What is a heat pump readiness assessment?

It is a measured survey that establishes whether your home can run a heat pump efficiently before you commit. We carry out a room-by-room heat-loss assessment, review insulation, airtightness and thermal bridging, and check whether your existing radiators or underfloor heating can deliver heat at the low flow temperatures a heat pump needs. You receive an honest readiness verdict — ready now, ready after specific works, or not yet viable — and a fabric-first plan to get there.

Why do I need a heat-loss survey before installing a heat pump?

A heat pump is only efficient at low flow temperatures, and that only works in a home with low, well-understood heat loss. A measured survey sizes the system correctly, identifies the fabric improvements that reduce running cost, and prevents the common outcome of an oversized, expensive unit running hot in an under-insulated home — the main reason people end up disappointed with a heat pump.

What flow temperature should a heat pump run at, and why does it matter?

Heat pumps are most efficient at low flow temperatures — typically 35–45 °C, compared with 60–70 °C for a gas boiler. The lower the flow temperature, the higher the efficiency (a better coefficient of performance). But low flow temperatures only keep rooms warm if heat loss is low and emitters are large enough, which is exactly what the assessment checks.

Will I definitely need to insulate before a heat pump?

Not always — some homes are already adequate. But many UK properties, especially solid-wall and pre-2000 stock, benefit from targeted fabric improvements first. Our assessment tells you exactly what, if anything, is needed to reach a sensible heat demand, rather than assuming either way.

Will my existing radiators work with a heat pump?

Some will, some will not. Radiators sized for a 70 °C boiler often need upsizing to deliver the same heat at 45 °C. We assess each emitter and identify which can stay, which need upsizing and where underfloor heating might be appropriate, so the distribution system matches the low-temperature design.

Does airtightness affect heat pump performance?

Yes. Uncontrolled air leakage adds a large, variable heat load that forces a bigger, less efficient heat pump than the building really needs. Reducing air leakage lowers the heat demand, allows a smaller unit and improves comfort — which is why airtightness is part of the readiness assessment.

Are you independent of heat-pump installers?

Yes. We do not sell or install heat pumps, so our readiness verdict is about your building, not a product sale. The independent report can be handed to your chosen MCS installer or heat-pump designer to inform a correctly sized, efficient design.

How is this different from the survey a heat-pump installer does?

Many installer quotes rely on a desktop heat-loss estimate from floor area and age. Our assessment measures the actual fabric performance — thermal imaging, airtightness and a room-by-room heat-loss survey — so the design is based on how your home really behaves. The two are complementary: our report gives your installer accurate inputs to work from.

What fabric improvements most often help a home become heat-pump ready?

Typically a fabric-first sequence: loft and roof insulation, targeted wall insulation, airtightness improvements and thermal-bridge correction, followed by emitter upgrades where needed. The right combination is specific to your property, and the assessment prioritises it by impact on the heat demand.

What do I receive after the assessment?

A measured heat-loss figure and an honest readiness verdict, a prioritised fabric-first improvement plan, guidance on the realistic flow temperature your home could run at, emitter and distribution recommendations, and an independent report you can hand to your installer or MCS designer.

Can you carry out the recommended fabric works as well?

Yes. Following our Investigate → Diagnose → Design → Remediate → Verify process, the same team can design and deliver the insulation, airtightness and thermal-bridge works that bring the home to readiness, and verify the improvement before the heat pump is installed.

What is a heat pump readiness assessment?

It is a measured survey that establishes whether your home can run a heat pump efficiently before you commit. We carry out a room-by-room heat-loss assessment, review insulation, airtightness and thermal bridging, and check whether your existing radiators or underfloor heating can deliver heat at the low flow temperatures a heat pump needs. You receive an honest readiness verdict — ready now, ready after specific works, or not yet viable — and a fabric-first plan to get there.

Why do I need a heat-loss survey before installing a heat pump?

A heat pump is only efficient at low flow temperatures, and that only works in a home with low, well-understood heat loss. A measured survey sizes the system correctly, identifies the fabric improvements that reduce running cost, and prevents the common outcome of an oversized, expensive unit running hot in an under-insulated home — the main reason people end up disappointed with a heat pump.

What flow temperature should a heat pump run at, and why does it matter?

Heat pumps are most efficient at low flow temperatures — typically 35–45 °C, compared with 60–70 °C for a gas boiler. The lower the flow temperature, the higher the efficiency (a better coefficient of performance). But low flow temperatures only keep rooms warm if heat loss is low and emitters are large enough, which is exactly what the assessment checks.

