Energy Performance Certificates (EPCs) in Duston

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.

Homeowners and landlords are legally required to have a valid Energy Performance Certificate (EPC) before marketing a property for sale or let. It gives buyers and tenants clear information about the property’s energy efficiency and expected running costs.

Tenants don’t need to obtain an EPC themselves, but they’re entitled to a copy from their landlord. Marketing a property without a valid EPC can lead to financial penalties.

Not sure if your property needs one, or how to get one? Get in touch.

RdSAP 10 collects more detailed data for a more accurate EPC rating. Key changes include:

• Every window is now individually measured and assessed.
• Insulation is recorded by location, type, and thickness.
• Heating systems and renewables are modelled more accurately.
• Ventilation, including extractor fans and flues, is recorded in more depth.
• Air tightness is now part of the modelling, using measured values where available.

Assessments may take slightly longer, but the result better reflects how the property actually performs.

Yes. The RdSAP 10 software generates improvement recommendations automatically from the data collected during your assessment, things like better insulation, a newer boiler, or renewables such as solar panels or a heat pump.

To be included, a recommendation must improve your SAP score by at least one point, and suggestions are ranked by cost-effectiveness. They’re standardised guidance based on the data gathered, not a full survey, so practical factors like planning restrictions or available space aren’t accounted for.

Because the efficiency gain rarely justifies the cost. Your assessment records window details in full, width, height, orientation, frame material, glazing type, age, and gap, but this is mainly used to calculate heat loss rather than to recommend replacement.

Replacing windows delivers a relatively small SAP score improvement for the money, so measures like better insulation, a heating system upgrade, or improved heating controls usually appear higher on the recommendations list instead.

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.

Look for an assessor who’s fully accredited and trained in the current RdSAP 10 procedures. You can check accreditation on the government’s EPC register.

A local assessor with a strong reputation and experience across different property types is often a good bet, construction, heating systems, and renewables all vary, and familiarity with these helps an assessor capture your home’s energy performance accurately.

Before booking, ask how long they’ve been accredited, whether they know local building styles, and whether they can offer clear pricing and timelines upfront.

Yes, heat pumps, solar PV, solar thermal, and battery storage are all recorded in your EPC assessment. Under RdSAP 10 they’re modelled in more detail, but your rating is based on calculated running costs, not carbon savings, so the actual impact varies by system.

• Heat pumps can improve your rating if they replace a less efficient heating system.
• Solar PV is modelled on system size, orientation, and overshading, and is likely to help your rating.
• Battery storage is recorded but currently has little effect on the score.
• Solar thermal can help by offsetting hot water demand.

Planning to install renewables? It’s worth checking with a qualified assessor first on how the improvement is likely to show up in your rating.

Yes. Start by contacting the assessor who carried out the survey, most concerns can be resolved with a conversation, and every assessor has a formal complaints process if you need to escalate.

Assessors keep detailed records and evidence from the inspection, so they can clarify or correct entries and reissue the report where appropriate. Bear in mind they can’t take your word alone for disputed items like floor or ceiling insulation, there needs to be documentary evidence.

If it’s still not resolved, you can escalate to the assessor’s accreditation scheme, who can investigate or require a reassessment. It’s worth acting promptly, since your EPC stays valid for 10 years regardless of any ongoing query.

A higher EPC rating makes a property more appealing to buyers and tenants, who increasingly weigh up running costs and energy efficiency. It’s also linked to lower bills and better comfort, both of which matter in a competitive market.

Some mortgage lenders now offer better terms for energy-efficient homes. For landlords it’s more than a selling point, from 2025 newly rented properties in England and Wales are expected to need at least an EPC Band C, with fines for non-compliance.

As standards tighten and buyers grow more energy-conscious, properties with poor ratings may become harder to sell or let, so improving your rating now helps future-proof the property.

The assessor needs to walk through the whole property, every room, the loft, boiler, hot water system, and meters, to collect the data required under RdSAP 10.

It’s non-invasive: no drilling, lifting floorboards, or opening up the boiler casing. They won’t carry out any work, but do need clear access to inspect walls, measure windows, check heating controls, and evidence any insulation that’s visible. If access to the loft hatch or boiler cupboard is blocked, they may have to make assumptions or arrange a second visit. Paperwork for solar PV, window installation dates, or cavity wall insulation is helpful if you have it.

Visits typically take 45 to 90 minutes. Read more about getting ready for your EPC.

Lighting is now assessed bulb by bulb rather than by fitting. Assessors count and classify every bulb in the property, LED, CFL, or incandescent, rather than estimating from fitting types.

This lets the EPC model reflect actual lighting energy use more accurately: the more low-energy bulbs you have relative to the total, the better your lighting score. Properties with a lot of halogen or incandescent bulbs may see a slightly lower score than under the old methodology.

The change reflects how widely LEDs have been adopted in UK homes, while still accounting for any inefficient bulbs that remain, giving a more realistic picture of a property’s actual energy use.

Battery storage is recorded as part of the EPC assessment under RdSAP 10, but it usually has little to no effect on the actual rating. EPCs are based on modelled energy costs rather than real usage, so unless a battery is specifically set up to cut electricity demand at peak times, it won’t meaningfully lower the estimated cost used in the calculation.

Batteries paired with solar can be genuinely useful in practice, they just don’t tend to move the needle on your EPC band yet. That could change as time-of-use tariffs and smarter systems become more common.

Having a smart meter is recorded on your EPC under RdSAP 10, but it doesn’t affect your rating or band. EPCs are based on your building’s construction, insulation, and heating systems, not how you monitor your usage.

A smart meter is noted for reference, similar to solar panels or battery storage, but it has no bearing on the calculated running costs behind your score. It’s important the assessor can access your meters to record the correct type. That could change in future EPC versions as smart energy management becomes more widespread, but for now it’s recorded, not scored.