Gas Safe Registered for gas-safe valve work
Plumbing
Underfloor heating
Wet underfloor heating design and installation for kitchens, bathrooms, extensions and full-house retrofits, pairing cleanly with combi boilers and heat pumps.
Pricing Quoted
Clear quote · Gas Safe registered · Checkatrade approved
- 1Send the detailsPhotos, postcode, what's happening: phone, WhatsApp or form.
- 2Same-day replyNigel confirms price, visit time or survey slot.
- 3Fixed quoteWritten down before any work starts. No surprises.
Vetted, certified, accountable.
All makes Bathrooms, leaks, taps and kitchens
Checkatrade Approved and reviewed
15 yrs Same engineers, same standards
Indicative scope
Exact pricing is confirmed before work starts and depends on the property, access, parts and fault diagnosis.
Single zone (kitchen / bathroom)
Quoted
15–25m², overlay or under-tile
- Loop design + heat-loss calc
- Manifold + zone valve + actuator
- Pipe (PEX-AL-PEX) + insulation
- Wiring centre + thermostat
- Boiler / heat-pump pairing
Multi-zone retrofit
Quoted
Whole ground floor, lift-and-relay or low-profile overlay
- Multi-zone manifold (typically 4–6 ports)
- Floor-by-floor loop design
- Insulation + reflective foil
- Smart thermostats per zone
- Recommissioned boiler / heat pump
New-build / extension
Quoted
Pipes in before screed pours
- Build-program coordination
- Pipe loop fitting before screed
- Manifold + smart controls
- Zone valves wired to boiler
- Final commissioning post-screed cure
UFH
Going underfloor in a refit or extension?
Wet underfloor heating design and installation for kitchens, bathrooms, extensions and full-house retrofits, pairing cleanly with combi boilers and heat pumps.
At a glance
Quick facts before you read on.
What's included
5 things, no extras on the day- Loop design + heat-loss calc
- Manifold + zone valve + actuator
- Pipe (PEX-AL-PEX) + insulation
- Wiring centre + thermostat
How we quote
Confirmed before work startsTypical 25m² kitchen install excluding flooring/screed.
Certification
Gas Safe RegisteredJob done to standards. Paperwork on the day.
Service area
Cardiff, Penarth, Barry, CaerphillyWet UFH is more efficient than radiators, runs at lower flow temperatures (which is exactly what heat pumps want), removes the visual clutter of wall-mounted rads, and is genuinely pleasant in winter. Done well, it’s a permanent comfort upgrade. Done badly, it’s an expensive cold floor.
What’s involved
For new builds and extensions, UFH is straightforward: pipes go in before the screed pours. We design the loop layout, calculate heat output room-by-room, and install pipework, manifold, and zone valves.
For retrofits, options vary by floor type:
- Suspended timber floor: pipes between joists, with insulation and spreader plates above. Good output, modest depth penalty (15–25mm rise).
- Concrete floor: overlay with low-profile UFH systems (12–15mm). Lifts the floor by an inch but works in almost any room.
- Lift-and-relay tiled floor: full depth (75–100mm) into a new screed. The most efficient option for a kitchen renovation, biggest disruption.
Heat pump compatibility
UFH and air source heat pumps are made for each other. The pump runs at low flow temperatures (35–45°C) which matches UFH design temperatures perfectly. We size the loops for heat-pump operation from day one, so there’s no retrofit pain later.
In Cardiff specifically, UFH-plus-heat-pump is the highest-efficiency residential heating combination available. With a well-insulated home and proper insulation under the loops, we typically see Coefficient of Performance (COP) values of 3.8–4.4 through the year. That means every £1 of electricity buys £3.80–£4.40 of heat. With the BUS grant on the heat pump (£7,500, or £9,000 if you’re coming off oil or LPG) and run cost savings, the typical payback against gas-and-rads is 7–9 years.
