WITH energy costs continuing to rise and government targets pushing homes towards higher efficiency standards, Enniskeane’s Jason Collins, Director of Cork-based SE Systems, says retrofitting has become one of the most effective ways for homeowners to cut bills, improve comfort, and future-proof their properties.

SE Systems helped improve the energy efficiency of more than 1,500 homes last year, works across a wide range of retrofit projects.

Jason’s advice to a successful retrofit is taking a structured “fabric first” approach—reducing heat loss in the home before investing in new heating technologies such as heat pumps. 

Jason Collins, director of SE Systems

He notes while the upfront investment can be significant, strong grant support and long-term energy savings make retrofitting increasingly attractive for homeowners.

Here is Jason’s top advice:

BER & Home Energy Assessment 

The retrofit process typically begins with a Building Energy Rating (BER) assessment and Home Energy Survey. This identifies where heat is being lost and outlines the most effective upgrades for the property.

The survey acts as a roadmap for the entire project, setting out recommended works, expected BER improvement, indicative costs, and the grants available for each measure.

A full survey usually takes around 90 minutes and involves measuring all heat-loss areas, including walls, floors, windows, doors and attic spaces. The cost is generally in the region of €200–€300.

Most homeowners using the One Stop Shop retrofit scheme are targeting a minimum BER of B2, which is widely achievable in Irish homes when works are carried out correctly.

Fabric first approach – Make the house Heat Pump Ready

When undertaking the retrofit, the key is to take a “fabric first” approach—improving the building itself before investing in more advanced systems.

So when retrofitting an older home, the most important principle is to focus on reducing heat loss first.

There’s no real benefit in upgrading your heating system if the house isn’t retaining heat efficiently. In most cases, the simplest and most effective starting points are the fabric – attic insulation, wall insulation, and basic air tightness (draught-proofing).

These measures are relatively low-cost, minimally disruptive, and can deliver immediate improvements in comfort and energy bills.

A well-insulated and airtight home also ensures that any future heating system, such as a heat pump, operates efficiently.

Understanding your home’s construction

Each property is different, and the construction type determines what wall insulation method is suitable.

Homes may have cavity walls, solid block, stone, or mass concrete construction.

Cavity walls can often be insulated relatively cost-effectively, with grants in some cases covering up to 80% of the cost. 

Solid walls or stone buildings generally require either external insulation or internal dry lining.

External insulation is often preferred to avoid reducing internal room sizes and to reduce thermal bridging. Grants available usually cover 20% - 40% of the costs. 

On retrofit projects, a typical target is a U-value of 0.27 W/m²K or better for walls.

Stone buildings require particular care, and specialist advice is strongly recommended to avoid moisture or structural issues.

Attic Insulation

Attic insulation remains one of the most cost-effective upgrades.

Typical installations involve upgrading to 300mm of insulation, along with insulating water tanks and pipework.

Costs generally range from €1,500 to €3,000, depending on house size, with SEAI grants often covering a large portion of the expense—frequently more than 80%.

There are different types of attic installation, but in general it is considered one of the quickest and most effective ways to improve heat retention in the home.

Solar PV Panels

Solar photovoltaic (PV) panels are now a common addition to retrofit projects. After grants, typical installation costs range from €4,000 to €7,000, depending on system size.

Most systems pay for themselves within four to six years, generating electricity for use in the home, with surplus power either exported to the grid or stored in a battery for later use.

Savings are very quantifiable and I think everyone should consider for their home. 

Heat pumps 

Heat pumps or renewable heating systems are replacing traditional oil/gas central heating system in Irish homes.

They work by extracting heat from outside air and transferring it into the home through a heat exchanger, using electricity to operate the system.

While electricity use increases, reliance on oil or gas is eliminated.

A well-designed heat pump system typically operates at around 300% efficiency (COP 3), compared to modern gas or oil boilers at around 90–97% efficiency.

Grant support of up to €6,500 is available for standalone heat pump installations, with higher supports possible under the SEAI One Stop Shop deep retrofit scheme of €12,500 depending on the overall works completed.

Average installation costs range from €13,000 to €16,000.

Mechanical ventilation systems 

As homes become more airtight (typically below 5 m³/hr/m² @ 50 Pa), proper ventilation becomes essential.

Mechanical ventilation systems, such as demand-controlled or heat recovery systems (MVHR) ensure a continuous supply of fresh air while removing moisture from wet rooms like kitchens and bathrooms.

Heat recovery systems also pre-heat incoming air, reducing your overall heating demand.

Heating controls 

How a homeowner uses their heating system has a major impact on running costs and efficiency.

Heat pumps are typically designed to maintain steady temperatures rather than being turned on and off. 

Recommended room temperatures are generally 19–21°C. Avoiding large temperature swings helps maintain efficiency and reduces energy use.

It is also important that radiator flow rates, thermostatic valves and zoning controls are correctly set during commissioning.

In most cases, the system should be balanced so that all radiators receive a consistent flow of heat rather than being heavily restricted in individual rooms, this may be a change in mindset for homeowners from traditional home heating habits.

Properly set up, heating controls ensure the home remains comfortable, efficient, and predictable in its energy use—helping homeowners maximise the return on their retrofit investment.

Common mistakes in retrofits

• Installing a heat pump before improving insulation 
• Oversizing or under sizing heating systems 
• Poor ventilation after airtightness upgrades 
• Skipping system balancing and commissioning of heat pumps

SEAI grant aid 

Homeowners can either complete upgrades in stages or opt for a full managed retrofit through the One Stop Shop system. While staged upgrades offer flexibility, the One Stop Shop approach ensures all measures work together properly, improving overall efficiency and helping achieve higher BER ratings, typically targeting a minimum B2 standard.

There are strong supports available through the Sustainable Energy Authority of Ireland (SEAI), including grants for insulation, Windows & Doors, heat pumps, Solar PV and full home retrofits under the One Stop Shop scheme.

These grants can significantly reduce the upfront cost and make upgrades much more accessible.

Beyond the initial savings, SEAI-supported upgrades also deliver long-term benefits including lower energy bills, improved comfort, better indoor air quality, and increased property value, particularly as higher BER-rated homes become more desirable in the Irish housing market.

SEAI Grants Available: https://www.seai.ie/grants/home-energy-grants/one-stop-shop/multiple-energy-upgrades