Radiator vs underfloor heating cost implications for heat pumps in Ireland (2026), including upgrade costs, efficiency differences and installation considerations.
1. Overview
Heat pumps operate most efficiently at lower water temperatures compared with traditional oil or gas boilers.
Because of this, the type of heating system installed inside the home significantly affects both:
Installation cost
System efficiency
Most Irish homes upgrading to heat pumps retain radiators, but many require larger radiators to deliver adequate heat output at lower temperatures.
Underfloor heating is often considered the most efficient heat distribution method for heat pumps but typically involves higher installation costs.
2. Radiator Heating with Heat Pumps
Radiators can be used with heat pumps if they are correctly sized.
Traditional oil or gas boiler systems typically operate at water temperatures between:
60°C – 80°C.
Heat pumps usually operate at lower flow temperatures:
35°C – 50°C.
Because of this difference, existing radiators may need to be replaced with larger models to deliver the same heat output.
3. Typical Radiator Upgrade Costs
Radiator upgrades are one of the most common retrofit costs when installing a heat pump.
| Upgrade Type | Typical Cost |
|---|---|
| Single radiator replacement | €150 – €400 |
| Larger radiator installation | €200 – €500 |
| Full house radiator upgrade | €1,500 – €4,000 |
The number of radiators requiring replacement depends on the heat loss calculation for the property.
4. Underfloor Heating Systems
Underfloor heating distributes heat through pipes installed beneath the floor surface.
This system operates efficiently with the lower water temperatures used by heat pumps.
Underfloor heating provides:
Even heat distribution
Lower operating temperatures
Improved thermal comfort
However, installation cost can be significantly higher in retrofit situations.
5. Underfloor Heating Installation Costs
Underfloor heating costs vary depending on whether the system is installed in a new build or as part of a retrofit.
| Installation Type | Typical Cost |
|---|---|
| New build installation | €4,000 – €8,000 |
| Retrofit underfloor heating | €6,000 – €12,000 |
| Single-room retrofit | €1,500 – €3,000 |
Retrofit installations often require floor removal or additional floor build-up.
6. Efficiency Comparison
| Heating System | Typical Flow Temperature | Heat Pump Efficiency |
|---|---|---|
| Standard radiators | 50 – 55°C | Moderate |
| Oversized radiators | 40 – 50°C | Improved |
| Underfloor heating | 30 – 40°C | Highest |
Lower operating temperatures allow the heat pump to run more efficiently and consume less electricity.
7. Installation Complexity
Radiator upgrades are generally simpler to install.
Typical radiator upgrade process:
Removal of existing radiators
Installation of larger units
Minor pipework adjustments
Installation typically takes:
1 – 2 days.
Underfloor heating installations are more disruptive and may involve:
Floor removal
Pipe installation
New floor screed or floor covering
Installation timelines can range from:
3 – 10 days depending on property size.
8. Example Cost Comparison
Example semi-detached house upgrade:
| Heating System | Estimated Cost |
|---|---|
| Radiator upgrades | €2,500 |
| Underfloor heating retrofit | €8,000 |
Heat pump installation cost:
€17,500
Total system cost comparison:
| System Type | Total Cost |
|---|---|
| Heat pump + radiator upgrades | €20,000 |
| Heat pump + underfloor heating | €25,500 |
Underfloor heating increases total installation cost but may improve system efficiency.
9. Comfort and Temperature Distribution
Underfloor heating provides more even heat distribution compared with radiators.
Radiators heat rooms through convection, which can create temperature differences within a room.
Underfloor systems heat rooms from the floor upward, creating more uniform temperatures.
Both systems can provide comfortable heating when properly designed.
10. Space and Aesthetic Considerations
Radiators occupy wall space and may affect furniture placement.
Underfloor heating systems are hidden beneath the floor surface.
This can provide greater flexibility in room layout.
However, retrofit underfloor systems may slightly increase floor height.
11. Typical System Choice in Ireland
Most heat pump retrofits in Ireland retain radiators due to lower installation cost.
Underfloor heating is more common in:
New build homes
Major renovations
Extensions
Retrofitting underfloor heating in existing homes can significantly increase project cost.
12. Typical 2026 Cost Summary
Radiator upgrades typically cost:
€1,500 – €4,000 for a full house.
Underfloor heating retrofit typically costs:
€6,000 – €12,000 depending on floor area.
Radiator systems remain the most common option in retrofit heat pump installations due to lower upfront cost.
Underfloor heating provides higher efficiency but requires more extensive installation work.
13. Other Resources
SEAI Heat Pump Grant Explained
Required Upgrades – Before Installation
BER Requirements for Eligibility