 9pm and had a tech "Steve" at my home in 30 mins. Steve diagnosed the problem and had m...

53196

Bobby came highly recommended by a friend. He was able to save my client money in replacing the system in the attic of a home that was closing for half the price of a well known company in Chandler. He was very professional and got the work done on time...

- Nancy Campbell
53704

We have lived in our home 20 years here in South Tempe and the house is now 30 years old. Although we have had new air conditioners installed and our duct work cleaned; the house would not cool down in the Summer months. I saw my neighbor replacing there ...

- Mark Ahles
87725

Climate care pro was amazing! They did an excellent job and i am very satisfied with their work. There very friendly and accommodating. I highly recommend this company because of their outstanding expertise!!

- Jophille Tagle
53183

Great service all around. Prompt, reliable, and fair prices. Also really great customer service demeanor. Would highly recommend to anyone.

- Mike Policky
56440

Bobby installed an A/C unit in my house and did a exceptionally nice job, I would recommend him to anyone needing an A/C or repairs. Friendly, honest and reliable.

- Dennis Benzing
53192

Bobby is very ethical in addition to being an expert in the field, with all the resources needed to face any situation. I know, since I own rental properties and have called him for multiple different types of repairs as well as quoting new replacement u...

53740

I highly recommend Climate Care Pro LLC for all your heating and cooling needs. I'm in the real estate business and have used them for years, and they have serviced many of my and my client's properties. They are very knowledgable, ethical, provide very f...

