Your terrace at 3pm in August.
Stone too hot to walk on. A pool that turns cold in September. CoolStone hides a network of water channels beneath your terrace — cooling the stone underfoot and moving that free solar heat into your pool. No panels. No noise. Nothing visible, anywhere.
Drag to see what the system does
- Stone slabs
- Bedding layer with CoolStone loops
- Insulation (XPS)
- Ground
- Ti heat exchanger — the terrace circuit ends here; a separate circuit feeds the pool
Your terrace is already a solar collector. We just connect it.
Portuguese terrace stone reaches 55–65 °C in summer sun — a huge store of free energy that currently does nothing but burn feet. CoolStone circulates fluid through channels hidden in the bedding layer beneath your stone, built entirely from proven, CE-certified European hydronic components.
Under the stone
High-contact hydronic loops draw heat out of the terrace, cooling the surface by 10–15 °C at peak sun.
Into the pool
A titanium heat exchanger passes the captured energy into your pool water — 150–220 kWh on a summer day, for the running cost of one small pump.
August night cooling
When the pool overheats past 30 °C in high summer, the same loops run at night — radiating pool heat to the sky and bringing the water back to refreshing.
Reality, not hype. Estimates until our pilot proves them.
Worked example: 80 m³ pool (~36 m² of water), 100 m² of active terrace, Algarve sun, automatic cover closed at night.
With automatic cover
- +4–7 °C warmer pool
- 6–10 weeks longer season
- ~90% of collected heat retained overnight
Without a cover
- +1–3 °C only — evaporation dumps 100–200 kWh/day
- 2–3 weeks of season extension at best
- Deck cooling unchanged — the terrace doesn't care
Why we tell you this: without a cover you would be filling a leaking bucket, and we would rather lose the sale than oversell the system. If you don't have an automatic cover, we'll quote one first.
Every system has limits. Here are ours.
It will not heat your pool in winter
December–February sun is too weak. Winter swimming needs a heat pump — CoolStone reduces its workload in the shoulder months, it doesn't replace it.
Your terrace won't feel cold
In August the stone drops from hotplate (55–65 °C) to morning-warm (40–48 °C). Walkable, not chilled.
Shaded terraces don't qualify
Performance depends on orientation, shading, stone colour and wind. We assess every site first — and we'll tell you honestly if yours won't perform.
These are estimates — for now
Our founding pilot is fully instrumented and we publish the measured results, good or bad. You'll see real data, not brochure numbers.
One villa. At cost. Measured and published.
We're selecting one Portuguese villa — ideally with a terrace being built or renovated this autumn — to be the first CoolStone installation. You get the system at cost with full engineering support. We get the data that proves it.
At cost
Components + engineering, zero margin. Founding price locked before you commit.
Fully instrumented
Deck, pool and energy sensors logging all season. You see everything we see.
Honest exit
Site assessment is free and obligation-free. If your terrace won't perform, we say so and shake hands.
