Independent Heating System Design for House Renovations
Complete heating system design for renovations, extensions and major refurbishments — from room-by-room heat loss calculations to radiators, underfloor heating, pipework and heat pump hydraulics.
Renovating a house provides an opportunity to design the heating system properly, before floors are laid, walls are closed and expensive decisions become difficult to change.
Whether you are renovating a Victorian property, extending a family home or completely refurbishing a large residential building, the heating system needs to be designed around the property you are creating, not simply the building that exists today.
Heat Loss Hub provides independent heating system design services for homeowners, architects and building contractors across England, Wales and Scotland.
We calculate the heating requirements of individual rooms, assess suitable heating emitters, establish appropriate operating temperatures and develop the technical design needed to bring the system together.
Our work is particularly suited to renovations involving heat pumps, underfloor heating, radiators and alterations to existing wet central heating systems.
We do not sell heat pumps, heating equipment or installation services. Our role is to provide the independent technical design that helps you and your appointed installer make informed decisions.
WHO IT'S FOR
Who Is This Heating Design Service For?
Our renovation heating design service is intended for projects where the heating system needs more consideration than simply replacing an existing boiler or choosing new radiators.
Typical projects include:
- Whole-house renovations and substantial refurbishments.
- Extensions that change the heating requirements of an existing property.
- Older properties undergoing insulation and glazing improvements.
- Homes replacing existing central heating with a heat pump.
- Renovations combining underfloor heating and radiators.
- Properties requiring new heating pipework or altered distribution systems.
- Large houses with several heating zones, plant rooms or complex pipework arrangements.
- Architect-led projects where heating decisions need coordinating with the building design.
We can work directly with homeowners or alongside an architect, builder or heating installation contractor.
Some customers approach us with completed architectural drawings and a clear specification. Others are still working through their options and need to understand what is technically achievable before making further decisions.
The first step is to establish what information is available, what decisions have already been made and which design services the project requires.
WHAT'S INCLUDED
What Does a Complete Heating System Design Include?
A complete heating design considers the building, the heat emitters, the heat source and the pipework connecting everything together.
Designing these elements independently can lead to problems that only become apparent during installation or once the heating system is operating.
Heat Loss Hub can provide the following design services as part of an agreed commission.
Room-by-Room Heat Loss Calculations
Every heating system design begins by establishing how much heat the finished property will require.
We calculate heat losses through the building fabric, including walls, floors, roofs, windows and doors, together with ventilation and air infiltration.
The calculations consider each room individually, using appropriate design temperatures and the proposed building specification.
This establishes:
- The design heating requirement of each room.
- The overall space-heating load of the property.
- The output required from radiators or underfloor heating.
- The basis for selecting and sizing a suitable heat source.
For renovations, the calculation must reflect the proposed finished building, including agreed insulation improvements, replacement glazing and alterations to the room layout.
Where existing construction details are uncertain, these need to be investigated or identified as assumptions rather than treated as confirmed information.
Our room-by-room heat loss calculation service is also available independently of a complete system design.
Radiators, Underfloor Heating and Design Flow Temperatures
Once the room heating requirements are established, we can assess how that heat should be delivered.
A renovation may include existing radiators in one part of the building, new radiators elsewhere and underfloor heating in an extension or on the ground floor.
Each emitter must be capable of providing sufficient heat at the proposed operating temperatures.
Where a heat pump is being considered, lower heating flow temperatures are generally desirable for efficiency, but the correct temperature depends on the building heat loss and the available emitter output.
We can assess existing radiators to establish which may be retained and which would need upgrading.
Where underfloor heating is proposed, the design needs to consider floor construction, floor coverings, available floor area, output requirements and the relationship with other heating circuits.
Our objective is to establish a coordinated emitter strategy rather than specify equipment before the heating loads are known.
Detailed underfloor heating circuit layouts and CAD drawings are available through our separate underfloor heating design service.
Heat Source and Hot Water Cylinder Selection
For renovations using an air source heat pump, equipment selection must be based on the calculated heating requirement and the intended system operating conditions.
Different heat pumps have different performance characteristics, including the heating capacity they can deliver at low outdoor temperatures and the selected water flow temperature.
We consider the relevant manufacturer performance data when assessing suitable equipment.
Where included in the commission, the design can also consider:
- The proposed heat pump capacity.
