EPC FAQs – Updated for RdSAP 10
EPC FAQs by Bluewire Hub, your go-to resource for clear, reliable answers about Energy Performance Certificates (EPCs). Whether you’re a homeowner preparing to sell, a landlord managing rental compliance, or a tenant wanting to understand your energy rating, this section is designed to support you.
These EPC FAQs cover the most common questions we’re asked, including how long an EPC is valid, what the ratings really mean, and what’s changed under the latest RdSAP 10 updates. We also explain what happens during an EPC assessment, how to choose a qualified assessor, and what to expect if you’ve added solar panels, heat pumps or insulation.
If you don’t see your question here, feel free to get in touch – we’re always happy to offer guidance based on real experience. We aim to keep things practical and free of jargon, so you can make informed, cost effective, decisions about your property.
We update this page regularly to reflect current legislation, updated guidance, and the latest EPC standards and methodology. That means the advice you read here is accurate, relevant, and based on how EPCs are actually carried by real life assessors working under RdSAP 10 conventions.
For fast, local advice from a qualified assessor, contact us directly – or explore the EPC FAQs below to get started.
An EPC shows how energy efficient a home is and is legally required when selling or letting residential property in the UK.
It rates the energy efficiency of a domestic property from A (most efficient) to G (least efficient). It includes estimated energy costs and tailored recommendations for improvement. EPCs are a legal requirement when a home is built, sold, or rented. They help prospective buyers and tenants understand running costs and inform decisions about upgrades and compliance.
Understanding who needs an EPC is essential for anyone involved in selling or renting property in the UK. Under the Energy Performance of Buildings Regulations, both homeowners and landlords are legally required to have a valid Energy Performance Certificate (EPC) before marketing a property.
Homeowners must obtain and provide an valid certificate to prospective buyers when putting their property on the market. This certificate gives buyers clear information about the property’s energy efficiency and expected running costs, helping them make informed decisions.
Similarly, landlords are responsible for securing a valid EPC before advertising a property to let. This ensures that tenants are aware of the property’s energy performance from the outset. It’s important to note that tenants themselves are not responsible for obtaining an EPC, but they do have the right to receive a copy from their landlord.
Failing to provide a valid EPC can lead to financial penalties and enforcement action by the relevant authorities. This applies equally to homeowners and landlords who market properties without the required certificate.
If you’re unsure whether your property needs an EPC, or how to obtain one, our team can help guide you through the process and ensure you remain compliant with the latest regulations, feel free to get in touch
RdSAP 10 changes include more detailed and precise data collection, leading to more accurate EPC ratings.
Key updates include:
-
All windows are now individually measured and assessed.
-
Insulation is recorded with more detail by location, type, and thickness.
-
Heating systems and renewable technologies are modelled more accurately.
-
Ventilation systems, including extractor fans and flues, are recorded in more depth.
-
Air tightness is now part of the energy modelling, and measured values can be entered where a valid certificate exists.
These RdSAP 10 changes lead to more tailored and realistic EPC results. Assessments may take slightly longer, but the final rating will better reflect the true performance of the property.
Yes, EPCs suggest improvements that balance cost and energy savings using current data and modelling.
Energy efficiency recommendations are generated automatically by the RdSAP 10 software based on data collected during the EPC assessment. These suggestions can include upgrades such as improving insulation, replacing an older boiler, or installing renewable technologies like solar panels or heat pumps.
To be included, energy efficiency recommendations must show they can improve the property’s energy rating by at least one point on the SAP scale. The software then prioritises them by cost-effectiveness, using typical installation costs and the expected improvement in energy performance.
However, it’s important to note that these recommendations do not take into account practical factors specific to the property—such as planning restrictions, available space, or individual preferences. They are intended as standardised guidance based on the data gathered, and further advice may be needed to determine what is truly suitable in each case.
EPCs rarely recommend window replacements as a first measure because the efficiency gains are typically limited when compared to the high cost of installation.
While the EPC assessment does record window data in detail—including the width and height of each glazed unit, orientation, frame material, glazing type, age (if known), and the glazing gap—this information is primarily used to calculate overall heat loss rather than to justify replacement.
In most cases, the RdSAP 10 software wont recommend window replacements as replacing windows delivers a relatively small improvement in the property’s SAP score. Given the cost threshold that each recommendation must meet to be considered cost-effective, window upgrades are usually outperformed by measures such as improving insulation, upgrading the heating system, or adding heating controls. As a result, more impactful and cost-efficient improvements tend to appear first in the EPC recommendations list.
How long does an EPC last?
