How old is your furnace? It would help to know the type furnace (gas, LP, electric, o

[teetee]

The Kenmore gas furnace I have is from 1986 (35 yrs). I recently saw an online post stated that a furnace is considered unsafe if it is 15 years or older and I was like ok, guess I have been on borrowed time for the last 20 years.

I did have to replace the limit switch to stop it from keep blowing cool air probably 5 years ago. I also add a few drop of mineral oil to both blowers but they have the seal bearing label on them which I just recently noticed so maybe I was just lubricating the parts that don't matter.

I am curious what your experience is. I contribute my furnace's long life to that though I live in the New England area, I keep the thermostat a few degrees below 60F during the winter so it probably has a lot fewer heating and cooling cycles comparing to others. I also replace the filters every season.

 

[wmc1000]

The Kenmore gas furnace I have is from 1986 (35 yrs). I recently saw an online post stated that a furnace is considered unsafe if it is 15 years or older and I was like ok, guess I have been on borrowed time for the last 20 years.

I did have to replace the limit switch to stop it from keep blowing cool air probably 5 years ago. I also add a few drop of mineral oil to both blowers but they have the seal bearing label on them which I just recently noticed so maybe I was just lubricating the parts that don't matter.

I am curious what your experience is. I contribute my furnace's long life to that though I live in the New England area, I keep the thermostat a few degrees below 60F during the winter so it probably has a lot fewer heating and cooling cycles comparing to others. I also replace the filters every season.

You have been very fortunate to get so many years out of your furnace. We had a similar aged unit in one of our DD's homes and the heat exchanged developed a crack in it after 19 years. The heat exchanger was warranted for 20 years but we didn't want to spend the labor cost to replace it in that old a unit as we figured it was the start of potentially other issues.

If you have had the heat exchanger visually inspected with no issues I would run it until it dies. If you plan to remain in your house long term it would make sense to replace the furnace on your schedule rather than wait for a breakdown as a 35 year old furnace is going to be really inefficient compared to the furnaces made today.

 

[Jerry1]

I think of a furnace as one of those things that’s either working or not. Outside of a cracked heat exchanger, I would assume you can keep a furnace running as long as you can get parts for it. Probably even able to change out the heat exchanger but I’m no HVAC technician. I can’t imagine what age has to do with anything other than new furnaces will likely be more efficient.

 

[aja8888]

Our 21 year old furnace quit last year. The tech that we have been using for HVAC for 30 years now, said the main controller circuit board had failed. He could not find a replacement. So we ended up with a new furnace.

 

[OldShooter]

... I recently saw an online post stated that a furnace is considered unsafe if it is 15 years or older and I was like ok, guess I have been on borrowed time for the last 20 years. ...

Well, that must be accurate -- it's the internet after all. Why not also check with someone who sells furnaces and ask them?

As an engineer, I would buy an assertion that age increases risk of being unsafe but not that unsafe automatically comes with age.

 

[Music Lover]

If you have had the heat exchanger visually inspected with no issues I would run it until it dies. If you plan to remain in your house long term it would make sense to replace the furnace on your schedule rather than wait for a breakdown as a 35 year old furnace is going to be really inefficient compared to the furnaces made today.

I'd run it until it dies.

A 35 year old furnace may have an efficiency of 80%. Increasing that to 95% will only save 15%. Even if you're paying $2000 a year for heat it may take 20 or more years for payback.

 

[finnski1]

Well technically I don't have a furnace. I have a boiler. In New England baseboard hot water heat is very common and I prefer it over forced hot air. It is a quiet comfortable heat without things blowing around. Mine is almost 24 years old and still working fine. I have it serviced /cleaned every year or two and never have had any real problems with it. It is reasonably efficient for it's age.
I thought I was stingy setting my heat at 64.
64 is reasonable with a sweatshirt and heavy socks. Don't think I could do 58 degrees.
Forgot to add that it is oil fired.

 

[Sue J]

When we moved in in 1983 the house had the original gas furnace from 1955 (28 years old). In 1993 we added air conditioning, adding an A/C unit into the old furnace and a compressor outside. It all worked just fine but we knew it was not as efficient as a new one.

