When researching underfloor heating for an existing home, many people come across two main installation approaches: traditional overlay underfloor heating systems and modern milled underfloor heating installed directly into concrete floors.
Because overlay systems have been widely used for many years, it is understandable that homeowners often assume an overlay or screed build-up is required for underfloor heating to work effectively. In reality, advances in installation techniques now allow water underfloor heating to be retrofitted into existing concrete or screed floors without an overlay, using precision milling.
Both methods can deliver excellent comfort when properly designed. The difference lies in how the heat is transferred and how the system integrates with the existing structure of the building.
What is an overlay underfloor heating system?
An overlay system involves installing insulation panels or low-profile boards on top of the existing floor, laying the underfloor heating pipework within them, and then covering the system with a new screed or floating floor construction.
This approach is commonly used in new builds and some renovations because it creates a complete heating layer above the structural slab. However, in retrofit projects it also introduces:
An increase in finished floor height
Longer warm-up times due to thicker build-up
The need to modify doors, skirting and thresholds
Additional drying time when new screed is used
What is underfloor heating without an overlay?
With a milled underfloor heating system, the heating pipes are installed directly into channels cut into the existing concrete or screed slab. No insulation boards or additional screed layers are added on top.
This creates a true low-profile underfloor heating system where:
The floor height remains unchanged
The pipework sits closer to the finished surface
The existing concrete acts as a stable thermal mass
The system can be installed quickly, often within 1–2 days
This method is particularly suited to retrofit underfloor heating in existing concrete floors, where maintaining levels and minimising disruption are important.
How heat transfer differs between overlay and milled systems?
Overlay underfloor heating
In an overlay system, heat travels through multiple layers:
This is why milled water underfloor heating is often described as a highly efficient low-temperature heating system for retrofit projects.
Why overlay systems became standard
Overlay systems were developed to standardise construction build-ups and simplify installation on site, especially in new developments. They remain a valid solution in many situations, particularly where insulation upgrades and full floor reconstructions are already planned.
The perception that underfloor heating must sit in an overlay is largely due to familiarity rather than performance limitations.
Why underfloor heating without screed is increasingly chosen for retrofit projects
For existing properties, particularly those with solid concrete floors, installing underfloor heating without an overlay offers several practical advantages:
No increase in floor height
No need to remove the existing slab
No long screed drying times
Faster installation programmes
Excellent compatibility with heat pumps
Even heat distribution using the concrete as a thermal store
Choosing the right underfloor heating system for your home
Both overlay and milled systems can provide comfortable, efficient heating when correctly designed. The most suitable option depends on:
Floor construction and available depth
Whether insulation upgrades are planned
Ceiling height limitations
The heat source (boiler or heat pump)
Desired response time and control
Installation timeframe and disruption tolerance
In many renovation projects where maintaining levels and achieving fast, efficient heating is a priority, underfloor heating installed directly into the concrete floor using milling offers a technically elegant and future-proof solution.
So is there a definitive answer?
The idea that underfloor heating must be installed with an overlay or thick screed comes from traditional construction practice rather than a technical requirement. Modern milling techniques allow water underfloor heating to be installed without an overlay, often delivering faster response times, lower running temperatures and excellent compatibility with low-carbon heating systems.
Understanding both approaches allows homeowners to make informed decisions based on performance, efficiency and practicality, rather than assumption.
Book a free underfloor heating assessment
If you’re considering underfloor heating in an existing property and want to understand whether a milled, no-overlay system is suitable for your concrete or screed floor, a professional assessment is the best place to start.
We’ll review your floor construction, heating system and renovation plans, and provide clear advice on the most efficient and practical solution for your home.
Retrofit underfloor heating requires a very different approach from traditional new-build installations. Existing floor structures, heating systems and finished levels all need to be carefully considered to ensure the system performs efficiently without disruption.
At Channel Heat Systems, we specialise in installing water underfloor heating into existing concrete and screed floors using precision milling techniques. This allows us to integrate a low-profile heating system directly into the existing slab without raising floor levels, removing the floor, or extending renovation timelines.
This guide explains the professional retrofit underfloor heating installation process, step by step, so you can understand how modern systems are designed, installed and commissioned for long-term comfort and efficiency.
Step 1: Initial assessment and system design
Every retrofit project starts with a professional assessment. At this stage, we review:
The existing floor construction (concrete or screed)
Floor depth and structural condition
Current heating system (boiler or heat pump)
Room layout and heat-loss requirements
Renovation plans and floor finishes
This information allows us to design a system that delivers the correct heat output, flow temperatures and zoning ensuring efficient performance from day one.
A proper design is essential, particularly in retrofit projects, where accuracy matters more than adding build-up.
Step 2: Preparing the existing concrete floor
Once the system design is finalised, the existing floor is prepared for installation.
Unlike traditional retrofit methods that involve removing floors or adding insulation boards and screed, our approach keeps the original slab in place. This avoids unnecessary demolition and helps maintain existing floor heights.
The surface is checked, marked out and prepared for precision milling.
