A Rush couple have lived in a converted Martello tower on the east coast for six years and heat it for almost nothing

Sea air whips the parapet, but the living room stays warm.
Six feet of stone hold the day’s heat like a battery.
In Rush, a small harbour town north of Dublin, two people have quietly made a historic fort into a modern home.

“We wanted a place with character, not just square rooms,” says Aoife, a designer who shares the tower with her partner, Mark.
They moved in six years ago, when the circular bunker was still part museum, part ruin.
Today it is bright, watertight, and astonishingly cheap to run.

Why they chose a circular fortress

Martello towers dot the Irish coast, built to watch invasions that never came.
This one stands above a strand, with gulls riding the wind and ferries gliding past the horizon.
“It felt solid, and oddly calm,” says Mark, who works in marine logistics.
“The shape invites you to think in circles, not in corridors.”

The couple saw potential in the tower’s mass, its deep embrasures, and the thick render that shrugs off weather.
They also saw challenges: no plumbing, no insulation, and a stair like a stone corkscrew.
“But we believed the bones were right,” Aoife says, “and the rest was just craft.”

Making stone behave like a battery

The thermal trick begins with airtightness.
Every gap was sealed, every window rebated, and a hidden membrane now wraps the inner shell.
“Stop the drafts, and the stone starts to work for you,” Mark notes.

Next came breathable insulation laid as a gentle liner: cork and lime on the walls, wood fibre beneath the floor.
No plastic sandwiches, no sealed cavities that might trap moisture.
“The tower still breathes, but more slowly,” Aoife says with a smile.

They embedded low‑temperature pipes for radiant heat in a thin lime‑crete slab.
Warm water moves through the loops, and the slab feeds the stone.
By evening, the whole structure glows with a soft hum you can almost feel.

Heat for almost nothing

Power comes from a quiet heat pump and a modest solar array tucked below the parapet.
On bright days, panels fill a hot‑water cylinder and nudge the slab.
On dimmer days, the pump sips electricity at off‑peak rates.

“Our winter bill was about €18 a month last year,” Mark says.
“In summer, it drops to nearly zero, because hot water is free most days.”
A tiny stove burns driftwood only for comfort, not for need.

Ventilation is handled by a quiet MVHR unit that recovers warmth from outgoing air.
Salt spray stays outside, while filtered freshness lives inside.
“The air is always dry, which makes 19°C feel cosy,” Aoife adds.

Living inside a circle

Rooms radiate like petals, each curved and intimate.
The kitchen wraps a deep embrasure, framing an everyday cinema of changing tides.
A compact mezzanine floats under the domed roof, giving a snug bedroom with moonlit views.

Furniture follows the tower’s arc, with shallow cabinets and banquette seats.
Lighting runs in low rings, keeping shadows soft and the stone gentle.
“Rectangles argue with circles,” Aoife laughs, “so we picked our battles.”

The old powder magazine is now a tiny studio, cool by nature and quiet as velvet.
Here, Aoife sketches patterns for textiles inspired by kelp and wave‑cut rock.
“Even the acoustics are kind, like being inside a drum with felted sides,” she says.

The quiet economy of care

Money saved on fuel went into careful repairs.
They lime‑washed the exterior, reset fractured stone, and kept the crenellated profile untouched by gadgets.
Solar gear hides behind the parapet, while cabling runs in old channels once used for pulleys.

“Low‑energy doesn’t mean high‑tech everywhere,” Mark argues.
“It means reducing the load, then using simple, reliable parts.”
He checks the system with a phone app, but most days he forgets it even exists.

What they learned

• Let the original fabric do the heavy lifting, then add the lightest, most reversible upgrades you can.

Community, memory, and a shared horizon

Neighbors still knock with stories: wartime watchmen, teenage dares, and smoky bonfires long since banned.
The couple host an annual open day, sharing the tower’s history and the energy numbers.
“People expect it to be freezing, then they step in and pause,” Aoife says.

Outside, the wind threads the stone‑cut stair, and the sea keeps its rhythm.
Inside, a small pump purrs, the slab gives back its warmth, and dinner bubbles softly on the hob.
Six years have made the round rooms feel inevitable, like a tide‑shaped idea that finally found its shore.

“Home isn’t a style, it’s a state,” Mark offers, resting a hand on the cool lintel.
“And if the walls can store the day, they can store our days too.”
The tower listens, quiet, and keeps their heat for almost nothing.