In this video
- Almost every mini-split ships with its outdoor unit pre-charged with refrigerant, but a standard bare line set still needs a vacuum pump, gauges, nitrogen, and know-how to install.
- A pre-vacuumed line set has already had the air and moisture pulled out, so you just release the outdoor unit's existing refrigerant into it instead of pulling your own vacuum.
- A pre-charged line set already has refrigerant sealed inside it (often with quick-connect fittings), which makes adding an extension easier but can leave you with more refrigerant than you actually need.
- Running longer than the included line set means buying extra refrigerant (R-32 or R-454B), which can cost anywhere from a few hundred to over $600 a jug.
- Airspool has customers measure the exact distance between the indoor and outdoor units, adds a couple feet of slack, and pre-charges the line set with the precise refrigerant amount for that run.
Questions this video answers
What's the difference between a pre-charged and a pre-vacuumed mini-split line set?
A pre-charged line set already has refrigerant sealed inside it, often through quick-connect fittings, so you're not adding any yourself. A pre-vacuumed line set just has the air and moisture removed ahead of time — the refrigerant itself still lives in the outdoor unit and gets released into the line set during installation.
Do I need a vacuum pump to install a mini-split myself?
Only if you're working with a standard mini-split and a bare, uncharged line set. In that case you'll need a vacuum pump, refrigerant gauges, and nitrogen, plus the know-how to use them. Pre-vacuumed and pre-charged line sets skip that step entirely.
What tools do I need to install a DIY mini-split?
For a standard line set that isn't pre-vacuumed or pre-charged, you'll need a vacuum pump, gauges, nitrogen for purging, and enough time and experience to do it correctly. Pre-charged systems cut that tool list way down and are far more DIY-friendly.
What happens if the distance between my indoor and outdoor unit is longer than the included line set?
You'll need to buy an extension and add more refrigerant to fill it, which can mean purchasing a full jug of R-32 or R-454B just to add an ounce or two. That refrigerant can run anywhere from around $300 to $600 or more, and you'll need to know how to properly weigh it in.
Why might a pre-charged line set have more refrigerant than I actually need?
Off-the-shelf pre-charged extensions are made in fixed lengths, so if your actual run is shorter than the set you buy, you end up with extra refrigerant sitting in the line. That's wasted expense and isn't ideal for the system.
How does Airspool make sure I get the correct refrigerant charge for my installation?
Airspool has you measure the exact distance between your indoor and outdoor units, add a couple of feet of slack, and then pre-installs the line set with the precise amount of refrigerant needed for that distance before it ships — on top of the outdoor unit already being properly charged.
What if I measure wrong and my line set ends up too short?
Airspool can still accommodate that after installation. It requires an extra set of valves and a bit more time, so there's a small added cost, but you'll still end up with a correctly pre-charged line set matched to your actual distance.
Which type of line set is easiest for a DIY mini-split installer?
A pre-charged line set is generally easier than a standard or pre-vacuumed setup because you avoid buying extra refrigerant for extensions. The most accurate and easiest option overall is one that's pre-measured and pre-charged specifically for your distance, which is the approach Airspool takes.
Transcript
Read the full transcript
So the question is, what's the difference between a pre-charged mini-split, a pre-charged line set, and a pre-vacuumed line set? Pre-charged mini-split: just about any mini-split you get now is going to be pre-charged, meaning there's refrigerant already in the outdoor unit. But for this type of standard mini-split, what you're going to need is a vacuum pump, gauges, patience, and nitrogen. You're going to have to ideally know what you're doing, and if you don't, you're going to have to borrow all those tools and learn how to do it. It's going to take you some time, so it's time versus money. That's the least expensive unit you can get. If you're an HVAC tech or whatever, you have all the tools and some time, no big deal.
Except, what happens when the distance between the indoor unit and the outdoor unit is greater than what the included refrigerant is set up for? A little bit of a conundrum, because then you're going to have to get a jug of refrigerant. R-32 these days runs maybe $300 for 20 pounds. R-454B, I think it's come down quite a bit, but that one's still $600 or so for 20 to 25 pounds. That's a big expense just to add maybe an ounce or half an ounce of refrigerant to fill that extra line set. So that's option number one.
Option number two is getting a unit that's pre-vacuumed. The line set already has a vacuum pulled on it, so when you attach it to the indoor and outdoor units, you release the refrigerant from the outdoor unit and there's enough in the system to fill that vacuum. The system will run just fine. Except, again, what happens if you need more line set and you're getting further away? You have to buy that extra line, and all of a sudden you have to buy more refrigerant, and you're going to have to know what you're doing again to make that addition correctly.
The third type is not only a pre-charged outdoor unit, but a pre-charged line set. That's a little bit easier, because if you want to do an extension, you can potentially buy one that already has refrigerant in that additional line set too. You'll need the tools to attach it, but you'll be okay. The only challenge with that method is that you might end up with way more refrigerant line than you actually need, which is a bit of an expense after the fact.
So here's what we do: we ask you to measure the distance between the indoor and outdoor unit, add a couple extra feet of slack so you're covered, and then we not only give you a pre-charged line set and a pre-charged outdoor unit, but we pre-install the line set with the exact amount of refrigerant for your distance. And if later on you realize you measured wrong, we can accommodate that too. There's a cost involved, since it requires another set of valves and a bit more time, but we'll get you an after-installation pre-charged line set to match.
That's probably the easiest way to do it, and it's the most accurate. And of course, naturally, we think it's the best way: a pre-charged line set that's pre-measured and pre-installed with the right amount of refrigerant, along with an outdoor unit that also has the correct charge.
