Are you thinking of installing an aerothermal system for domestic hot water? We tell you everything our customers ask us as certified installers of photovoltaic systems from brands such as Fronius, SMA, Tesla, SolarEdge, Victron, Kostal or Wallbox. Because yes, aerothermal can be a great idea, but it is not always for everyone.
Key factors when choosing photovoltaic DHW aerothermics
- Minimum accumulation volume: 180-200 L for 4 persons.
- Compatibility with external solar control signals (e.g., activating the fan heater when there is a surplus).
- Installation flexibility: initially operating in recirculation mode (without outdoor unit) and later adaptable to outdoor air.
- High efficiency (COP ≥ 4.5, class A+++)
- Low sound level if installed near inhabited areas.
- Outdoor temperature range compatible with your local climate (ideal down to -20 ºC or -25 ºC).
- Quality components and ease of maintenance (stainless steel tanks are better than enameled ones).
The good thing about Aerothermics
- High energy efficiency: Equipment with COP > 4.5 consumes very little electricity to heat the water.
- Ideal for photovoltaic: You can program the fan heater to work when you have solar surpluses → maximum self-consumption.
- Quiet models: There are options with indoor units from 28 dB, almost imperceptible.
- Simple installation and maintenance: If you replace an electric boiler, no complex work is required.
- Sustainable and gas-free: No combustion or emissions, only electricity (and better if it comes from the sun!).
Real example:
We recently installed a Panasonic Aquarea in a 4-person household with Fronius panels and Tesla Powerwall battery. The equipment was programmed to activate only when there is a solar surplus. Result: 100% of DHW covered between March and October with free energy.
We must also know what is wrong with Aerothermics.
- High initial investment: Between €6,000 and €9,000, although it is amortized in a few years.
- Low efficiency with extreme cold: You need a model that works well at -20 ºC or below.
- Requires space (indoor or outdoor): Either you have outdoor air available, or you need recirculation mode.
- Not all integrate well with photovoltaics: Many models allow it, but you need someone who knows how to integrate it correctly (this is where Fotovol comes in!).
Quick comparison: DHW fan heater for 4 persons
| Make / Model | Power heating/cooling | COP | ACS Volume | Noise int/ext | Min. working temp. | Price approx. |
|---|---|---|---|---|---|---|
| Panasonic Aquarea All in One | 9 / 8.2 kW | 4.48 | 185 L | 28 / 59 dB | -20 ºC | 5.900 € |
| Mitsubishi Ecodan | 8.5 / 7.5 kW | 4.8 | 200 L | 40 / 58 dB | -20 ºC | 6.500 € |
| Vaillant aroTHERM Plus | 9 / 7.5 kW | 4.79 | 185 L | 29 / 39 dB | -25 ºC | 8.700 € |
| Hitachi Yutaki S Combi 2.0 | 8 / 6.5 kW | 4.6 | 220 L | 37 / 54 dB | -20 ºC | 6.200 € |
| Daikin Altherma 3 Supra | 7.5 / 5.35 kW | 4.6 | 180 L | 28 / 62 dB | -25 ºC | 6.600 € |
Why choose us as an installer of aerothermal energy?
Because wenot only install aerothermal, we are also certified experts in the leading brands in photovoltaics and storage. That allows us to:
- Coordinate activation for solar surplus reliably.
- Design systems that maximize self-consumption and efficiency.
- Configure everything from a single interface or app when possible.
