# Mini Split Installation in Bethany, OR

> Mini split installation in Bethany: third-floor bonus rooms and offices the central air can't cool, an honest duct check first, and Washington County permits.

URL: https://firlandsportlandminisplits.com/service-areas/bethany/

Service area, Oregon

Mini split installation in Bethany: third-floor bonus rooms and offices the central air can't cool, an honest duct check first, and Washington County permits.

(971) 458-4515

Last Updated: November 12, 2026

58.4%

of Bethany homes were built in 2000 or later (U.S. Census Bureau, ACS 5-year)

65.9%

of Bethany homes heat with natural gas (ACS 5-year)

Permits

Washington County Building Services

Electric utility

PGE

## Rooms that need help in Bethany

### A newer house with one hot room

Central air cools most of the house, but a third-floor bonus room or an office over the garage stays warmer than the rest.

### Tall, narrow houses on small lots

Side yards of a few feet and a neighbor's window across them leave few good spots for an outdoor unit.

### Unincorporated, not Portland or Beaverton

Bethany is unincorporated Washington County. The county, not a city, issues and inspects the permits.

## The one room the central air misses

A newer Bethany house with central air can still have a bonus room, top floor or office that never stays as cool as the rest.

Bethany is one of the newest communities on the west side: well over half its homes were built since 2000. [Firlands Portland Mini Splits](https://firlandsportlandminisplits.com/) works with those houses differently from older ones.

### A different question

The question isn’t how to heat a house with no ducts; it’s why one room won’t follow the thermostat, and whether a head or a duct fix is the answer.

### Why the top room runs hot

A third-floor or over-garage room has more roof and outside wall per square foot than any other room. It gets the afternoon sun, the heat that rises from below, and a supply duct sized as an afterthought. The thermostat sits in the hall downstairs and never sees it.

Project

## What a third-floor bonus room fix in Bethany looks like

### The problem

The third-floor bonus room is the warmest room in the house from June on, and the central air can't pull it down without freezing the floors below. It doubles as a home office, so it is in use all afternoon.

### The house

The house is narrow and tall on a small lot, with side yards about five feet wide. The bonus room has outside walls on the front and one side, but the side wall faces the neighbor's house five feet away.

### What we decide, and why

Before anything else, we check the ducts: the room has one supply and the return is in the hall below, so a damper change helps only a little. One 12,000 BTU head goes on the inside wall facing the windows, where it throws air across the room. That wall doesn't reach outside, so the condensate runs to a small pump hidden in the line cover.

### The work

We run 42 feet of line set from the head through the attic space beside the room and down a cover on the back corner of the house to a ground stand on the back patio edge. The pump sits in the cover just below the head, wired from the same circuit, and discharges to the downspout. The 20-amp circuit comes from the garage panel two floors down. Nitrogen test, vacuum below 500 microns, and the drain and pump tested with water.

The back corner keeps the cover off the street-facing wall, and the outdoor unit faces the yard rather than the neighbor's bedroom window across the five-foot side yard.

### What it changes

The office stays at the set temperature on July afternoons, and the central air goes back to serving the floors it was built for.

Location

North Bethany

House

2014 three-story, about 2,400 square feet, gas furnace with central air

Equipment

One 12,000 BTU cold-climate wall head with a condensate pump

Price

$9,140, permits included

Time on site

1 day, then the final inspections

## Try the ducts first, then add a head

We look at the ducts before we quote a head, because sometimes a simple duct fix solves the room without a head.

| What we find | What it means | Usual answer |
| --- | --- | --- |
| A closed or half-shut damper | The room is starved by a setting | Open and rebalance it |
| A crushed or disconnected run in the attic | Air is leaking before it arrives | Repair the run |
| One small supply and no return | Air can’t move through the room | A head, or a new return |
| Three outside walls, under the roof | The load is bigger than the duct | A head |

If a duct fix covers it, we tell you, and we don’t sell a head. When it doesn’t, a [single-zone mini split](https://firlandsportlandminisplits.com/single-zone-mini-split-installation/) takes over the room on its own schedule while the central system keeps the rest.

## Where the head and outdoor unit go in a newer house

On tall, narrow Bethany houses the hard part is the outside: small lots, short side yards and close neighbors.