Will I definitely need to insulate before a heat pump?

Not always — some homes are already adequate. But many UK properties, especially solid-wall and pre-2000 stock, benefit from targeted fabric improvements first. Our assessment tells you exactly what, if anything, is needed to reach a sensible heat demand, rather than assuming either way.

Will my existing radiators work with a heat pump?

Some will, some will not. Radiators sized for a 70 °C boiler often need upsizing to deliver the same heat at 45 °C. We assess each emitter and identify which can stay, which need upsizing and where underfloor heating might be appropriate, so the distribution system matches the low-temperature design.

Does airtightness affect heat pump performance?

Yes. Uncontrolled air leakage adds a large, variable heat load that forces a bigger, less efficient heat pump than the building really needs. Reducing air leakage lowers the heat demand, allows a smaller unit and improves comfort — which is why airtightness is part of the readiness assessment.

Are you independent of heat-pump installers?

Yes. We do not sell or install heat pumps, so our readiness verdict is about your building, not a product sale. The independent report can be handed to your chosen MCS installer or heat-pump designer to inform a correctly sized, efficient design.

How is this different from the survey a heat-pump installer does?

Many installer quotes rely on a desktop heat-loss estimate from floor area and age. Our assessment measures the actual fabric performance — thermal imaging, airtightness and a room-by-room heat-loss survey — so the design is based on how your home really behaves. The two are complementary: our report gives your installer accurate inputs to work from.

What fabric improvements most often help a home become heat-pump ready?

Typically a fabric-first sequence: loft and roof insulation, targeted wall insulation, airtightness improvements and thermal-bridge correction, followed by emitter upgrades where needed. The right combination is specific to your property, and the assessment prioritises it by impact on the heat demand.

What do I receive after the assessment?

A measured heat-loss figure and an honest readiness verdict, a prioritised fabric-first improvement plan, guidance on the realistic flow temperature your home could run at, emitter and distribution recommendations, and an independent report you can hand to your installer or MCS designer.

Can you carry out the recommended fabric works as well?

Yes. Following our Investigate → Diagnose → Design → Remediate → Verify process, the same team can design and deliver the insulation, airtightness and thermal-bridge works that bring the home to readiness, and verify the improvement before the heat pump is installed.

Diagnostics · Heat Pump Readiness

Heat Pump Readiness Assessment

Before you install a heat pump, find out whether your home can actually run one efficiently. A measured heat-loss survey, fabric and airtightness assessment and emitter review — so a low-temperature heat pump performs as promised, instead of running hot, expensive and disappointing.

The Retrofit IQ methodology

One process — every service is a stage of it.

This is engineering-led work, so our process adds a Predict stage — building-physics modelling, heat-loss and condensation-risk calculation and performance forecasting before anything is built.

Stage 1Investigate

Stage 2Diagnose

EngineeringPredict

Stage 4Design

Stage 5Remediate

Stage 6Verify

The Predict stage is where engineering decisions are made on calculations, not assumptions — see the Building Physics Assessment.

What this service is

Heat Pump Readiness Assessment — in plain English.

A Heat Pump Readiness Assessment establishes, before you commit, whether your home can run a heat pump efficiently. We carry out a measured room-by-room heat-loss survey, assess the fabric and airtightness, and review whether your existing emitters can deliver heat at the low flow temperatures a heat pump needs — so the system is sized correctly and runs efficiently, rather than hot, expensive and disappointing.

Why it matters

Why heat pump readiness assessment is important.

A heat pump is only as efficient as the building it heats. These systems are designed to run at low flow temperatures, which only works in a home with low, well-understood heat loss — otherwise the unit runs hot, expensive and disappointing, and the homeowner blames the technology rather than the fabric. A readiness assessment measures the real heat demand room by room, checks the fabric and airtightness, and reviews whether existing emitters can deliver heat at low temperatures. Doing this before installation means a smaller, cheaper, quieter, genuinely efficient system — and avoids the all-too-common badly performing heat pump.

When to commission it

The right time to bring us in.

Before getting heat-pump quotes, so the design is based on measured data not a desktop estimate
When existing radiators already struggle on the coldest days
When you want to know which fabric upgrades are needed first to size a smaller system
Before committing to a grant-funded installation that assumes a ready building
When a previous heat-pump quote seems oversized, noisy or expensive to run

Common problems we solve

The symptoms that bring people to this service.