An Energy Performance Certificate is valid for 10 years from the date of issue. There is no legal requirement to renew it within that time, unless you are selling or letting the property again—at which point a valid certificate must be in place.
However, we recommend updating your EPC if you’ve made significant energy improvements. This might include installing a new boiler, upgrading insulation, adding solar panels, or fitting an air source heat pump. A new EPC will reflect these changes and may result in a higher energy rating.
An up-to-date certificate not only helps when marketing a property but may also support compliance with future regulations or eligibility for funding schemes. Increasingly, we’re seeing mortgage lenders take EPC ratings into account, with properties that achieve higher ratings often qualifying for lower interest rates.
The cost of a domestic EPC should be between £96 and £175. This variation depends mainly on your property’s location, size, age, and layout complexity. For example, a small flat with straightforward construction will generally be at the lower end of the price range, while a large detached house with multiple heating zones and renewable systems may cost more.
The cost of a domestic EPC typically covers the assessor’s time spent researching prior to the assessment, the detailed data collection required under the latest RdSAP 10 standards whilst on site, and the time needed to prepare the report after the visit. While cheaper options may be available online, it’s important to choose an assessor with the right qualifications and experience to ensure accuracy and compliance with regulations.
The headline fee shown on UK-wide websites isn’t always the final amount you pay — it is often much higher. Using such platforms that advertise low fees often means the majority of what you pay goes to the website, not the local assessor who actually carries out the work. To ensure the assessor receives fair compensation and you receive a service tailored to your property, it is always best to contact a local accredited assessor directly.
Finding a reliable and qualified EPC assessor is key to receiving an accurate and trustworthy certificate. Always look for assessors who are fully accredited and trained in the latest RdSAP 10 procedures. You can search for qualified assessors on the government’s official EPC register.
Alternatively, you might consider a local provider with a strong reputation, such as Bluewire Hub Ltd, who stays current with evolving standards and has experience across many property types. This experience matters because properties differ widely in construction, heating systems, and renewables, and an assessor familiar with these variables can better reflect your home’s energy performance.
Before booking, check if the assessor holds valid accreditation, ask how long they have been a qualified EPC assessor, do they understand local building styles, and can they offer clear pricing and timelines.
During an EPC assessment, the assessor will spend between 45 and 90 minutes inspecting your property. The exact time depends on the property’s size and complexity. They will measure windows, doors, calculate the floor area, heat loss and party walls, and access roof spaces to understand your home’s fabric and insulation levels.
Heating systems, ventilation, hot water systems, and any renewable technologies like solar panels or heat pumps are carefully examined. The assessor will also note fuel types and controls, including thermostats and programmers.
With RdSAP 10, the EPC assessment data collection is more detailed than before, helping produce a more precise energy rating. The process is non-invasive; the assessor won’t drill holes in walls or ceilings or move furniture or personal items, but will need access to all rooms, the loft, boiler, and meters.
If the assessor is unable to physically evidence an item such as wall or floor insulation then they may not be able to include that in their report. It can be beneficial to liaise with your assessor to ensure you have the correct documentation available when they arrive.
You don’t usually need to be present, but being available to answer questions can help clarify any unique features of your property leading to a more accurate rating.
You can read more about the process here.
Renewable energy systems — including heat pumps, solar photovoltaic (PV) panels, and solar thermal systems — are included in EPC calculations. Under RdSAP 10, these renewable systems are assessed in greater detail than before, with improved modelling for system type, efficiency, and interaction with your home’s heating and electricity demands.
However, EPC ratings are based on calculated energy running costs, not carbon emissions. This means the actual impact on your EPC band depends on how much the renewable system reduces those estimated costs.
-
Heat pumps can improve an EPC rating if they replace less efficient heating systems.
-
Solar PV systems are now modelled more accurately under RdSAP 10. The rating considers system size, orientation, overshading, and whether the system is connected to the properties supply. Having a Solar PV system is likely to improve your EPC rating.
-
Battery storage systems, while recorded, currently have little or no effect on the EPC rating.
-
Solar thermal systems can contribute positively as they typically offset a significant proportion of hot water demand, particularly in homes with high usage.
If you’re planning to install renewables, it’s best to consult a qualified EPC assessor beforehand. They can advise how the improvements are likely to be reflected in your rating.
Can I query my EPC if I believe the EPC contains errors or does not accurately reflect your property? Absolutely you can query or appeal the rating. The first step is always to contact the assessor who carried out the survey. In the first instance have a conversation with them to highlight your concerns or questions. If you aren’t satisfied they will have a formal complaints policy so you can ask them how can I formally query my EPC.