- Operating flow temperatures.
- Heating system water volume and flow requirements.
- Hot water storage requirements.
- Cylinder sizing and reheat performance.
- Available plant and equipment space.
- The proposed location of the heat pump and associated equipment.
The aim is to select equipment that suits the building and the heating distribution system, rather than designing the rest of the installation around a product chosen in advance.
Pipework, Circulation Pumps and Hydraulic Design
A heating system must do more than produce enough heat. It must also circulate the required volume of water through the correct parts of the system.
This is particularly important in larger renovations and properties containing several heating circuits.
Depending on the agreed design scope, our hydraulic work can consider:
- Primary pipework between the heat pump and the heating system.
- Distribution pipework serving radiators and underfloor heating.
- Required system flow rates.
- Pipe sizing and pressure losses.
- Available circulation pump pressure.
- Additional pumps where necessary.
- Buffer vessels, volumisers and hydraulic separation where justified.
- The interaction between heating zones and emitter types.
- Hot water priority and associated hydraulic arrangements.
We assess the arrangement according to the technical requirements of the installation rather than assuming that additional pumps, buffers or low-loss headers are always necessary.
Where required, hydraulic schematics can be developed to explain how the major system components should be connected and operate together.
System Arrangements and Technical Documentation
The purpose of the design is to provide useful technical information that can be taken forward into the installation.
Depending on the services commissioned, this may include heat loss reports, emitter schedules, equipment specifications, design temperatures, pipework requirements, hydraulic arrangements and supporting drawings.
The precise documents are agreed as part of the design scope.
Our role is to establish and document the proposed design. The appointed contractor remains responsible for verifying site conditions, final installation details, installation quality, commissioning and applicable certification.
SERVICE LEVELS
Choose the Level of Heating Design Your Project Needs
Not every renovation requires the same amount of design work.
Some homeowners already have an installation contractor and simply need an independent heat loss calculation.
Others need the complete heating system developed before their builder begins first-fix work.
We therefore offer separate levels of service rather than assuming every customer needs one fixed package.
Heat Loss Calculation Only
A standalone room-by-room heat loss calculation establishes the heating requirements of the property.
It can be commissioned independently where a homeowner, architect or heating contractor needs reliable heating-load information before making further decisions.
A heat loss calculation does not, by itself, constitute a complete heating system design.
Complete Heating System Design
This service takes the heat loss results further by considering the heating emitters, system temperatures, heat source, pipework and hydraulic arrangements.
The agreed work is used to develop a coordinated system specification for the renovation.
This is suitable for homeowners who want an independent technical design before commissioning or proceeding with an installation.
Detailed Underfloor Heating Design
Where underfloor heating is required, detailed design can be commissioned separately.
This can include pipe spacing, circuit layouts, manifold arrangements, circuit lengths, flow requirements and CAD drawings.
A detailed UFH layout is distinct from establishing that a room requires underfloor heating and calculating its required output.
By separating the services, we can agree what is needed, what will be delivered and the associated design fee before work begins.
DESIGN APPROACH
Designing for the Finished Property
One of the most important considerations during a renovation is that the existing building may be very different from the property once the work is complete.
The project might involve replacing windows, insulating walls, upgrading the roof, adding an extension or changing the ventilation arrangements.
These improvements can alter the heating requirements significantly.
A heating system designed around the property’s current condition may not be appropriate once the renovation is finished.
Equally, a design based on insulation improvements that are later omitted or changed could produce heating equipment and emitter specifications that no longer match the building.
We therefore work from the proposed finished construction specification and make the relevant design assumptions clear.
Where different insulation or refurbishment options are still being considered, we can discuss whether separate calculations or design scenarios are appropriate.
Any subsequent changes to the building specification may need to be reviewed before the heating design is finalised.
Our existing guide to installing a heat pump during a renovation or extension explains the importance of making these decisions early.
HYDRAULICS
Hydraulic Design: Making the Complete System Work Together
Hydraulic design is one of the most important parts of a heating system, but it is often one of the least understood by homeowners.
It concerns how heating water moves through the installation.
A renovation might contain underfloor heating downstairs, radiators upstairs, several heating zones, a hot water cylinder and a heat pump located some distance from the main building.
Each of these has requirements that must be considered together.
For example, increasing the pipe length between a heat pump and the building increases the resistance the circulation pump must overcome.
