# What a Portland multi-zone mini split install looks like, start to finish

> A Portland multi-zone mini split install from the first photos to the final inspection: the visit, the estimate, each day on site, the tests and the handover.

URL: https://firlandsportlandminisplits.com/blog/what-a-portland-multi-zone-install-looks-like/

Blog, Inside a Job

A multi-zone mini split install walkthrough: four rooms, one outdoor unit and an old Portland two-story, from the visit to the handover.

Last Updated: November 12, 2026

The short answer

A typical four-head job in an older Portland two-story takes one visit, a written estimate, a city permit and two to three days on site. The outdoor unit goes in first, then the line sets and drains, then the heads and the circuit, then the pressure test, vacuum and startup.

A multi-zone system puts several indoor heads on one outdoor unit. Here is how [Firlands Portland Mini Splits](https://firlandsportlandminisplits.com/) runs one in a common Portland case: an older two-story, warm upstairs and cool downstairs, with no ducts to the second floor. It follows the job from the first photos to the final inspection.

## A typical Portland multi-zone job

The house is a 1920s two-story with a gas furnace in the basement and no ducts upstairs. Three bedrooms and a stair landing bake in August; the living room downstairs is fine on the furnace.

Old houses like this are common on the east side: more than 40% of Northeast Portland’s homes and more than a third of Southeast’s were built before 1940 (U.S. Census Bureau). The furnace stays. The heads cool the upstairs in summer and take over most of the heating in spring and fall.

## The call and the photos

You send photos of each upstairs room, the panel and the side yard. From those we give a rough range on the phone and book the visit.

Firlands’ typical range for three or four heads on one outdoor unit is $9,000 to $18,000 and up. Where a job lands in that range depends on what the visit finds. The [cost guide](https://firlandsportlandminisplits.com/guide/mini-split-installation-cost-portland/) shows the full set of ranges.

## The visit

We measure each room, note which walls face out, and work out how the line sets get from the second floor to the ground. In an old two-story that’s the question that sets the price.

### What we look at

- **Each room’s size, windows and sun.** The west bedroom under the roof needs a bigger head than the small north one. Heads are sized room by room, not from the house’s square footage. [How many mini splits do I need?](https://firlandsportlandminisplits.com/guide/how-many-mini-splits-do-i-need/) explains the count.
- **The route down.** A closet stacked over a closet makes a hidden chase; otherwise the lines run down the outside wall in a painted cover.
- **The outdoor unit’s spot.** In Portland it can’t sit in the front setback, and in a side yard it stays five feet tall or less. A stand keeps it above ice.
- **The panel.** One new 240-volt circuit feeds the outdoor unit; the heads draw power through it.
- **The paint.** A house built before 1978 gets lead-safe dust containment wherever we open a wall.

## The written estimate

The estimate lists each head and its capacity, the outdoor unit, the line-set routes, how each head drains, the circuit, the permits, the price and what isn’t included.

For this house: three 9,000 BTU heads and one 12,000 BTU head on the west bedroom, a 36,000 BTU cold-climate outdoor unit, two line sets through the closet chase and two down the side wall, two gravity drains and two condensate pumps on the inside-wall heads. [Single or multi-zone](https://firlandsportlandminisplits.com/guide/single-zone-vs-multi-zone-mini-split/) covers the choice behind it.

## Day one: outside

The outdoor unit goes in first, on a stand or bracket where the visit placed it. Then the wall openings: one three-inch hole per head, behind where the head will hang.

Inside, each opening is worked under dust containment, and the floor is covered from the door to the wall. Outside, the line sets go up the wall or into the closet chase, with the drain line and the control cable alongside. The cover goes on and gets painted to match the siding.

## Day two: inside

The heads go up on their wall plates and connect to the line sets. Drains are set to fall to the outside, or to a pump where a head is on an inside wall.

### The drains get tested before anything else

Every drain is tested with water: we pour it into each head’s tray and watch it leave the house. A pump gets its float switch checked too, so a blockage shuts the head off instead of dripping down the wall. The [condensate drain guide](https://firlandsportlandminisplits.com/guide/mini-split-condensate-drain/) explains why this matters in a two-story.

## Day three: the tests and startup

The new circuit is connected at the panel. Then the refrigerant side is proven before anything is released.

| Step | What it proves |
| --- | --- |
| Nitrogen pressure test | Every flare and joint holds without leaking |
| Vacuum held below 500 microns | Air and moisture are out of the lines |
| Refrigerant released, charge checked | The system has what the manual calls for at these line lengths |
| Startup in heat and cool | Each head heats and cools its room |

You get the readings on paper, and we set up each remote with you. Then we walk the house together: heads, drains, line covers, the outdoor unit and the panel.

## After the install

The job closes when the City of Portland’s final inspection passes. We include the permit fees in the price and schedule the inspection.

This house heats with gas, so Energy Trust’s ductless incentive doesn’t apply; it pays only where the heads replace electric resistance heat. In a house with baseboards, the application is due within 60 days, and the installer signs it with you ([rebates in Oregon](https://firlandsportlandminisplits.com/guide/mini-split-rebates-oregon/)).

### Where to read more

[Multi-zone installation](https://firlandsportlandminisplits.com/multi-zone-mini-split-installation/) covers the service in full, and the [installation process guide](https://firlandsportlandminisplits.com/guide/mini-split-installation-process/) has the same steps for a single room. The [Northeast Portland](https://firlandsportlandminisplits.com/service-areas/northeast-portland/) and [Southeast Portland](https://firlandsportlandminisplits.com/service-areas/southeast-portland/) pages cover what changes on each side of town.

## Questions about this post

### Do I need to be home for the whole multi-zone install?

Someone needs to be there at the start of each day to let us in and at the end of the last day for the walk-through. In between, it helps to have the rooms cleared around each head and the path to the panel open.

### Will the power be off during the install?

Only on the last day, and only for the time it takes to connect the new circuit at the panel, usually well under an hour. The rest of the house runs normally while the outdoor unit, lines and heads go in.

### What do I get at the end of a multi-zone job?

A system that's been pressure-tested, evacuated and started, every drain tested with water, the test readings on paper, the remotes set up with you, and the city permit closed with the final inspection.

## Keep reading

- [Decision Guide**Single zone vs multi zone mini split: which should you choose?** One outdoor unit per room, or one outdoor unit for several rooms, and why the answer isn't always the cheaper one.](https://firlandsportlandminisplits.com/guide/single-zone-vs-multi-zone-mini-split/)
- [Learn**How many mini splits do I need?** Count the rooms you close a door on, not the square feet. Then group the heads onto outdoor units.](https://firlandsportlandminisplits.com/guide/how-many-mini-splits-do-i-need/)
- [Learn**What happens during a mini split installation?** The mini split installation process, every step from the first call to the city's final inspection, and what you get at the end.](https://firlandsportlandminisplits.com/guide/mini-split-installation-process/)
- [Learn**How does a mini split condensate drain work?** Where the water goes, gravity or pump, and the common reasons a head starts to drip.](https://firlandsportlandminisplits.com/guide/mini-split-condensate-drain/)
- [Seasonal**How do you get a mini split in before a Portland summer?** Plan in spring, not during the first heat wave: what each step needs and what you can settle now.](https://firlandsportlandminisplits.com/blog/getting-a-mini-split-in-before-portland-summer/)

## Get an estimate for your house

(971) 458-4515