In 2011 (56 years old) something broke, the furnace still worked but it didn't react to the thermostat. We had a repair company come out and it needed a part from a previous century so we decided to replace it. We knew it was coming, not a surprise, and we had the money set aside for a major repair/replace like that.

The new furnace is high efficiency gas and we also replaced the A/C from 1993. It's all been great.

 

[RobbieB]

The one that came with the house lasted 26 years and I only replaced it to take advantage of the rebates. It still worked fine. And was verified as operational to get the rebates which were incentive to be more energy efficient, not just fix your old junk that didn't work.

New one running now for 11 years.

 

[Music Lover]

Well technically I don't have a furnace. I have a boiler. In New England baseboard hot water heat is very common and I prefer it over forced hot air. It is a quiet comfortable heat without things blowing around. Mine is almost 24 years old and still working fine. I have it serviced /cleaned every year or two and never have had any real problems with it. It is reasonably efficient for it's age.
I thought I was stingy setting my heat at 64.
64 is reasonable with a sweatshirt and heavy socks. Don't think I could do 58 degrees.

I don't get the dislike for forced air. It's extremely comfortable, quiet, and it doesn't blow things around.

I refuse to have to wear a sweatshirt inside my house...I'm frugal on some things but comfort isn't one of them. Then again, it only costs me $500 to heat my house for the entire year, in spite of a 6 month heating season.

 

[finnski1]

I don't get the dislike for forced air. It's extremely comfortable, quiet, and it doesn't blow things around.

I refuse to have to wear a sweatshirt inside my house...I'm frugal on some things but comfort isn't one of them. Then again, it only costs me $500 to heat my house for the entire year, in spite of a 6 month heating season.

Well by definition it does blow things around. Also need to humidify /dehumidify the air, filter the air etc etc. I have no filters and do virtually nothing to my system. Ductwork can harbor mold etc around here. Then you can pay a duct cleaning specialist hundreds to keep it clean. All for a heating method I don't like as much as baseboard hot water. No thanks.
Didn't say I wasn't comfortable. 64 degrees is fine. Do you really want to pay extra for heat to just to wear a t shirt all winter. I don't like it too hot, actually feels worse to us than too cool. YMMV.

 

[Music Lover]

Well by definition it does blow things around. Also need to humidify /dehumidify the air, filter the air etc etc. I have no filters and do virtually nothing to my system. Ductwork can harbor mold etc around here. Then you can pay a duct cleaning specialist hundreds to keep it clean. All for a heating method I don't like as much as baseboard hot water. No thanks.
Didn't say I wasn't comfortable. 64 degrees is fine. Do you really want to pay extra for heat to just to wear a t shirt all winter. I don't like it too hot, actually feels worse to us than too cool. YMMV.

And by moving air around it also circulates air through the house. I keep the heat at a temp that allows me to wear a T-shirt but I don't consider that an extra. I'm spending $500 each winter season when it's set at 21 (70F) when we're home, turning it down will save me maybe $100? My comfort is worth far more than $100.

I'm not sure where you live and your climate, but duct cleaning around here is rarely needed and in fact, many people consider it a scam. Perhaps after moving into a home that had pets (dander/hair) or after a renovation that created a lot of drywall dust it might be useful, but I've never had it done and I've been here for 25 years.

It takes 2 minutes to change a filter.

 

[RetiredAt55.5]

Well by definition it does blow things around. Also need to humidify /dehumidify the air, filter the air etc etc. I have no filters and do virtually nothing to my system. Ductwork can harbor mold etc around here. Then you can pay a duct cleaning specialist hundreds to keep it clean. All for a heating method I don't like as much as baseboard hot water. No thanks.
Didn't say I wasn't comfortable. 64 degrees is fine. Do you really want to pay extra for heat to just to wear a t shirt all winter. I don't like it too hot, actually feels worse to us than too cool. YMMV.

