Heat Pumps Just Got Simpler — And This Apple Veteran Is Behind It
California set a bold goal: 6 million heat pumps installed by 2030. As of today, it has reached only 2.3 million. To close that gap, the state would need to average 2,000 installations every single day for the next five years. The problem is not ambition. The problem is that heat pumps, as we know them, are simply too expensive and too complicated to install at that kind of scale.
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| Credit: Merino Energy |
The Woman Who Helped Sell AirPods Now Wants to Reinvent Heat Pumps
Mary-Ann Rau is not your typical climate-tech founder. She spent years at Apple, where she appeared in product keynotes introducing new AirPods to the world. Later, she joined Quilt, a heat pump startup focused on premium home electrification. But it was her personal experience trying to electrify her own San Francisco home that pushed her to go further.
Rau had already installed solar panels, an induction stove, and an EV charger. Heat pumps were supposed to be the final piece. What she got instead was sticker shock. A typical mini-split system in California can cost between $4,000 and $6,000 per zone, and installation alone can take an entire day. For someone with her income and resources, it felt out of reach. For most Californians, it simply is.
"That's when I realized that if it was inaccessible for me, it's out of reach for the vast majority of Californians and Americans," she said.
Merino Energy and the $3,800 Heat Pump That Installs in One Hour
Rau co-founded Merino Energy, a startup that has been operating in stealth until now. The company has built a product called the Merino Mono, and the premise is refreshingly direct. It costs $3,800 — installation included — and takes roughly one hour to put in. That is a dramatic shift from the current market standard.
What makes the Mono different starts with its design. A traditional mini-split system has two separate components: an indoor heat exchanger and an outdoor condenser unit. Connecting the two requires skilled labor, copper line brazing, and refrigerant charging — all of which drive up both cost and complexity. Merino collapses those two parts into a single indoor unit about the size of a radiator placed beneath a window.
That one design decision changes almost everything about how the product is sold and installed.
No Outdoor Unit, No Electrical Upgrade, No Problem
One of the biggest hidden costs of traditional heat pump installation is electrical work. Many homes require panel upgrades or new dedicated circuits to handle a standard system. Merino eliminates that barrier entirely. The Mono plugs into a standard 120-volt outlet — the same kind used by a microwave.
"If you can plug in a microwave and it works on that outlet, then the Merino Mono is gonna work on that outlet," Rau explained.
Installation involves cutting two small holes in the wall — one to draw in air, one to exhaust it. From the outside, only the intake and exhaust ports and a condensate pipe are visible. There is no outdoor compressor unit to mount, no refrigerant lines to run across walls, and no separate contractor coordination required. Six installers have already signed up across the Bay Area and Los Angeles, and the company is currently accepting preorders for delivery later this year.
Smart Features Designed for Modern Living
The Merino Mono is not a stripped-down compromise. It includes the connectivity and intelligence expected of next-generation climate products. The unit is Wi-Fi connected and equipped with occupancy sensing, so it knows when someone is in the room. Multiple units within a home can coordinate with each other to optimize both comfort and energy use.
Merino is even developing an integration with Oura Ring health trackers. When the ring detects that the wearer has entered REM sleep, the heat pump can automatically lower the room temperature by a couple of degrees — a feature grounded in sleep science that shows cooler temperatures support deeper rest. It is a small detail, but it speaks to how seriously the company is thinking about the full user experience, not just the hardware.
Where Efficiency Lands — And Why It Still Makes Sense
There is a meaningful trade-off to acknowledge. In condensing the system into a single indoor unit, Merino has accepted some efficiency loss. The Mono carries a SEER2 rating of 15.2. By comparison, a premium two-zone system from a competing startup achieves a rating of 25. Larger outdoor condensers simply move heat more efficiently.
But Rau argues — compellingly — that maximum efficiency is not always the right metric. For apartments, condos, and dense urban housing, running refrigerant lines to an outdoor unit is often impractical or impossible. For renters, landlords will rarely approve complex installations. For low-income households, a $4,000 to $6,000 upfront cost per zone is simply not an option, no matter how efficient the system.
"It's a solution where the cost is proportional to the problem that we're trying to solve," Rau said.
The Mono is not trying to replace premium whole-home systems. It is trying to reach the people and buildings those systems never could.
A Low-Income Housing Project Is Already Leading the Way
Merino is not waiting for perfect conditions to scale. The company is currently in the middle of installing 48 heat pumps at the Civic Center Apartments, a low-income housing development in Richmond, California. It is a deliberate first deployment — proof that the product works in real-world conditions for residents who stand to benefit the most from lower energy costs and better climate control.
The company's near-term focus remains California, where the political and regulatory climate strongly supports electrification. From there, the plan is to expand into Hawaii, Oregon, and Washington — states with similar utility structures and strong clean energy policies. The installer network is growing, and the preorder pipeline is open.
Why This Matters Beyond One Startup
The story of Merino Energy is about more than a clever product. It is a window into one of the central tensions in the energy transition: the gap between what governments set as targets and what the market can actually deliver.
California's 6 million heat pump goal was never going to be achieved by selling the same $6,000 systems through the same slow installation process. Hitting that number requires something structurally different — a product that lower-income households can afford, that renters can actually use, and that installers can put in quickly enough to meet demand at scale.
The Merino Mono is a serious attempt to build that product. Whether it succeeds will depend on how quickly the installer network grows, whether the preorder pipeline converts into real deployments, and how the product performs over time in diverse real-world conditions.
But the fundamental insight behind it is sound. If the goal is millions of heat pumps, the answer is not a better version of what already exists. It is a different kind of heat pump entirely — one that anyone can afford, anyone can install, and almost anyone can host.
Rau put it plainly: "If we can reduce the amount of time and complexity of installing a heat pump, then we can scale adoption."
That is not just a product pitch. That is the actual problem the climate needs solved.
