# Whole House Mini Split Installation in Portland, OR

> Whole house mini split installation in Portland: every room zoned, cold-climate outdoor units, a backup heat plan and both city permits. From $15,000.

URL: https://firlandsportlandminisplits.com/whole-house-mini-split/

Service

Whole house mini split installation: every room heated and cooled by ductless heads, planned as one system with a winter backup plan.

(971) 458-4515

Last Updated: November 12, 2026

Room by room

Each head sized to its room, not to the square footage

Tested

Nitrogen pressure test and a deep vacuum on every line set

Drained

A planned drain or pump for every head, tested with water

Permitted

Mechanical and electrical permits on every install

Baseboards in every room, an oil furnace near the end of its life, or a house that has never had cooling. You want one system for the whole place, not a head here and a window unit there.

A whole-house mini split heats and cools every room from ductless heads, planned together. [Firlands Portland Mini Splits](https://firlandsportlandminisplits.com/) designs it room by room, chooses outdoor units that keep heating on Portland’s coldest nights, and writes down the backup plan before anything goes on the wall.

## Can mini splits really heat your whole house?

Yes, if every room that closes off gets its own heat and the outdoor units are sized for winter, not just July.

Most whole-house trouble comes from treating the house like one open room. A head in the hall heats the hall; the bedrooms behind closed doors stay cold. Getting it right means:

- a zone for each room or open area, with the closed rooms covered
- a head type that fits each room, not the same wall head everywhere
- outdoor units chosen for their published output at 24°F
- a backup plan in case the equipment needs a repair in winter

[How many mini splits do I need?](https://firlandsportlandminisplits.com/guide/how-many-mini-splits-do-i-need/) goes through the room count.

Project

## What a whole-house job in Lents looks like

### The problem

Every room has a baseboard heater, the winter bills climb every year, and the house has no cooling. The two small back bedrooms bake on summer afternoons.

### The house

The house has a living room, a kitchen and dining area, a family room in an enclosed back porch, a primary bedroom and two small bedrooms off a short hall. It has a vented attic with about three feet of headroom at the center and a crawlspace below. Built before 1978, it gets lead-safe dust containment wherever we drill.

### What we decide, and why

The smallest wall heads are still too big for rooms that size, and they short-cycle. Instead one small ducted unit in the attic feeds both bedrooms through two short insulated ducts and ceiling grilles. Wall heads go in the living room (12,000 BTU), the kitchen and dining area (9,000), the family room (9,000) and the primary bedroom (9,000). Both outdoor units are cold-climate models chosen for their output at 24°F, Portland's design low.

### The work

Two outdoor units on pads along the back of the house, each on its own 240-volt circuit. Taking out eleven baseboard heaters frees the breaker space for both. Line sets run along the eave line in covers, and the ducted unit's line set and drain go through the attic. The ducted unit sits in a secondary drain pan with a float switch that shuts it off if its gravity drain ever backs up. Every line set gets a nitrogen pressure test and a vacuum below 500 microns, one at a time.

The bathroom keeps its small baseboard heater. It's the room where a few minutes of instant heat matters, and it costs little to leave on its own thermostat.

### What it changes

The whole house heats and cools from five zones, the baseboards come off everywhere but the bathroom, and because the heads replace electric resistance heat in the main living space, the owner can apply for Energy Trust's ductless incentive.

Location

Lents, East Portland

House

1950s single-level ranch, about 1,250 square feet, electric baseboard in every room

Equipment

Five indoor units (four wall heads and one small ducted unit) on two cold-climate outdoor units, 24,000 and 30,000 BTU

Price

$26,400, permits included

Time on site

4 days after permits, then the final inspections

## What happens on the first visit

A whole-house visit takes longer than a one-room visit, because we walk every room and the attic and crawlspace too.

