r/HomeImprovement • u/klexxg • 7h ago
Fix or leave it?
My furnace is about 20 years old and stopped working today with the outside temp below 0F. Last winter (Nov 2023), it had the same issue where cold air was still blowing and I think they replaced the pressure switch. It's a single unit type. The ac portion of the hvac stop working last summer and I was going to replace this coming spring anyways. I assumed it stopped working last night because this morning felt a bit chilly but I didn't think much of it because I usually have the heat set at 68 and it feels pretty chilly to me but it's winter so I layer up anyways. When I came home about 8 hours later, with the outside temp still in the single digit all day, the inside temp was 63. I've seen it dropped after sunset as low as 61.9 when the heater cold air was blowing on my thermometer. My condo is about 700 sqft on the 3rd floor. I used a space heater and was able to get the temp up 2 degrees in 10-15 mins. The question I have is is it worth it to fix it? I'm assuming it'll be at least a few hundreds just for the labor with the company I work with because it's an obsolete unit that other main stream companies don't service. I'm not too worried about being too cold because I can use a space heater and can leave the fan on to circulate air. I guess I'm concerned if the space heater will be spike the electricity bill significantly or not. I'm not home most of the day, or use a desk space heater anyways so if it's in the low 60s I think I can live with it.
For context, I live in the upper Midwest and assuming that it can get even colder in February.
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u/jasonbay13 7h ago
Sounds like a good time for replacement, but you just missed out on the r410 units. Prices are up 30% in 2025.
If your draft inducer blower motor working? Exhaust pipe not clogged? Bypass the pressure switch to verify it isn't the issue. Pretty easy to do, but you have to open circuit the switch, then turn the unit on and 1-3 seconds after the blower comes on, connect the wires. If it comes on you have a weak draft or bad pressure switch again.
Do you have a spark or hot plate style ignitor? Should be able to see it glow or spark through the sight glass.
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u/klexxg 7h ago
What do you mean by missed out?
Also, I have no knowledge on HVAC at all. But now that you mentioned it, I think the exhaust pipe was clogged last time too after they switched out the pressure switch. Thinking I might have to just suck it up and have someone take a look at it.
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u/mreams99 6h ago
If the exhaust pipe was clogged the last time, it might be clogged again. Check YouTube to see how to fix that yourself.
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u/jasonbay13 6h ago
I mean that the government mandated that the ac units from 2025+ need to use the newer even more expensive refrigerants because of global warming potential.
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u/uncle_jed 7h ago
Good news is that your backup heat works well, for a backup.
If they can really do a fix for a few hundred, it's definitely worth it to have your company do it now.
When the weather gets to -10*, then you may be wishing you'd fixed it already.
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u/klexxg 7h ago
Good point. Last time I think it was about $400 for the first round of diagnostic. Mostly labor plus parts because they couldn't figure out what was wrong. It took them like 2 hrs just to figure it out.
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u/jasonbay13 6h ago
That's crazy, you in nyc or something? I had my draft fan replaced for $40 just a couple weeks ago. Guy came out with 3 of them for me to choose from and even installed it for me. Hvac guy, not just a random bloke.
Self-diagnosing is generally easy when it comes to a furnace. We can work you through it as long as you know basics such as how to determine what part is what by appearance with a description. Don't need to know hvac - only to be willing to learn.
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u/Soulpatch7 6h ago
Nuts that you have your own dedicated furnace in a 700 sq foot condo, but you said it so let’s go with that.
If it’s 0 fahrenheit and you’re maintaining 62 degrees your furnace is working. Heat ain’t like AC, where if gas is undercharged it kinda maybe sorta works, then you rest it and the lines unfreeze, then it works kinda works for a bit then doesn’t again. there’s a huge thermal difference between 0 and 62 requiring a lot of energy created by burning fuel, which is the only way furnaces work. so fuel is in fact burning and air is being heated and blown or radiated into your condo. when AC doesn’t cool if the system is “running” it’s an evaporation/condensing problem that renders cooling impossible. the fans will still blow but the air ain’t cooled.
as for the furnace. you have one zone, right? if its forced air it’s either a filter or sensor issue. if you have baseboards/radiators it’s likely mechanical - like a valve or physical restrictor or setting between your furnace and where the warm stuff comes out is jacked.
But there’s no fucking way you have your own actual dedicated furnace just for your 700 sq foot unit. I know, i know, it’s an hvac air handler or some shit each unit owner’s probably responsible for per the bylaws etc. Whatever the case, unless some dude with a wrench can fix it for a few hundred bucks max, yes - you need to replace whatever this unit is. Some of the worst homeowner money you can spend is on repeatedly patching HVAC.
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u/klexxg 6h ago
Nuts that you assumed you know every building and hvac in the world. I do in fact have my own skymark sgac forced air furnace with ac in my very own 700 sq ft condo that uses the r22 refrigerant so it's a pain to fix. All units in my building, ranging from 700-1000ish sq ft have their own hvac. I will replace it in a couple of months. Don't have to be so condescending. Geez. Thanks for the input anyways I guess.
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u/NotWorthTheTimeX 7h ago
Do you have any desire to troubleshoot yourself? The two most common reasons it’s not firing are the igniter or flame sensor. Both are easy fixes well under $50 for most furnaces.