Mini-Split line lengths can be changed.

[Mikes61]

My plan is to install a 24,000 BTU mini split in my new 40’ x 23’ garage, that is attached to my 20’ x 20’ old garage. There is a 9’ wide walkthrough going from one garage to the other. The ceilings are each 8’ and both garages will be insulated.

My question is, will my HVAC install guy shorten the line sets on whatever mini split I buy? I’m thinking a Mitsubishi.

Or, if I got a Mr. Cool DIY precharged minisplit, what do I do with all the extra length of the line sets? The shortest ones I’ve found are 15’ and I probably only need 7’.

 

[rlitman]

8' isn't a whole lot to coil up. Coiling up Mr Cool linesets so as not to pool oil is something that's been discussed here before. Ordinary linesets get cut to size as part of typical installs.

 

[mike93lx]

For the Mr cool, you are stuck with what it comes with.

On the Mitsubishi, the lines et can be shortened, but there may be a limit. Check the manual for that.

 

[PCustoms]

My plan is to install a 24,000 BTU mini split in my new 40’ x 23’ garage, that is attached to my 20’ x 20’ old garage. There is a 9’ wide walkthrough going from one garage to the other. The ceilings are each 8’ and both garages will be insulated.

My question is, will my HVAC install guy shorten the line sets on whatever mini split I buy? I’m thinking a Mitsubishi.

Or, if I got a Mr. Cool DIY precharged minisplit, what do I do with all the extra length of the line sets? The shortest ones I’ve found are 15’ and I probably only need 7’.

If you're hiring someone to install, I would ask them

Also are they OK installing/servicing equipment you bought?

 

[bluedog225]

I thought modern units operated at a pressure that allowed loops. Horizontal or vertical.

 

[mike93lx]

I thought modern units operated at a pressure that allowed loops. Horizontal or vertical.

I had a freidrich system that had a loop in the lines et with no problem for years. But I'm no expert

 

[WildBill]

I thought modern units operated at a pressure that allowed loops. Horizontal or vertical.

It seems to be a never ending argument. But I know of tons of mini splits installed with loops that have worked fine for many years, including my Mr.Cool setup. Mine is coiled vertically lower than the condenser.

From the Mr.Cool website -
Excess linesets in your MRCOOL system do not need to be placed directly behind the condenser. They can be positioned in various locations—behind the unit, mid-run, or elsewhere—depending on your installation setup. However, if the lineset is coiled at an elevation higher than the condenser, make sure to coil it horizontally, not vertically, to avoid the formation of oil traps that can affect system performance.

 

[Mikes61]

It seems to be a never ending argument. But I know of tons of mini splits installed with loops that have worked fine for many years, including my Mr.Cool setup. Mine is coiled vertically lower than the condenser.

From the Mr.Cool website -
Excess linesets in your MRCOOL system do not need to be placed directly behind the condenser. They can be positioned in various locations—behind the unit, mid-run, or elsewhere—depending on your installation setup. However, if the lineset is coiled at an elevation higher than the condenser, make sure to coil it horizontally, not vertically, to avoid the formation of oil traps that can affect system performance.

My plan is to coil it inside the 2“ x 6” walls if I go with the Mr. Cool unit. The walls are already insulated with R19 and I’ve removed the new drywall in the area I want to put the lineset. Sound okay?

I want a clean install looking at it from the outside.

 

[mike93lx]

My plan is to coil it inside the 2“ x 6” walls if I go with the Mr. Cool unit. The walls are already insulated with R19 and I’ve removed the new drywall in the area I want to put the lineset. Sound okay?

I want a clean install looking at it from the outside.

You won't get it between studs, at least in my experience the lineset won't coil that tightly

 

[bluedog225]

And coiling too tightly may kink it. No bueno.

You could always frame out a box for it. With a header etc. Like a window. Just not a window.

 

[Mikes61]

You won't get it between studs, at least in my experience the lineset won't coil that tightly

Okay that’s good to know. I don’t want 7ish ft. of lineset coiled up on the inside of my drywall or on the outside of my stucco. Even with the plastic housing they sell to hide it. Its new construction so I want to do it right.

Looks like I’m paying my HVAC friend to do the install.

Any other ideas guys?

 

[dscheidt]

Any other ideas guys?

The cost difference between a Mr cool and the equivalent unit with a lineset you can cut is more than the cost of the tools required to install it.

edit: words, don't forget them

 

[WildBill]

You can potentially coil it horizontally under the outside unit to hide it, its only going to be a couple of loops. Or flat in a single U shape in a stud bay in the ceiling area above the inside unit, I've done that a couple times to take up an extra couple of feet. By the time you route it through the walls etc. you probably won't have a lot left over. I am always surprised by how 3-4 ft seems to disappear when installing these.

 

[aggie113]

I ordered a TOSOT (rebranded GREE) that came with a 16ft lineset, I swapped it for a 25ft lineset and was advised that for optimal performance I would need to have 60 grams of refrigerant added as the lineset is empty and the refrigerant is stored in the compressor unit. Of course you could also cut and reflair the lines if you wanted something other than 16 or 25 feet.

