CASE STUDY
A New Chapter for a 1970s Home
A detached 1970s bungalow in Co. Kerry, inherited as a family property and vacant for several years, extended and redesigned before being retrofitted from E1 to A3 — cutting carbon emissions by over 90%.
€24,100 SEAI Grant Secured
Full Project Management
Oil Heating Eliminated
BEFORE
E1
320.79
kWh/m²/yr
73.64
kgCO₂/m²/yr
AFTER
A3
53.71
kWh/m²/yr
6.87
kgCO₂/m²/yr
267.08 kWh/m²/yr
improvement in energy performance
A3
New BER Rating
E1
Previous BER Rating
€24,100
SEAI Grant Secured
€18,711
Client Net Cost
€44,871
Total Project Value
94m²
Floor Area
32 wks
Mar to May 2025
6.87
kgCO₂/m²/yr Improvement
THE STORY
Bringing a 1970s Bungalow Back to Life
Jennifer Casey inherited this detached bungalow in Kilcummin, Co. Kerry — a family property that had stood empty for several years.
Built in the 1970s, the house needed more than an energy upgrade: an E1 rating, a dated layout, and running costs to match. Jennifer wanted to bring it up to today’s standards and reshape it to suit modern living, while making the most of the SEAI grants available.
The redesign went beyond a standard retrofit. The front elevation was slightly extended and the roof pitch increased, creating the space and structure for a full insulation upgrade – roof insulation above the new pitch, wall insulation to the internal lining, and floor insulation paired with a new heat pump-fed underfloor heating system that replaced the old oil boiler entirely
REIL managed the project end-to-end alongside Driver Renewables, REIL’s Kerry-based retrofit contractor, covering the extension, building fabric, heating system, ventilation, and grant administration from survey to sign-off. Works ran for around 32 weeks, from March to October 2025.
The result: a jump of 267.08 kWh/m²/yr — taking the property from E1 to A3 and cutting carbon emissions by over 90%.
Why this project stands out
- BER improved from E1 to A3
- Energy value improved by 267.08 kWh/m²/yr
- Condensing oil boiler replaced
- €24,100 in SEAI grants secured
- Full project management from survey to sign-off
- Completed in 32 weeks (Mar-Oct 25)
THE PERFORMANCE UPLIFT
Before and After Results
| Measure | Before | After |
|---|---|---|
| BER Rating | E1 | A3 |
| Energy Value | 320.79 kWh/m²/yr | 53.71 kWh/m²/yr |
| Carbon Emissions | 73.64 kgCO₂/m²/yr | 6.87 kgCO₂/m²/yr |
| Heating System | Fossil fuel heating system | Air source heat pump |
| Energy Position | Inefficient E-rated property | Energy-positive property |
267.08
kWh/m²/yr Improvement
A family property and vacant for several years retrofitted from E1 to A3 — cutting carbon emissions by over 90%.
From Oil-Fired to A3: A Home Reimagined
From the roof down, every element of the property was touched – a structural extension paired with a complete fabric and heating overhaul.
SCHEDULE OF WORKS
▦
Roof Elevation & Insulation
With the new roof pitch in place, insulation was installed above to dramatically reduce heat loss through the roof.
⌂
Wall & Floor Insulation
Insulation was fitted to the internal wall lining throughout the property and underfloor to address heat loss at ground level.
▣
Air Source Heat Pump & Underfloor Heating
A new air source heat pump was installed feeding an underfloor heating system throughout the home, replacing the old oil boiler.
▥
External Doors & Windows
New high-performance windows and external doors were installed throughout the property to reduce heat loss, eliminate draughts, and close the remaining gaps in the building’s thermal envelope.
◎
Air Tightness Works
Targeted air tightness measures closed gaps across the building fabric, working alongside the new ventilation system to lock in heat without compromising air quality
✓
Mechanical Ventilation (MVHR)
A mechanical ventilation system was installed to maintain healthy indoor air quality in the newly airtight home, managing moisture and preventing condensation as the building fabric was upgraded.
PROJECT GALLERY
Before & After: The Kilcummin Transformation
Before: The 1970s Bungalow
After: A3-Rated and Extended
New Heat Pump & Hot Water Cylinder
Reconfigured back of house
The Redesigned Lounge
Finished Bedroom, A3-Rated Comfort
REAL-WORLD IMPACT
The Numbers That Matter
Because the property was vacant before the retrofit, there’s no pre-retrofit bill to compare against. What the numbers below show is what it actually costs to run the newly extended, A3-rated home today – heat pump, underfloor heating, cooking and every appliance included, with the old oil boiler gone and no oil deliveries or fuel bill to budget for.
€
1,235
A fully renovated, A3-rated home - oil boiler gone, heat pump and underfloor heating in - for around €1,235 a year in electricity.
Electricity Bill
€243.41
9-week period (Mar – May 2026)
Electricity Bill
€179.62
9-week period (May – Jul 2026)
Oil Bill
€0
Heat pump covers all heating & hot water
Projected Annual Cost
~€1,235
Electricity only - no other fuel
CLIENT REVIEW
★★★★★
“I am very happy with how my house turned out — warm, comfortable and energy efficient. REIL’s one-stop-shop approach was easy to deal with, and Martin and his plumber Ciaran at Driver Renewables were excellent throughout. I’d highly recommend their team.”
T
Jennifer Casey
Kilcummin, Co. Kerry
CONCLUSION
What This Project Demonstrates
This project shows how much is achievable in a single deep retrofit – even starting from one of the lowest BER ratings on the scale. A vacant family home in Co. Kerry, built in the 1970s, has been extended, redesigned, and brought up to A3, cutting carbon emissions by over 90%.
Managed end-to-end by REIL and delivered by Driver Renewables, the project demonstrates what a fully coordinated retrofit – covering fabric, heating, ventilation and grant administration – can achieve for an older home, whatever its starting point.
HOW REIL MAKES IT SIMPLE
One Managed Process From Survey to Sign-Off
Jennifer had a single point of contact throughout and was not required to manage contractors, applications, or compliance separately.
1
Initial Assessment
REIL assesses the home and identifies the right whole-home upgrade pathway.
2
Retrofit Plan
A coordinated upgrade plan is created across fabric, heating, and grant requirements.
3
Grant Management
SEAI grant administration is managed as part of the overall project process.
4
Installation
The building fabric, heating system, and supporting works are coordinated together.
5
Sign-Off
The completed project delivers an A3 BER and an energy-positive result.
Could Your Home Achieve a Similar Upgrade?
REIL manages the full home energy upgrade process, from assessment and retrofit planning to SEAI grants, installation, and final BER.