Professional heating design
Heat Loss Surveys and Room-by-Room Calculations
Understand how much heat your home needs before choosing a heat pump, boiler, radiators or underfloor heating.
Enerus surveys the property and produces a detailed digital report using room measurements, building-fabric information, design temperatures and recognised calculation methods.
A clearer place to start
What is a heat loss survey?
A heat loss survey establishes the heating power each room needs at the selected indoor and outdoor design temperatures.
The calculation considers room dimensions, exposed walls, floors and ceilings, construction types, insulation, windows, doors and ventilation. Those losses are calculated room by room and then combined to establish the design heat load for the complete property.
This removes the need to size a heating system from floor area, bedroom count or the output of an existing appliance. It creates the evidence needed to select equipment and check whether radiators or underfloor heating can deliver the required warmth.
Who benefits?
When do you need a room-by-room heat loss calculation?
The same property data supports several different heating decisions.
Heat pump installation
Establish design load, heat pump capacity, flow-temperature targets and the emitter upgrades the home may require.
Explore heat pumps → 2Boiler replacement
Avoid simply copying an oversized existing boiler and understand the home’s actual space-heating requirement.
Explore boilers → 3Underfloor heating
Compare required room output with available heated area, floor construction and proposed operating temperature.
Explore underfloor heating → 4Radiator upgrades
Check the required emitter output in every room at the flow temperature planned for the heating system.
Ask about radiator design →From property to report
How your heat loss survey works
Accurate design depends on collecting the right information, recording assumptions and turning the results into useful recommendations.
Step 1 of 4
Tell us about the property and project
We establish what the calculation will be used for and gather useful information before the survey.
- Property address, type and approximate age
- Existing and proposed heating system
- Available plans, extension details or renovation proposals
- Known insulation and glazing improvements
Step 2 of 4
Measure and assess each room
The survey records the dimensions and heat-loss surfaces that make each room behave differently.
- Room length, width and height
- Windows, external doors and exposed surfaces
- Wall, floor, roof and glazing construction
- Existing radiators or other heat emitters
Step 3 of 4
Calculate fabric and ventilation losses
Professional design software applies the recorded dimensions, thermal values and selected design temperatures.
- Fabric heat loss through building elements
- Ventilation and air-change allowance
- Individual room design heat loss
- Whole-property peak heating demand
Step 4 of 4
Receive the report and design outputs
The result is presented in a digital report so the figures can inform the next stage of the heating project.
- Room schedule and total design heat loss
- Emitter outputs and potential upgrades
- Relevant design temperatures and assumptions
- Heating-system recommendations for the agreed scope
A useful design document
What your heat loss survey includes
The report brings the building information and room calculations together in a format that can guide equipment and emitter selection.
Property measurements
Dimensions and exposed surfaces recorded for each included room.
Fabric assessment
Walls, floors, roofs, windows and doors assigned suitable thermal values.
Ventilation losses
Heat required to warm replacement air included in each room calculation.
Design temperatures
Room targets and the relevant external design condition clearly stated.
Room-by-room results
Individual design heat loss expressed in watts or kilowatts for every included space.
Whole-home heat loss
Combined property demand used to inform selection of the heating appliance.
Emitter assessment
Required radiator or underfloor-heating outputs for the proposed design conditions.
Digital PDF report
A detailed record of the calculation, assumptions and agreed design recommendations.
Illustrative report preview
What do room-by-room results look like?
This simplified example shows how different rooms can require very different heat outputs. It is not a calculation for your property.
| Room | Area | Target temperature | Example heat loss |
|---|---|---|---|
| Living room | 18.0m² | 21°C | 1.82kW |
| Kitchen | 11.0m² | 20°C | 1.27kW |
| Entrance hall | 8.0m² | 18°C | 1.19kW |
| Downstairs WC | 2.9m² | 18°C | 0.87kW |
| Utility room | 3.4m² | 18°C | 0.95kW |
| Landing | 2.7m² | 18°C | 0.63kW |
| Bedroom 1 | 15.0m² | 18°C | 1.09kW |
| Bedroom 2 | 11.0m² | 18°C | 0.87kW |
| Total | 72.0m² | — | 8.69kW |
Why the detail matters
One calculation, several design decisions
Select a heating application to see how the survey results are used.
Heat pump sizing and lower-temperature design
Heat pumps are normally designed to provide steady heat over longer periods. The whole-property heat loss informs capacity selection, while individual rooms determine the emitter output required at the proposed flow temperature.
An undersized unit may struggle at cold design conditions. Unnecessary oversizing can affect cycling, controllability, cost and performance.
