Will this improve my EPC rating?

The work it recommends generally will, but the survey itself is advisory. If you need a new rating, a registered domestic energy assessor produces the EPC.

Should I insulate my solid walls?

Possibly, but the detail matters more than the decision. Impermeable insulation on a breathable wall can trap moisture and cause damage, so the measure has to be designed for the construction.

Should I get a heat pump?

Improve the fabric first. A heat pump sized for a poorly insulated building costs more to install and runs less efficiently than one specified after the losses have been reduced.

Energy efficiency survey (building fabric performance assessment)

Energy efficiency survey

A fabric-first assessment of how your building loses heat and what to do about it, in order — and how that differs from an EPC.

Ask KJ about energy improvements 01706 318200

Last reviewed 31 August 2026

How is an energy efficiency survey different from an EPC?

An EPC is a standardised rating produced to a fixed methodology for sale, letting and compliance. An energy efficiency survey is an advisory inspection of your actual building: how the fabric performs, where heat is lost, what improvements suit that construction, and in what order they should be done. It is not a certificate and it is not lodged on a register; it exists to inform spending decisions.

At a glance

Purpose: Advice on improving a specific building, not a compliance rating.
Approach: Fabric first: reduce demand before changing the heating system.
Construction matters: Solid-wall and traditional buildings need different measures to modern cavity homes.
Not produced: No EPC is generated. That is a separate assessment by a registered assessor.

Why the EPC is not the plan

EPCs are produced to a standardised methodology using assumed values where the assessor cannot see the construction. That is appropriate for comparing properties at scale and unhelpful for deciding what to spend on one house.

The recommendations on an EPC are generic consequences of the input data. They can suggest measures that are wrong for the building — most notably where a traditionally constructed, breathable wall is treated as if it were a modern cavity.

Fabric first, in a defensible order

Reducing heat demand before resizing or replacing a heating system is the sequence that avoids waste. A heat pump specified for a leaky building is oversized, expensive and less efficient than one specified after the fabric has been improved.

The survey establishes the current fabric, identifies the biggest and cheapest losses, and sets out an order of works that keeps each stage useful on its own if the budget stops.

Loft insulation depth, coverage and eaves ventilation
Wall construction and whether cavity or solid-wall measures apply
Floor construction, draughts and air leakage paths
Glazing, doors and the condition of seals
Heating controls and how the property is actually used

Traditional buildings need care

Solid-walled and traditionally constructed buildings work by allowing moisture to pass through and evaporate. Insulating them with impermeable materials can trap moisture within the wall, damaging fabric and embedded timbers.

The right measures exist, but they are specific and need designing rather than fitting. Where a building is listed or in a conservation area, consent may also be required before external changes are made.

Grants and schemes vary by nation

Support for energy improvements is administered differently in England, Scotland, Wales and Northern Ireland, and eligibility and schemes change. Check the current position with the relevant government service for your nation rather than assuming an England scheme applies UK-wide.

EPC and energy efficiency survey compared

Different documents, different purposes. Many owners need both, for different reasons.

	EPC	Energy efficiency survey
Purpose	Standardised rating for sale, letting and compliance	Advice on improving this specific building
Method	Fixed methodology with assumed values	Inspection of the actual construction
Output	A rating and generic recommendations	A prioritised, costed-order improvement plan
Registered	Lodged on the national register	Not lodged; advisory only

Who this is for

A good fit if

Owners planning to spend on insulation, glazing or heating and wanting the right order
Buyers of period property who want a realistic view of running costs
Landlords planning fabric improvements ahead of letting standards
Anyone whose EPC recommendations look wrong for their building

Not the right choice if

Producing an EPC — that requires a registered domestic energy assessor
Designing a heat pump system, which is a heating engineer's calculation
Guaranteeing a specific reduction in energy bills

Spending in the right order

Almost every wasted pound in domestic retrofit comes from doing stage three before stage one.

1.Find out where the heat actually goes
Assumptions about which element is worst are wrong surprisingly often.
Thermal imaging
2.Fix draughts and loft insulation first
The cheapest measures usually deliver the largest proportion of the saving.
3.Match wall measures to the construction
Solid-wall and cavity buildings need genuinely different treatments.
4.Move to a whole-house plan if the work is substantial
A staged retrofit assessment coordinates measures so they do not undermine each other.
Retrofit assessment

When to bring in a specialist

EPC production: a registered domestic energy assessor.
Heating system design and sizing: a qualified heating engineer.
Listed building and conservation area consent: your local authority conservation officer.

Common questions

Limitations and sources

The survey is advisory and non-intrusive; it does not produce or replace an EPC.
Energy savings depend heavily on occupancy and fuel prices, so no specific bill reduction is promised.
Grant schemes and eligibility differ between England, Scotland, Wales and Northern Ireland and change over time.
Nothing on this page is a professional opinion about a specific property. KJ Surveyors has not inspected your building, and general guidance cannot replace an inspection and report.

Source: UK Government · checked August 2026

Source: Historic England · checked August 2026

Source: Scottish Government · checked August 2026

Last reviewed 31 August 2026.

Where to go next

retrofit assessment — for a coordinated whole-house improvement plan.
EPC assessment — when you need the certificate itself for a sale or letting.
thermal imaging — to see exactly where the fabric is failing.

Planning to spend on energy improvements?

Tell KJ the property age, construction and what you are considering. KJ will explain what an assessment should establish before you commit.

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KJ gives general guidance only and has not inspected your property. A professional opinion follows an inspection by a surveyor.