Step 3: Precision milling of heating channels
This is the key step that makes retrofit underfloor heating possible.
Using specialist milling equipment, we cut accurately spaced, depth-controlled channels directly into the existing concrete or screed floor. These channels follow the exact pipe layout defined during the design stage.
Because the channels are milled into the slab itself:
There is no increase in floor height
No need for new screed layers
Minimal dust and disruption
Faster heat transfer once the system is operating
This method allows underfloor heating to be installed cleanly and efficiently, even in lived-in homes.
Step 4: Installing the underfloor heating pipework
Once the channels are milled, the underfloor heating pipes are laid neatly into the grooves and secured in place.
The pipes sit close to the finished floor surface, which is one of the reasons milled systems offer:
Faster heat-up times
Improved responsiveness
Excellent performance with low-temperature heat sources such as heat pumps
Careful installation at this stage ensures even heat distribution and long-term reliability.
Step 5: Pressure testing and system checks
Before the floor is sealed, the entire system is pressure-tested to confirm there are no leaks and that the pipework is performing exactly as intended.
This step is critical in any water underfloor heating installation and ensures the system is safe, durable and ready to be commissioned.
Step 6: Sealing the channels and preparing for the final floor finish
After testing, the channels are sealed and the surface is made ready for the final floor covering.
Because there is no screed to dry, there is no waiting period. The floor can typically be tiled, finished with engineered wood, vinyl or other suitable coverings almost immediately.
This is one of the reasons retrofit installations can often be completed in just 1–2 days.
Step 7: Connecting to the heating system and commissioning
The underfloor heating system is then connected to the manifold and integrated with the existing heating system – whether that’s a modern boiler or a heat pump.
Controls are configured, zones are set up, and the system is fully commissioned to ensure:
Correct flow temperatures
Balanced heat distribution
Efficient operation alongside any existing radiators
The result is a system that delivers steady, even warmth throughout the space!
Why this retrofit underfloot heating installation method works so well
By installing underfloor heating directly into the existing concrete floor, this approach avoids the most common issues associated with retrofitting:
No raised floors
No door trimming or threshold changes
No long drying times
Bo major building work
At the same time, it delivers the comfort and efficiency benefits underfloor heating is known for, making it a practical upgrade for many homes that were previously considered unsuitable.
Is retrofit underfloor heating right for your home?
Most properties with concrete or screed floors are suitable, but every home is different. Floor depth, condition and existing heating systems all need to be assessed properly before installation.
That’s why a professional assessment is the best way to understand what’s possible.
Book a free retrofit underfloor heating assessment
If you’re planning a renovation or want to upgrade how your home is heated, our team can help you explore whether retrofit underfloor heating is right for your property. Request a free consultation today!
Underfloor heating is no longer limited to new builds or major renovations. With modern installation techniques, it’s now a realistic option for many existing homes, including those with concrete floors and traditional heating systems.
Below, we answer the six most common questions homeowners ask when considering underfloor heating, clearly and honestly.
1. Can underfloor heating be retrofitted into an existing home?
Yes – in most cases, underfloor heating can be retrofitted successfully.
Older systems often required removing floors or adding thick screed layers, which made retrofitting disruptive and impractical. Today, modern low-profile and milled systems allow underfloor heating to be installed into existing homes with minimal disruption.
Retrofit underfloor heating is commonly installed in:
ground floors with concrete or screed
extensions and renovations
older properties with cold floors
open-plan living spaces
A professional assessment is essential, but many homes previously considered unsuitable are now ideal candidates.
2. How does milling work on a concrete slab?
Concrete floor milling is a precision technique that allows underfloor heating pipes to be installed directly into an existing concrete or screed slab.
Using specialist machinery, narrow, depth-controlled channels are cut into the slab surface. The heating pipes are laid into these channels, pressure-tested, and sealed, leaving the floor ready for the final finish.
Key benefits of milling on a concrete slab include:
In most cases, underfloor heating is cheaper to run than traditional radiators.
Underfloor heating operates at lower water temperatures (typically 35–40°C), while radiators often require 65–75°C. Because heat is distributed evenly across the entire floor, rooms stay comfortable at lower thermostat settings.
When correctly designed and installed, homeowners often benefit from:
reduced energy consumption
more stable indoor temperatures
improved efficiency with heat pumps or modern boilers
4. Can you install water underfloor heating on an existing concrete floor?
Yes, water underfloor heating can be installed on existing concrete floors using the right installation method.
Milled systems allow water pipes to sit within the concrete slab rather than above it, creating a low-profile system that delivers fast, even heat without affecting door heights, skirting boards or thresholds.
Once installed, the system connects to a manifold and thermostats just like any other wet underfloor heating system – but with improved responsiveness due to pipe proximity to the surface.
5. Can underfloor heating be added to an existing heating system?
Yes, underfloor heating can usually be added to an existing heating system!
In many homes, underfloor heating operates alongside radiators using the same heat source. A mixing unit or control system is used to reduce the water temperature for the underfloor heating circuit, while radiators continue to operate at higher temperatures if required.
