# Mini Split Installation in Sherwood, Oregon

> Mini split installation in Sherwood, Oregon: converted garages, bonus rooms and offices in 1990s and 2000s houses, with city and county permits.

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

Service area, Oregon

Mini split installation in Sherwood, Oregon: converted garages, bonus rooms and offices in 1990s and 2000s houses, with city and county permits.

(971) 458-4515

Last Updated: November 12, 2026

67.6%

of Sherwood homes were built in the 1990s and 2000s (U.S. Census Bureau, ACS 5-year)

66.0%

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

Permits

City of Sherwood (mechanical); Washington County (electrical)

Electric utility

PGE

## Rooms that need help in Sherwood

### A garage turned into a room

A gym, office or studio in the garage was never on the furnace ducts. It stays near outdoor temperature in winter.

### A furnace that's 25 years old

Houses built in the 1990s are reaching the age where the original furnace and air conditioner come due together.

### Two offices for one install

The City of Sherwood issues the mechanical permit; Washington County handles every electrical permit inside the city.

## The room the furnace never reached

If your Sherwood house is comfortable everywhere except a converted garage, a bonus room or an office the ducts were never planned for, a mini split fixes that one room.

Sherwood grew fast in the 1990s and 2000s: about two-thirds of its homes date from those two decades, and two-thirds heat with gas. [Firlands Portland Mini Splits](https://firlandsportlandminisplits.com/) adds heat and cooling to the rooms those houses left out, without reworking a furnace that’s doing fine everywhere else.

### Why one room gets left out

A furnace and its ducts are sized for the house as it was built. A garage that becomes a gym, an office over it, or a finished attic adds load the system was never designed for. A head gives that room its own heat and cooling.

Project

## What a Sherwood garage conversion mini split looks like

### The problem

Half of the garage is now a home gym and office, and it is near outdoor temperature in January and stuffy in August. The furnace ducts never reached it, and a space heater can't keep up.

### The house

The garage has an insulated ceiling but bare concrete and an insulated roll-up door on the remaining half. The panel is on the garage wall itself, and the side yard is narrow but clear.

### What we decide, and why

One 12,000 BTU cold-climate head on the back wall, sized for the slab and the door, heats and cools the converted half. Extending a furnace duct is the other option, but it overloads a furnace sized before the garage was living space.

### The work

The head sits on the back wall with a 15-foot line set straight out to a wall bracket on the side yard, high enough to clear the trash bins. The circuit is a short run from the panel on the same wall. Nitrogen test, vacuum below 500 microns, and the drain falls through the wall to a splash block.

The bracket keeps the unit off the narrow side path and above the splash line, and the short run keeps the price at the low end of the range.

### What it changes

The gym and office are usable through the year, and the furnace keeps serving the house it was sized for.

Location

Sherwood, south of Sunset Boulevard

House

1998 two-story with a converted two-car garage, gas furnace

Equipment

One 12,000 BTU cold-climate wall head, wall-bracket outdoor unit

Price

$5,980, permits included

Time on site

1 day, then the final inspections

## Heating and cooling a converted garage

A converted garage needs a head sized for its slab, its door and its outside walls, and an outdoor unit that stays clear of the driveway and the side path.

- **Size for the slab and door.** Bare concrete and a roll-up door lose heat faster than a framed wall. We size the head from that, not the floor area alone.
- **A short line run.** Where the panel is on a garage wall and the outside wall is right there, the price stays down.
- **A wall bracket or a pad.** In a narrow side yard, a bracket keeps the unit off the path and above the trash bins.
- **Drain to the outside.** The head on an outside wall drains by gravity through the same hole.

[Garage mini split installation](https://firlandsportlandminisplits.com/garage-mini-split-installation/) covers insulation and door details in more depth.

### Why not extend a furnace duct?

A furnace sized before the garage became living space usually can’t carry the extra room, and a duct through the garage wall needs fire-rated details. A head avoids both.

## Insulate first, then size the head

What the garage conversion did to the walls, ceiling and door decides the head size more than anything else.

