Domestic hot water (DHW) systems are an essential part of any residential property’s energy performance. When it comes to Energy Performance Certificates (EPCs), the type of hot water system installed can significantly influence the building’s energy rating. Two common types of DHW systems are storage (tank-based) and on-demand (instantaneous) systems. Understanding their impact on EPC scores helps homeowners and landlords make informed decisions to improve energy efficiency.
What Are Storage and On-Demand Hot Water Systems?
Storage Systems: These typically include a hot water cylinder or tank that stores heated water for later use. They often rely on a boiler or immersion heater to maintain water temperature.
On-Demand Systems: Also known as instantaneous water heaters, these systems heat water only when needed, without storing it.
How Domestic Hot Water Systems Affect EPC Ratings
EPC assessments take into account the efficiency and heat losses associated with DHW systems, which directly influence energy consumption and carbon emissions.
Storage Systems: Pros and Cons for EPC
Advantages:
Can be integrated with renewable heating systems such as solar thermal panels or heat pumps.
Suitable for properties with high simultaneous hot water demand.
Disadvantages:
Heat loss from the tank, especially if poorly insulated, reduces system efficiency.
Continuous energy usage to maintain stored water temperature can lower EPC scores.
On-Demand Systems: Pros and Cons for EPC
Advantages:
No heat losses from stored water, making the system more energy-efficient.
Typically results in lower energy consumption and can improve EPC ratings.
Disadvantages:
May have limited flow rates, potentially less suitable for larger households.
Efficiency depends on electricity or gas source; electric instantaneous systems can have high running costs.
Factors Influencing EPC Impact Beyond System Type
Insulation Quality: Well-insulated tanks minimize heat loss and improve EPC outcomes for storage systems.
Energy Source: Use of renewable or highly efficient boilers improves overall rating.
System Controls: Timers, thermostats, and smart controls help optimize hot water use and reduce waste.
User Behavior: How occupants use hot water influences actual energy consumption versus predicted EPC values.
Tips to Improve EPC Scores Related to Hot Water Systems
Upgrade to efficient, well-insulated storage tanks or high-efficiency on-demand heaters.
Incorporate renewable technologies like solar thermal where possible.
Use smart controls to reduce standby losses and unnecessary heating.
Regularly maintain systems to ensure optimal performance.
How EPCRate Helps Optimize Your EPC Assessment
At EPCRate, our London-based EPC assessors carefully evaluate your domestic hot water system’s type, condition, and efficiency during the energy assessment. We provide clear recommendations tailored to your property to enhance your EPC score and reduce energy costs.
Discover our expert EPC services or conveniently book an assessment with transparent pricing.
Contact EPCRate for Expert EPC Assessments in London
For professional advice on how your domestic hot water system impacts your EPC rating and practical upgrade guidance, contact EPCRate via our contact page. Let us help you achieve better energy efficiency.