We measure each room, note its windows and which way they face, and look at the insulation above and below. We ask which rooms you use, when, and which doors stay shut. Then we sketch a zone plan:

1. **Which rooms share a head.** Open living, dining and kitchen areas often do.
2. **Which rooms need their own.** Bedrooms, a back family room, a west attic room.
3. **Which rooms are too small for a wall head.** Two small bedrooms can share one small ducted unit.
4. **How many outdoor units, and where.** Side or rear yard, under five feet tall, out of the front setback.
5. **What the panel can take.** Removing baseboard heaters usually frees the breaker space.

You get a written estimate listing every indoor unit and its capacity, the outdoor units, the line-set routes, the drains and pumps, the circuits, the permits, the price and what’s not included.

## Getting heat into every room

A ductless head heats the room it’s in; it can’t push air around corners. So the plan covers each closed room on purpose.

### Open areas

A living room open to the kitchen and dining area can run on one head, placed so its air crosses the whole space.

### Bedrooms

A bedroom with the door shut needs its own heat. The smallest wall heads run around 6,000 to 9,000 BTU, which is more than a small bedroom needs, so they cycle on and off. Two small bedrooms side by side often do better on one [small ducted unit](https://firlandsportlandminisplits.com/ducted-mini-split-installation/) with a short duct to each room.

### Bathrooms

Bathrooms are small and need instant heat after a shower. Leaving a small baseboard heater there is often the simplest answer.

### Rooms that never feel even

If one room runs warm and the next one cold, the cause is almost always a head in the wrong place or a room with no head of its own. Uneven rooms are easier to prevent in the design than to fix later. [How to size a mini split](https://firlandsportlandminisplits.com/guide/mini-split-sizing/) shows how each room’s load is worked out.

## Winter: cold-climate units and backup heat

For a house that depends on its mini splits for all its heat, we choose the outdoor units by what they deliver in the cold, not their rating at 47°F.

Portland’s design low is 24°F, and the January 2024 ice storm took the airport down to 15°F. Cold-climate models publish their heating capacity at 5°F and keep a large share of it there. We size from that cold-weather figure for the rooms that need heat.

### Backup heat, planned up front

A cold-climate system rarely needs help, but a failed part in January is another matter. Backup heat is a decision we write into the estimate:

- **Keep one or two small baseboards** in a bathroom or a back room.
- **Split the zones across two outdoor units**, so one failure leaves half the house heated.
- **Place the outdoor units above drifting snow** and out of the roof drip, so ice can’t block the coil.

[Do mini splits work in cold weather?](https://firlandsportlandminisplits.com/guide/do-mini-splits-work-in-cold-weather/) goes into cold-climate ratings in detail.

## What a whole-house system costs

Firlands’ typical range for a whole-house system with five or more heads is **$15,000 to $30,000 and up**, set by the room-by-room load.

| Job | Typical range |
| --- | --- |
| Three or four heads covering the main rooms | $9,000 to $18,000+ |
| Whole house, five or more heads, often two outdoor units | $15,000 to $30,000+ |
| Each additional head on a new system | adds $2,000 to $4,000 |
| A service upgrade if the panel can’t take it | $2,500 to $6,000 |

What moves it: the number of rooms, how many outdoor units, line-set length, ducted units in the attic, pumps, and panel work. Your price comes from the visit and the written estimate, with the city’s permit fees included.

If the house heats with electric baseboards, Energy Trust of Oregon may pay an incentive when the heads replace that heat in the main living space; see [mini split rebates in Oregon](https://firlandsportlandminisplits.com/guide/mini-split-rebates-oregon/). [What will it do to my electric bill?](https://firlandsportlandminisplits.com/guide/mini-split-electric-bill/) covers running cost.

## When whole-house ductless isn’t the right call

Sometimes a smaller job, or a different system, fits the house better.

- **Only the main rooms are the problem.** A [multi-zone system](https://firlandsportlandminisplits.com/multi-zone-mini-split-installation/) on the rooms you use, with baseboards kept elsewhere, costs less.
- **The house has baseboards and a tight budget.** Start with the living space; see [baseboard heat to mini split](https://firlandsportlandminisplits.com/baseboard-heat-to-mini-split/).
- **The house is on oil.** The tank needs a plan too; see [oil heat to mini split](https://firlandsportlandminisplits.com/oil-heat-to-mini-split/).
- **The house has good ducts.** A ducted central heat pump is a different job; [mini split vs central heat pump](https://firlandsportlandminisplits.com/guide/mini-split-vs-central-heat-pump/) sets out the choice.