01Considering a heat pump but unsure the home can run one efficiently
02Radiators that already struggle to heat rooms on cold days
03Cold rooms, draughts and high bills hinting at significant heat loss
04An installer quote based on a desktop estimate, not a measured survey
05Uncertainty about which fabric upgrades are needed first
06A wish to avoid an oversized, noisy or costly-to-run system

Typical symptoms

What you tend to notice first.

Considering a heat pump but unsure whether the home can run one efficiently
Existing radiators that already struggle to heat rooms on cold days
Cold rooms, draughts and high bills suggesting significant heat loss
An installer quote based on a desktop estimate rather than a measured survey
Uncertainty over which fabric upgrades are needed before installation
A wish to avoid an oversized, noisy or costly-to-run system

How we investigate

Our diagnostic approach

01Measured room-by-room heat-loss survey using a fabric assessment, not a desktop estimate
02Thermal imaging and airtightness checks to quantify real losses
03Review of wall, roof and floor insulation and the realistic upgrades available
04Emitter survey — whether existing radiators / underfloor can run at low flow temperatures
05Assessment of ventilation and moisture behaviour as the fabric is tightened
06Modelling of the heat demand a low-temperature system would need to meet

Diagnostic equipment used

What we bring on site

Calibrated FLIR thermal imaging camera
Blower door fan for airtightness assessment
Moisture meters and surface-temperature probes
Temperature and humidity data loggers
Fabric U-value and heat-loss modelling tools

Building physics — why this works

The science behind the diagnosis.

Heat pumps achieve their high efficiency (a COP of 3–4) by delivering heat at low flow temperatures — typically 35–45 °C rather than the 60–70 °C of a gas boiler. That only works if the building's heat loss is low enough for large, low-temperature emitters to keep rooms warm. Reduce heat loss through fabric and airtightness first and you can size a smaller, cheaper, quieter heat pump that runs efficiently; skip that step and the system runs hard, costs more and underperforms. Fabric first, heat pump second is building physics, not preference.

What you get

Measured benefits — not vague promises.

A measured whole-house heat-loss figure and an honest readiness verdict
A prioritised, fabric-first plan to reach the required heat demand
Guidance on the realistic flow temperature your home could run at
Emitter and distribution recommendations for low-temperature heating
A smaller, cheaper, quieter and more efficient system once ready
An independent report to hand to your installer or MCS designer

What we design and deliver next.

Every recommendation follows our methodology — Investigate → Design → Verify — so the diagnosis on this page leads directly into an engineered, buildable and independently verified solution.

A measured whole-house heat-loss figure and an honest readiness verdict
A prioritised, fabric-first plan to reach the heat demand a heat pump needs
Guidance on the realistic flow temperature your home could run at
Emitter and distribution recommendations to support low-temperature heating
Airtightness and thermal-bridge improvements that reduce the required system size
An independent report to hand to your heat-pump installer or MCS designer

Common construction defects we find

What goes wrong on site — and why it matters.

Our diagnoses are grounded in real site experience. These are the workmanship and detailing failures we repeatedly find on this kind of work — the difference between a building that should perform and one that actually does.

Heat loss never measured

Sizing based on floor area or a quick desktop estimate routinely oversizes the unit and ignores the fabric upgrades that would let it run efficiently.

Undersized emitters left in place

Radiators sized for a 70 °C boiler cannot deliver enough heat at a heat pump's 35–45 °C flow temperature, so rooms run cold or the system runs hot.

Microbore pipework restricting flow

Narrow legacy pipework throttles the larger flow rates a low-temperature system needs, hurting both output and efficiency.

Air leakage inflating heat demand

An untested, leaky envelope adds a large uncontrolled load that forces a bigger, less efficient heat pump than the home really needs.

Cold bridges undermining comfort

Uncorrected cold surfaces keep rooms feeling cool at low flow temperatures, prompting occupants to push the system harder.

What we assess

Whole-house heat loss (room-by-room) using a measured fabric survey, not a desktop estimate
Wall, roof and floor insulation levels and the realistic upgrades available
Airtightness and uncontrolled air leakage that drives up the heat demand
Thermal bridges and cold surfaces that undermine low-temperature heating
Existing emitters (radiators / underfloor) and whether they can deliver heat at a low flow temperature
Ventilation and moisture behaviour as the fabric is tightened

What you receive

A measured heat-loss figure and an honest readiness verdict — ready now, ready after specific works, or not yet viable
A prioritised, fabric-first improvement plan to reach the heat demand a heat pump needs
Guidance on the flow temperature your home could realistically run at
Emitter and distribution recommendations to support a low-temperature system
An independent report you can hand to your heat-pump installer or MCS designer