Assessors are required to keep detailed evidence and records of the inspection and may be able to clarify the entry and if required correct any mistakes and reissue the report if appropriate. Remember that the assessor isn’t able to take your word for an element that you are disputing, there must be clear documentary evidence to substantiate the claim. This is particularly important when discussing floor or ceiling insulation that may not be easily accessible.
If the issue is not resolved, you can escalate your concern to the assessor’s accreditation scheme. These bodies have procedures to investigate complaints and may carry out audits or require reassessments.
It’s important to act promptly, as the validity of your EPC remains for 10 years regardless of appeals. Correcting inaccuracies can help ensure your property is correctly valued and compliant.
EPC rating impact on property value is increasingly important in today’s property market. A higher Energy Performance Certificate (EPC) rating can improve a home’s appeal to prospective buyers and tenants, who are becoming more aware of energy efficiency, running costs, and environmental impact.
Properties with better EPC ratings are often associated with lower utility bills and a more comfortable living environment — factors that directly influence purchasing and rental decisions. In competitive markets, a higher rating can give your property an edge over similar homes with lower energy performance.
Lenders are also taking note. Some mortgage providers now offer preferential products for homes with higher EPC ratings, recognising that energy-efficient properties may carry lower financial risk due to reduced household expenditure.
For landlords, the EPC is more than a selling point — it’s a legal requirement. From 2025, all newly rented properties in England and Wales are expected to require a minimum Band C EPC rating, with potential fines for non-compliance. Upgrading your property now not only ensures legal readiness but can also help secure tenants who are actively seeking energy-efficient homes.
Assessing the EPC rating impact on property can also help safeguard your investment in the long term. As legislation becomes more focused on sustainability, and buyers become more energy-conscious, properties with poor EPC ratings may become harder to sell or let. Taking steps to enhance energy performance now can help future-proof your property against tightening standards and rising energy costs.
Updated EPC after improvements is advisable if you’ve made changes to your home’s energy performance. While your original certificate remains valid for 10 years, it reflects the condition of the property at the time of the assessment. Any upgrades carried out after that date — such as new insulation, a replacement boiler, or solar panels — won’t be reflected in your current rating.
This also applies if you’ve made structural changes to the property. For example, if you’ve added an extension, converted a loft or garage, or significantly altered the layout, these changes may affect how heat is retained and distributed in the home. An updated EPC will take account of the increased floor area, new heating zones, window types, and insulation levels introduced during the work.
Having an updated EPC allows you to demonstrate the full benefits of these improvements, which can positively influence your property’s marketability, compliance with future legislation, and eligibility for grants or funding schemes. For landlords, this is particularly relevant if the changes could bring the property closer to, or above, the proposed Band C rating required for new tenancies from 2025.
An updated assessment can also help highlight any remaining areas for improvement and ensure your energy rating reflects the current state of the property, rather than outdated assumptions.
If you are a landlord, or homeowner, looking for advice around improving your EPC rating have a read of our article here.
Th EPC inspection process involves a full walk-through of the property and requires access to all areas, including every room, the loft, boiler, hot water systems, and energy meters. This is necessary to collect the data required under RdSAP 10 and to ensure the final rating is accurate and compliant.
The visit is non-invasive so the assessor will not be drilling walls, lifting floor boards, or opening boiler casings as part of the process. The visit should cause minimal disruption to the occupier, and the building. The assessor won’t carry out any work or alterations, but they will need clear access to inspect walls, measure windows, assess heating controls, and evidence any insulation where visible. If access to areas like the loft hatch or boiler cupboard is blocked, this may affect the assessment, as either, assumptions have to be made, or the assessor may have to arrange to visit again once the access has been cleared.
Having paper work to clarify details around solar PV systems, window installation dates and cavity wall insulation can be beneficial.
In most cases, the assessment takes between 45 and 90 minutes depending on the property’s size and complexity. Being prepared and allowing easy access helps the visit run smoothly.
You can read more about the EPC inspection process here.
EPC lighting changes under RdSAP 10 mean the way lighting is assessed for Energy Performance Certificates (EPCs) has changed significantly to improve accuracy. Unlike previous versions where lighting was evaluated based on the type of light bulbs in each fittings, assessors now count every individual light bulb in the property. Each bulb is recorded and classified according to its type whether it is an LED, CFL, or incandescent bulb.
