Monthly Archives: December 2025

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:

• no increase in floor height
• no removal of the existing slab
• faster heat transfer due to shallow pipe depth
• clean, controlled installation with minimal dust

This method is one of the most effective ways to install water underfloor heating on existing concrete floors.

3. Is underfloor heating expensive to run?

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
• transition gradually toward low-temperature heating

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
• the floor is not concrete or engineered screed
• moisture levels are excessively high
• the surface is heavily contaminated or unstable

This is why a proper technical assessment is essential before installation.

The importance of workmanship and system design

A milled system’s performance depends heavily on:

• channel spacing
• pipe bend radius
• depth tolerances
• manifold design
• flow temperature planning
• pressure testing
• zoning strategy
• 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.