Loop design: the bit most installers skip
Loop pitch (the spacing between pipe runs) matters more than people realise. Closer pitch (100–150mm) gives faster response and higher peak output but uses more pipe and runs at higher pump speed. Wider pitch (200mm+) is cheaper but slower and lower-output.
We design loop pitch room-by-room based on:
- Heat loss: exposed external walls and large windows need closer pitch on the perimeter.
- Floor finish: tile transmits heat fast, carpet very slowly. Carpeted rooms need closer pitch and higher flow.
- Boiler vs heat pump: heat pumps benefit from closer pitch because flow temp is lower.
- Zone strategy: each room ideally on its own loop or paired loop with similar heat loss.
A 25m² kitchen typically gets 100–120m of pipe in 2–3 loops. Insulation underneath the pipe is critical. We use 50mm Celotex or PIR board with reflective foil above; the Building Regs minimum is too low for properly efficient operation.
Pricing
A typical 25m² kitchen install (including manifold, pipe, zone valve, controls, and commissioning, but excluding flooring and screed): £1,800–£2,800 fitted. Whole-house retrofits quoted on a per-room basis after a survey.
Specific pricing examples:
- Single-zone kitchen UFH: £1,800–£2,400
- Bathroom UFH (under tile): £550–£900
- Whole ground floor retrofit (4 zones): £4,800–£7,500
- New-build extension UFH: £60–£90 per m² depending on zone count and finish.
Common mistakes other firms make
- Insufficient insulation underneath. Without insulation, half the heat goes downward. We use 50mm PIR board with foil above, every job.
- Mixed loop lengths on one manifold port. A 90m loop and a 30m loop on the same port will never balance. We size each port for similar pipe length.
- Ignoring screed cure time. Running fresh screed too hot too soon cracks it. We commission slow: 25°C for 7 days, then ramp.
- No zone valves. Per-zone control is the difference between UFH that runs efficiently and UFH that runs everywhere all the time.
Materials and warranty
We use PEX-AL-PEX pipe (cross-linked polyethylene with aluminium core) for stability and oxygen-barrier reasons. Manifolds are usually Heatmiser, Polypipe, Wundatherm or Watts depending on zone count. Smart thermostats are typically Heatmiser Neo or Hive Multizone. The pipe carries a 10-year manufacturer warranty; workmanship is 12 months.
Fitted UFH alongside a Vaillant heat pump. PHBLUE handled both. The integration just worked. The pump runs at low flow temps perfectly matched to the loops, and the bills have come in £40/month lower than the old gas system in winter. The kitchen is properly warm for the first time in seven years.
Recent jobs near you
A few of the jobs we have finished lately, with the postcode and what was involved.
- CF64 April
Penarth single-storey extension, UFH fitted before screed pour, Vaillant heat-pump paired.
- CF14 March
Whitchurch kitchen retrofit, low-profile overlay, 18m².
- CF11 March
Pontcanna basement bathroom, single zone, screed pour.
- CF24 February
Roath ground-floor whole-floor retrofit, 4-zone manifold + Hive smart controls.
How the job runs
- 01
Survey + design
1–2 hoursHeat-loss calculation per room, loop layout sketched, manifold position chosen, zone strategy agreed. Free survey, fixed-price quote within 48 hours.
- 02
First-fix
1–3 daysPipework, manifold, insulation laid. For new builds and extensions this happens before the screed pour. For retrofits, after floor lift.
- 03
Screed / overlay
Drying timeScreed laid by builder (we hand back), or we overlay with low-profile board for retrofit. Drying / cure time before commissioning.
- 04
Commissioning
1 daySystem filled, vented, pressure-tested. Each loop balanced. Smart controls paired with the boiler or heat pump. Full handover walkthrough.
- 05
Aftercare
12 monthsFree balance return after first month. 10-year pipe warranty. 12-month workmanship guarantee.
Common questions
How long does a boiler installation take?
A like-for-like combi swap is usually a single working day. System or regular boiler upgrades, or installs that need the flue rerouted, take one to two days. Back-boiler removals add half a day for the chimney sweep and asbestos check. We'll give you a firm timeline at quote stage so you can plan around it.
