Underfloor Heating - Coín
Wet underfloor heating in a renovated Coín farmhouse — 180m² of pipe loops on the ground floor connected to an existing gas boiler, with Airzone smart zoning replacing a single thermostat across the whole property.
By Ben Hayden
Project Overview
The Challenge
The Coín cortijo was being renovated from top to bottom — the owners had the rare opportunity to install underfloor heating before the new tiles went down, but the traditional open-plan ground floor (150m²) presented a specific challenge: a single central heating circuit would create large temperature differentials between the sunny south-facing living area and the cooler north kitchen. The owners also wanted seamless heat pump integration, as the cortijo was being designed with a solar array and the entire HVAC and hot water system needed to work as a single energy-managed unit rather than separate systems.
The Solution
Wet underfloor heating system for new build villa. Integrated with air source heat pump for maximum efficiency.
Technical Specifications
- Wet UFH for 180m² floor area
- 8-zone manifold system
- Smart room thermostats
- Integrated with ASHP system
- Energy-efficient operation
Our Installation Process
Thermal Modelling & Manifold Zone Design
We modelled the ground floor heat demand by orientation, glazing area, and expected occupancy pattern, designing 6 independent zones with separate manifold circuits. The south-facing living room (45°C flow, low density pipe layout) was thermally separated from the shaded kitchen (higher pipe density for faster heat-up). All zone manifolds were connected to a central Uponor Smatrix Wave Plus controller for individual programming.
Screed Design & Pipe Installation
Uponor EVAL PE-Xa pipe (16mm, 0.2m spacing) was installed over 30mm of rigid insulation board with reflective foil face. Pipe loops were pressure-tested to 6 bar before the 65mm anhydrite self-levelling screed was poured. The screed was allowed to cure for 28 days before commissioning — a critical step that many installers rush, causing thermal shock cracks in the screed.
Heat Pump Integration & Solar Scheduling
The Daikin Altherma 3 heat pump provides the primary heat source for both the UFH circuits and a 200L DHW cylinder. The system was configured to run heat pump heating during solar peak hours (10:00–15:00), using surplus solar generation to provide essentially free heating. UFH's thermal mass means the floor stores heat effectively — the system can run for 4 hours during peak solar and the floor radiates warmth for 8–10 hours afterward.
Pressure Test, Screed Sign-Off & Handover Documentation
All UFH pipe loops were pressure-tested to 6 bar for 24 hours and witnessed before the anhydrite screed was poured — a mandatory requirement under EN 1264-4. After the 28-day curing period, the system was commissioned at 25°C flow temperature for the first week, ramped to 40°C over days 8–14, and then to the operating setpoint of 45°C — following the Uponor screed start-up protocol to prevent thermal shock. Final zone surface temperature measurements were taken with a contact thermometer at mid-room. The completed installation package — UFH heat loss calculation, zone manifold drawing, pipe pressure test certificate, Uponor product guarantee, and Boletín Eléctrico for the thermostat circuits — was issued to the client for their property records.
Results
Even heat distribution
Backed by Research
Underfloor heating performance advantages are well-established by engineering research and regulatory standards. Here's the evidence:
Radiant UFH achieves equivalent comfort at 2–3°C lower air temperature than convective heating
Radiant heat warms objects and people directly — eliminating the ceiling-stratification problem of convective heating where hot air rises and the occupied zone stays cool. At equivalent perceived comfort, UFH systems operate at lower temperatures, reducing energy consumption.
REHVA — Federation of European HVAC Associations ↗Electric UFH installations require a Boletín Eléctrico under REBT ITC-BT-10
All fixed electrical heating systems in Spain — including electric underfloor heating — must be certified by an authorised electrician who issues a Boletín Eléctrico (electrical installation certificate), required for property insurance coverage and resale documentation.
BOE — REBT (Low Voltage Electrical Regulations) ↗Smart UFH thermostats with adaptive start reduce energy consumption by up to 25%
Programmable thermostats with adaptive learning technology calculate how long the floor takes to reach target temperature and start heating accordingly — eliminating the waste of running the system longer than needed and enabling precise zone-by-zone control.
Warmup — Smart Thermostat Research ↗Properties with underfloor heating in Málaga municipalities may qualify for IBI property tax reduction
Some Málaga municipalities classify underfloor heating as an energy efficiency improvement eligible for IBI property tax reductions under their local ordinances. Eligibility varies by municipality — check with your local Ayuntamiento or a qualified gestor before applying.
Diputación de Málaga ↗Frequently Asked Questions
Related Services
LIT services in Coín directly related to this work.
About the Author
Ben Hayden is an English speaking electrician and independent energy advisor based in Marbella, Spain, with over 15 years of electrical experience across Europe. He provides independent energy and electrical checks for overseas property owners and managers across the Costa del Sol — helping clients cut electricity bills, navigate Spanish regulations, and make confident decisions on solar PV, heat pump, EV charger and battery storage projects. Ben advises in plain English on projects where the paperwork is in Spanish and the stakes are high. His writing has appeared in ExpatArrivals, The Olive Press, Euro Weekly News, BuildingTalk and pv magazine.
Want a similar project?
A completed installation case study. For a new heating or cooling project, contact Agua Therm directly.
Enquire with Agua ThermProject Details
- Location
- Coín, Málaga
- Completed
- October 2025
- Service
- Underfloor Heating
- Author
- Ben Hayden
