My furnace/ac lasted 18 years is all, it was all electric. We went to gas furnace this time. It was expensive more than I thought it would be 7300.00

When I asked how long the new ones lasted they told me 15-18 years. I was hoping for longer. My son just had to replace his gas furnace it was 35 years old.

Furnace lasted 15 years. It died last December at the coldest time of the winter. We could have had it repaired but given the age and the cost of repair we opted to replace it along with A/C and water heater. All the same age. A/C was still working last summer but had the old Freon. The water heater ironically died a day before it was due to be replaced.

The furnace we had before the one that died last year was from the 1950s.

Okay, this makes me feel better. I guess my furnace /AC really has lived to the end of its days. I’ll have to get furnace and ac, plus water heater and I may throw in a generator. Maybe I can get a better price if I bundle it all together. Goodbye money!

I think ours is around 4 years old. The previous one was from before DH bought the house, so maybe 15 years. We do not have systems that last a long time based on our type of house and what is used on them.

Our gas furnace ( we have 2- 2 zone) was original to the house- 28 years old and still kicking. We have had them inspected (and most recently because we are selling the house) and were told that yes the life expectancy is 15 ish years though the older ones like these can last more. We were also told (and I believe) iif it ain't broke don't fix it.

Now the A/C units we replaced I believe after about 8 years so they are now about 20 years old. I think one is not long for the world but is working fine.

The water heaters on the other hand we have had very poor luck with. I think we are on the fourth one - first few lasted about 5 to 7 years. This last one was replaced in late 2013 until it cracked and had to be replaced a few months ago. Since it was under 5 years it was covered for replacement (yay I guess?) but we did have to pay for labor.

I think sometimes there is a good amount of luck involved with all of these things.

Our house was built in 2004 and a builder grade gas pack unit was put in (5 ton AC). The AC components went in 2016 so we replaced the whole system with a better grade unit. I'll be happy if I get 15 years out of it.

I have a split system for the upstairs where the furnace works but the AC does not. I can replace the AC component separately (split system) and plan on doing so soon because it uses the old coolant (harder to get and is getting pricey).

My brother just recently replaced the original to the house gas furnace in his 1950 built home (our childhood home). The old unit was so efficient, his gas costs in Northern IL were less than $150/month in some serious cold weather. There was nothing wrong with the unit but he wanted central air.

Thanks everyone. The “if it ain’t broke don’t fix it “ idea is my dilemma. My ac and heat have been working fine except for the new clunking sound. So do I replace it while it’s still working, knowing it could go at any time, or wait until it dies, which could happen in our current 100 degree weather or over the winter when it’s 10 degrees. Doing it under emergency conditions is never ideal. I’d like to do it in October when it’s neither roasting nor freezing.

Ah, life’s conundrums.

A calculation may help make a more informed choice: years ago when I replaced my AC with a better more efficient model when the old one died, my summer electric bills decreased. Depending on the price of your electricity and how much AC you need in the summer (I'm in Texas and need a lot of AC), you could figure in the cost savings due to efficiency if you replaced now.

You should post this question on the HVAC forum - not sure why you did not cross post initially. I got some pretty good help there when we got our central A/C installed about three years ago (maybe four). We had a window unit before (which was noisy), but mostly we just opened windows for cool air, since we get cool Pacific breezes most of the summer. However, summers have been getting hotter, and our hottest months are September and October, and we finally decided that we wanted more control over our temperature. We use very little heat, as our winters are extremely mild, and if we do not use heat at all, the house temperature will not go below 62°, which I know is cold, but not life-threatening. Our mean temperature is January is 58°, with temperature range normally from 50° low to 67° high, although it can get above 80° in January.

Our heater (which is in the attic) is probably 15 or more years old - I have not checked, but then we don't use much in the way of heat. Now that we have A/C, we use it much more than we use heat, but these days I like to keep the house cool. During the day I have the thermostat set at 74°, but in the winter, I have it set for 70° for heating. We always turn the complete system off when we go out of town, and we can turn it back on remotely shortly before we get back, although that is not really all that necessary.

We don't have heat yet, but it's supposed to get hot Saturday and Sunday. If we were further from the beach, it would get even hotter this week-end.

Our geo-thermal system was installed in 2003. I have it serviced every Spring and will replace it at the first signs of old age. So far my guy says everything looks fine.

We bought a new heat pump (heating and ac unit) a year ago. Our old one was almost 18 years old and had never had a problem but it was going to cost a little over $1200 to fix the old one so we decided, based on its age and the problem, to replace it now. The weather had not become unbearable yet and we could tough it out for a few more days with the fan until the new one was installed. Turned out to be a good choice imo since the newer units are so much more efficient and less costly to run.