- **The head.** On the wall that throws air across the room, often an inside wall. That wall can’t drain by gravity, so the head gets a small condensate pump hidden in the cover. The [condensate drain guide](https://firlandsportlandminisplits.com/guide/mini-split-condensate-drain/) covers both options.
- **The line route.** Through the attic or eave space to a back corner, so one cover runs down the back of the house instead of the street side.
- **The outdoor unit.** On the patio edge or a back-yard stand, facing your yard rather than a neighbor’s bedroom window across a narrow side yard.
- **The ceiling option.** Where the room has attic above it, a [ceiling cassette](https://firlandsportlandminisplits.com/ceiling-cassette-mini-split-installation/) keeps the wall clear. [Cassette vs wall mount](https://firlandsportlandminisplits.com/guide/mini-split-cassette-vs-wall-mount/) compares them.

[Mini split placement](https://firlandsportlandminisplits.com/guide/mini-split-placement/) covers clearances in detail.

### Homeowners associations

If your subdivision has an association, its rules may cover what’s visible from the street. We give you a sketch with the outdoor unit’s location and the cover color to send them before we schedule, so nothing has to move later.

## Washington County permits north of Highway 26

Bethany isn’t part of Portland, Beaverton or Hillsboro. It’s unincorporated Washington County, and the county issues the permits.

A Bethany home may have a Portland mailing address; the permit office follows the land, not the mail.

### How the county permits work

The county takes mechanical and electrical permit applications through its online portal, and county inspectors do the inspections. We apply for both, book them and close the job out with the final, with the fees in your price. [Mini split permits](https://firlandsportlandminisplits.com/guide/mini-split-permit-portland/) explains what the inspector checks.

## What a Bethany job costs

Firlands’ typical range for a standard single head is $4,000 to $8,500; the third floor usually pushes a job higher.

### Why the top floor costs more

A third-floor room means a longer line set to the ground, often a condensate pump, and sometimes a lift for the cover. Harder single-zone jobs run $8,500 to $12,000 and up, and a pump on its own typically adds $150 to $500.

### Two rooms on one floor

When the bonus room and a bedroom on the same floor both run hot, one outdoor unit can serve both. Two heads on one outdoor unit run $6,500 to $12,000 when a second room, such as a bedroom on the same floor, needs help too.

Sizing the outdoor unit for both at the start costs less than adding a second system later, and it keeps the yard to one unit.

### Incentives

Bethany is on PGE, and two-thirds of its homes heat with gas. Energy Trust of Oregon’s ductless incentive only applies when the new system replaces electric resistance heat in the main living space, so a head added to a gas-heated house doesn’t qualify. [Mini split installation cost](https://firlandsportlandminisplits.com/guide/mini-split-installation-cost-portland/) has the rest of the breakdown.

## Window unit or mini split for a Bethany bonus room?

A window unit is cheaper up front; a head heats as well as cools, runs quieter, and leaves the window free.

Third-floor rooms in newer houses often have small or high windows that make a window unit awkward, and some associations limit units visible from the street. A head also heats the room on its own in spring and fall, so the furnace doesn’t run for the whole house to warm one office. [Mini split vs window AC](https://firlandsportlandminisplits.com/guide/mini-split-vs-window-ac/) compares running costs.

## Rooms over the garage and backyard units

Two other spaces in Bethany houses are worth planning for: the room over the garage, and a finished garage or backyard unit.

- **Room over the garage.** Cold floors in winter and heat in summer, because the garage below is unconditioned. A head sized for the floor’s heat loss fixes both.
- **Converted garage or studio.** A [garage mini split](https://firlandsportlandminisplits.com/garage-mini-split-installation/) heats and cools it without touching the house system.
- **A backyard unit.** An [ADU mini split](https://firlandsportlandminisplits.com/adu-mini-split-installation/) gives it its own heat and cooling.

## North Bethany to Rock Creek

Bethany runs from the Sunset Highway north toward the farmland past Kaiser and Springville roads, and the houses get newer as you go north.

- **Around Bethany Village and Bethany Boulevard.** Houses from the 1990s and 2000s, with central air that’s due for a look, and bonus rooms over garages.
- **Rock Creek and the West Union Road area.** Similar ages, larger lots in places, and more room for an outdoor unit.
- **North Bethany.** The newest streets. Where a lot is small and the side yards are narrow, siting the outdoor unit takes the most care.