A garage with insulated walls, an insulated ceiling and a weather-sealed door might need 9,000 BTU. The same room with bare stud walls and an uninsulated roll-up door can need 15,000 or more, and it still feels cold at floor level.

### Our advice on the visit

On the visit we look at what’s insulated and tell you if adding insulation first would let a smaller head do the job. When it is the cheaper path, the head then runs quieter and less often.

## A one-day garage install

A single head on a garage wall with the panel nearby is usually one day on site, then two sets of inspections.

1. **Morning.** Mount the head, core the wall, and set the bracket or pad outside.
2. **Midday.** Run the short line set, the control cable and the drain, and wire the new 240-volt circuit from the panel.
3. **Afternoon.** Nitrogen pressure test, a vacuum held below 500 microns, refrigerant released, drain tested with water, and the test readings handed to you on paper.
4. **Later.** The city’s mechanical and the county’s electrical inspections, which we book and close out.

## Permits: Sherwood and Washington County

A Sherwood install takes two permits from two offices: the city for mechanical, the county for electrical.

| Permit | Who issues it | How it’s filed |
| --- | --- | --- |
| Mechanical (heat pump, line set) | City of Sherwood Building Department | Oregon’s ePermitting system |
| Electrical (new circuit, disconnect) | Washington County | The county’s online portal |

The city’s building page says plainly that electrical work inside Sherwood is permitted and inspected by Washington County. We file both, schedule both inspections and close them out with both finals. The fees are in your price. [Mini split electrical requirements](https://firlandsportlandminisplits.com/guide/mini-split-electrical-requirements/) covers what the electrical inspector looks for.

## When the original furnace and AC come due

Houses built in the 1990s are reaching the age where the original furnace and air conditioner both need replacing, and that’s a bigger decision than one room.

| Situation | What usually fits |
| --- | --- |
| Ducts sound, the whole house needs heat and cooling | A central heat pump on the existing ducts |
| A few rooms are the real problem | Heads in those rooms; the old system runs a few more years |
| Upstairs too hot, main floor fine | Two or three heads upstairs on one outdoor unit |

[Mini split vs central heat pump](https://firlandsportlandminisplits.com/guide/mini-split-vs-central-heat-pump/) compares the bigger options, and [single zone vs multi zone](https://firlandsportlandminisplits.com/guide/single-zone-vs-multi-zone-mini-split/) helps when it’s several rooms.

## What it costs in Sherwood

Firlands’ typical range for a standard single head is $4,000 to $8,500, and a converted garage with a short run sits toward the low end.

Two heads on one outdoor unit run $6,500 to $12,000, and three or four heads $9,000 to $18,000 and up. Heating and cooling a backyard studio or ADU typically runs $5,000 to $12,000 and up; [ADU mini split installation](https://firlandsportlandminisplits.com/adu-mini-split-installation/) covers those. [Mini split installation cost](https://firlandsportlandminisplits.com/guide/mini-split-installation-cost-portland/) has the full breakdown.

### Incentives

Sherwood is PGE territory. Energy Trust of Oregon’s ductless incentive applies only when the system replaces electric resistance heat in the main living space, so a garage or bonus-room head in a gas-heated house doesn’t qualify.

## Bonus rooms and upstairs offices

A bonus room over the garage is the other space worth planning for: it runs hot in summer and cold over the unheated space below.

A [single-zone head](https://firlandsportlandminisplits.com/single-zone-mini-split-installation/) sized for the floor’s heat loss and the roof above fixes both. Where a second room on the same floor needs help, a [two-head system](https://firlandsportlandminisplits.com/multi-zone-mini-split-installation/) covers both from one outdoor unit. If an older ductless unit is already there and failing, [mini split replacement](https://firlandsportlandminisplits.com/mini-split-replacement/) explains how we decide whether the lines can be reused.

## Old Town to the newer edges

Sherwood runs from Old Town out to the newer subdivisions on its edges.

- **Old Town.** Older houses on smaller lots, where the outdoor unit spot and a short line run take the most planning.
- **The 1990s and 2000s subdivisions.** Two-story houses with gas heat: garages, bonus rooms and the eventual furnace replacement.
- **The newest streets.** Modern ducted systems, where a head goes in for a space finished after the house was built.

