Subterranean greenhouses — also known as walipini or pit greenhouses — are partially or fully built below ground level to leverage the earth’s stable temperature for year-round growing. These structures are gaining popularity among eco-conscious homeowners for their energy efficiency, reduced heating needs, and unique integration with sustainable living spaces.
But when it comes to Energy Performance Certificates (EPCs), subterranean greenhouses create some unusual assessment scenarios.
How Subterranean Greenhouses Affect Energy Performance
Thermal stability: The earth around the structure acts as insulation, moderating internal temperatures and reducing the need for mechanical heating or cooling.
Passive solar gain: South-facing glazing (in the Northern Hemisphere) captures sunlight effectively during colder months.
Humidity and heat exchange: Air circulation between the greenhouse and the main home can impact heating and cooling loads.
While these factors improve real-world energy efficiency, EPC modelling may not fully capture the benefits unless the greenhouse is physically connected to the dwelling.
EPC Modelling Challenges
EPC assessments for homes with subterranean greenhouses face several issues:
Unconventional geometry: Below-ground structures can confuse standard building shape assumptions.
Non-standard insulation profiles: Soil insulation isn’t directly represented in most EPC software.
Seasonal interaction with the main home: If the greenhouse shares ventilation or heat exchange, modelling needs extra assessor input.
Learn more about our experience with unusual building designs on our About Us page.
Residential EPC Considerations
If your subterranean greenhouse connects to your home, its influence on EPC ratings depends on how it interacts with the heating, ventilation, and air conditioning (HVAC) system. Our Residential EPC service ensures such features are accurately reflected in your assessment.
Rapid EPC Certification for Specialist Projects
Homeowners needing quick EPC updates after building or modifying a subterranean greenhouse can benefit from our Same Day Energy Performance Certificate (EPC) service.
Cost vs. EPC Gain
While subterranean greenhouses can be cost-effective to operate, EPC score improvements may vary depending on the degree of integration with the main property. For pricing details, visit our Pricing Plan page.
Expert Guidance
If you’re unsure how your subterranean greenhouse will affect your EPC rating, get in touch via our Contact Us page for tailored advice.
