Seasonal lake-sourced cooling systems use deep, naturally cold water from nearby lakes to provide energy-efficient cooling during warmer months. This approach drastically reduces reliance on conventional air-conditioning systems, cuts electricity consumption, and offers a sustainable alternative for both commercial and residential buildings.
While highly efficient in practice, these systems can be tricky to reflect accurately in Energy Performance Certificate (EPC) assessments.
How Lake-Sourced Cooling Works
Water intake: Cold water is drawn from deep areas of a lake where temperatures remain stable year-round.
Heat exchange: The cool water passes through a heat exchanger, absorbing building heat without mixing with potable water supplies.
Seasonal operation: Used primarily in summer months, then switched off when ambient conditions no longer require cooling.
EPC Modelling Challenges
EPC software is built for year-round HVAC operation and may not fully account for seasonally operated systems. Key limitations include:
Annualised energy use assumptions: EPC tools average cooling demand across the year, which may understate seasonal efficiency gains.
Lack of a direct input field: Many EPC systems do not list “lake-sourced cooling” as a standard option, requiring custom entries.
Interdependence with other systems: If the building also uses conventional chillers as backup, EPC may combine both into a blended efficiency figure.
To learn more about our expertise with non-standard energy systems, visit our About Us page.
Residential EPC Considerations
For homes located near lakes, seasonal water-sourced cooling can be a game-changer for comfort and running costs. Our Residential EPC service ensures these systems are assessed with detailed technical notes.
Same-Day EPC for Specialist Installations
If you need a fast update to your EPC after installing a lake-sourced cooling system, our Same Day Energy Performance Certificate (EPC) option delivers rapid, accurate results.
Cost Implications
While the system installation can be expensive, the operational savings are significant. For EPC-related pricing, check our Pricing Plan page.
Speak to an EPC Expert
If you want to know how your seasonal lake-sourced cooling will be factored into your EPC, get in touch with our assessors via the Contact Us page.
