A 30 year old furnace which can't provide the sufficient heat and needs to be repaired on a frequent basis should be replaced. A lower MERV filter usually doesn't fix the problems you are describing. I question the intentions of the HVAC technician wanting to keep repairing an old furnace. I recommend getting quotes for a new furnace.

A 30 year old house May lack sufficient insulation and weather stripping as well. Check the attic for what’s there and supplement as needed. Have an energy audit completed to see where there are air leaks (that will show if there’s insulation in the walls or if it’s settled). Have insulation blown in. If windows are drafty, plastic them up for the winter if there’s not time to fix the leaks now. Check the basement, crawl space etc for drafts. Correct where possible.

Hopefully the furnace can last longer. And I agree with getting quotes in the meantime for a new one.

30 years old? They didn't make them that good in the 1990s! She needs a new furnace but first get an energy audit to identify any major sources of heat loss. Get several estimates for the new system and insist on a heating load determination to accurately assess the size of furnace she needs.

My DH got salty with me when I read @mike_home answer. Her house is built on a slab, with solar gain thru windows on the south, minimal to no west or north exposure. I would not feel she looses much heat thru her exterior. This also would not explain variations in the temp when outside temps aren't swinging that much.

I too question why the old crony is keeping this one going.

When your furnace doesnt heat your house warm after multiple repairs sounds like a better reason than most… not sure what she is waiting for if has money to replace?

I like Mike but if my wife secound guessed me based on what a feller on the web said I might get a bit salty myself.

Good point @klem1. He was salty before I read the response though!! Her house was 58 when she got home at 9 pm. She has 3 people coming out tomorrow to talk a new furnace. And Dad is salty about that and thinks she is throwing her $$ away.

The biggest expense on a natural gas furnace would be replacing a heat exchanger because it's cracked -- so a furnace this old (30 years) would have used up it's life.

There are many other parts that can be costly as well in terms of you repair an old furnace waiting for it to break again.

On a furnace most of the time the "break" can be gaps of time that cause the furnace to "belch" due to some safety or error code. A 30 year old furnace would put it at 1992? A whole lot of garbage was made then too. Some error codes are erratic in that they will reset automatically which leads you down a maze of trying to "guess" what is the problem.

1992? > That was near the time that furnaces had manual light pilots. Certainly who ever has been working this probably added electronic ignition. No one wants to just keep going to relight a pilot light.

So to add electronic ignition if that was done, you'd add another layer of safety controls to prove that flame, ignition and so on. If the furnace doesn't sense flame for whatever reason it's going to shut off.

Over heating: same thing. It's going to shut off. If it shuts off there is no heat.

Error code 101: As a furnace ages it can develop a "personality" --- if you keep using the same guy to repair it he is probably more likely to know the personality of it more than anyone. Some are only in this business to replace only to replace again and again. I see that alot in person.

If you use someone else to replace the furnace this guy you have used all this time may decide to move on as well. This isn't to suggest you shouldn't replace a 30 year old furnace. If it's time, then it's time. But you've got a trusted guy that comes and keeps coming to fix it. I can't make this any more clear.

If you live somewhere there is an actual winter every year -- 30 years is a long time for a furnace.

Everything made today is junk? Yeah, that's why they give you a warranty to make you somewhat whole if something goes amiss. Many of them come with lifetime heat exchanger warranties. They come pre-loaded with safeties too numerous to mention here.

Your house sits on a slab? So this sounds more like a southern location than a northern one.

Don't choose one for a brand name, they are essentially all the same thing -- some manufacturer's do things better than others, but this doesn't necessarily mean much except that the cost to repair it past about 10 years or so (provided it's registered) can be less costly than some certain brands.

Some certain brands have better parts distribution in place to get parts in a timely fashion. So costs run the roost both ways. Sitting there shivering in the dead of winter "regardless of cost" isn't fun.

I service the Katy, Texas area.

We lived in northern Indiana where we definitely have winter. Most all production builder homes build on slab. That is becoming more prevalent even in the houses nearing a mil (which is a big house here)

She has called three other firms that all have a good reputations in our area and is more than willing to not use dad's friend again. He is retirement age anyway. She is in her 30's and a large group of guys she went to school with have a well respected HVAC company that is one coming out to access the situation.