I like my baseboard hot water system too. More so once we converted from oil to gas as part of installing the new furnace in 1997. Still running great, especially once I learned how to clean the thermocouple instead of replacing it every year or so.

Of course, adding central air is a significant problem without existing ductwork.

 

[youbet]

I thought I was stingy setting my heat at 64.
64 is reasonable with a sweatshirt and heavy socks. Don't think I could do 58 degrees.

We used to set our heat in the mid-60's during the day and 60 at night. As the years went by, DW mentioned she was uncomfortable with that temp during the day so I thought about the cost. It turned out that cutting back on dining out one meal per month more than covered the cost of setting the temp to 72 during the day and also resetting the smart thermostat to keep it warm later and get it warm earlier. (We still like to sleep in a cool room. But we really like getting up to 72 temps!)

We're in Illinois living in a small, tight, easy to heat home.

We do have a wood stove in the family room. We don't fire it up very often but when we do I'll manually set the thermostat down and close the doors to the family room. Then our bedroom is cool by bedtime and we're warm watching TV or listening to music in the family room. But we definitely don't save money trying to use the wood stove to heat the whole house. Even though I burn some scrap wood, free wood is getting hard to come by here in the city and purchased wood is pricey. The wood stove is just fun to play around with and it's nice to cuddle up in front of on a frigid winter evening.

Edit: Oh yeah, almost forgot the thread subject! We had this house built 44 years ago. We're on our third HVAC system. The current one is about 4 years old. Gas forced air.

 

[rodi]

My PA house had an oil forced air furnace that was older than me... circa 1957. It was still running when I sold in 2001. I did have a maintenance contract on it - they would do an annual inspection, cleaning, etc... And replace things if they broke. They lost money on me: one year it was a blower, another year it was something else (don't remember what.)

The house we're in now had the original 1963 furnace until about 10 years ago. Forced air natural gas. We replaced it when it started making a loud BANG noise randomly about 3 x week.

I am of the use it till it doesn't work or is unsafe. The statement that it's unsafe if it's 15 years old or more is designed to sell furnaces... doesn't take into account type (electric baseboard, boiler, heat pump, oil FA, gas FA, radiators...whatever...

 

[finnski1]

We used to set our heat in the mid-60's during the day and 60 at night. As the years went by, DW mentioned she was uncomfortable with that temp during the day so I thought about the cost. It turned out that cutting back on dining out one meal per month more than covered the cost of setting the temp to 72 during the day and also resetting the smart thermostat to keep it warm later and get it warm earlier. (We still like to sleep in a cool room. But we really like getting up to 72 temps!)

We're in Illinois living in a small, tight, easy to heat home.

We do have a wood stove in the family room. We don't fire it up very often but when we do I'll manually set the thermostat down and close the doors to the family room. Then our bedroom is cool by bedtime and we're warm watching TV or listening to music in the family room. But we definitely don't save money trying to use the wood stove to heat the whole house. Even though I burn some scrap wood, free wood is getting hard to come by here in the city and purchased wood is pricey. The wood stove is just fun to play around with and it's nice to cuddle up in front of on a frigid winter evening.

we have the house programmed on a 24 hr cycle. 64 during the day, 60 overnight (can't sleep if too warm) and back to 64 an hour before we get up.
The entire house is enclosed in SIPS and is very energy efficient(No thermal bridges) and therefore easy to heat.
We have a centrally located woodstove as well. We typically only burn it for a few hours at night for ambience and for that occasional time when we come in from snow shoeing etc.and you want that quick blast of heat. Much nicer to sit or stand in front of a woodstove than standing over the baseboard
The stove makes it harder to regulate the house temps and it quickly will rise to 72 or 73 deg and then we all feel hot.
Because the house is so tight the stove can actually induce drafts in the house that aren't normally there as it tries to pull oxygen form somewhere. Typically it creates a draft under the front door. The dog actually likes that because it is tiled and he can sleep on the tiles with his nose by the draft.

