Heating, cooling, and hot water without gas

Aerothermal energy distributes heat or cold through systems such as underfloor heating, low-temperature radiators or fan coils. During winter, it extracts heat from the outside air and transfers it to the inside of the home. In summer, the cycle reverses: the system extracts heat from inside and expels it outside, providing efficient and sustainable cooling.

An aerothermal system can have a lifespan of between 20 and 25 years, as long as it is properly maintained.

Aerothermal energy uses the energy of the air to generate heat efficiently, and if it is powered by electricity from a photovoltaic installation, the system becomes even more sustainable and economical. This solution allows you to cover both heating and domestic hot water, drastically reducing dependence on traditional energy sources.

In most cases, yes. A typical family in a 120 m² home goes from spending around €1,300 a year on gas to around €500 in electricity — a saving of 30% to 60% depending on tariff and insulation. A gas boiler still makes sense if it's recent and gas is cheap in your area. If it's over 10 years old or your bills have risen two winters in a row, switching starts to pay off even without subsidies. At Eltex we calculate your exact break-even point with your own data before recommending anything.

Real savings depend on what you're replacing: compared to butane or heating oil, savings are typically 50–65%; compared to natural gas, 30–50%; compared to direct electric heating, 60–75%. In concrete terms, a 120 m² home with a heat pump uses around 4,000 kWh of electricity per year for heating, versus the equivalent of 13,300 kWh with a gas boiler. The average annual saving is between €700 and €1,300, depending on your electricity tariff.

An air source heat pump installation in a 120 m² home costs between €10,000 and €17,400, depending on the emitter system: around €10,000–€12,000 if existing radiators are adapted, and €15,000–€17,400 if underfloor heating is installed from scratch. Subtract the 2026 subsidies available — CAE grants, IRPF income tax deduction, and municipal tax rebates — and the net investment for many families falls to between €5,000 and €9,000.

In 2026 there are four subsidy streams that can be combined: the Plan Renove scheme returns up to €3,000 per qualifying installation; the IRPF income tax deduction allows you to claim back 40% to 60% of the cost if the work improves your home's energy certificate; many municipalities apply a discount of up to 50% on the IBI property tax for several years and reduce the ICIO construction tax by up to 95%; and regional authorities have additional funds of between €500 and €2,000. Grants have deadlines and limited budgets — installations earlier in the year typically have more options available.

Yes, modern heat pumps extract heat from the air and function down to -20°C. What changes is efficiency: at mild temperatures (7°C to 15°C) the COP is between 3.5 and 4.5, meaning for every €1 of electricity you get €3.50 to €4.50 of heat. When temperatures drop below 0°C, COP can fall to 2 or 2.5, so the unit uses more electricity than usual on those days. In inland or northern Spain with harsh winters, correct equipment sizing and adequate insulation are essential to keep savings real throughout the season.

No, if the outdoor unit affects the building façade or shared elements, you need a favourable vote from the homeowners' association under Spain's Horizontal Property Law. In many apartments this is achievable, especially if the unit goes on a private terrace or a secondary façade, but enclosed interior lightwells or protected facades can make it very difficult. Before quoting anything, we assess exactly what your building allows and whether an air-to-air system in your own space is more realistic than a full air-to-water installation.

A heat pump works with conventional radiators, but with important nuances. Standard aluminium radiators need water at 60–70°C to deliver adequate heat; a heat pump performs best producing water at 35–45°C, the temperature range of underfloor heating. If you keep your existing radiators, the unit can work at higher temperatures, but COP drops — and with it, some of the promised saving. The most common fix is adding low-temperature radiators in the main rooms or upsizing existing ones, which is typically cheaper than full underfloor installation and avoids major structural work.

At night, the heat pump draws electricity from the grid like any other appliance — unless you have lithium battery storage, which carries a high upfront cost and a lifespan of 8 to 12 years. The most efficient way to use solar without batteries is to program the heat pump to run during peak solar production hours midday, and use the hot water accumulator tank as a "thermal battery": water heated at noon retains heat for several hours, reducing what the unit needs to buy from the grid overnight. This is a design decision, not an afterthought — we build it into every solar-paired installation.

Without any grants, the typical payback period is 6 to 10 years, depending on what you're replacing and your current bills. The shorter end — 5 to 7 years — applies when replacing butane, heating oil, or direct electric heating, where the bill saving is largest. Against cheap natural gas it can be 8 to 12 years. After payback, the saving is pure gain for the remaining 15 to 20 years of the system's working life. Every year you delay while running an expensive system is savings you don't recover.

In most cases, no. If the property sits empty for more than 200 days a year, the actual energy consumption isn't high enough to recover the investment in a reasonable timeframe. A heat pump makes sense in a second home only if you use it frequently — most weekends throughout the year — or if you have solar panels that can run it autonomously when you're away. In that scenario it can be programmed to operate only during solar generation hours, maintaining a minimum temperature at zero grid cost. If neither applies, modern electric radiators remain the more honest recommendation.

The outdoor unit generates between 40 and 50 dB(A) under normal operation — equivalent to the hum of a modern refrigerator or a quiet conversation in a room. It is not silent, but it is also not comparable to a window air conditioner running at full power on a hot day. Perceived noise depends heavily on placement: an enclosed interior lightwell amplifies sound more than an open façade. At Eltex we position the unit to minimise transmission to bedrooms and fit anti-vibration mounts as standard.

Four factors determine whether your home is a good candidate: insulation level (a poorly insulated home loses efficiency before heat reaches the emitters), available outdoor space for the unit (terrace, garden, façade, or rooftop), electrical panel capacity (the heat pump may require upgrading your contracted power from 3.5 kW to 5 or 8 kW), and current emitter type (radiators, underfloor heating, or fancoils). At Eltex we assess all four in the free study and tell you whether to install now, insulate first, or wait until your current system reaches end of life.