- Establish design heating demand
- Select an appropriate heat pump output
- Test radiator performance at lower temperatures
- Support the detailed MCS design process
Radiator sizing at the intended flow temperature
A radiator must be able to replace the heat its room loses. Its published output changes with the mean water temperature, so a radiator that performs adequately with a boiler may provide less output on a lower-temperature system.
The calculation helps identify which existing radiators can remain and which may require an upgrade.
- Required output for each room
- Existing emitter output assessed
- Proposed flow temperature considered
- Upgrades targeted rather than assumed
Boiler selection based on the property demand
Existing boilers have often been selected with a large allowance or sized principally around hot-water delivery. A heat loss survey separates the space-heating requirement from assumptions based on the old appliance.
For combi boilers, domestic hot-water demand may still determine the available model range, but the heating calculation supports improved setup and modulation decisions.
- Understand the real space-heating load
- Avoid copying the old boiler output blindly
- Inform system temperatures and controls
- Support radiator and balancing decisions
Underfloor-heating output and floor-area checks
Underfloor heating has a finite output based on available heated area, floor construction, finishes, pipe arrangement and water temperature. The room heat loss provides the load that the floor must meet.
Identifying any shortfall early allows the design, fabric or supplementary emitters to be reconsidered before installation.
- Compare demand with available floor output
- Inform pipe spacing and circuit design
- Consider floor finishes and temperature limits
- Identify rooms needing additional attention
Professional survey and report
Heat loss survey pricing
Professional surveys start from £295.
The final price depends on the size and complexity of the property, its location, the available information and the design outputs required. We confirm the scope and price before the survey is arranged.
This keeps the service appropriate for anything from a typical existing home to a larger renovation or property with unusual construction.
Why choose Enerus?
Heating designers as well as installers
Enerus works across heat pumps, boilers, radiators and underfloor heating. That whole-system experience helps turn a set of heat-loss figures into practical design decisions.
- Professional heating-design software
- Room-by-room rather than floor-area-only calculations
- Experience with lower-temperature heating systems
- Clear assumptions and digital reporting
- North East property and climate knowledge
- A route from calculation to complete system design
Local survey coverage
Heat loss surveys across the North East
Enerus surveys a wide range of North East properties, including modern developments, Victorian terraces, rural off-gas-grid homes, solid-wall houses and larger renovation projects.
The building itself determines the calculation. Its age can provide clues, but insulation, alterations, glazing, exposed surfaces and construction details must still be considered.
Design grounded in the property
From survey information to a correctly sized system
Room measurements, construction details and emitter performance are brought together before equipment is selected.
Common questions
Heat loss survey FAQs
How much does a heat loss survey cost?
Enerus professional heat loss surveys start from £295. The final price depends on property size, complexity, location and the agreed report and design scope.
Does every room need to be assessed?
A proper room-by-room calculation requires information for every heated room within the agreed scope. Access is normally needed unless reliable plans and construction information provide an appropriate alternative.
Can a heat loss calculation be completed from drawings?
Calculations can often be produced from sufficiently detailed architectural drawings and specifications, particularly for new builds or planned renovations. The available information and need for verification should be agreed first.
Is a room-by-room calculation required for a heat pump?
Room-by-room heat loss and emitter design form an essential part of a properly designed domestic heat pump system and the applicable MCS design process.
Will the report tell me which radiators need replacing?
Where radiator assessment is included, the report can compare required room output with existing or proposed emitter performance at the selected system temperatures.
Is a heat loss survey the same as an EPC?
No. An EPC provides a standardised assessment of a property’s energy performance. A heating heat-loss calculation is used to establish room and whole-property design heating loads.
Does the result predict my annual energy bill?
No. Peak design heat loss is not annual energy consumption. Running costs also depend on weather over the year, occupancy, controls, system efficiency, hot-water use and energy tariffs.
Can the survey be used for underfloor heating?
Yes. The room loads can be compared with the output available from the proposed heated floor area, construction and operating temperatures.
Does the survey include a heat pump or boiler quotation?
The survey and installation quotation should be treated as separate scopes unless your written proposal says otherwise. Tell Enerus what you intend to use the report for when requesting the survey.
Can I use the report when discussing the project with another professional?
The digital report is intended to provide useful design information. Its suitability for a particular third-party design, compliance submission or installation should be confirmed by the professional relying on it.
Replace guesswork with a design
Find out how much heat your home really needs
Request a professional heat loss survey and receive the room-by-room information needed to plan your heating system with confidence.