Thanks for additional comments. I alwYs like to hear other people’s rationale for doing something. Lars, I did not want expert opinions on the subject, just the experiences of every day HAVAC users. That’s why I didn’t cross post on the other forum. I get confused when people start talking about tons and SEERS and things like that which I don’t understand. I have a trustworthy company that services my system and I let them worry about it.

Ours in our house is just over 20 years old and I cringe about this time every year. We had (KNOCK ON WOOD!!!) only some minor repairs over the years. In the rental house the unit is very old (not even sure how old), and we put in about $600 in repairs last year but the guy who works on it says to hold out as long as we can - that the new units aren't as good quality/last as long as the newer ones. If a costly repair comes up, we'll have to make a decision and will probably replace. Same with ours I guess.

This thread interested me because my daughter and her family are suffering through this heat wave with no ac. Their unit went out Friday. They had to replace their furnace two years ago and should have done the ac at the same time. The hvac contractors are so backed up it will be another week before they can get a new unit. In addition they were quoted a price almost 2,500 more than it would have cost two years ago. I feel so bad for them with 4 kids under the age of 8. The temperature right now is 102 with a "feel like" of 112.

Satine how horrible!!! Is there any way they could buy/rent one of those freestanding units to cool a single room down until they get a new unit?

We've been in this house 37 years. Have replaced the a/c and gas furnace. Have also dealt with major a/c repairs twice. One I lived through (very uncomfortably), the other necessitated a 2 night stay in a hotel. You might consider going tankless with the water heater. One of the best decisions we made in the remodel.

Also recommend the tankless water heater.

Satine, how awful for your kids. We had a huge storm go through and it has cooled off some but its still humid as heck. I'd be checking into a hotel if I had no AC.

What's so great about a tankless water heater? I have a regular water heater and never run out of hot water. My friend has tankless and raves about it but I don't know why.

My understanding (via my mechanical engineer husband) is that people should replace their furnace every eight to 10 years because the newer units are more efficient and thus result in cost savings on fuel. The unit may last longer, but you will pay more in energy consumption and carbon footprint.

Dedtired, a tankless water heater will not run out of water even if you have multiple guests and extra showers, but the main sell on them (from what I have seen) is that they use far less energy because they don't have to heat 330-50 gallons of water and keep it hot all the time. A tankless heater heats only the water being used on demand. They also don't have a large tank that can rust or develop leaks and flood your home.

My AC is 5 years old this week. We had installed those units to replace the existing ones in our home -- we hadn't been very happy with either. The newer unit needed a new coil for the second time in a few years -- and one of the coils put in was the wrong part with the wrong coolant. Required the entire AC and heating system to be replaced. It was such a mess that we decided to cut our losses and pull both systems and start completely over. We went from $150 service call to something that added some zeros and then some -- but we got rid of such junk, got a great system relocated in our attic so the service is easier and safer, complete with some new ducts, gas lines, a little vent work -- and the owner monitors phone calls from home after hours and helped us trouble shoot one evening to avoid a service call the next day. We went to a 2 speed system that runs high for cooling and low when it needs to dehumidify -- a great feature in a humid climate, and it is more energy efficient. And quieter -- never hear that kick and push of air when it runs. Don't miss it. We didn't have to replace the second system, but I have never regretted the decision. It's been great and I have an AC company I trust again.

dedtired, what sort of "clunking sound", if it is when it turns on and off, it could be nothing more than the air filter being sucked in or let go when it turns off, if the filter doesn't fit tightly in the place that it goes. Just a thought.

Clunking could also be ductwork flexing with change in air pressure. Our systems are about 5 years old or so, installed by the PO. Mini split heat pump, gas condensing furnace backup, and hybrid water heater that runs off electricity or the heat pump or combination of both.

Our last house had an oil fired Thermopride warm air furnace that had to be 25 years old, and we were advised by two different heating contractors not to replace it. The quality was very good, so even though it had a few rusty spots, it wasn’t worth putting in a newer model. Trane AC split system was 15 years old when we left, no problems. I considered it “new”.

I hate having to make those decisions - do I replace it now or do I wait and see how many more years I might get out of it. I think in your situation I'd probably replace it - 25 years is a decent lifespan. Unfortunately the newer models probably won't last that long. The government now requires HVAC systems to be more efficient which apparently requires more 'stuff' inside that can break.

The new HVAC system that we installed 5 years ago in our last house was significantly quieter and maintained the temperatures better than the old one.

