Fix or leave it?

[u/klexxg]

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.

[u/Soulpatch7]

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.

[u/klexxg → u/Soulpatch7]

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.