Radiator vs Underfloor Heating Cost Implications (2026)
Radiators versus underfloor heating for heat pumps in Ireland, including retrofit cost, flow temperatures, efficiency, disruption and a worked total-system comparison.
Full-house radiators: €1,500–€4,000 | Retrofit underfloor: €6,000–€12,000
Choosing Heat Emitters for a Heat Pump
Heat pumps operate at lower water temperatures than traditional oil or gas boilers, so the heat-emitter system has a major effect on both installation cost and efficiency.
Most Irish retrofit projects retain radiators, but some rooms may need larger emitters. Underfloor heating works very efficiently at low temperatures but is far more disruptive to retrofit.
The decision should therefore balance upfront cost, floor works, comfort and expected heat-pump efficiency.
Flow Temperature & Efficiency
Standard radiators: 50–55°C — moderate efficiency
Oversized radiators: 40–50°C — improved efficiency
Underfloor heating: 30–40°C — highest efficiency
Lower flow temperatures generally allow a heat pump to achieve a higher COP.
Radiators vs Underfloor
Radiator Upgrade Costs
Single replacement: €150–€400
Larger radiator: €200–€500
Full-house upgrade: €1,500–€4,000
Underfloor Heating Costs
New-build installation: €4,000–€8,000
Retrofit installation: €6,000–€12,000
Single-room retrofit: €1,500–€3,000
Installation & Total-System Cost Comparison
| Option | Upgrade Cost | Heat Pump Cost | Combined Cost |
|---|---|---|---|
| Radiator upgrades | €2,500 | €17,500 | €20,000 |
| Underfloor retrofit | €8,000 | €17,500 | €25,500 |
Radiator upgrades: normally around 1–2 days. Underfloor retrofit: around 3–10 days depending on floor area and build-up.
Comfort & Space
Underfloor heating gives more even heat distribution and frees wall space because the emitter is hidden beneath the floor.
Radiators are less invasive and cheaper to upgrade, but occupy wall space and may need to be physically larger for low-temperature operation.
Retrofit underfloor systems can also increase finished floor height.
When Each Option Makes Most Sense
| Situation | Usually More Practical |
|---|---|
| Existing home, light retrofit | Radiator upgrade |
| Major renovation with floors already being replaced | Underfloor heating |
| New build or extension | Underfloor heating |
| Budget-sensitive retrofit | Radiators |
| Priority on lowest flow temperature | Underfloor heating |
Most Irish heat-pump retrofits retain radiators because of the lower installation cost.
Cost, Efficiency & Disruption
Upfront Cost
Full-house radiators: €1,500–€4,000
Retrofit UFH: €6,000–€12,000
The cost gap is substantial in existing homes.
Efficiency
Oversized radiators can work well at 40–50°C.
UFH commonly runs at 30–40°C and gives the strongest efficiency potential.
Disruption
Radiator changes usually take 1–2 days.
UFH retrofit can take 3–10 days and may involve floor removal and new screed.
Summary
For retrofit heat pumps, radiator upgrades remain the most common choice because they cost around €1,500–€4,000 for a full house.
Underfloor heating typically costs €6,000–€12,000 to retrofit but can operate at lower flow temperatures.
Underfloor heating is strongest where floor works are already planned; otherwise, oversized radiators often provide the better cost/disruption balance.
Other resources:
SEAI Heat Pump Grant Explained
Required Upgrades – Before Installation
BER Requirements for Eligibility