She is going to ask on Nextdoor how many of her neighbors have replaced their furnace just out of curiosity. And I was off a year her house was built in 1993 and she has owned it for 5 years, its a small 1350 sq ft ranch.

Thanks all for your input. We will see what the HVAC people say. She did have problems with the pilot light and I am sure it has an igniter now if not before,

Her house is holding at 58.

There's some things going on here that are more important than a furnace. Friends and family should be forever and when they falter it's best to fix rather than find replacements. You folks might need a family conference and/or talk with your minister more than you need advice from strangers about a furnace.

Suggest your daughter check with her utility company about rebates.

My husband has lived in this town for 65 years so he knows many people. The current HVAC guy is just someone that his father knew. I would not know him if he walked up to me and my husband does not see him thru work or socially. It was someone he knew for our DD to call when she first had issues.

And again, the father is in his late 80s and the son mid 60s so they will not be in business many more years and she will need to find someone at that point.

The first guy was out and said it was a control panel issue. He got the heat on and showed her what to do if it goes back out by doing a reset (I think that's what she said). Said it was about a $500 fix when it goes completely out and he was impressed her furnace was still running. at 30 years, They are working up quotes for replacement.

Ironically the grandson of old man HVAC works for the company that she had out (the guys she went to school with)

"Running" isn't the same thing as operating safely. Turning on and producing heat isn't the acid test for keeping an old furnace.

What's usually the weak link in furnaces from a safe performance standpoint is the heat exchanger. They're prone to cracks, rust, seam leaks, etc., the effect of which is to leak combustion exhaust gases containing carbon monoxide and other unhealthy chemicals into the home. Without a thorough inspection (which can require some disassembly of the mechanism) and testing of air at the supply vents, there's no way to know. A furnace with a heat exchanger leak should be replaced immediately.

The other thing to consider is that newer furnaces are available that are higher efficiency than older models, meaning, lower operating costs. It's like the difference between paying higher costs of repair and operation for an old car, or getting a new one that's more efficient and safer.

RN,

I always find it interesting when the story takes a few sudden turns... yeah Indiana wasn't what I was expecting. LOL.

I'd agree with you then that this place is ready for a new furnace. It sounds like a small knit town in where everyone knows everyone so that's not necessarily a bad thing.

My post was mostly about big city logic and the common theme in my neck of the woods is mostly "somebody done somebody wrong" and reviews or likes were mostly made up bot accounts or a long list of relatives employed to drum up business.

People often chide me for not having 1000's of reviews. The fact of the matter is most reviewers that get what they pay for don't leave reviews. Some will never leave a review because they don't want to be tracked. If you're not tracked (or verified) there is no real way to say the review is "real".

I get bombarded with AI bot like garbage trying to sell me some new thing about either writing copy (ads) --- or creating fake reviews. So it is a thing... no one wants to work any more, hire a robot to do it... remotely. ;-)

Things go bad alot in this business so the warning the old guy is telling you about they make nothing but junk today isn't necessarily far off the mark. That said most manufacturer's of furnaces offer life time heat exchanger warranties. That is only the heat exchanger though, many more high priced parts and in some cases hard to find parts because most of them are made in farther out places in the world. Assembled in the USA only goes so far.

Some jobs I get are due to the following scenario:

I had a friend or a friend of a friend or a family member sell me "XYZ" HVAC system / part / piece or other and ever since then the unit does this or that and my old unit never did this or that?

I then ask them why they are calling me, why not call the friend? Well we're no longer friends, or the family member and I are no longer on speaking terms. The old logic goes something like this: Don't mix business with pleasure. HVAC is the comfort business?

Let me see if I understand Ray. Fellers that double deal friends and family should opt for big city life because he will soon run out of friends to double deal in a small town? I'll buy that. (;

Yes in the first paragraph I said we were in the midwest but its easy to overlook things. Our town has roughly 120, 000 people so not super small but when you have lived here forever it's surprising how many you know.

Luckily my husband is in a specialty service industry where his customers are corporations and factories. That makes it so we rarely have to mix business and pleasure.

I also feel that the HVAC industry is one of those area where "I got done wrong and I will bad mouth this company" because something broke out of anyone's control.

DD in sticker shock at the prices for 96% efficiency, will lower her standards Monday when the shops open back up.

All I can tell you is that I decided to replace my 30+ year old furnace (and A/C unit) - that was oversized for the house, also - before my hand was forced and before prices increased (as they always do).