## Services in Sherwood

- [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**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**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/)
- [Service**Multi-zone installation** Multi zone mini split installation: two to five rooms on one outdoor unit, each head sized to its own room and set to its own temperature.](https://firlandsportlandminisplits.com/multi-zone-mini-split-installation/)
- [Service**Replacement** Mini split replacement for an aging or failed system, reusing the line set and circuit only when they pass the test.](https://firlandsportlandminisplits.com/mini-split-replacement/)

## How a job usually runs in Sherwood

### 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

- Old Town Sherwood
- Woodhaven
- Sunset Boulevard area
- Murdock Road area
- Edy Road area
- Sherwood West edge
- Brookman area

### Landmarks

- Old Town Sherwood
- Tualatin River National Wildlife Refuge
- Stella Olsen Park
- Sherwood Center for the Arts
- Snyder Park

### Getting around

- Pacific Highway (99W) along the north side
- Tualatin-Sherwood Road
- Roy Rogers Road
- Sunset Boulevard
- Sherwood Boulevard

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

## Sherwood: questions

### What does a garage or bonus-room mini split cost in Sherwood?

Firlands' typical range for a standard single head is $4,000 to $8,500, and a converted garage with a short line run sits toward the low end. Two heads on one outdoor unit run $6,500 to $12,000. Permit fees are included, and the written estimate sets your price.

### What permits does a Sherwood mini split need?

A mechanical permit from the City of Sherwood's Building Department, applied for through the state's ePermitting system, and an electrical permit from Washington County, which permits and inspects all electrical work inside the city. We file both and book the inspections.

### Can I run a furnace duct to my converted garage in Sherwood instead?

Sometimes, but a furnace sized for the house before the garage became living space usually can't carry the extra room, and a garage duct needs fire-rated details. A head heats and cools the garage on its own, without touching the furnace.

### My Sherwood furnace and AC are both old. Mini split or central heat pump?

If the ducts are sound and the whole house needs it, a central heat pump on the ducts is usually the simpler replacement. If only a few rooms are the problem, heads in those rooms can buy the old system a few more years. We lay out both.

### Is there an Energy Trust incentive for a Sherwood garage mini split?

Not usually. Energy Trust of Oregon's ductless offer requires the system to replace electric resistance heat in the main living space, and a garage isn't the main living space. A Sherwood house heated with baseboards can qualify when the heads go in the main rooms.

## Nearby service areas

- [Oregon**Tualatin** Mini split installation in Tualatin: electric furnace and baseboard houses, ductless versus ducted heat pumps, and the city and county permit split explained.](https://firlandsportlandminisplits.com/service-areas/tualatin/)
- [Oregon**Tigard** Mini split installation in Tigard: cooling for hot upstairs rooms in gas-heated houses, Bull Mountain slopes, City of Tigard permits and typical price ranges.](https://firlandsportlandminisplits.com/service-areas/tigard/)
- [Oregon**Wilsonville** Mini split installation in Wilsonville for townhomes, condos and single-level homes on electric heat, with city mechanical and county electrical permits.](https://firlandsportlandminisplits.com/service-areas/wilsonville/)

## Guides for houses in Sherwood

- [Decision Guide**Mini split vs central heat pump: which fits a Portland house?** It comes down to your ducts: whether they exist, where they reach, and what shape they're in.](https://firlandsportlandminisplits.com/guide/mini-split-vs-central-heat-pump/)
- [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**What are the electrical requirements for a mini split?** The circuit, the disconnect, the panel and the permit, and what changes in an older Portland house.](https://firlandsportlandminisplits.com/guide/mini-split-electrical-requirements/)
- [Cost Guide**How much does mini split installation cost in Portland?** Typical ranges by job, what moves the number, and the public costs inside it.](https://firlandsportlandminisplits.com/guide/mini-split-installation-cost-portland/)

## Get an estimate in Sherwood

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

(971) 458-4515