Do I Need A Permit To Install A Mini Split?

You would think it’s such a little thing, they do call it a mini split cause it’s small, right? Why would I need to fork over most of a hundred dollars to a local government to have a ductless heating and cooling unit installed? As you can see on the image above, in my county it’s on the list.

Do I need a permit is question number 24 in the 30 questions you need to know about and ask when buying new HVAC equipment.

I’ve contracted in more than half a dozen counties and belonged to a nation wide contractors group where we talk a lot about permit stuff and I’ve never heard of a county that didn’t require getting a permit for installing any HVAC equipment.

If you know a county that doesn’t require permits for HVAC then comment below, I may move there.

The total cost in my county in Oregon is now about $80 less some change. It’s a good idea to know what your local permitting agency requires. It varies from county to county. Just call them.

Local building jurisdictions will say that permits are required for installation of a mini split. Why? They say for public safety. It’s true that there are scabs that will take advantage of home owners. Permitting agencies require contractors to have licenses and licenses require continuing education.

If you choose to not obtain a permit to install a mini split it could have repercussions when it comes time to sell your home. If you are asked if there was any work done on the home that was not permitted you need to be honest.

And when you get a permit then the inspectors will come to look and see all the other stuff I have done or need to do. What then?

I remember on the closing paperwork on a house we sold, it asked specifically if we had any work done without a permit when it was required. It falls on the home owner to know and take responsibility even when a contractor doesn’t.

So what’s so dangerous about installing a ductless HVAC unit that it requires a permit and an inspection?

Am I going to get electrocuted switching it on or off via the remote control? Is the unit going to explode if I don’t get a permit?

I have noticed that inspectors that check out my jobs, they don’t know a lot of details about my industry, but they know to look for certain items such as:

  1. Did i seal up any holes
  2. Did I hang any piping or duct every four feet
  3. Did I use grommets in holes for thermostat wires
  4. Is the correct breaker or fuse installed
  5. Did I seal any duct work related to my work

Overall I would say that these inspections take no more than 10 minutes. A lot of times even less. Sometimes you feel it’s just a revenue game. But, there is an element of trust involved.

After some time, even years, these inspectors begin to know the type of work that some contractors do. I’ve had them show up and hardly glance at the job. Just knowing the reputation of the contractor is enough for some inspectors to sign off on a job. Not saying that that’s the right thing to do. Just that it happens.

One time I missed completing a short section of duct that I was moving to another location on the plenum to gain more air flow. The inspector caught it and called me to make sure I would complete the duct. He signed off on the job with the duct incomplete. I got right on it and sent him a picture of the completed duct. We just built a little more trust.

What’s The Code For Installing A Mini Split?

I can only write about codes in general because they vary for different parts of the country and the world actually. But here are a few things that stand out universally.

Most inspectors will default to the manufacturers installation instructions. Clearances are a big deal. With ductless heat pumps and air conditioners both the indoor and the outdoor units have specific clearances to walls and objects that may interfere with the operation of the equipment.

It’s all written in the paperwork that comes with each unit.

Theirs a minimum and maximum length of refrigeration tubing. Most manufacturers have the maximum length in an easy to find manner but that minimum length is something I’ve had to call tech support more that once to find the answer.

Some are 10 foot minimum or even 11 feet. It’s an important issue as it could prevent you from validating a warranty. Inspectors will never catch this type of limitation, but you should.

It’s easy to install an outdoor unit with the indoor unit right on the other side of the wall and think you’re saving copper with a 5′ refrigeration line and come to find out it doesn’t run properly because the line set is too short.

Breakers and wire size are another easy item for inspectors to look for and scrutinize. Most of the mini splits I’ve recently installed have been 15K BTU units and my electrician has been running a number 12 wire with a 20 AMP breaker.

So inspectors have they’re niche items they look for and cruse through the jobs making sure they are keeping the public safe. It’s a good idea by the looks of some of the jobs I’ve seen.

Drain lines are another pet peeve of most inspections. Got to have a quarter inch fall per foot or your gonna back up the condensation in the pan and it’s gonna run down the wall and soak the floor.


Even if your having a professional install your ductless mini split and you pulled all the proper permits it never hurt to read through the installation instructions. They aren’t very hard to absorb.

Scan the highlights and read thoroughly what you remember from this article. You could save yourself from being one of those customers that thought they got a lemon.

Chad Peterson

Chad Peterson is a veteran of the HVAC industry since 1977. "I like to explain heating and air conditioning problems in a way the average home owner can understand. "

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