- Joel Rosas

All Heating & Furnace Repair Companies in Scottsdale, AZ

Porch Pro Headshot Clear Air Conditioning & Heating, Inc
Furnace Repair
Serves Scottsdale, Arizona
(124)
Clear Air Conditioning & Heating Inc. was started on Jan 1st, 2009 after the separation of the partners of Fresh Air Conditioning & Heating, LLC. Curt & Michele Wellendorf (owners) have been working in the HVAC industry for over 25 years and have many long term relationships with residential and co...Read more about Clear Air Conditioning & Heating, Inc
Clear Air Conditioning & Heating Inc. was started on Jan 1st, 2009 after the separation of the partners of Fresh Air Conditioning & Heating, LLC. Curt & Michele Wellendorf (owners) have been working in the HVAC industry for over 25 years and have many long term relationships with residential and co...Read more about Clear Air Conditioning & Heating, Inc
Porch Pro Headshot Frostic Air
Furnace Repair
Serves Scottsdale, Arizona
(60)
"I use Frostic air for business and for my home. Very nice to have a company that is reliable, dependable and honest. I would not hesitate recommending Michael , and Frostic air to family and friends!! "
"I use Frostic air for business and for my home. Very nice to have a company that is reliable, dependable and honest. I would not hesitate recommending Michael , and Frostic air to family and friends!! "
Porch Pro Headshot Brewer One Hour Air Conditioning & Heating
Furnace Repair
Serves Scottsdale, Arizona
(114)
Brewer One Hour Air Conditioning & Heating carries a strong reputation in Arizona as being the leader in offering quality and innovative heating and air conditioning solutions to both the residential and commercial markets. Our skilled and friendly technicians are equipped to meet and exceed our cus...Read more about Brewer One Hour Air Conditioning & Heating
Brewer One Hour Air Conditioning & Heating carries a strong reputation in Arizona as being the leader in offering quality and innovative heating and air conditioning solutions to both the residential and commercial markets. Our skilled and friendly technicians are equipped to meet and exceed our cus...Read more about Brewer One Hour Air Conditioning & Heating
Porch Pro Headshot Affirmative Air  LLC
Furnace Repair
Serves Scottsdale, Arizona
(110)
Affirmative Air Conditioning is a family run air conditioning repair company in Mesa, AZ with over 20 years experience in air conditioning repair in Mesa and air conditioning repair in Chandler. Mike Rozanoff, the owner prides himself on the accuracy of his air conditioner diagnostics. Affirmative A...Read more about Affirmative Air LLC
Affirmative Air Conditioning is a family run air conditioning repair company in Mesa, AZ with over 20 years experience in air conditioning repair in Mesa and air conditioning repair in Chandler. Mike Rozanoff, the owner prides himself on the accuracy of his air conditioner diagnostics. Affirmative A...Read more about Affirmative Air LLC
Porch Pro Headshot Climate Care Pro LLC
Furnace Repair
Serves Scottsdale, Arizona
(18)
Climate Care Pro LLC is a honest, fair, reliable and reputable company based in Arizona with a combined 30+ years experience. We employee the best in the business and our techs are NOT paid on commission! Climate Care Pro LLC is involved in giving back to the community such as donating our time and ...Read more about Climate Care Pro LLC
Climate Care Pro LLC is a honest, fair, reliable and reputable company based in Arizona with a combined 30+ years experience. We employee the best in the business and our techs are NOT paid on commission! Climate Care Pro LLC is involved in giving back to the community such as donating our time and ...Read more about Climate Care Pro LLC
Porch Pro Headshot Ken Muncy Air Conditioning, Inc.
Furnace Repair
Serves Scottsdale, Arizona
Based in Gilbert, Arizona, Ken Muncy Air Conditioning has been providing commercial and residential indoor comfort systems in the Metro Phoenix area for over 40 years. We are specialists in service, replacement, and new construction. Ken is a former Trane employee and has an expert knowledge of Tran...Read more about Ken Muncy Air Conditioning, Inc.
Based in Gilbert, Arizona, Ken Muncy Air Conditioning has been providing commercial and residential indoor comfort systems in the Metro Phoenix area for over 40 years. We are specialists in service, replacement, and new construction. Ken is a former Trane employee and has an expert knowledge of Tran...Read more about Ken Muncy Air Conditioning, Inc.
Porch Pro Headshot Xtreme Service LLC.,  DBA: AZ AIR TECH
Furnace Repair
Serves Scottsdale, Arizona
(25)
Honest and Dependable A/C Company with years of experience. 3 Employees. Charge by the job. No trip charges. Emergency Service Available. A+ BBB Rated
Honest and Dependable A/C Company with years of experience. 3 Employees. Charge by the job. No trip charges. Emergency Service Available. A+ BBB Rated
Porch Pro Headshot Jamie's Air Conditioning and Mechanical Services LLC
Furnace Repair
Serves Scottsdale, Arizona
Our business is our livelihood but it is also so much more. Jamie's Air Conditioning And Mechanical Services LLC was started to fill in a void in the current market and to make a business that the people of Phoenix and surrounding areas can place their trust in. Over the years we have never lost our...Read more about Jamie's Air Conditioning and Mechanical Services LLC
Our business is our livelihood but it is also so much more. Jamie's Air Conditioning And Mechanical Services LLC was started to fill in a void in the current market and to make a business that the people of Phoenix and surrounding areas can place their trust in. Over the years we have never lost our...Read more about Jamie's Air Conditioning and Mechanical Services LLC
Porch Pro Headshot Apex Mechanical, LLC
Furnace Repair
Serves Scottsdale, Arizona
Apex Mechanical, LLC is a locally owned and operated licensed, bonded, and insured HVAC service and installation company founded in 2018. We are dedicated to providing the highest level of customer service at an affordable price. The Owner/Operator is NATE certified (North American Technician Excell...Read more about Apex Mechanical, LLC
Apex Mechanical, LLC is a locally owned and operated licensed, bonded, and insured HVAC service and installation company founded in 2018. We are dedicated to providing the highest level of customer service at an affordable price. The Owner/Operator is NATE certified (North American Technician Excell...Read more about Apex Mechanical, LLC
Porch Pro Headshot Angel's Heating & Cooling, LLC
Furnace Repair
Serves Scottsdale, Arizona
Angel's Heating & Cooling is a licensed, bonded and insured HVAC specialist based in Tempe serving the entire metropolitan area . New A/C installations and more, they have 28 years of experience. Angel's Heating & Cooling is accredited by the Arizona Registrar of Contractors and The United States En...Read more about Angel's Heating & Cooling, LLC
Angel's Heating & Cooling is a licensed, bonded and insured HVAC specialist based in Tempe serving the entire metropolitan area . New A/C installations and more, they have 28 years of experience. Angel's Heating & Cooling is accredited by the Arizona Registrar of Contractors and The United States En...Read more about Angel's Heating & Cooling, LLC
Porch Pro Headshot A C Zone
Furnace Repair
Serves Scottsdale, Arizona
As a homeowner, you can easily be overwhelmed by questions when it comes time to understand HVAC systems and to choose what fits your needs. This is what we believe: deciding which HVAC system is right for your home shouldn't be a complicated process. So we've made learning about HVAC systems easier...Read more about A C Zone
As a homeowner, you can easily be overwhelmed by questions when it comes time to understand HVAC systems and to choose what fits your needs. This is what we believe: deciding which HVAC system is right for your home shouldn't be a complicated process. So we've made learning about HVAC systems easier...Read more about A C Zone
Porch Pro Headshot Budget Water Heater Repair Scottsdale
Furnace Repair
Serves Scottsdale, Arizona
With Budget Water Heater Repair Scottsdale you will get advantages from low cost pricing, a 100% guarantee on all water heater services, and a reliable crew that always shows up on time. For quick water heater repair services, call the our experts.
With Budget Water Heater Repair Scottsdale you will get advantages from low cost pricing, a 100% guarantee on all water heater services, and a reliable crew that always shows up on time. For quick water heater repair services, call the our experts.
Porch Pro Headshot Fountain Hills Air Conditioning & Heating, Inc
Furnace Repair
Serves Scottsdale, Arizona
Serving Fountain Hills, Scottsdale, Mesa, Gilbert, Rio Verde Carefree, Cave Creek, Tempe and the Phoenix area with heating & air conditioning repair, service and installation since 1974.
Serving Fountain Hills, Scottsdale, Mesa, Gilbert, Rio Verde Carefree, Cave Creek, Tempe and the Phoenix area with heating & air conditioning repair, service and installation since 1974.
Porch Pro Headshot Classic Heating And AC Repair Scottsdale
Furnace Repair
Serves Scottsdale, Arizona
Classic Heating And AC Repair Scottsdale for domestic and commercial projects, for heating & AC repair services at reasonable costs from professionals. Call us now on (480) 795-4869.
Classic Heating And AC Repair Scottsdale for domestic and commercial projects, for heating & AC repair services at reasonable costs from professionals. Call us now on (480) 795-4869.

Latest projects near Scottsdale

Recent projects booked on Porch
Phoenix 85018
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
Natural gas
Furnace problems
Inconsistent or fluctuating heat, System keeps cycling on and off
When problems started
A couple of weeks ago
Furnace age
5-10 years old