This more detailed approach means the EPC calculations can better represent the actual energy use of lighting in the home. By identifying the number and types of bulbs, the EPC model can differentiate between energy-efficient lighting, such as LEDs, and less efficient options like incandescent bulbs. The software now calculates lighting efficiency based on the proportion of low-energy bulbs (such as LED or CFL) to the total number of bulbs in the home. Properties with a higher number of inefficient bulbs (e.g. halogen or incandescent) may now see a slightly lower EPC score than under the previous methodology.
The EPC lighting changes change reflect the widespread adoption of low-energy lighting in UK homes while still accounting for any remaining inefficient bulbs. This allows homeowners to see how lighting choices impact their energy performance rating and encourages upgrading to more efficient options where possible.
By moving away from assumptions based on fittings and focusing on actual bulbs, RdSAP 10 provides a more realistic and tailored assessment. This contributes to an EPC that better represents a property’s current energy use, helping homeowners understand where energy savings can be made and improving the overall reliability of the certificate.
Battery storage and EPC ratings are now more closely connected following changes introduced under RdSAP 10. Domestic battery systems — typically installed alongside solar photovoltaic (PV) panels — are now recorded as part of the EPC assessment. This allows assessors to capture a fuller picture of your home’s energy features.
However, even though battery storage is included in the assessment, it usually has little to no impact on the actual EPC rating. This is because EPCs are based on modelled energy costs rather than actual usage or carbon savings. Unless a battery is specifically set up to reduce electricity demand during peak hours, it does not significantly lower the estimated energy cost used in the rating calculation.
Most battery systems store excess solar energy for later use, which can be very effective in practice. But because they don’t always show a measurable cost saving in the EPC model, they rarely improve the rating band.
That said, including battery storage in the EPC provides transparency and may become more relevant in future. As software improves and time-of-use tariffs become more common, smarter battery systems could eventually play a more influential role in determining a property’s energy performance rating meaning there is a better link between battery storage and EPC ratings.
EPC and smart meters are now linked under RdSAP 10, with smart meters recorded as part of the assessment. However, having a smart meter installed does not currently influence the EPC rating or band your property receives.
This is because Energy Performance Certificates are based on the building’s construction, insulation levels, heating systems, and overall energy cost assumptions — not on the way energy is used or monitored. A smart meter helps you track real-time usage and may encourage better energy habits, but it doesn’t affect how efficient your home is from a fabric and systems perspective.
Under the RdSAP 10 methodology, the presence of a smart meter is noted for reference on the certificate, much like solar panels or battery storage. It provides a more complete picture of the home’s energy features but does not impact the calculated running costs that determine your score. It is vital that the assessor is able to access your meters in order to record the correct meter type on the assessment.
Looking ahead, smart meters could play a more active role in future EPC versions, especially as time-of-use tariffs and smart energy management become more widespread. For now, they are recorded but don’t carry any weight in the final EPC result.
An Energy Performance Certificate (EPC) assesses a property’s energy efficiency and environmental impact, rating it from A (most efficient) to G (least efficient). EPCs provide guidance on energy-saving improvements and are required by law when a property is sold or rented.
An EPC is valid for ten years. Significant property changes, such as installing new heating systems or insulation, may affect the rating, so a new assessment may be recommended.
Costs vary depending on property size, type, and location. Bluewire Hub offers competitive rates, which include a full assessment and a certificate for legal compliance.
A typical EPC assessment takes 45–90 minutes, depending on property size and complexity. The assessor inspects all rooms, heating systems, insulation, and energy-using features to produce an accurate rating.
Yes. Landlords must provide a valid EPC to tenants before renting. Failure to comply can lead to fines. EPCs also help attract tenants by demonstrating energy efficiency.
Yes. Scheduling a floor plan alongside an EPC is efficient, reducing multiple visits and providing a comprehensive overview in one appointment.
How to tell what type of floor you have is a common question for homeowners considering insulation or energy improvements. Knowing whether your floor is solid or suspended affects both your property’s heat loss and the options available for insulation.
A suspended timber floor usually has air vents or air bricks visible at ground level on the outside walls. These are designed to keep air flowing under the floorboards to prevent moisture build-up. Suspended floors may also feel slightly springy underfoot compared to a solid concrete floor.
Solid floors, often made of concrete, have no such vents or bricks and feel firm and unyielding underfoot. Tiled or screeded finishes are another clue, as these are typically applied over solid construction. You may also notice there’s no visible void space between the ground and the floor.
If you’re still unsure how to tell what type of floor you have, a qualified surveyor or energy assessor can confirm your floor type as part of an inspection. Understanding your floor type is important for choosing the right insulation method and meeting building regulations.
Floor insulation without disruption is often possible, depending on the construction of your home. Many homeowners worry about mess and upheaval, but there are practical options available to improve insulation with minimal disturbance.