This approach allows homeowners to:
upgrade specific rooms or floors first
improve comfort without replacing the entire heating system
Underfloor heating can also be integrated with heat pumps, making it a flexible option for future sustainable upgrades.
6. How much does it cost to retrofit underfloor heating?
The cost of retrofitting underfloor heating depends on several factors, including:
total floor area
number of heating zones
condition and depth of the concrete slab
manifold and control requirements
whether it’s being added to an existing system
While retrofit underfloor heating may cost more upfront than radiators, it often delivers long-term savings through lower running costs and improved efficiency.
Milled systems are typically more cost-effective than removing floors or pouring new screeds, especially when time, disruption and additional building work are considered.
Final thoughts
Modern underfloor heating is far more accessible than many homeowners realise. With techniques like concrete floor milling and flexible system integration, it’s now possible to add efficient, low-profile heating to existing homes — without major renovation work.
The key is correct design, professional installation, and choosing a specialist who understands both the heating system and the structure of your home.
Get a free underfloor heating assessment
If you’re considering underfloor heating and want clear advice on what’s possible in your home, our team can help. Get in touch today for a free underfloor heating assessment!
Retrofitting underfloor heating into a home with concrete floors has long been considered difficult or impractical. Traditional retrofits often meant breaking out the slab or adding multiple layers of insulation and screed – a disruptive, expensive process that dramatically changed floor levels.
Milling has changed the landscape of retrofit heating.
Using specialist machinery, engineers can create extremely accurate channels in an existing concrete or screed floor, allowing water underfloor heating pipes to be recessed neatly into the slab. This method delivers modern underfloor heating without raising floor levels or rebuilding the room from the ground up.
Below, we explore how milling actually works, why it delivers such strong heating performance, and when it’s the most suitable retrofit solution.
What milling actually involves (and why it’s so precise)
Concrete milling uses a high-torque, depth-controlled grinder to cut shallow, evenly spaced channels directly into the surface layer of the slab. Unlike traditional cutting tools, a milling machine removes material in a controlled pattern, ensuring:
perfect pipe spacing,
consistent depth,
smooth channel curves, and
minimal vibration or damage to the surrounding structure.
The depth is carefully calculated to ensure the pipes sit as close to the finished floor surface as possible, which is vital for fast heat transfer.
Once the channels are milled, pipes are clipped into place and the floor is sealed to create a stable, ready-for-finishing surface.
No new screed layers. No build-up. No structural changes.
The engineering reason milling works so well
Most traditional underfloor heating systems bury the pipework beneath 50–70 mm of screed. While this works in new builds, it creates a slow-responding thermal mass which means that heating takes longer to reach the room, and fine temperature control becomes harder.
With a milled system, the distance between the pipe and the floor finish is drastically reduced, often to single-digit millimetres.
This results in:
1. Lower heat-up times
The floor becomes warm noticeably faster which is ideal for lived-in homes where response time matters.
2. Lower flow temperatures
Because the pipes are close to the surface, heat doesn’t need to penetrate thick screed layers. The system can run at lower water temperatures – improving efficiency and perfectly complementing heat pumps.
3. More uniform heat distribution
The channels ensure accurate pipe spacing, which prevents hot/cold patches and creates a consistently warm surface.
Milling vs other retrofit methods
There are several retrofit UFH techniques, but each has trade-offs. Milling solves the biggest drawbacks found in other approaches.
Overboard systems
Easy to install – Adds 15–25 mm to floor height – May require new doors, skirting, thresholds – Slower heat-up due to boards and coverings
Low-profile screed systems
Good for larger areas – Adds new screed layer – Requires curing time before use (weeks) – Can add noticeable height
Full slab removal
Allows for traditional UFH – High cost and major disruption – Not suitable in many existing homes
Milled systems (like the ones provided by Channel Heat Systems)
No height increase
Fast installation (usually 1–2 days)
Works with most concrete and screed floors
Immediate commissioning – no drying time
Highly energy-efficient due to shallow pipe depth
Minimal disruption or dust
For lived-in homes, milling is generally the least disruptive and most technically efficient retrofit option available today.
When milling is suitable (and when it isn’t)
Concrete milling is ideal for:
ground-floor concrete slabs
screeded extensions
open-plan kitchens
older homes with uninsulated floors
rooms that feel cold despite radiators
spaces where radiators limit furniture or layout
It may not be suitable if:
the slab is extremely thin or structurally compromised
insulation review beneath the slab (where applicable)
Poor-quality milling or design can reduce efficiency dramatically. This is where specialist experience matters.
At Channel Heat Systems, we use depth-calibrated milling equipment and design layouts tailored to each room’s heat loss. Every system is pressure-tested and commissioned so that it performs from day one.
Why homeowners choose milled underfloor heating
Clients typically choose milling because they want:
underfloor heating without rebuilding their home
a warm, comfortable space with no cold floors
reduced heating bills through low-temperature operation
a system compatible with both boilers and heat pumps
a clean, modern solution with no radiators
And above all – a fast installation with very little disruption.