## Services in Bethany

- [Service**Single-zone installation** Single zone mini split installation: one indoor head and one outdoor unit for the room the furnace never reaches, sized to that room.](https://firlandsportlandminisplits.com/single-zone-mini-split-installation/)
- [Service**Garage and workshop** Garage mini split installation for a workshop, home gym or studio, sized for the insulation the building really has.](https://firlandsportlandminisplits.com/garage-mini-split-installation/)
- [Service**Ceiling cassette** Ceiling cassette mini split installation for rooms with no wall to spare: open kitchens, window walls and remodels.](https://firlandsportlandminisplits.com/ceiling-cassette-mini-split-installation/)
- [Service**Concealed ducted** Ducted mini split installation: a slim air handler hidden in the attic or knee wall, feeding two or three rooms through small grilles.](https://firlandsportlandminisplits.com/ducted-mini-split-installation/)
- [Service**ADUs and additions** A mini split for an ADU, an addition or a sunroom, planned with the build instead of after it.](https://firlandsportlandminisplits.com/adu-mini-split-installation/)

## How a job usually runs in Bethany

### The call

You tell us the rooms and send a few photos; we give a rough range.

### The visit

We measure each room, look at the walls, the panel and where the outdoor unit can go.

### The estimate

A written estimate: each head, the line-set route, drains, circuit, permits and price.

### Install and handover

Pressure test, vacuum, startup, a walk-through, and the permits closed out.

## Neighborhoods, landmarks and routes

- North Bethany
- Bethany Village
- Rock Creek
- Kaiser Road area
- Springville Road area
- West Union Road area
- Bethany Boulevard corridor

### Landmarks

- Bethany Presbyterian Church
- Cedar Mill Community Library at Bethany
- Rock Creek Trail
- Bethany Village Centre
- Highway 26 at Bethany Boulevard

### Getting around

- Highway 26 (Sunset Highway) along the south edge
- Bethany Boulevard north-south
- Kaiser Road
- Springville Road
- West Union Road

[Open Bethany, Oregon in Google Maps](https://www.google.com/maps/search/?api=1&query=Bethany%2C%20Oregon)

## Bethany: questions

### What does a one-room mini split cost in Bethany?

Firlands' typical range for a standard single head is $4,000 to $8,500. A third-floor room with a long line run or a condensate pump runs $8,500 to $12,000 and up. Washington County permit fees are included, and the written estimate after the visit sets your price.

### Should I fix my ducts before adding a mini split in a newer Bethany house?

We check them first. If a room has a closed damper, a crushed run or no return, a fix can help. If it has three outside walls or sits under the roof, ducts sized for the rest of the house won't carry it, and a head will.

### Who issues the permit for a mini split in Bethany?

Washington County Building Services, because Bethany is unincorporated. The county takes mechanical and electrical applications through its online portal. We file both, book the inspections and close them out with the final.

### Will my HOA in Bethany allow an outdoor unit?

Rules vary by association, and some cover what can be seen from the street. We plan the unit for a back or side yard and give you a sketch with its spot and the cover color to submit before we schedule the work.

### Is there a rebate for adding a mini split to a gas-heated Bethany house?

Energy Trust of Oregon's ductless incentive needs the new system to replace electric resistance heat in the main living space, so a head added to a gas-heated house doesn't qualify. Bethany is on PGE, so an electrically heated home can qualify.

## Nearby service areas

- [Oregon**Oak Hills** Mini split installation in Oak Hills: cooling post-and-beam houses with radiant floors and no attic, lines kept off exposed beams, Washington County permits.](https://firlandsportlandminisplits.com/service-areas/oak-hills/)
- [Oregon**Cedar Mill** Mini split installation in Cedar Mill: cooling for gas-heated houses with no central air, outdoor units sited under tall firs, and Washington County permits.](https://firlandsportlandminisplits.com/service-areas/cedar-mill/)
- [Oregon**Aloha** Mini split installation in Aloha: 1970s split-levels and ranches, a head on each level, Washington County permits and Energy Trust incentives. Typical ranges.](https://firlandsportlandminisplits.com/service-areas/aloha/)

## Guides for houses in Bethany

- [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/)
- [Learn**Where should a mini split go?** Head placement inside, the outdoor unit outside, and the Portland rules and weather that decide both.](https://firlandsportlandminisplits.com/guide/mini-split-placement/)
- [Decision Guide**Window AC vs mini split: which is right for your room?** A summer stopgap or a permanent system that also heats. What each one does to the room, the bill and the window.](https://firlandsportlandminisplits.com/guide/mini-split-vs-window-ac/)
- [Decision Guide**Should you get a ceiling cassette or a wall-mounted mini split?** The four kinds of indoor unit, what each needs from the house, and which rooms suit which.](https://firlandsportlandminisplits.com/guide/mini-split-cassette-vs-wall-mount/)

## Get an estimate in Bethany

Tell us which rooms aren't working and where the house is in Bethany.

(971) 458-4515