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Energy·applied

Heat Pumps

Why it matters

Half of the energy a household consumes over a year is typically spent on one thing: keeping warm. For a century the answer has been combustion, burning gas, coal, or wood inside or near the home. Combustion has a hard ceiling: a fuel yields at most the heat chemically stored in it, and every unit of it ends as CO₂ in the atmosphere.

A heat pump is the single device that breaks this ceiling. It moves heat instead of making it, concentrating warmth that already exists in the outside air or ground and delivering it indoors. That is fundamentally cheaper: for one unit of electricity, a heat pump delivers roughly three units of warmth. When that electricity comes from your own roof, the result is a home that stays warm with no flame, no fuel deliveries, no emissions, and no dependence on the pipelines that make heating a geopolitical weapon. For Ukraine, where winters have been used as leverage in war, a heating system that cannot be cut off is resilience itself.

The physics of moving heat will outlive every technology on the horizon; what will change is who installs and tunes these machines. That work is already shifting toward sensor-driven commissioning, and it remains some of the most satisfying systems work in a building: the moment a heat pump, storage, and floors are balanced and the house simply stays warm on sunlight, you have tuned an organism.

Role in 001's holistic picture

In the autonomous building organism, the heat pump is the metabolic core: it converts the electricity harvested by solar panels into the warmth the body needs, at a rate beyond any resistive heater or boiler. It always works in an ensemble. Upstream, an efficient envelope decides how little heat is needed at all — approaching the Passive House limit, almost none; downstream, radiant floors let the pump run at gentle temperatures where its efficiency peaks, and a buffer tank turns midday solar surplus into evening warmth, making heat the cheapest battery in the house. Deciding when to run the pump — on midday sun, ahead of a grid outage — is energy management's job. This chain, demand reduction first, then efficient conversion, then storage, is the Energy Innovation Model in miniature.

In the world

COP — the ratio of heat delivered to electricity drawn — typically holds at 3–4 across a season, sinks to 1.5–2 in humid −15 °C frost, and a ground-source unit holds 4–5 in the same cold. Whether a given machine actually earns its rated number is now something ordinary owners measure in the open. On HeatpumpMonitor.org, a community dashboard from OpenEnergyMonitor, roughly 594 UK households publish their heat pumps' live-metered performance — 413 on certified meters, 210 with a full year of data — turning the rated number into evidence anyone can check. It is the honest-measurement culture House 001's own not-yet-metered COP belongs to.

How 001 engages with it

House 001, our living lab in Ivano-Frankivsk, heats without fossil fuels: a heat pump feeding low-temperature radiant surfaces, and we keep testing and tuning this heating system season by season. The most interesting part is the pump itself — a DIY conversion of an ordinary air-to-air air conditioner. An air conditioner already contains the entire heat-pump machine; House 001 demonstrates how low the entry threshold to fossil-free heating can drop once you treat it that way.

The conversion also delivered its sharpest lesson, and it is about control, not refrigerant. The donor's inverter logic keeps serving its original job: heat the air, then throttle. Run with the indoor unit blowing, the compressor eases off the moment the room reaches the remote's setpoint — satisfied by its own warm air — and moves too little heat into the floor. Run with the blower wheel removed so everything goes to water, and the floor's underbuilt loops shed heat more slowly than it arrives, while the compressor's logic stays a black box either way. The earned conclusion, now a design rule: a DIY hydronic conversion wants a simple fixed-speed on-off donor whose full output the builder commands — not an inverter unit that keeps deciding for itself.

For UA Unity Hub in the Carpathians, we walked the full decision landscape, and changed our minds repeatedly: site logistics killed our first concept, a ground loop nearly won on efficiency before drilling logistics ruled it out, and forest ecology arguments removed wood firing from the baseline. The accepted concept rests on an air-to-water heat pump feeding radiant surfaces. The full reasoning, including the rejected options, is in our publication on heating a mountain eco-community.

Maturity: applied. Running through full seasons at House 001; designed and accepted as the primary heat source for UA Unity Hub. Not yet "validated" by our own standard: the COP is an engineering assumption, not yet metered. Closing that gap is planned instrumentation work.

Further reading