Most milled projects are completed in 1–2 days, and the heating can be used almost immediately.
Is milling right for your home?
For most concrete and screed floors, the answer is yes – milling is one of the smartest and most efficient ways to upgrade a heating system. But suitability depends on depth, condition and layout, which is why an assessment is essential.
If you’re planning a renovation or struggling with cold floors, this method may be the ideal solution.
Get a free assessment for your concrete floor
Our team specialises in precision-milled underfloor heating installations for both retrofit and new-build properties. We can evaluate your floor and tell you exactly what’s possible – no pressure, no obligation.
Retrofitting underfloor heating into an existing property used to be considered disruptive, costly and impractical, especially in homes with concrete or screed floors. Traditional methods often required either removing the existing floor or adding new build-up layers, leading to increased floor height, weeks of disruption and additional structural work.
Floor milling has changed this completely.
Modern milling technology allows for precise, clean channels to be cut directly into the existing floor, making retrofit underfloor heating not only possible, but fast, efficient and cost-effective.
In this article, we explain what floor milling is, how it works, why it is now widely used in underfloor heating installations, and whether your home may be suitable.
What is floor milling?
Floor milling is a specialised process used to create narrow, accurate channels in existing concrete or screed. These channels are designed to hold water-based underfloor heating pipes without altering the finished floor height.
Using high-precision grinding equipment, experienced teams can cut channels cleanly and with minimal dust. Once the pipework is installed, the channels are sealed and the floor is ready for the final finish.
Why milling is ideal for retrofit underfloor heating
Unlike traditional installation methods, floor milling allows underfloor heating to be integrated into existing homes without major construction work.
Key benefits of milling:
No floor height increase – pipes sit within the slab, not above it
Minimal dust and disruption
No removal of the existing floor structure
Fast installation (typically 1–2 days)
Faster heat-up times due to low thermal mass above pipes
Reduced energy use thanks to more efficient heating response
This makes milling the preferred retrofit solution for homes with concrete floors, extensions and older properties where internal heights cannot be compromised.
How milled underfloor heating works
Here is how the process typically takes place:
The existing screed or concrete is assessed for suitability.
Precision milling equipment is used to cut channels following the system design.
Flexible underfloor heating pipes are laid into the channels.
The system is pressure-tested to ensure safe operation.
The channels are sealed and repaired.
The floor is ready for the final covering (tile, engineered wood, vinyl, etc.).
Unlike other systems, there is no waiting time for screed drying. In most cases, the heating can be commissioned immediately after installation.
How milling improves heating performance
Because the pipes are recessed into the existing slab and positioned closer to the surface, the system provides faster heat transfer and better control. This reduces running costs and enhances comfort.
In fact, installing underfloor heating through milling can improve responsiveness by 20–30% compared to traditional deep-screed systems, making it especially suitable for energy-efficient heating sources such as heat pumps and modern gas boilers.
When milling is the best solution
Floor milling is particularly suitable when:
A home has solid concrete or screed floors
The property is being renovated without full floor removal
Internal floor height cannot be raised
Radiators are underperforming, especially in large open-plan spaces
The client wants fast installation without disruption
Common examples include extensions, glass rooms, open-plan kitchens, and older properties where traditional heating is no longer effective.
Is milled underfloor heating right for your project?
Most homes with concrete or screed floors are suitable, provided the existing slab is sound. A professional technical assessment should be completed before installation to determine depths, layout and suitability.
If you’re considering underfloor heating during renovation or converting a cold room into a usable space, milling is one of the most efficient and least invasive options available.
Why choose Channel Heat Systems for precision-milled underfloor heating
Channel Heat Systems specialises in precision-milled underfloor heating installations for both retrofit and new-build projects.
Our team uses advanced milling technology to install systems without height build-up, mess or long downtime. Every system is pressure-tested, connected to the manifold and fully commissioned by experienced engineers.
Installation typically takes just 1–2 days, and the floor is ready for your final finish without expensive structural adjustments.
Get a free underfloor heating assessment
If you’re exploring underfloor heating for your renovation or new-build project, we can help determine whether floor milling is a suitable solution.
Contact us today for professional advice and a free assessment.
Underfloor heating has become one of the most desirable ways to heat modern homes, offering comfort, efficiency, and far better heat distribution than traditional radiators. But for many homeowners, the installation process still feels unclear: How does it work? Can it be retrofitted? What type of system is best?
This guide explains everything you need to know about underfloor heating installation services, from system types to installation methods, timescales, and suitability for your home.
What underfloor heating installation involves
Underfloor heating works by circulating warm water through pipes installed beneath the floor. Unlike radiators, which heat the air around them, underfloor systems deliver radiant warmth that rises evenly through the entire room.
A professional installation typically includes:
Heat-loss calculations and system design
Preparing or milling the subfloor
Installing the pipework
Connecting the system to a manifold
Pressure testing and commissioning
Making the floor ready for the final finish (tile, wood, vinyl, etc.)
