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Green Building Certification and Compliance Services

We will support your project with a number of compliance services, including Part L, Part O and Part G. We work on both domestic and non-domestic projects of all sizes, helping clients, developers, architects & contractors ensure compliance and legislation is met.   

Part L Calculations: SAP & SBEM 

Part O: Overheating Calculations 

Energy Performance Certificates (EPCs)

EPC Analysis & Optioneering 

Air Pressure Testing 

Thermal Bridging Analysis

Display Energy Certificates 

Part G Water Efficiency Calculations

Parc Eirin case study


Parc Eirin



Rhondda Cynon Taf


Morganstone Ltd


“TRJ have worked with Greenbuild/Viro for a number of years now, and they continue to provide an excellent service in helping us deliver Part L compliance across all our schemes to ensure we handover our projects on time. We would definitely recommend them.”

Tim Gwilliam, T Richard Jones (TRJ) Ltd

  • What is an Energy Performance Certificate (EPC)?
    An Energy Efficiency Certificate (EPC) provides detailed information about a property’s energy consumption and typical energy costs, along with suggestions for improving energy efficiency and saving money. EPCs measure and rate a property’s energy efficiency on a scale from A (most efficient) to G (least efficient). These certificates are mandatory when a property is built, sold, or rented out, and they remain valid for 10 years. A valid certificate must be shown to prospective buyers or renters before selling or renting out a property. Failure to comply can result in a fine.
  • What is a good EPC rating for a house or building?
    EPC ratings range from A to G, with A representing the highest energy efficiency and G the lowest. A higher rating indicates greater energy efficiency for your property. While the average rating in the UK is D, aiming for a C or higher is ideal. Newer homes typically achieve better ratings due to updated building codes and regulations.
  • What does a EPC survey involve?
    EPC surveys typically include an assessment of the whole building, including windows, loft insulation levels, lighting, and heating system. It usually takes at least 45 minutes to carry out a survey for a commercial, non-domestic or residential building. The data collected enables us to calculate your property's expected energy costs and carbon emissions. Our experienced and accredited assessors go a bit further than the typical survey, to provide a detailed assessment with more advanced and tailored recommendations for energy efficiency improvements, beyond those listed in a standard EPC certificate. Our consultants will also happily guide you through the survey process, explaining the results and any unfamiliar terms in more detail.
  • How can I improve my EPC rating?
    Improving your EPC rating can involve several steps aimed at increasing your property's energy efficiency. Here are some effective strategies: Upgrade Insulation: Install or improve insulation in your loft, walls, and floors to reduce heat loss. Replace Old Windows and Doors: Upgrade to double or triple glazing to minimise heat loss and improve energy efficiency. Install an Efficient Boiler: Replace an old boiler with a modern, energy-efficient model. Use Renewable Energy Sources: Install solar panels, heat pumps, or other renewable energy systems. Upgrade Heating Controls: Install smart thermostats and heating controls to optimize energy usage. Improve Lighting: Replace incandescent bulbs with energy-efficient LED lighting. In addition, whilst the following are not considered in an EPC survey, you should also think about: Install Energy-Efficient Appliances: Use appliances with high energy efficiency ratings. Seal Drafts: Use draft excluders and seal gaps around windows and doors to prevent heat loss. Conduct Regular Maintenance: Ensure your heating and cooling systems are regularly serviced to maintain their efficiency.
  • How long does an EPC last?
    An Energy Performance Certificate (EPC) provides a property with an energy efficiency rating ranging from A (best) to G (worst) and remains valid for 10 years. During this period, the certificate can be used multiple times. After 10 years, the EPC expires, and a new certificate must be obtained if the property is to be marketed for sale or rent.
  • How long does an EPC survey take?
    The duration of an EPC survey can vary depending on several factors, including the size, type, complexity, and location of the property. However, on average, a survey for a typical commercial, non-domestic or residential property usually takes about 45 minutes to 1 hour. During the survey, the assessor will take measurements and collect data on the property’s energy-related features. After the inspection, the assessor will analyse all the collected data to calculate the property’s energy efficiency rating. This process generates the EPC, which includes the energy efficiency rating, typical energy costs, and recommendations for improving energy efficiency. At Viro, we aim to provide the survey results as quickly as possible, often within the same day or within one or two working days.
  • How much does an EPC cost?
    The cost of an Energy Performance Certificate (EPC) can vary depending on the size, type of property, and location. For a more accurate estimate, contact providers in your area. Our consultancy service involves a detailed assessment and tailored recommendations for energy efficiency improvements that go beyond those listed in a standard EPC certificate. Once certified, your certificate is valid for 10 years.

Arrange Compliance Services

Connect with our in-house team of consultants for specialist compliance guidance and advice.

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