I also have two very small ERV's directly vented thru the exterior wall up at eye level. They work great for having enough air exchanges and providing fresh air when the house is all closed up during winter. The ventilation is very important in a tight house and you can literally tel the difference if they are off.
https://shop.buildwithrise.com/products/twinfresh-comfo-ductless-energy-recovery-ventilator?variant=40044933185713¤cy=USD&gclid=Cj0KCQiAsqOMBhDFARIsAFBTN3e3lKSGX6x83jPaVOSCkAxsCxLFPeEOLFPR875C1XkD9F06LQqL2oEaAnXcEALw_wcB

 

[Qs Laptop]

I have a gas Carrier 94% efficiency forced air furnace installed in 2002. I had to replace the burner elements about 4 years ago. I had to replace the start-up capacitor for the squirrel cage fan about 2 years ago. I clean the flame sensor every 5 years or so.

Exactly what becomes unsafe with a furnace? Carbon monoxide fumes getting into the house? Any furnace built since the 90's probably has safety interlocks that won't allow it to run if the exhaust is not getting outside. Besides, a CO2 detector should catch this.

 

[Mr._Graybeard]

Well technically I don't have a furnace. I have a boiler. In New England baseboard hot water heat is very common and I prefer it over forced hot air. It is a quiet comfortable heat without things blowing around. Mine is almost 24 years old and still working fine.
Forgot to add that it is oil fired.

Boilers can go for a long time, especially cast iron. Our oil-fired unit is 33 years old, although we've added a pellet boiler to the system that has become our primary heat source.

That said, the old oil dragons aren't that efficient. Our oil unit may hit 80% efficiency on a good day.

 

[jazz4cash]

Our 21 year old furnace quit last year. The tech that we have been using for HVAC for 30 years now, said the main controller circuit board had failed. He could not find a replacement. So we ended up with a new furnace.

Our 21 year old gas furnace just had the main controller circuit board replaced. Last month the blower motor and cage failed. Previously we replaced the AC evap coil. It’s a builder grade 100BTU 90% efficiency Goodman unit. I think a gas furnace can go a good long time.

 

[Mr._Graybeard]

The house we're in now had the original 1963 furnace until about 10 years ago. Forced air natural gas. We replaced it when it started making a loud BANG noise randomly about 3 x week.

After the second BANG I probably would have evacuated.

 

[Sunset]

Ours is a Goodman (cheap brand) but it has lasted 28 years.

I did replace the motor (myself) about 10 yrs ago as the A/C pan dripped water on the motor until the motor died.

I had it "cleaned and inspected" 2 years ago, no issues found except igniter was getting older.

Due to a poster here, I decided to buy a spare igniter and flame sensor in case the furnace goes out in Winter. For $30 it's cheap protection.

 

[freedomatlast]

I would imagine that anyone that's telling you that all furnaces older than 15 years are unsafe expects to profit by selling you a new one.

This is simply untrue and I certainly wouldn't buy a new one from someone who is purposely misleading you.

The boiler in one of my rental properties is 57 years old with no issues. Do you think a new one would last 57 years? I doubt it.

As long as the heat exchanger isn't cracked, it can be repaired.

Also, anytime someone tells you your furnace can't be fixed because they can't find parts probably isn't looking very hard. Next time get the part number and do an internet search yourself before you give up.

 

[Dash man]

We have two zones in our 20 year old home. The original inefficient Carrier units lasted 9 and 15 years. We replaced the first one with a Trane unit…big mistake. We’ve had more repairs than I can count, fortunately covered under warranty. But the warranty has expired, so we may replace it if anything expensive happens. The second unit was replaced with a Goodman which has run perfectly for 5 years with only annual servicing.
I will say when we installed the Trane, and again the Goodman, our gas bills dropped significantly. It took maybe 7 years to pay us back for the Trane. I haven’t calculated the savings from the Goodman, but did note the savings.

 

[Marita40]

I had mine replaced last year. It dated from 1986 as well. There was a small issue with it last year, and the repairman said if major parts fail, they were not replaceable anymore. New furnaces are so much more efficient now. I got a Weil McClain. This is MN and not a place to take chances with winter heat.

 

[Ronstar]

27 yo. Started out propane now on natural gas