A well-designed and correctly installed system should produce consistent, low-temperature heating with excellent energy efficiency.
Types of underfloor heating systems
There are two main types of systems installed in UK homes:
Water (wet) underfloor heating
Warm water is circulated through a network of pipes beneath the floor. This is the most efficient, comfortable and future-proof option, ideal for both new builds and retrofit homes.
Suitable for:
Concrete floors
Screed floors
Timber suspended floors
Extensions and renovations
Whole-house installations
Electric underfloor heating
Electric heating mats installed below the floor surface. Quicker to install but more expensive to run long-term, and less suited to heating large spaces.
Most homeowners choose water-based systems for comfort and energy savings.
Retrofit underfloor heating installation
Retrofitting underfloor heating used to be complicated and disruptive, often requiring floors to be removed or built up significantly. Modern installation methods have changed that completely.
At Channel Heat Systems, we use an advanced floor-milling technique that allows underfloor heating to be installed directly into existing concrete or screed floors.
Why milling is the best retrofit solution
No floor height increase
No need to remove existing floors
Clean, dust-free cutting
Pipes sit just beneath the final floor finish
Faster heat-up times
Installation typically completed in 1–2 days
Retrofit underfloor heating is now suitable for almost every home, including older properties, extensions, and ground-floor rooms that previously felt cold or inefficient.
New-build underfloor heating installation
For new-build homes, underfloor heating is often installed before the final screed layer. This allows for full integration and maximum energy efficiency.
Key advantages include:
Ideal pairing with air-source and ground-source heat pumps
Excellent energy performance
Even temperature distribution
More space — no radiators needed
Low-maintenance, long-lasting system design
Whether you’re building a single property or a full development, professional UFH installation ensures the system performs for decades.
How long underfloor heating installation takes
Installation times depend on the size of the property and the method used.
Typical timescales:
Milled retrofit system: 1–2 days
New-build screed system: 2–5 days (including curing time if screed is fresh)
Electric mats: Same day
A professional team will provide a clear schedule and ensure minimal disruption.
What underfloor heating costs
Prices vary depending on:
Total floor area
Number of heating zones
System type (retrofit or new build)
Manifold requirements
Floor construction
Controls and thermostats
Although underfloor heating can cost more upfront than radiators, it typically reduces running costs by 15–25% and is especially efficient when paired with a heat pump.
The long-term savings and comfort often outweigh the initial investment.
Why choose Channel Heat Systems as your underfloor heating installer in the UK?
Channel Heat Systems specialises in both new-build and retrofit underfloor heating installations, including advanced milled-floor systems for concrete and screed in the UK.
Our services include:
Full system design and consultation
Precision milling for retrofit homes
Professional pipe installation
Manifold connection and setup
Complete pressure testing and commissioning
Fast, clean installations with no floor build-up
What sets us apart is our ability to install underfloor heating in properties that were traditionally considered unsuitable, all with minimal disruption.
Get a free underfloor heating assessment
If you’re considering underfloor heating for your home or project, our team offers expert advice and a free underfloor heating assessment to determine the best solution for your space!
Many homeowners assume that underfloor heating can only be installed in new builds or homes with timber floors. But that’s not true anymore.
Thanks to modern floor milling technology, it’s now possible to retrofit a water underfloor heating system into an existing concrete or screed floor without ripping anything up or raising floor levels.
Let’s explore how it works, why it’s efficient, and what makes it one of the most practical heating upgrades for British homes.
Why retrofitting underfloor heating in a concrete floor used to be difficult
For years, homeowners were told that installing underfloor heating in existing concrete floors was too disruptive or expensive as traditional systems often required:
Breaking out the existing slab
Pouring new screed
Raising floor height, which caused issues with doors and thresholds
This made retrofitting underfloor heating messy, time-consuming, and costly until new precision milling techniques changed everything.
How modern channel-cut systems make retrofit underfloor heating possible
At Channel Heat Systems, we use advanced floor-milling equipment to create precise, dust-free channels directly in your existing concrete or screed floor. These channels hold flexible water heating pipes, which sit just below the surface of your final floor finish.
This innovative approach allows underfloor heating to be installed in virtually any home – cleanly, quickly, and without major construction.
Key advantages include:
No digging or breaking up concrete
No added floor height or screed build-up
Minimal dust and disruption
Typical installation time of 1–2 days
Once installed, your new underfloor heating is pressure-tested, connected to the manifold, and ready for your chosen flooring whether tile, engineered wood, or vinyl.
Why underfloor heating in concrete floors is energy efficient
Because the heating pipes are placed closer to the surface, heat transfer is faster and more consistent than in traditional systems. Concrete also acts as a natural heat store, distributing warmth evenly across the entire floor area.
This results in:
Even, comfortable warmth throughout the room
Faster response times
Lower running costs (typically 15–25% less than radiators)
Excellent compatibility with heat pumps and efficient boilers
In short, concrete floors aren’t a drawback but a thermal advantage.
How long retrofit underfloor heating installation takes
For most homes, installation is completed in just 1–2 days, depending on the size of the area. Because no additional screed or build-up is required, there’s no drying time meaning your new heating system can be used almost immediately.