I opted for a smaller variable stage, high efficiency (I think 93%?) - heat is more evenly maintained - and the gas bill went down so much that the gas company sent techs out three times to check my meter! Similar results for the new A/C as well. My investment has paid off over the years.

Your DD needs to take that into account when making her choices - out of pocket now, versus savings over the next (whatever time she thinks she will be in the house). Plus saving on the repair bills, and increased comfort in the home.- is worth something.

It might be hard to find a contractor who will do a load calculation - I found only one that said he would, but only if I signed a contract first. A fellow on this (HVAC) forum actually did one for me. Most of the "reputable" companies I contacted simply wanted to install same size furnace.

I agree about checking with her utility company to see if they offer a free energy audit. They usually come with discounts, sometimes even freebies, to make the home more efficient - with utilities prices constantly rising, every little bit helps, right? - and often are offering rebates on new HVAC equipment. Depending on her income she might qualify for more assistance.

I looked at reliability ratings on Consumer Reports (the ratings come from owner's actual experiences) and did notice that certain brands were consistently more prone to issues.

PS: I bought Rheem, and it has been 16 years now with not a single problem.

" I can skew a load calculation just as easy "

I'll bet you do, on the rare occasion (by your description) when you do load calculations at all.

In my area, the top contractors (the ones who are very busy) use conscientiously done load calculations as a tool on every job. They're required for permits anyway. When meeting with HVAC contractors to get bids, I used their attitudes and practices about load calcs as a way to separate the good ones from the hacks.

her house was built in 1993 and she has owned it for 5 years, its a small 1350 sq ft ranch

We lived in northern Indiana where we definitely have winter.

DD in sticker shock at the prices for 96% efficiency, will lower her standards Monday when the shops open back up.

I am trying to gather the important information out of all the noise on this posting. The winter design temperature for norther Indiana is about 5 F degrees. A house built in 1993 likely has insulation of R-13 in the walls, R-30 in the attic. It is a single level 1350 sq. foot house. This gives some data points for the heating load. Find out the size (input BTU) of the current furnace. I think we can assume it was a 78-80% efficiency rating when it was new.

There are big ranges of models and prices of furnaces. No need to buy the highest priced model. However buying the low end budget model may not be the best choice if the funds are available. The most important things are the correct size and a good installation. If you are able to get model numbers and prices, feel free to post them for comments.

And Dad is salty about that and thinks she is throwing her $$ away.

I hope I didn't cause stress in your house. i can provide reasons why a replacement is a better long term option versus a more repairs.

Dad is a cheap*** about everything, nothing new there.

The current furnace is 60,000 BTU and I would agree that it was probably 78-80% efficiency.

She is still gathering proposals but is sure she will replace the current one.

A 60,000 BTU input, which at 80% efficiency has a 48,000 BTU output is consistent with the size and location of the house. I would not go any smaller, and larger is not necessary if this furnace was able to keep the house at 70 - 72 degrees on the coldest nights of the year.

Is there also an outside AC condenser? If so, what is the plan for keeping it as is or replacing it?

The AC was replaced shortly before she move in.

Thoughts on 2 stage versus 1 stage? Her humidifier hasn't worked since she moved in she says (by filter being dry) Do they actually do anything? Not sure ours does but who knows? Maybe our house would be drier without it.

A 2-stage furnace is worth the extra money in my opinion. It is more about comfort and less about efficiency and saving money. The disadvantage is it cost more initial and potentially higher repair costs.

I would avoid installing a humidifier. They become long term maintenance problems. Houses built on slabs tend to be drier than those with basements and crawl spaces. If she does not have a low humidity I would not worry about it. The humidifier can be added at a later date if it is necessary.

The furnace had quit again today. She tried the hard reboot and didn't get it started. She had decided on a 2 stage 80% so she notified the guy. He lives in her neighborhood so he swung by and got it going. Also fiddled with the existing humidifier and will just need to replace tubing on it. Hopefully this time Wednesday she will have a new furnace.....and peace of mind.

Sounds like a deal. Most people poo-hoo 80% furnaces these day but they are a straight swap, no new venting required, and no condensate drain issues. The 2 stage will be more comfortable than a single stage (no blasts of air in the middle of the night, waking everybody up!)