Six steps, one Saturday, no vacuum pump and no gauges. This guide walks the whole job before you spend a dollar — so you know what you’re getting into, and where the two spots are that trip people up.
Five questions. If you can say yes to all five, you can do this job. If you can’t, that’s worth knowing now — and there’s a fix for every one of them.
Can you drill a 3-inch hole through your wall? A hole saw on a regular drill. This is the part people dread and it takes about ten minutes.
Do you have somewhere outside for the condenser? A level pad or a wall bracket, within 25 feet of the indoor unit — that’s the line set length in the box.
Do you have the right power at that spot? See the table below. The 12K runs on 115V. Everything bigger needs 230V.
Can you get a second person for an hour? Only for lifting the outdoor unit and holding the indoor unit while you hook the bracket.
Are you willing to read the manual in the box? This guide gets you oriented. That manual is the authority for your exact model.
That’s an electrician for an afternoon, not a reason to skip the project. Running the circuit is the one part we’d hand to a pro even if you’re handy — it has to meet code, and it’s the cheapest part of the job to get done right.
This is the single thing that decides how your install goes. Check it before you pick a size, not after the pallet shows up.
| System | Power | Covers | Price |
|---|---|---|---|
| DIY 5th Gen 12K | 115V | Small room | $2,359 |
| DIY Easy Pro 18K | 230V | Medium room | $1,806 |
| DIY 5th Gen Hyper Heat 18K | 230V | Up to 800 sq ft | $3,173 |
| DIY 5th Gen 24K | 230V | Large room | $3,329 |
The 12K is the only one that runs on standard 115V. If you want the Hyper Heat — the one that keeps heating at −22°F — you’re running a 230V circuit. Worth knowing on day one.
Room size isn’t the whole story — ceiling height, insulation and sun exposure all move the number. Use the sizing calculator and it’ll tell you in about thirty seconds.
On a normal mini split, an HVAC tech shows up with a vacuum pump and a manifold gauge set, pulls the air and moisture out of the line set, then releases the refrigerant. That step is the reason these were never a homeowner job. It needs equipment you don’t own and a license you don’t have.
The DIY line ships with the line set already charged and sealed. The QuickConnect® fittings thread on by hand and torque down with a wrench. No pump, no gauges, no refrigerant handling, nothing to certify.
That’s the whole trick. Everything else in this job is drilling, mounting, and wiring — work you’ve done before under a different name.
Installing it yourself is what this equipment is designed for. The DIY 5th Gen and Hyper Heat lines carry 5-year parts and 7-year compressor coverage — with registration. Register the unit when you’re done. It takes five minutes and it’s the step people forget.
Indoor air handler, outdoor condenser, 25 ft pre-charged QuickConnect® line set, wall mounting plate, remote, and the installation manual.
A torque wrench. The QuickConnect fittings have a spec, and eyeballing it is how people end up with a slow leak they don’t find until August. Borrow one, rent one, or buy the cheap one — just use one.
Read all six before you pick up a tool. The order matters, and knowing what’s coming makes every one of them easier.
Inside: high on an exterior wall, clear of furniture and curtains, with the air able to reach across the room. Outside: level ground or a solid wall, out of the way of foot traffic and roof runoff.
The two have to be within 25 feet of each other — that’s your line set. Walk it with a tape measure before you commit, and remember the line runs down the wall, not straight across.
Find your studs, level the mounting plate, and screw it to the wall. Then drill the 3-inch pass-through with the hole saw, following the location the plate gives you.
Drill with a slight downward slope toward the outside. Condensate drains out through that hole by gravity. A hole that’s level or tilted inward will run water down your wall, and you won’t find out until the humid weather hits.
Check for wiring and plumbing in the wall before the saw goes in. Ten seconds with a stud finder beats a very bad afternoon.
Feed the line set, drain hose and communication cable out through the hole, then lift the air handler onto the plate until it clicks down. This is the lift where the second person earns their beer.
Keep the line set in gentle curves. A kinked refrigerant line is not repairable in the field — it’s the one mistake in this whole job that can’t be undone, so bend it wide and slow.
Pad or bracket, then set the condenser on it and check it with the level in both directions. Leave clearance around it for airflow — your manual gives the exact distances for your model.
In snow country, get it up off the ground on a bracket or riser so it isn’t sitting in a drift come January.
Thread each QuickConnect® fitting on by hand first until it seats. Hand-threading is how you catch a cross-thread before it becomes a leak. Then bring it to the torque spec in your manual with the wrench.
Land the communication cable on the matching numbered terminals at both ends, route the drain hose downhill the whole way, and seal the wall penetration with exterior caulk.
Tighter is not better here. Past spec you deform the flare and create the exact leak you were trying to prevent. The spec is in the manual, and it is a real number, not a suggestion.
Open the service valves fully with the hex key — this is the single most forgotten step in a DIY install. A unit that runs but never gets cold or warm is almost always a valve someone left closed.
Then power it on, run it in cooling, run it in heating, and check under the indoor unit for drips. Let it run half an hour before you call it done.
Register the unit. That’s what activates the 5-year parts and 7-year compressor coverage. Do it the same day, while the model and serial numbers are still sitting in front of you.
A guide that tells you anyone can do anything isn’t a guide, it’s a sales pitch. Here’s where we’d tell our own family to pick up the phone.
| Situation | Who |
|---|---|
| You need a new 230V circuit or a disconnect box | Electrician |
| Your panel is full, or you don’t know if it has room | Electrician |
| The run is longer than the 25 ft line set in the box | HVAC pro |
| Second-story or roof mount for the condenser | HVAC pro |
| You kinked the line set | HVAC pro |
| It runs but won’t heat or cool after you’ve checked the valves | HVAC pro |
There are certified MRCOOL contractors in all fifty states, and we can put you in touch with one near you — whether you want them for the whole job, just the electrical, or a hand when something isn’t behaving.
Warranty covers parts. Labor, removal and re-installation are on you. Worth knowing before you assume a warranty claim is free — and another reason to get the install right the first time.
Find your size first. It takes thirty seconds and it answers the power question at the same time — which is the thing that decides everything else.
Find your size Talk to a contractor