Tell me about the current state of the art in HVAC

I can explain exactly how a heat pump works at a technical level. However, where my knowledge is lacking is in the more practical matters of: what’s the current state of the art? What products are available?

Let me describe the scenario:
I live in a condo complex of a hundred or so units. Buildings are about 10 units each, all the same. Individual units average around 1200 sq-ft, though some are smaller or larger. 3 stories; ground floor has (individual) garages; units are on second and third floors. They were all built at the same time, about 30 years ago. They all came with the same basic setup for the HVAC: an air handler within the unit, a condenser in the garage, and a weird “furnace” which is really a hot water loop from the (gas) water heater to the air handler. Apollo Hydroheat brand, which is now out of business. The condenser has a 2x2’ hole to the outside for ventilation.

Needless to say, this system is ancient, breaking down, and increasingly hard to repair. It’s also inefficient (don’t know the A/C SEER rating, but it can’t be good, plus it’s effectively a gas furnace). It’s also just kinda crappy in general, with a loud blower, and is slow to cool. Some owners have managed to repair their systems, but it’s expensive–particularly for something so out of date.

I’m trying to figure out the best way forward–ideally for everyone in the complex. What I would like is a fully modern system with a high SEER rating and a heat pump instead of a gas furnace. Oh, and this is the CA Bay Area, so it never gets truly scorching or freezing. Let’s say 40 to 100 F. No need for a backup furnace or extreme cooling levels.

Some vague questions:

  • The current condensers are a thru-the-wall type, with a 2x2’ vent. From some looking around, it appears that fully outdoor units tend to have higher SEER ratings. Is this true? I may be able to convince the HOA board to allow outdoor condensers, but this remains to be seen. What are the best options for either type?
  • Mini-split vs. central air handler. Am I even making the right distinction here? Are there other types? If the current air handler is replaced, the replacement will have to fit into a highly specific space. The new one will have to be smaller or equal in all dimensions. That seems to restrict the options. On the other hand, it seems that mini-split is the new thing. No central handler, just one unit per zone. Pros, cons?
  • Related to mini-splits: I see that there is the “cassette” type that mounts above the ceiling. These appear very convenient and unobtrusive. Any downsides?
  • Any particular brands I should look for (or watch out for)?
  • How about installation? There is a local company that repairs the current units. But I am skeptical about going with them since they seem to have a good business in making expensive repairs to the old system. I’m not sure I can trust that they’ll inform me about the best options out there.

Right now, I’m just gathering information. We have a new HOA board, which is for the moment responsive. What I’m hoping is that, because this is a real problem for everyone, they’ll be amenable to me being a guinea pig of sorts, if it means they get an answer for the best way forward.

Thoughts, ideas? Honestly, even if you have no answers, and just want to share your own HVAC installation story, I’m all ears. Pretty much any information is useful at this point.

Wow this is weird, it shows your post date as Jun 25th, 10 months ago yet it showed up as a new topic with no additional posts.

Anyway I can give you my outcome with self installing a mini-split. It’s the type where there is a wall mounted unit on the inside. I installed it last fall, I have estimated I have saved at least $1000 in heating costs this past winter, and that unit is not even a high efficiency energy star model. My furnace is high efficiency propane. The total cost for installing including having to buy a better vacuum pump, build a stand for it and some electrical equipment was about $1600, so payback looks like it’s going to be pretty quick. To my advantage I did have an old abandoned central air system so the outside electric was preexisting and just needed a new breaker and whip (connection to the new heat pump.)

I am actually shocked at how well it has done in terms of savings. If I had it all over to do I would have gotten the one that can heat when outside temps are -20F, instead of mine that goes down to -5F, as what I didn’t know at the time is it’s just not the lower limit, but efficiency at the lower limit, meaning when it’s 5F out the better unit would be running much more efficiently then my current one. I would have also upsized it as I sized it for cooling, not heating and it appears that heating requires more BTU’s than cooling does in northern climates. With that said I still did very well and getting the better unit would be slightly better but would be diminishing returns.

I wonder if the thread got bumped by a spammer who was quickly banished before you got there.

That’s almost undoubtedly what happened. Even when the spammer post gets cornfielded, Discourse still “remembers” that the spam post was the most recent post in the thread, and moves it up to the “recent posts” list.