This makes channel-cut underfloor heating one of the fastest and cleanest retrofit methods available today.
Typical costs of installing underfloor heating in existing concrete floors
The cost of retrofit underfloor heating depends on the total floor area, number of heating zones, and the chosen control system. However, because our process avoids removing and relaying floors, it’s often more affordable than traditional installations and offers long-term savings through better efficiency.
Concrete is also one of the best materials for low-profile underfloor heating, thanks to its strength, stability, and excellent heat conductivity.
Why choose Channel Heat Systems for retrofit underfloor heating
If you’ve ever considered underfloor heating but hesitated because you’re worried it’s expensive to run, you’re not alone. It’s one of the most common questions UK-based homeowners ask us, especially with rising energy costs.
The truth? When designed and installed properly, underfloor heating is one of the most efficient and cost-effective ways to heat your home.
Let’s break down why – and what really makes the difference.
1. Underfloor heating uses lower temperatures
Traditional radiators often run between 65–75°C, because they heat the air around them. Underfloor heating works differently as it radiates warmth evenly across your floor, gently heating the entire space.
Because of this, it only needs to run at 30–40°C to keep your home comfortably warm. That means your boiler or heat pump uses less energy to achieve the same comfort, lowering your energy bills.
2. Even heat = Greater efficiency
Radiators can leave you with hot and cold spots, leading to higher thermostat settings and wasted energy. In contrast, underfloor heating spreads warmth evenly, so you can set your thermostat lower and still feel perfectly warm.
That even heat distribution can reduce overall energy consumption by up to 25%, depending on insulation and usage.
3. The underfloor heating installation method matters
Not all underfloor systems are equally efficient. Traditional installation methods that add extra screed or build-up layers can trap heat and slow response times.
At Channel Heat Systems, we use precision floor-milling technology to cut clean, dust-free channels directly into your existing concrete or screed.
Our heating pipes sit just beneath the final floor finish, ensuring:
4. Pairing with modern heat sources to ensure maximum savings
Underfloor heating works perfectly with condensing boilers, but it truly shines when paired with heat pumps. This is because heat pumps operate most efficiently at lower water temperatures, combining the two can improve energy efficiency by 30–40% versus radiators.
That’s why so many homeowners choose underfloor heating when transitioning to renewable heating.
Heat pumps operate most efficiently at lower water temperatures. Combining the two can improve energy efficiency by 30–40% versus radiators.
So, what’s the real cost to run the underfloor heating?
The actual running cost depends on your home’s insulation, energy source, and control system, but generally, underfloor heating can be 15–25% cheaper to run than radiators.
In well-insulated homes, or when connected to a heat pump, the savings can be even higher. And because underfloor systems provide stable, gentle warmth, they avoid the “blast-and-cool” cycles that waste energy with traditional heating.
Underfloor heating can be 15–25% cheaper to run than radiators.
Final thoughts
So, is underfloor heating expensive to run? In most cases – absolutely not.
When installed correctly, it’s a low-temperature, high-comfort system that reduces waste, improves efficiency, and feels wonderful to live with.
Fully tested and commissioned for long-term reliability
Contact us to learn more or request your free quote!
Frequently Asked Questions
Does underfloor heating use more electricity than radiators?
No. In fact, it typically uses less energy overall because it runs at much lower water temperatures and spreads heat more evenly. If your system is powered by a heat pump, the efficiency gains are even greater.
Can underfloor heating be used with gas boilers?
Yes. Modern condensing gas boilers work very efficiently with underfloor heating because the lower return water temperature improves their performance.
Can I use it under any floor type?
Absolutely. Our systems work perfectly beneath tiles, engineered wood, vinyl, or laminate, as long as the flooring is compatible with radiant heat.
Is it worth installing underfloor heating in an existing home?
Yes, especially with our milled-floor retrofit method, which requires no floor height build-up and can be completed cleanly within 1–2 days.
How long does underfloor heating take to warm up?
Because our pipes sit directly beneath the final floor layer, you’ll usually feel warmth within 30–60 minutes, depending on the floor finish and insulation.
Does it require maintenance?
Very little. Once installed and pressure-tested, water underfloor heating systems require minimal maintenance and can last for decades with proper setup.
If you’ve ever mentioned wanting underfloor heating in your existing home, you’ve probably heard the objections: “Too disruptive.” “Too expensive.” “You’d need to rip up all your floors.” “It’ll take weeks.” “Your doors won’t fit anymore.”
For decades, these concerns were entirely valid. Retrofit underfloor heating genuinely was complicated, messy, and impractical for most occupied homes.
But technology has moved on dramatically – and most homeowners haven’t caught up with what’s now possible.
Modern retrofit underfloor heating, particularly for concrete floors, bears almost no resemblance to the disruptive process people imagine. What used to require weeks of major building work can now be completed professionally in 1-2 days, with your family staying in the house throughout.
Let’s separate the outdated assumptions from current reality and show you exactly what retrofit underfloor heating involves in 2025.