 

[bluedog225]

Gree or some rebranded Gree seems to be a solid choice.

 

[fitter30]

Most minis want a minimum line set of 10' check with install manual. That minimum length is to minimize noise and vibrations. Line loops to shorten length should be in the horizontal plane for proper oil return. Minimum loop diameter should also be in the manual.

 

[bluedog225]

Do you guys get the energy star certified units and apply for the tax credits? Is that ongoing or is there some September deadline. Thanks.

edit-shoot. I got my mini split threads mixed up.

Mini split choice

I got a quote for two 24k mini splits for my 2260 sq ft shop in Oregon. They quoted two different units and I'm trying to decide which to go with. Daikin 22.0 SEER2, 12.0 EER2, 10.0 HSPF2 R-454B RXM24WVJU9 and FTXM24WVJU9 For $600 more: Mitsubishi 23.5 SEER2, 13.35 EER2, 10.5 HSPF2 R-454B...

www.garagejournal.com

 

[racecougar]

Any other ideas guys?

Buy the mini split of your choice, buy a line set, and cut/flare at the appropriate length. It is not at all difficult to do. A cheap eccentric flaring tool does the job. https://www.amazon.com/dp/B01CR4VC4E?tag=atomicindus08-20

 

[pcmeiners]

Do you guys get the energy star certified units and apply for the tax credits? Is that ongoing or is there some September deadline. Thanks.

Not many of us at GJ like to throw money away, so yes . Dec 31 2025 is the deadline unless it get extended (unlikely).

My (5) DIY minisplits installs saved $5000 via the Fed tax break and I think it was $2200 from my utility rebate, that was over 2 years.

 

[bluedog225]

I need to place the order now and go ahead and install if I’m going to make year end.

What’ a good place to order? The very cheap eBay units don‘t quality for the credit.

Thanks

 

[mike93lx]

I bought a mini years ago from Sylvane. No idea if they are still competitive

I'd check pricing at supplyhouse

 

[inphx]

I need to place the order now and go ahead and install if I’m going to make year end.

What’ a good place to order? The very cheap eBay units don‘t quality for the credit.

Thanks

I have had good experience with https://www.acwholesalers.com/ on a handful of purchases

 

[bluedog225]

Just fyi.

This is from AI. Though I only trust it about 75% with lists like this.

Federal Tax Credit (25C) Requirements for Ductless Mini-Split Heat Pumps in 2025

Must be installed in a U.S. primary residence (some secondary residences may qualify; rental-only properties do not).

• Must be placed in service by December 31, 2025.
• Must be an air-source heat pump (ductless mini-splits included).
• Must be recognized as ENERGY STAR Most Efficient 2025.
• Installation costs and equipment costs both qualify.
• Credit equals 30% of total cost, capped at $2,000 per year for heat pumps.
• A Qualified Manufacturer (QM) PIN must be provided on IRS Form 5695 when filing.
• Taxpayer must retain manufacturer certification and purchase/installation receipts for IRS records.
• Credit is nonrefundable (reduces tax liability only, no refund beyond owed taxes).
• Cannot be combined with the same year’s claim for another 25C heat pump beyond the $2,000 cap.

 

[manwithtools]

Go here to confirm your model qualifies:

Tax Credit Eligible ENERGY STAR Certified Air-Source Heat Pumps

And to the OP, the lines can be shortened. Mitsubishi for example has a 16' minimum. Others may have different specs. You can use a tube bender to make a series of vertical Z-bends in your stud cavity for the lines. That's the plan for me, but I have a pole building, so 8' between posts to make the bends.

 

[Highbeam]

The allowed minimum bend radius is quite small so you can easily fit between studs. Most installs have a 90 degree bend right after the lineset goes through the wall that uses this tight radius. Heck yes, be careful about kinks.

 

[ekk33]

Flare your own and add these to be sure of no leaks

FlareSeal - Leak-Free HVAC Flare Connections for Mini Splits & Refrigeration

Prevent refrigerant leaks with FlareSeal - the permanent, serviceable flare connection solution for HVAC mini splits, refrigeration systems, and more. Easy clip-on installation.

www.flareseal.com

 

[KenC]

Flare your own and add these to be sure of no leaks

FlareSeal - Leak-Free HVAC Flare Connections for Mini Splits & Refrigeration

Prevent refrigerant leaks with FlareSeal - the permanent, serviceable flare connection solution for HVAC mini splits, refrigeration systems, and more. Easy clip-on installation.

www.flareseal.com

I'll second that, along with some Nyloc or similar magic. Both came with the last one I bought from Parker-Davis, Pioneer brand.
They are what appears to be a hardened copper with tiny concentric rings stamped into them to seal against the flare and fitting.

So far, so good. And I don't even have a newer flare tool, just the old rigid bar and tool, but really high quality, not a HF version.