An R290 air-to-water heat pump is a heating system that pulls warmth from outdoor air and delivers it to your radiators, underfloor heating, and hot water, using propane (R290) as the refrigerant. R290 matters because it has an extremely low global warming potential and can reach the higher water temperatures older radiators need, which makes it one of the most future-proof choices as the EU phases down high-emission refrigerants.
If you are replacing a gas or oil boiler, a heat pump is usually the single biggest step you can take to cut both carbon and running costs, especially when paired with solar. This guide explains how the technology works, why R290 is a smart pick, how to size it, and how a hybrid AC/DC design lets it run on your own panels.
Key Takeaways
- An air-to-water heat pump moves heat rather than burning fuel, so it delivers several units of heat per unit of electricity.
- R290 (propane) has a very low global warming potential (around 3) and supports high flow temperatures, which suits retrofits and EU F-gas compliance.
- The Deye R290 heat pump comes in 10kW (1-ph), 12kW (1-ph), 12kW (3-ph), and 16kW (3-ph) versions for heating, cooling, and hot water.
- Its Hybrid AC/DC design has a built-in MPPT input, so it can run on direct PV by day and grid AC otherwise.
- Sizing must come from a professional heat-loss calculation, and installation must be done by a certified professional.
How an air-to-water heat pump works
A heat pump does not make heat by burning fuel. It moves heat. A refrigerant absorbs warmth from the outside air, even in cold weather, then a compressor raises its temperature, and a heat exchanger transfers that heat to the water in your central heating and hot-water cylinder.
Because it moves heat instead of generating it, a heat pump delivers more energy as heat than it consumes as electricity. That ratio is the Coefficient of Performance (COP): for every 1 kWh of electricity, a well-matched system delivers several kWh of heat. This is why heat pumps cost far less to run than direct electric heating and, in most homes, less than gas.
"Air-to-water" means it draws from outdoor air and delivers to water (radiators, underfloor loops, hot-water tank), as opposed to air-to-air systems that heat air directly.
Why R290 refrigerant matters
Every heat pump uses a refrigerant. The type matters for two reasons: environmental impact and performance.
- Very low global warming potential. R290 (propane) has a GWP of roughly 3. By comparison, many older refrigerants have GWPs in the hundreds or thousands. As the EU F-gas regulation phases down high-GWP refrigerants, natural refrigerants like R290 are the direction of travel, so choosing one now protects you from future restrictions.
- High flow temperatures. R290 can comfortably produce hot water at higher temperatures than some alternatives. That is valuable in retrofits, where existing radiators were sized for a hot gas boiler and need a warmer flow to keep rooms comfortable.
In short, R290 combines green credentials with the practical ability to heat older homes, not just new, low-temperature builds.
The Deye R290 range: hybrid AC/DC
The Deye Solar R290 Air-to-Water Heat Pump is built around one standout idea: it can run directly on solar.
- Hybrid AC/DC technology. A built-in MPPT input lets you connect compatible PV panels directly. By day, the heat pump runs on that solar; when the sun is low or absent, it draws AC from the grid. With no PV at all, it works like a conventional electric heat pump.
- Heating, cooling, and hot water. Full DC inverter operation supports all-season comfort, not just winter heating.
- Four versions to match the home:
| Model | Output | Supply | Typical use |
|---|---|---|---|
| 10 kW | 10 kW | Single-phase | Smaller / well-insulated homes |
| 12 kW | 12 kW | Single-phase | Mid-size homes |
| 12 kW | 12 kW | Three-phase | Mid-size, three-phase supply |
| 16 kW | 16 kW | Three-phase | Larger homes / higher demand |
- Smart monitoring. Wi-Fi control and Deye Cloud energy management are built in; the DYNT-WIFI data logger brings the system online for remote status checks.
The hybrid-solar angle is the real differentiator. Heating is the largest energy use in most homes, so running it partly on your own panels, rather than entirely on grid electricity, is where a solar household sees the biggest bill impact.
How to size an air-to-water heat pump
Sizing is not a guess, and it is not "match the old boiler." An oversized heat pump short-cycles and runs inefficiently; an undersized one cannot keep up on the coldest days. The correct method is a professional heat-loss calculation for your specific home, which accounts for floor area, insulation, windows, climate zone, and your desired indoor temperature.
As a rough orientation only:
- A well-insulated modern home needs far less heating power per square metre than an older, draughty one.
- An older or larger home with original radiators will need more output and a higher flow temperature, where R290's high-temperature ability helps.
Case 1: Insulated family home. A reasonably insulated home with underfloor heating might be served by a 10–12kW unit. Underfloor systems run at low flow temperatures, which suits a heat pump well.
Case 2: Older home with radiators. A larger, older property with existing radiators needs both more output and warmer water. Here a 16kW three-phase unit and R290's higher flow temperature keep rooms comfortable without replacing every radiator.
Use these as context for a conversation with your installer, not as a substitute for a proper calculation.
⚠️ Installation is not included with the product, and this system must be installed by a certified professional to ensure safety, compliance, and warranty validity. R290 is a flammable refrigerant, so professional handling is essential.
Running it on solar
A heat pump and a solar system are natural partners. Daytime is when solar peaks and when you can pre-heat your home or hot-water tank. Three ways to combine them:
- Direct PV via the MPPT input: The hybrid AC/DC design uses solar panels directly when available, bypassing the grid during sunny hours.
- A balcony or rooftop PV system: Feed your home's main supply using the Deye solar inverter range. For smaller apartments or spare roof space, a plug-and-play balcony setup helps too, and you have two independent options: either a Deye SUN-M160G4 microinverter for a panels-only grid-tie system, or the all-in-one AE-FS2.0-2H2 balcony energy storage, which has a built-in inverter and MPPT so panels plug straight into it. Either one offsets your home's baseline running costs.
- Smart scheduling: Use a wireless CT and Deye's central energy management to lean on your primary residential solar array and a properly sized home battery first, so the heat pump runs during peak solar hours.
Note that a balcony micro-storage unit like the AE-FS2.0-2H2 is sized for everyday household loads, not for running a 10–16 kW heat pump directly. To store solar for evening heating, pair the heat pump with a properly sized residential home battery.
Frequently asked questions
What is R290 and is it safe? R290 is propane, a natural refrigerant with a very low global warming potential. It is flammable, so the unit must be installed and serviced by a certified professional, but in normal operation it is a safe, well-established refrigerant.
Can a heat pump heat an older house? Yes, especially an R290 model that reaches higher flow temperatures. A heat-loss calculation will confirm the right size and whether any radiators need upgrading.
Does it provide hot water and cooling too? Yes, the Deye R290 range supports heating, domestic hot water, and cooling.
Can it really run on solar? The Hybrid AC/DC design has a built-in MPPT input for direct PV, and it falls back to grid AC when solar is unavailable.
Conclusion: future-proof heating that loves solar
An R290 air-to-water heat pump is one of the most future-proof ways to heat a home: a natural refrigerant that meets tightening EU rules, high flow temperatures that suit retrofits, and a hybrid AC/DC design that runs on your own solar. The keys to success are correct sizing, always from a professional heat-loss calculation, and certified installation.
Get those right, and you replace a fossil boiler with a system that cuts both your carbon and your bills.
Explore the range: see the Deye R290 Air-to-Water Heat Pump and the DYNT-WIFI monitoring logger, or browse all Deye HVAC systems. Then book a professional sizing assessment.