What is retrofit underfloor heating?
Retrofit underfloor heating means installing a water-based heating system into your existing property without major renovation work. Unlike new build installations where heating pipes are incorporated during construction, retrofit systems work with your home as it currently exists – finished floors, fitted kitchens, occupied rooms and all.
The key word is “retrofit” which effectively means adapting modern heating technology to fit existing structures rather than requiring complete floor reconstruction.
Why water underfloor heating for retrofits?
When discussing retrofit heating, we’re specifically talking about wet (water-based) systems rather than electric alternatives. Here’s why:
Running costs: Water systems operate at 35-45°C and typically cost £3-£5 per square metre annually to run. Electric systems require significantly more, around £10-£14 per square metre yearly.
Whole-home capability: Water systems connect to your existing heat source, making them practical and economical for large areas. Electric systems work well for small spaces like bathrooms but become prohibitively expensive for entire ground floors.
Heat pump compatibility: If you’re considering or already have a heat pump, water underfloor heating maximises efficiency by working at the low temperatures where heat pumps perform best.
Long-term value: Professional water systems typically last 25-50 years with minimal maintenance, whilst delivering consistent performance and genuine energy savings.
The traditional retrofit problem (and why it put people off)
To understand why modern retrofit is different, you need to know what made traditional installation so problematic.
Traditional retrofit underfloor heating required:
Complete floor removal: Lifting and disposing of existing floor coverings, subfloors, and often the screed beneath. This created enormous mess and required skips, disposal costs, and major disruption.
Significant floor build-up: Installing insulation boards (typically 50mm), pipes, and new screed (50-75mm) added 100-125mm to floor height. This cascaded into multiple problems:
Doors needed rehanging or replacing
Thresholds required adjustment throughout the house
Stairs might need modification
Kitchen units and fitted furniture became problematic
Period features and original proportions were compromised
Weeks of disruption: The process genuinely took 2-4 weeks per floor, during which rooms were completely unusable. Most families needed to move out temporarily.
Enormous cost: Labour costs alone for this level of work often exceeded £10,000-£15,000 for a typical ground floor, before materials.
These weren’t exaggerations or scare stories. Traditional retrofit underfloor heating genuinely was this disruptive and expensive. No wonder people assumed it was impossible for normal family homes.
How modern retrofit technology changed everything
The breakthrough came from precision engineering and specialised equipment that approaches the problem completely differently.
The modern retrofit underfloor heating approach: Introducing channel-cutting technology
Rather than building layers ON TOP of your existing floor, modern retrofit uses precision milling equipment to create channels directly INTO your concrete floor.
Here’s how it works:
Step 1: Floor assessment and design
Professional survey measures concrete thickness, identifies any embedded services, and calculates heat requirements for each room. Detailed pipe layouts are designed specifically for your space, accounting for heat loss areas, room shape, and usage patterns.
Step 2: Precision channel milling
Specialised grinding equipment cuts channels directly into your existing concrete or screed. These channels are milled to exact depth and spacing according to the design. Industrial dust extraction captures debris at source – typically 99%+ capture rate –keeping your home clean throughout.
Step 3: Pipe installation
Professional-grade pipes (we use 16mm for faster response times) are installed into the channels. They sit below your original floor level, not above it. Pipes are secured properly and the complete system is pressure-tested before any sealing occurs.
Step 4: Channel sealing and floor restoration
Channels are filled with specialised compound that bonds to the existing concrete. The floor surface is restored to its exact original level – not approximately, but precisely. Once set, the floor is ready for any covering you choose.
Step 5: System commissioning
Connection to your existing heat source, pressure testing, flow balancing, and professional commissioning ensure optimal performance from day one.
The dramatic differences this creates
Modern retrofit technology solves every major problem that made traditional installation impractical:
Zero floor height increase
Because pipes sit IN the floor rather than ON it, your floor level stays exactly where it is. This single factor eliminates dozens of complications:
Doors close perfectly – no modifications needed
Thresholds between rooms stay level
Kitchen units, fitted furniture – all unchanged
Period features and proportions preserved
Ceiling height fully maintained
This makes retrofit possible in properties where traditional methods simply couldn’t work: Victorian terraces with tight door clearances, Edwardian homes with original features, any property where floor height cannot change.
1-2 day installation timeline
Professional retrofit installations typically complete within 1-2 days for most residential projects. Not weeks. Days.
Day 1: Equipment arrival, channel cutting, pipe installation, pressure testing
Day 2: System connection, commissioning, floor restoration
Your rooms are walkable within hours of completion. The entire process happens whilst you remain in your home, using other rooms normally.
Minimal disruption and mess
Industrial dust extraction systems capture debris at source during channel cutting. Protective coverings shield furniture and adjacent spaces. Professional teams work cleanly and methodically.
The difference between modern retrofit and traditional installation is stark: instead of living in a building site for weeks, you experience manageable disruption measured in hours rather than days.