A system with several zones must also maintain suitable water flow under its intended operating conditions.
If the pipework is undersized or circulation requirements are overlooked, the system may struggle to deliver the required heat even when the heat pump itself has sufficient capacity.
A properly considered hydraulic design establishes the required flow rates, assesses pipework resistance and determines how the various components should operate together.
The solution is not automatically to add a larger pump or additional hydraulic separation.
Where hydraulic design is included in the commission, we evaluate these requirements and develop an arrangement appropriate to the proposed system.
For further technical information, see our heat pump pipework and hydraulics guide.
REMOTE DESIGN
Can We Design Your Renovation From Architectural Plans?
In many cases, yes.
Heat Loss Hub provides remote heating design services throughout England, Wales and Scotland using architectural plans, construction specifications and supporting property information.
This approach is particularly suited to substantial renovations where the proposed finished layout and construction details have already been established.
Architectural drawings provide much of the geometry needed for the calculation, including room dimensions, floor areas, window and door positions and building layout.
However, drawings alone do not always establish the thermal properties of an existing building.
For example, the construction of an original external wall may need further investigation, even where an architect has produced detailed drawings for a new extension.
We assess the available information before confirming whether remote design is appropriate.
What Information Do We Need?
Useful information may include:
- Architectural floor plans, elevations and sections.
- Proposed wall, floor and roof construction details.
- Insulation specifications or U-values where available.
- Window and external door specifications.
- Room heights and relevant building dimensions.
- Details of existing heating equipment and radiators.
- Proposed underfloor heating areas.
- Intended heat pump and cylinder locations.
- Relevant photographs or videos of the existing property.
- Information about any retained pipework or heating circuits.
You do not need to have every item ready before contacting us.
An initial review can help establish what is available and what further information would be needed for the proposed design.
Read more about our heat pump design from architectural plans service.
When Is an On-Site Survey More Appropriate?
A technical survey may be preferable where important details cannot be established from the drawings or supporting information.
This is more likely in older properties with uncertain construction, complex existing heating systems, limited documentation or difficult equipment and pipework locations.
An on-site survey can help establish the information needed before a reliable design is produced.
We undertake surveys locally in Yorkshire and consider longer-distance visits, including London and other areas, where appropriate for the project.
The suitable approach is discussed before the work is commissioned.
DELIVERABLES
What Documentation Will the Installer Receive?
The design documentation depends on the agreed scope of work.
For a complete heating system design, the deliverables can include:
- Room-by-room heat loss calculations and design assumptions.
- Whole-property design heating requirement.
- Proposed emitter requirements and radiator schedules.
- Design flow temperatures.
- Heat pump and cylinder specifications.
- Relevant pipework sizes and flow requirements.
- Hydraulic arrangements and supporting schematics.
- Separately commissioned detailed UFH layouts and CAD drawings.
These documents provide a technical basis for the installer to develop and carry out the work.
Where some information cannot be confirmed during the design, the relevant assumptions and items requiring site verification should be identified.
Our independent design service does not replace the installation contractor’s responsibility for verifying site conditions, completing installation-specific checks, carrying out the installation and commissioning the finished system.
It also does not automatically include architectural design, electrical design, statutory approvals or certification services.
Those responsibilities remain with the relevant appointed professionals.
COORDINATION
Working With Your Architect and Building Contractor
Heating design is closely connected to other parts of a renovation.
The position of a hot water cylinder may affect the plant room layout.
Underfloor heating may influence the floor build-up and finished floor levels.
Larger heating pipes may require space within floors, risers or service routes.
The heat pump location can affect external pipework, acoustic considerations and access for installation and maintenance.
These decisions are easier to coordinate when the heating requirements are understood early.
We can work from the architect’s drawings and provide relevant heating design information for the homeowner, architect, building contractor and appointed heating installer.
Where a project is still evolving, it is important to establish which drawing revision and construction specification the heating design is based upon.
If room layouts, insulation specifications, window sizes or other relevant details subsequently change, the effect on the heating design may need to be assessed.
Any additional calculations, redesigns or revised documentation can be agreed separately where required.
This helps keep responsibility and the scope of work clear for everyone involved.
TIMING
When Should Heating System Design Begin?
Ideally, heating design should begin once sufficient information about the proposed renovation is available, but before construction decisions make changes difficult.