If your home has a suspended timber floor, floor insulation without disruption is usually achievable. The work can often be carried out from below, accessed through a cellar or crawl space, which avoids the need to lift floorboards or disrupt your home’s interior finishes. This method is effective and commonly used in homes with accessible underfloor areas.
For solid floors, insulation typically needs to be installed over the existing surface. While this can raise the floor level slightly, modern insulation materials are designed to minimise impact. Some adjustments to skirting boards, doors, and thresholds may be required, but the work is generally straightforward and can make a noticeable difference to warmth and comfort.
Professional installers will ensure that any existing ventilation, particularly for suspended floors, is preserved or improved as required by building regulations.
Improving floor insulation helps reduce heat loss, enhances energy efficiency, and may positively affect your EPC rating. It’s often a practical choice for homeowners seeking energy improvements without major disruption.
Is floor insulation worth it? In most cases, the answer is yes. Insulating floors brings multiple benefits for homeowners who want to improve comfort, reduce energy bills, and achieve better energy performance ratings.
Uninsulated floors can account for a surprising amount of heat loss, particularly in older properties with suspended timber floors. By adding insulation, you help retain heat within your home, reduce the need for heating, and create a more comfortable living space, especially during colder months.
Solid floor insulation also helps prevent cold bridging and makes floors feel noticeably warmer underfoot. Improved thermal comfort is often one of the first benefits homeowners notice after insulation is installed.
From a financial perspective, the answer to is floor insulation worth it is reinforced by the reduction in heating costs and the potential for improving your EPC rating. A better EPC can help with future saleability, rental potential, and compliance with forthcoming regulations.
If you’re unsure where to start with energy-saving home improvements, floor insulation is often recommended as a practical, cost-effective measure with long-term benefits.
Does floor insulation affect ventilation? Yes, it can — especially with suspended timber floors. Proper ventilation must always be maintained to prevent problems like moisture build-up, condensation, and even structural damage beneath the floor.
Suspended timber floors rely on airflow beneath the property, typically provided through air bricks or vents at ground level. This cross-ventilation prevents damp conditions, protecting the floor timbers and other structural elements. When adding insulation to these types of floors, it’s vital to ensure that the ventilation is not blocked or reduced. Professional installers will address this by maintaining or enhancing existing airflow as required by building regulations.
Solid floors do not need underfloor ventilation as there is no void beneath them, but general room ventilation remains important for overall air quality and moisture control.
If you’re asking, does floor insulation affect ventilation, the answer is that it certainly can, but responsible installation will preserve healthy airflow. A qualified installer or energy assessor can advise on the best approach to ensure your home remains both warm and well-ventilated.
Good insulation and effective ventilation go hand-in-hand to create a comfortable, energy-efficient home.
Estate agents use floor plans to show potential buyers or tenants the property layout. Accurate plans help visualise room sizes, flow, and living space, improving marketing and aiding decision-making.
Floor plans include room dimensions, window and door placement, layout of living spaces, and sometimes furniture suggestions. They are essential for sales, lettings, and planning purposes.
All our floor plans meet estate agent and property marketing standards. They are professionally measured, accurate, and delivered in clear digital format suitable for listings or EPC submissions.
Yes. We can turn hand-drawn sketches or older plans into polished, digital formats suitable for marketing or compliance. This ensures your property meets estate agent requirements.
Yes. We can add room labels, annotations, and key features to highlight a property’s best points, making it visually appealing to potential buyers or tenants.
Yes. All our digital floor plans are compatible with major property portals, ensuring seamless integration for online listings and marketing.
Production time varies by property size, but most plans are completed within 3–5 working days. Digital copies are ready for marketing, estate agent listings, or inclusion with EPC certificates.
Landlords, building owners, and businesses with water systems that could support bacterial growth need legionella risk assessments. This includes showers, taps, and hot water tanks in residential or commercial properties.
A full assessment should be reviewed annually, or whenever the water system or building usage changes. Regular monitoring ensures compliance and reduces risk.
While basic checks can be performed by landlords, professional assessments ensure legal compliance and reduce liability. Our experts provide detailed reports and practical recommendations.
Still confused about EPC FAQs?
If you didn’t find the answer you were looking for in our EPC FAQs, we’re here to help. Whether you have questions about your current EPC, are planning energy improvements, or need a new assessment, please don’t hesitate to get in touch.
Contact us today, and we’ll be happy to provide advice tailored specifically to your property and circumstances. Our goal is to support you with clear, jargon free, practical guidance every step of the way.