Why fabric first, heat pump second

Heat pumps are most efficient at low flow temperatures — which only works in a low-heat-loss home
Reducing heat loss before sizing the heat pump means a smaller, cheaper, quieter unit
Existing radiators often only work at high flow temperatures unless the fabric is improved
Airtightness and insulation improvements cut running cost whatever heating you choose
We are independent of installers — our verdict is about your building, not a sale

Typical findings

What we commonly discover during heat pump readiness assessment investigations

01Whole-house heat loss far higher than a desktop estimate assumed
02Existing radiators undersized for the low flow temperatures a heat pump needs
03Significant air leakage inflating the heat demand and the required system size
04Uninsulated or under-insulated walls, floors and lofts dominating the heat loss
05Cold bridges keeping rooms cool at low flow temperatures
06Microbore or restrictive pipework limiting achievable flow rates

Findings reflect patterns observed across completed RetrofitIQ projects — every survey is interpreted in the building’s specific context.

Real Retrofit IQ Investigations

See this service applied on real investigations

IG8 · Whole-flat measured heat-loss survey + costed improvement report
IG8, London · March 2026 · Checkatrade

All investigations Project gallery

FAQs

Heat Pump Readiness Assessment — common questions

What is a heat pump readiness assessment?+
It is a measured survey that establishes whether your home can run a heat pump efficiently before you commit. We carry out a room-by-room heat-loss assessment, review insulation, airtightness and thermal bridging, and check whether your existing radiators or underfloor heating can deliver heat at the low flow temperatures a heat pump needs. You receive an honest readiness verdict — ready now, ready after specific works, or not yet viable — and a fabric-first plan to get there.
Why do I need a heat-loss survey before installing a heat pump?+
A heat pump is only efficient at low flow temperatures, and that only works in a home with low, well-understood heat loss. A measured survey sizes the system correctly, identifies the fabric improvements that reduce running cost, and prevents the common outcome of an oversized, expensive unit running hot in an under-insulated home — the main reason people end up disappointed with a heat pump.
What flow temperature should a heat pump run at, and why does it matter?+
Heat pumps are most efficient at low flow temperatures — typically 35–45 °C, compared with 60–70 °C for a gas boiler. The lower the flow temperature, the higher the efficiency (a better coefficient of performance). But low flow temperatures only keep rooms warm if heat loss is low and emitters are large enough, which is exactly what the assessment checks.
Will I definitely need to insulate before a heat pump?+
Not always — some homes are already adequate. But many UK properties, especially solid-wall and pre-2000 stock, benefit from targeted fabric improvements first. Our assessment tells you exactly what, if anything, is needed to reach a sensible heat demand, rather than assuming either way.
Will my existing radiators work with a heat pump?+
Some will, some will not. Radiators sized for a 70 °C boiler often need upsizing to deliver the same heat at 45 °C. We assess each emitter and identify which can stay, which need upsizing and where underfloor heating might be appropriate, so the distribution system matches the low-temperature design.
Does airtightness affect heat pump performance?+
Yes. Uncontrolled air leakage adds a large, variable heat load that forces a bigger, less efficient heat pump than the building really needs. Reducing air leakage lowers the heat demand, allows a smaller unit and improves comfort — which is why airtightness is part of the readiness assessment.
Are you independent of heat-pump installers?+
Yes. We do not sell or install heat pumps, so our readiness verdict is about your building, not a product sale. The independent report can be handed to your chosen MCS installer or heat-pump designer to inform a correctly sized, efficient design.
How is this different from the survey a heat-pump installer does?+
Many installer quotes rely on a desktop heat-loss estimate from floor area and age. Our assessment measures the actual fabric performance — thermal imaging, airtightness and a room-by-room heat-loss survey — so the design is based on how your home really behaves. The two are complementary: our report gives your installer accurate inputs to work from.
What fabric improvements most often help a home become heat-pump ready?+
Typically a fabric-first sequence: loft and roof insulation, targeted wall insulation, airtightness improvements and thermal-bridge correction, followed by emitter upgrades where needed. The right combination is specific to your property, and the assessment prioritises it by impact on the heat demand.
What do I receive after the assessment?+
A measured heat-loss figure and an honest readiness verdict, a prioritised fabric-first improvement plan, guidance on the realistic flow temperature your home could run at, emitter and distribution recommendations, and an independent report you can hand to your installer or MCS designer.
Can you carry out the recommended fabric works as well?+
Yes. Following our Investigate → Diagnose → Design → Remediate → Verify process, the same team can design and deliver the insulation, airtightness and thermal-bridge works that bring the home to readiness, and verify the improvement before the heat pump is installed.