Dramatically lower cost
Modern retrofit installation costs are a fraction of traditional methods. Without weeks of labour, floor removal, disposal costs, and major building work, the financial barrier drops substantially.
For properties with concrete floors, retrofit underfloor heating now costs broadly similar to complete radiator system replacement, making it a realistic consideration rather than an impossible luxury.
Is your property suitable for retrofit underfloor heating?
Not every home is an ideal candidate, but many more are suitable than most people realise.
Here’s what matters:
Ideal properties for modern retrofit:
Concrete or screed floors: The channel-cutting approach works beautifully with solid floors. Most UK properties built from the 1930s onwards have ground floor concrete construction making them perfect for this method.
Adequate floor depth: Channels typically require 75-100mm total floor depth (concrete plus screed) for safe milling. Most residential floors exceed this comfortably, but we verify during assessment.
Ground floor areas: Living rooms, kitchens, hallways, conservatories, and extensions benefit most from underfloor heating. These are typically the spaces with concrete construction.
Properties with tight clearances: Ironically, homes where traditional methods couldn’t work such as Victorian and Edwardian properties with minimal door clearances are often perfect candidates for modern retrofit because zero floor height increase solves the constraint completely.
Renovation projects: If you’re already renovating kitchens, bathrooms, or extensions, retrofit underfloor heating integrates perfectly into the project timeline and budget.
Properties requiring alternative approaches:
Suspended timber floors: Upper floors with timber joists require different techniques, either between-joist installation or overlay systems. These are viable but involve different considerations.
Very thin screed: Some properties have minimal screed depth that makes channel milling impractical. Alternative systems exist but costs increase.
Listed buildings: Conservation requirements may limit options or require specific approvals, though modern retrofit often qualifies precisely because it preserves original features and floor levels.
Properties with underfloor services: Extensive pipework or cables in screed (less common in older properties) may complicate channel routing. Professional assessment identifies these situations.
Common retrofit underfloor heating concerns addressed
“Will it work with my existing boiler?”
Most modern boilers work perfectly well with underfloor heating. The system operates at lower temperatures than radiators, which is actually easier on your boiler and more efficient.
Older boilers may need a mixing valve to ensure water temperature stays optimal. We assess compatibility during the free survey and advise honestly about whether any modifications are needed.
If you’re considering boiler replacement anyway, combining the projects makes excellent sense as pairing underfloor heating with a heat pump delivers maximum efficiency and government grant eligibility.
“What about leaks – can pipes be accessed?”
Modern pipe materials and professional installation make leaks extremely rare. Quality pipes with proper pressure testing before sealing virtually eliminate this risk.
In the unlikely event of a leak, we provide detailed as-laid diagrams showing exact pipe locations. Repairs involve accessing the specific affected area only, not ripping up entire floors. This is why documentation and professional installation matter so much.
Most professional installations include warranties covering materials and workmanship for multiple years, providing peace of mind.
“Won’t it take ages to heat up?”
This depends entirely on pipe diameter and system design. Many retrofit installations use standard 12mm pipes that genuinely do take 2-3 hours to heat rooms – this is a valid concern with poorly designed systems.
We use 16mm pipes specifically to address this issue. The larger diameter provides 33% better water flow, delivering warmth within 30-60 minutes rather than hours. This makes retrofit underfloor heating as responsive as radiators whilst maintaining all the efficiency benefits.
Proper system design, sizing, and commissioning ensure quick response times rather than the sluggish performance that gives underfloor heating an undeserved reputation for being slow.
Choosing the right retrofit underfloor heating installer
The quality of your retrofit installation depends entirely on installer expertise and equipment. This isn’t a job for general builders or heating engineers without specific retrofit experience.
What to look for:
Specialised equipment: Channel-cutting requires professional-grade grinding equipment with industrial dust extraction. Installers using basic angle grinders cannot achieve the precision or cleanliness professional retrofit demands.
Retrofit experience: Ask for examples of completed retrofit projects in properties similar to yours. Period properties, tight clearances, occupied homes – these require specific expertise.
Transparent pricing: Detailed quotations with clear breakdowns. No hidden costs or “additional work discovered” charges. Fixed pricing that doesn’t change once work begins.
Professional design: Room-by-room heat calculations, pipe layouts optimized for your space, proper zoning and controls. Not generic “standard layouts” that ignore your property’s specifics.
Comprehensive service: Survey, design, installation, pressure testing, commissioning, documentation, and warranty. Professional retrofit includes all these elements as standard.
Ready to explore retrofit underfloor heating for your property?
We offer free, no-obligation assessments for UK homeowners considering retrofit underfloor heating:
What you’ll receive:
Professional property survey and floor evaluation
Heat loss calculations and system design recommendations
Transparent pricing with complete cost breakdown
Honest advice about whether retrofit makes sense for your specific situation
No pressure to proceed, just expert guidance!
Get a free assessment today: 📞 0203 9166 264
📱 +44 7951 041911
📧 info@channelheatsystems.co.uk
Professional retrofit underfloor heating installation across the UK – specialised equipment, transparent pricing, rapid installation, proven results.