## What's included

- A room-by-room load and a zone plan for the whole house
- Wall heads, floor consoles or small ducted units, chosen room by room
- One or two cold-climate outdoor units matched to the zones
- Line sets, drains and pumps planned for every indoor unit
- Dedicated 240-volt circuits, often freed up by removing baseboard heaters
- Removal of the baseboard heaters the system replaces
- Pressure tests, deep vacuum, startup and a walk-through of every zone
- Mechanical and electrical permits and the final inspections

## How to heat the whole house

|  | Whole-house ductless | Ductless in the main rooms, baseboard kept elsewhere | Ducted central heat pump |
| --- | --- | --- | --- |
| Best for | Houses with no usable ducts | A tighter budget, or rooms rarely used | Houses with good existing ducts |
| Room-by-room control | Every room | Main rooms only | Usually one or two zones |
| Typical range | $15,000 to $30,000+ | $9,000 to $18,000+ (three or four heads) | A different job, not ours |
| Backup heat | Planned in the design | The baseboards that stay | Usually electric strips in the air handler |

## Related resources

- [Learn**Do mini splits work in cold weather?** Portland's winters are mild with sharp exceptions: freezing rain, an east wind and a few nights in the teens.](https://firlandsportlandminisplits.com/guide/do-mini-splits-work-in-cold-weather/)
- [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**How do you size a mini split for a Portland room?** Mini split sizing in BTUs: design temperatures, the load calculation, and why two rooms the same size can need very different heads.](https://firlandsportlandminisplits.com/guide/mini-split-sizing/)
- [Learn**How much will a mini split add to my electric bill?** Running costs worked out from PGE, Pacific Power and NW Natural rates, against baseboards and a gas furnace.](https://firlandsportlandminisplits.com/guide/mini-split-electric-bill/)
- [Learn**What mini split rebates are available in Oregon?** What Energy Trust pays, which homes qualify, how state and city programs work, and what's changed for the federal credit.](https://firlandsportlandminisplits.com/guide/mini-split-rebates-oregon/)
- [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/)

## How a job runs

### 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.

## Whole-house systems: questions

### Can mini splits heat a whole house in Portland?

Yes, when every room that closes off gets heat and the outdoor units are cold-climate models chosen for their output near 24°F, Portland's design low. Where it goes wrong is one big head in the hallway expected to reach the bedrooms. That leaves closed rooms cold.

### Do I need backup heat with a whole-house mini split?

Not always, but we plan for it. Cold-climate units keep heating well below freezing, and Portland only drops into the teens on a few nights a year. A small baseboard left in the bathroom, or the existing heat kept in one room, keeps a room warm if the outdoor unit ever needs a repair in January.

### How many outdoor units does a whole house need?

Often two for five or more heads. One outdoor unit has a limit on how many heads and how much line it can serve, and two units mean a failure leaves half the house heated. A compact house with four or five close rooms can run on one.

### Why use a ducted unit for small bedrooms?

The smallest wall head is still too big for a small bedroom, so it short-cycles. One small ducted unit in the attic or a closet can feed two small rooms through short ducts and ceiling grilles, which runs steadier and leaves the walls clear.

### Does Energy Trust pay toward a whole-house ductless system?

If the house is heated by electric baseboard or wall heaters and the system replaces that heat in the main living space, Energy Trust of Oregon's ductless incentive currently pays $800 for a typical owner-occupied single-family home, more for income-qualified and attached homes.

## Related services

- [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**Baseboard to mini split** Replace baseboard heat with a mini split: ductless heads take over in the rooms that use the most heat, and add cooling.](https://firlandsportlandminisplits.com/baseboard-heat-to-mini-split/)
- [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/)

## Get an estimate for whole-house systems

Which rooms, when they're uncomfortable, and what heats them now. We'll call back with a rough range and set up the visit.

(971) 458-4515