Related comparisons

Weighing this up against the alternatives?

Independent, building-physics-led comparisons from our knowledge base — written to help you understand the difference before you decide which survey or approach you actually need.

Browse the full comparison library

Home Problems Knowledge Base

Common problems we diagnose

The symptoms that most often lead homeowners to a heat pump readiness assessment. Each guide explains the building physics behind the problem — and how we diagnose the real cause before any work begins.

Browse the full Home Problems Knowledge Base

Where this fits

Part of one connected building-performance journey.

Every Retrofit IQ service is one stage of a single methodology — Investigate → Design → Verify. Explore how this service connects to the wider network of diagnostics, engineering and quality assurance.

Investigate

Building Performance Diagnostics

Design

Building Performance Engineering

Verify

Building Performance Quality Assurance

Building Performance Engineering

View the Building Performance Engineering hub

Related & verification

The engineering and quality-assurance services that most often follow this one.

Next step

One company. One process. One point of responsibility.

We don’t simply identify problems. We investigate, diagnose, design solutions, carry out the work and verify the results. Book a Home Health Diagnostic Survey and we’ll tell you exactly which remedial works (if any) are actually needed.

Book a Survey Call 0753 824 3578

Real investigations Project gallery Verified reviews About George

Specialist engineering assessment

Want engineering certainty before you invest?

Commission a Retrofit IQ Building Physics Assessment

After this investigation, you can commission a Building Physics Assessment for an advanced engineering analysis. A standard survey identifies the problems; this uses advanced building physics modelling to predict how your building is expected to perform after the proposed upgrade — before any work begins.

Most contractors recommend insulation. Retrofit IQ predicts how your building is expected to perform first.

Reviewed by a Certified Passive House Designer

Learn about Building Physics Assessment

The assessment can add

Building performance prediction

Advanced building physics modelling

Thermal bridge analysis

Heat flow and heat loss calculations

Moisture movement analysis

Interstitial condensation risk assessment

U-value calculations

Summer overheating prediction

Winter performance prediction

Comparison of multiple insulation options

Retrofit IQ Building Physics Report

One company · the whole process

Investigate → Diagnose → Design → Remediate → Verify

RetrofitIQ is not only a diagnostics company. We take projects from first investigation through to verified improvement — and you decide how far we go. Engage us for an investigation on its own, an investigation plus targeted remedial works, or a complete building-performance and retrofit project.

Investigate

Diagnose

Design

Remediate

Verify

Option 1

Investigation only

A measured diagnosis — thermal imaging, blower door testing, moisture and building-physics analysis — with a clear, costed report you can act on however you choose.

Option 2

Investigation + remedial works

We investigate, then carry out targeted remedial works — airtightness, insulation, ventilation or thermal-bridge corrections — and verify the result.

Option 3

Complete retrofit project

A full fabric-first, Passive House-informed retrofit from diagnosis through design, installation and verification — one accountable team, one point of responsibility.

Remediation & retrofit works we can carry out

Airtightness improvements & draught-proofing
Internal wall insulation (IWI)
External wall insulation (EWI)
Loft & roof insulation
Suspended floor & underfloor insulation
Thermal-bridge detailing & correction
Extract ventilation & MVHR installation
Soundproofing & acoustic upgrades
General building-fabric improvements

Book a Survey

Evidence from Real Projects (8)

Real project and investigation images from our own fieldwork, matched to this page — not stock photography.

Blower Door Airtightness Test Setup

Thermal Bridging Visible Through Masonry Blockwork Wall

DampSutton

Sample Building Performance Investigation Report — Thermal Imaging

CondensationLewisham

Acoustic Floor Upgrades: Mineral Wool Insulation Between Joists

Heat LossHarringey

Thermal Bridge at Internal Corner Wall Junction

Heat LossNewham

Thermal Bridge at Wall-Ceiling Junction Near Window

View all Heat Loss evidence

No related investigations yet.

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Areas we cover · London & surrounding counties

Heat Pump Readiness Assessment across London & the surrounding areas.

Explore building performance diagnostics, damp and condensation investigations, airtightness testing and retrofit advice in your area. We cover London, Greater London, East London, Essex, Kent, Surrey, Hertfordshire and the surrounding counties.

All areas we cover