Yes — a home with no AC ductwork is a perfect candidate for a ductless mini-split heat pump. Mini splits were built exactly for this: they heat and cool through slim indoor units connected to an outdoor unit by a thin line set, so there's no need to add ducts. For the Peninsula's many older, duct-free homes, ADUs, and additions, it's often the cleanest and most efficient way to get modern comfort.
DefinitionWhat is a ductless mini split, exactly?
A ductless mini split is a heat pump system with an outdoor compressor and one or more indoor "heads" mounted on a wall or ceiling. Refrigerant runs between them through a small line set (about three inches), so installation needs only a tidy penetration rather than new ducts. Each indoor head delivers both heating and cooling and is controlled independently. For the full terminology, see our glossary.
When it makes senseWhen is ductless the right choice?
- No existing ductwork — older homes, radiant or wall-heater homes.
- ADUs and additions — comfort for a space the main system can't reach.
- Rooms that run hot or cold — zoned control fixes the one stubborn room.
- First-time cooling — add AC where adding ducts would be invasive or costly.
Deciding between ductless and a central system? Our heat pump vs. AC + furnace guide compares the approaches, and heat pump cost covers typical ranges for single- and multi-zone setups.
Failure modesWhere ductless installs go wrong
- Undersizing or oversizing the heads for the rooms they serve.
- Poor head placement that fights the room's airflow or looks awkward.
- Sloppy line-set routing — the giveaway of a rushed install.
Comparing ductless quotes? The details matter — head count, sizing, and line-set routing. Send yours for a free second opinion from the owner and we'll check the design, not just the price.
Why Plum installs Mitsubishi ductless
We're a Mitsubishi Electric Elite Diamond Contractor — the top tier of Mitsubishi's ductless program (more on that in what is a Diamond Contractor). Mitsubishi mini splits are quiet, efficient, and reliable, and Diamond status means our crews are trained and certified to install them to the standard that protects your warranty. Sam, the owner, designs the zoning himself, and most single-zone installs are a single, clean day — see how long installation takes.
ActionYour next step
Wondering how ductless would lay out in your home? Book a no-pressure in-home design visit, and check current incentives on the Rebate Hub while you're at it.
Educational guidance; system design depends on your home's layout and a load calculation. Plum HVAC · CSLB #1087978 · Mitsubishi Electric Elite Diamond Contractor.
Educational guidance for Mountain View & Peninsula homeowners — not a formal quote. Every recommendation should be confirmed against your home's actual conditions during an in-home visit. Incentive amounts and program status change; verify current eligibility before you buy.
Quick answers
Can I get a heat pump if my house has no ductwork?
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Yes. Ductless mini-split heat pumps were designed for exactly this. They deliver heating and cooling through small wall- or ceiling-mounted indoor units connected to an outdoor unit by a thin line set — no ducts required. They're ideal for older Peninsula homes, ADUs, and additions.
How many rooms can one ductless system cover?
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A single outdoor unit can serve one zone or, in a multi-zone configuration, several indoor heads — so you can do one room, a few key rooms, or whole-home comfort. Each indoor head is independently controllable, which is great for homes where some rooms run hot or cold.
Are ductless mini splits noticeable inside the home?
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Modern Mitsubishi indoor units are slim, quiet, and unobtrusive, with several mounting styles. Most homeowners are surprised how little they notice them — and how quiet they are compared to a forced-air furnace kicking on.
How Long Does a Mini Split Installation Take?
Most single-zone installs are a single day. What sets the timeline, and how we keep your home clean start to finish.
5 min read → CompareHeat Pump vs. AC + Furnace: Which Is Better?
One electric system that heats and cools vs. two separate units. The trade-offs that actually matter on the Peninsula.
7 min read →