Which boiler brand should I pick?
PHBLUE's existing site says we service and repair all major boiler makes and models, including Worcester Bosch, Vaillant, Ideal and Baxi. The right brand depends on the house, budget, warranty and parts availability, so we confirm the recommendation in the quote.
What's included in a fixed-price boiler quote?
A written boiler quote should set out the boiler, flue work, controls, any filter or system-cleaning work, warranty position, registration requirements and removal of the old unit where included. We confirm the exact scope before work starts.
How much should a new boiler cost in 2026?
Boiler prices depend on the model, flue route, controls, system condition, access and whether extra pipework or cleaning is needed. Send the boiler details and postcode and we will confirm the price before work starts.
Will you remove the old boiler?
Yes, every install includes removal and recycling of the old unit, packaging take-away, and a full clean-down before we leave. You'll get the warranty paperwork and the Gas Safety Certificate handed to you on the day.
Do you service boilers you didn't install?
Yes. The existing PHBLUE site says we service and repair all boiler makes and models, including Worcester Bosch, Vaillant, Ideal, Baxi and more.
How much does an air source heat pump actually cost?
After the BUS grant, most installs land between £6,000 and £10,000, depending on the property, the size of the system, and what's needed for radiator and pipework upgrades. That's net of the £7,500 mains-gas rate; if you currently heat with oil or LPG the grant is £9,000, so take another £1,500 off. We give you a fixed quote after a free survey.
Will it actually heat my house in winter?
Yes: modern air-source heat pumps work down to about -25°C. The Welsh climate is well within their operating window. They run cooler than a gas boiler (so radiators feel less hot to the touch) but they run for longer, keeping the house at a steady comfortable temperature.
Do I need to replace my radiators?
Sometimes. Heat pumps work best with slightly larger radiators because they run at lower flow temperatures. We'll calculate that during the survey and only swap radiators where it's genuinely needed.
How loud is it?
About as loud as a fridge: roughly 40–45 dB at one metre. Most installs are positioned where the noise is irrelevant.
How much does a new bathroom cost in Cardiff?
For a standard 3-piece bathroom (bath, basin, WC) refit including tiling, flooring and second-fix electrics: £6,500–£9,500 fitted, depending on tile choice and whether the layout moves. Wet rooms and en-suites with shower trays start £8,500. We quote fully fixed-price after a survey; supply-only items are at trade plus 10%.
How long does a bathroom installation take?
A straight refit (same layout, same waste positions) is 5–7 working days. Layout changes that need waste pipe reroutes add 2–3 days. We work clean: dust sheets up, daily clean-down, the rest of the house stays liveable.
Do you do tap repairs or just full installs?
Both. Most tap drips are a £20 cartridge, and we charge £90 for the first hour (covers diagnosis and most repairs) and £55 per hour after. If your taps are end-of-life we'll tell you and quote a swap, never the other way round.
What's the difference between a powerflush and a magnetic filter?
A powerflush is a one-time deep clean of the heating system using a high-flow pump and inhibitor, which clears years of magnetite sludge from radiators, boilers and pipework. A magnetic filter (MagnaClean or equivalent) is fitted permanently on the return pipe and traps sludge as it circulates, year on year. Both are needed for a long-lasting modern system. Powerflush £450; magnetic filter retrofit £180 fitted.
My water pressure is low, can you help?
Yes, first we'll find out whether it's coming in low (a problem with the incoming main, your stopcock, or a partially-closed valve), or dropping mid-house (a leak, a cylinder issue, or scale in the pipework). Diagnostic visit is £90 and gets credited if you go on to have the work done.
Are you WaterSafe registered?
Yes: WaterSafe approved plumber scheme. That's the recognised standard for any work that touches the mains supply (stopcocks, incoming mains repairs, unvented cylinders, water softeners). It's also the scheme insurers and conveyancers look for on home reports.