Heat Pump + UFH Retrofit Cost Per Room UK 2026

Heat pumps deliver highest efficiency at low flow temperature (35C ideal). Heat distribution emitters need to be sized accordingly:

• UFH: typically designed for 28-35C flow temp. Large surface area (entire floor) compensates for low delta-T (flow temp vs room temp).
• Standard radiators: typically designed for 70-80C flow temp historically. At heat pump's 35-45C flow, output drops 40-60% vs nameplate.
• Oversized radiators (K2 + fins): designed for 45-55C flow. Adequate for heat pump but still 10C+ higher flow temp than UFH.

SCOP impact:

• UFH-only system: SCOP 3.8-4.5 typical for well-installed property.
• Mixed UFH + oversized radiator: SCOP 3.5-4.0 typical.
• Standard radiator-only (oversized to compensate): SCOP 3.0-3.5 typical.
• Original undersized radiators (not upgraded): SCOP 2.5-3.0 typical.

Gap of 0.5-1.0 SCOP points = ~GBP 150-300/year running cost difference for typical UK 3-bed. UFH retrofit saves this annually but install cost is significant.

Small bathroom or utility (3-5m2):

• Overlay system: GBP 1,500-2,500 (boards + UFH pipework + manifold + electrician/plumber).
• Screed system: GBP 2,000-3,500 (more durable; waterproofs better for wet rooms).
• Tile finish typically follows: GBP 800-1,500 separately.

Medium room (12-18m2 typical bedroom or living room):

• Overlay system: GBP 3,000-5,500 (most cost-effective for retrofit).
• Screed system: GBP 4,000-7,000.
• Floor finish (wood, vinyl, tile): GBP 1,500-4,000 separately.

Large room or open-plan (25-40m2):

• Overlay system: GBP 5,500-10,000.
• Screed system: GBP 7,000-13,000.
• Floor finish: GBP 3,000-8,000.

Whole house retrofit (100m2 3-bed):

• Overlay: GBP 12,000-20,000 + GBP 8,000-15,000 floor finish = GBP 20,000-35,000 total.
• Screed: GBP 15,000-25,000 + floor finish = GBP 23,000-40,000 total.
• Plus 4-6 weeks disruption with kitchen/bathroom downtime.

Overlay UFH adds 20-30mm insulation boards with routed channels for UFH pipework on top of existing floor:

Process:

• Remove existing floor finish (carpet, vinyl, wood) where present.
• Lay insulation boards over existing subfloor (concrete or timber).
• Snake UFH pipework through routed channels.
• Pour thin self-levelling compound (~5mm) over pipework.
• Install new floor finish.

Pros:

• Lower disruption (no floor lift).
• Lower cost than screed system.
• Easier retrofit in occupied properties.
• Heat-up faster (less thermal mass).

Cons:

• Raises floor height 25-30mm (doors, skirting, thresholds).
• Slightly lower heat output per m2 than screed.
• Pipework more accessible if leak occurs (also harder to ignore visually if visible at edges).

Typical brands: Polypipe Overlay, Wunda Quickdeck, Thermogroup ProGrid.

Screed-bed UFH is the gold-standard install method - UFH pipework cast into 50-75mm screed bed:

Process:

• Lift existing floor finish + subfloor where needed.
• Lay insulation boards (typically 100mm).
• Snake UFH pipework + secure to insulation.
• Pour 50-75mm screed bed encasing pipework.
• Cure screed (2-3 weeks).
• Install new floor finish on cured screed.

Pros:

• Higher heat output per m2 (~30% more than overlay).
• More durable + longer lifetime.
• No floor height issue (replaces existing floor at same level).
• Better acoustic performance (mass damps impact noise).

Cons:

• Higher install cost.
• Major disruption (1-2 weeks downtime per room).
• Long screed cure time before flooring possible.
• Heat-up slower (more thermal mass to warm).

Screed systems typically chosen for new builds + major renovations where floor is being replaced anyway.

1. Major renovation timing. If you're already replacing flooring + planning kitchen/bathroom refit, marginal UFH install cost is GBP 50-100/m2 (pipework + insulation) vs the GBP 100-300/m2 standalone cost. Combine UFH retrofit with renovation = best ROI.
2. Extension construction. New build extension should have UFH as default - no retrofit cost premium; integrates perfectly with heat pump.
3. Wet rooms (bathroom, kitchen) for comfort. Selective UFH in tile-floored wet rooms delivers significant comfort benefit at moderate cost (GBP 1,500-3,000 per room). Worth doing standalone.
4. Whole-house retrofit ONLY when: property currently has solid floors with poor insulation; planning to live there 20+ years; willing to absorb major disruption; can afford GBP 15-25k upfront for SCOP gain that may pay back in 30-80 years.

What NOT to do: retrofit whole-house UFH just for the SCOP gain on running cost - economics don't work standalone. Stick with oversized radiators if no renovation timing applies.

1. Oversized K2 + fin radiators throughout. ~30% larger heat output for same wall space; supports 45C flow temp operation. Cost GBP 1,500-3,000 for typical UK 3-bed. Achieves SCOP 3.5+ without UFH cost.
2. Selective UFH in wet rooms only. Bathroom + en-suite + utility = ~10-15m2 total = GBP 4,500-10,000 install. Comfort win without whole-house UFH cost. Rest of house uses oversized radiators.
3. Electric UFH in wet rooms. Direct electric resistance UFH mats; cheap install (~GBP 80-150/m2); NOT connected to heat pump (runs at COP 1.0). Comfort-only solution; high running cost if used heavily.

Most cost-effective approach for typical UK 3-bed: oversized radiators throughout + selective wet-room UFH for comfort. Total cost ~GBP 6,000-13,000 (vs GBP 20-35k for full house). Achieves SCOP 3.5+ with significant comfort benefit in key rooms.