This is particularly important before:
- Underfloor heating pipework is installed.
- New floors or screeds are constructed.
- Heating distribution pipework is concealed.
- Plant rooms and cylinder cupboards are finalised.
- Heat pump positions and external service routes are fixed.
- Radiators and other heating equipment are ordered.
Early design allows the heating requirements to inform the construction work, rather than forcing the heating installation to accommodate decisions that have already been made.
However, not every project follows the ideal sequence.
If your renovation is already underway, we can review the available information and establish what design work is still possible and what constraints must be considered.
HOW IT WORKS
How Our Heating Design and Quotation Process Works
1. Tell Us About Your Project
Start by describing the property, the renovation work and what you would like us to design.
You can provide architectural drawings, construction specifications and information about the existing heating system where available.
2. Initial Project Review
We review the information to understand the proposed work and identify any essential details that are missing.
This helps establish whether the project is suitable for remote design or whether an on-site survey is needed.
3. Agree the Design Scope and Fee
We explain the proposed services, the documentation to be delivered and the associated quotation.
A heat-loss-only commission will have a different scope from a complete heating system design or a detailed UFH design.
The scope is agreed before the work begins.
4. Calculations and System Design
We carry out the commissioned calculations and develop the design around the supplied and verified project information.
Where further decisions or information are necessary, these are identified as part of the design process.
5. Final Design Documentation
We provide the agreed reports, schedules, specifications and drawings.
The documents can then be used by your appointed heating contractor and other relevant professionals to progress the project.
Once the agreed deliverables are completed, the design commission is concluded. Further design changes or additional services can be considered separately if the project develops.
FAQ
Frequently Asked Questions
Not necessarily, but accurate drawings and suitable construction information are essential for a reliable remote design.
For major structural alterations or extensions, architectural drawings are often the most practical starting point.
Where plans are not available, an on-site survey or additional measurement work may be necessary.
Yes. In fact, establishing the building heat loss, emitter requirements and proposed heating temperatures should inform the choice of heat pump.
Selecting equipment before those requirements are understood can lead to an unsuitable or unnecessarily expensive system.
Potentially.
Existing radiators can be assessed against the required room heating outputs and proposed water temperatures.
Existing pipework may also be suitable, but its adequacy depends on factors such as internal diameter, layout, flow requirements and pressure losses.
A design can identify where changes may be required, subject to verification of concealed or uncertain pipework.
Yes. Many renovation projects combine underfloor heating in new or refurbished areas with radiators elsewhere.
The system must be designed around the heating requirements, flow temperatures, hydraulic arrangement and appropriate controls.
The presence of two emitter types does not automatically mean the installation requires a particular buffer or hydraulic separation arrangement.
Our main specialism is heat pump heating system design, including the radiators, underfloor heating, pipework and hydraulics required for a complete wet heating system.
We also provide independent underfloor heating design for systems using other heat sources.
If your renovation has not reached the point of selecting a heat source, we can discuss which calculations and design work would be appropriate at that stage.
Yes. Our design documentation is intended to provide the technical information needed to plan and progress the installation.
The appointed contractor must still verify the final site conditions and carry out the installation, commissioning and applicable certification requirements.
Changes to insulation, glazing, room layouts, floor construction or heating equipment may affect the original calculations and system design.
Where changes are significant, the design should be reviewed before installation proceeds.
Additional assessment or revised drawings can be commissioned separately.
The cost depends on the size and complexity of the property, the information available and the work required.
A standalone heat loss calculation is different from a complete heating system design, while detailed UFH circuit layouts and other additional design work may require separate fees.
We review the project and confirm the proposed scope and quotation before work begins.
GET STARTED
Send Us Your Renovation Plans
If you are renovating a house, extending your property or planning a complete heating system replacement, we can help establish the technical design work required before installation begins.
Whether you need a room-by-room heat loss calculation, complete heat pump heating system design or detailed underfloor heating drawings, the starting point is understanding the property and the work you are undertaking.
You can send us your architectural drawings, construction specifications and any relevant heating information for an initial project review.
We will establish whether the work can be completed remotely or whether a technical survey would be more appropriate, then provide a quotation for the agreed services.
Independent heating system design. No equipment sales. No installation commissions.
Alternatively, email hello@heatlosshub.co.uk with details of your renovation project.