Solar energy in the Algarve: holiday homes, holiday rentals and pools — how the sizing changes

Why the same panel produces more in the Algarve

In the Algarve, each kWp installed produces around 1,620 kWh a year, and a 5 kWp system comes to roughly 8,100 kWh — 12 to 15% more than in central and northern Portugal. Orientation, tilt and heat change the figure for each roof, and the final sizing always comes from the site visit.

The region has around 2,850 hours of sun a year, low relief and clear skies, which give it the best irradiation on the mainland. When south is not available, a roof facing east and west loses less than people think and spreads production more evenly across the day.

But the sun is not everything. Elsewhere in Portugal, the question is how much you use. In the Algarve there is a second one — when the house is occupied — and the answer changes the number of panels and decides whether a battery pays off.

Holiday homes: size on consumption, not on the roof

A holiday home is often occupied for three or four months a year and empty the rest of the time. A large system produces all year round for a house with nobody in it, and the surplus is paid at a fraction of the price you pay to buy electricity.

Here the rule runs against intuition: the system is made smaller than the roof allows. We size on the house's real average consumption, even if that leaves roof space unused.

Once the installation is registered, the surplus can be sold to an electricity supplier. It is paid below what the same energy is worth when used at home, but it means the output of the empty months is not lost.

In most cases the battery is left out: storing energy for a house with nobody in it does not pay for itself. When someone insists on storage, we show them the numbers first — a battery often adds years to the payback without adding any real saving.

Holiday rentals: summer works in your favour, occupancy decides

With a holiday rental the profile is different. Peak consumption — guests, air conditioning, laundry — comes in summer, exactly when the panels are at their peak. Few activities line up consumption and production this closely.

Out of season the logic reverses: the house uses little, and much of the output would go to the grid at a low price. That is why the numbers are worked out on the real occupancy of your listing, not on a national average, and the return is calculated on the nights actually sold. Filling the roof is the most common mistake in the region.

In hotels the reasoning is the same, with one difference in their favour: kitchens, refrigeration, pools and climate control draw power during the day, every day. At the 60 kWp hotel in Faro that we have published as a case study, the decision came down to sizing for real consumption instead of covering the roof, and the saving in the first year was €18,400.

The pool and the air conditioning: loads that can be moved in time

In a permanent home, the Algarve offers the scenario where solar pays best in Portugal: air conditioning from May to October, the pool pump, hot water — high consumption, and during the day. In that case we size on summer consumption and schedule the big loads for the sunny hours.

The pool pump is the easiest load to move. A typical pump uses between 3 and 6 kWh per day of operation; scheduled for the middle of the day, it uses energy that would otherwise go to the grid, and two to four modules are enough to cover it.

What weighs most with a pool is heating the water. There, the pool heat pump, scheduled for midday, is the solution that pairs best with solar. The air conditioning does the same with no scheduling at all: it draws the most power exactly when there is the most sun.

Salt, flat roofs and heat: what changes in the installation

The whole Algarve coast is a saline environment, and in many homes pool chlorine adds to it. The panels are certified for salt mist; what suffers are cheap fixings and connectors. That is why we use A4 stainless steel and anodised aluminium without exception, and the connectors are protected from the sea air.

Much of the housing stock has flat roofs or terraces. Ballasted mounting avoids piercing the waterproofing, but it means checking the slab's load capacity before going ahead — which is done on the site visit. The structure is sized for coastal wind, and on the Costa Vicentina, the west coast, where the wind is strong and constant, the fixings are reinforced.

Then there is the heat. A panel loses output as it heats up, and an Algarve roof passes 60 °C in August. That is why we prefer N-type cells, which lose less power with heat than P-type cells.

400 km away: what changes in the service and what stays the same

Our base is in Condeixa-a-Nova, about 400 km from the Algarve. We are not a local installer and we do not pretend to be: we plan the work in blocks so the distance does not show in the result.

The study is done remotely: with your bill, your address and satellite imagery, we do the first sizing and the proposal without anyone travelling, and within 24 working hours you have concrete numbers. Site visits are grouped on set dates, and the equipment arrives before the team: a villa is finished in one or two days, and a hotel or a larger rental in a week.

Support starts remotely too. The inverter is monitored online, and most faults are solved by phone or by remote access. When a visit is needed, we group the trip with other visits to the region and schedule the date. We do not promise same-day call-outs, and we prefer to say so before you sign.

What does not change is the licensing, which is the same as in the rest of the country. Up to 30 kW, all you need is prior registration of the UPAC — the self-consumption production unit — with the DGEG, the Portuguese energy authority, and we handle it for you. Above that, a production licence is required: we handle the whole process, but allow a few extra weeks.

If you have a house in the Algarve, the first question is not how many panels fit on the roof. It is how many months a year the house is occupied.