When we moved into our new place last fall DH replaced the water heater which was 13 years old. That's about the average life span. We discussed tankless with our HVAC guy. I would have loved to gain more storage space in our utility room. The tankless hang on the wall and are significantly smaller than a regular one. I don't remember all the reasons but we ended up with a regular water heater. However we had a drip pan installed beneath it and there is a sensor in the drip pan. If it gets wet it automatically shuts off the incoming water to minimize water damage and since it's on an outside wall there's also a small drain pipe that empties any excess outside.

This house was built 13 years ago and we happily discovered that our HVAC system was only 4 years old so hopefully we'll get at least another 10 years out of it.

Our a/c and water heater were both fairly new when we bought in 2006, but we had to replace our furnace in July 2016; it was the original from when the house was build in 1988. The odd thing about it was that the part that broke was the blower so neither the ac or the heater would work. It was 3800 just for the heater which is gas. Of course mid July without a/c is miserable but these things always seem to happen at the worst of times don’t they?

A few years ago, after we lost power (along with our access to water) for 4 days in the heat of summer, we decided to get a generator. We really wanted a Genrac installation but when quotes were in the 5,000 range we couldn’t justify the expense for something that really doesn’t happen all that often. We came across a solution instead that was a lot less expensive but still made sure we would be comfortable. We bought a larger portable sized generator from Costco and put it in a permanent spot behind the house. We then had an electrician install an electrical panel that would work with the generator. He ran a permenant extension cord from the generator to the panel so all we have to do is plug one end into the generator, plug the other into the panel, flip a switch and start the generator (with a remote). Takes a whole 60 seconds to do and we’re up and running but the cost was only 1500 and we’ve used it maybe 3-4 times in the past 6 or 7 years.

I'm in southern Maine and WISH my house had AC right now, but the dogs and I are in my office with a great window AC unit, so we're OK. I also have one in the bedroom. Here, we really seldom need AC, but this heat wave is affecting so many people. I'd rather have -20 weather than this as I can get warm anytime.

I bought my sweet 1937 cape in Dec 1986. The PO's had put a commercial grade oil furnace in the daylight basement, and other than having it cleaned each fall, and having done whatever little tweaks need to be done then, I have never had an issue with it. It also heats my water. I feel VERY lucky.

Our central air unit is not a part of our furnace. After several years of constant service calls because of Freon leaks which were never completely resolved, and the rising cost of the old Freon, we replaced our entire 20+ year old a/c system in April. At first, the yearly service call took care of the issue for the summer, but the last 2 years we had been without ac for about 1/2 the summer, waiting for service calls over and over. So far it’s been a pleasure with the new system especially when having sleepover guests, who always managed to arrive when we needed Freon replaced.

ETA correct age of old system

Tankless water heaters are not always the better choice, especially if you use more than 41 gallons of hot water per day. Also, a gas water heater may cost less to run than an electric tankless heater, depending on how much hot water you need. In California (or at least Los Angeles), water heaters must be installed outdoors. We thought about tankless when we had to replace ours but decided to stay with a gas heater, as gas is so much cheaper. In California, another advantage is that the tank water heaters have a reservoir of water that might be useful, in case of earthquake, if you do not have a pool or hot tub. We have a hot tub and so would be able to get water from that for bathing and cleaning, and so that is less of an issue for us.

We just got a new furnace and a new AC system installed last week. The furnace was at least 40 years old, but we haven't used it since we bought the place because we have a pellet stove and a fireplace. We have pretty mild winters so the pellet stove was fine unless we had a freezing period, when we'd have to light the fireplace. Summer temperatures rarely go over 90 and we used to have a lot of big trees shading our place, but they're gone now and it's been harder and harder to cool the house with just a couple portable AC units. So we took the plunge. And we haven't even used the AC unit yet, the hottest we've had since it was installed was 85 and I couldn't see using it for that!

For that reason I suspect our new AC unit will last us at least 10 years, it's not going to get that much use. But the furnace will be a blessing-no more uneven heating! The new unit is 97% efficient (gas) while the old unit was probably 70%...it was a dinosaur. One tech thought it was produced by Montgomery Wards!

Last year we had to replace our gas WH. I briefly considered tankless but considering the age of our home and the ultimate value-we're not in the high end area-we just went with a new gas WH. Our old one lasted at least 20 years! I don't expect that life span from the new one. It's very unfortunate, new equipment just doesn't have that life span the old stuff did, but the price we pay for efficiency I guess.

Hey, thanks everyone. I’ve read every word of your comments and learned a lot. Miraculously, the clunking noise has stopped. It was coming from the blower. Maybe something was stuck in there? I don’t know. I will call and cancel the HVAC guy for tomorrow.

i used to get that noise from the duct flexing but my new contractor fixed that somehow. It was really annoying. Every time the heat or ac went on there would be a fairly loud bang.

I know this system is about to give up the ghost but I will probably wait until something goes wrong before replacing it.