FloElen Construction at the Heart of SEAI Deep Retrofit Pilot Project

As part of their drive to reduce carbon emissions and improve the energy performance of homes in Ireland, the Sustainable Energy Authority of Ireland (SEAI) part-funded Deep Retrofit Pilot Programmes in 2018 and 2019.  To participate in this programme and qualify for a grant, a home, upon completion of the retrofit works, would have to achieve at least an A3 on the Building Energy Rating (BER) scale, improve its energy performance by at least 150Kw/M2/Y on the BER scale, achieve less than 5M3/H/M2@50Pa in a post works air tightness test and have been built before 2006.

FloElen Construction was the main contractor on one of these Deep Retrofit Pilot Programmes and our project involved the deep retrofitting of 5 homes between May and October 2018 and another 4 homes between April and October 2019.  The homes were your typical 3 or 4 bedroomed suburban 1930’s to 1970’s two storey, semi-detached/terraced houses with one exception which was a rural 4 bedroomed bungalow.  The up-grade approach taken by the designers on this project was to implement what is called a “Fabric first approach”, that is, to make as many improvements to the physical building as possible and as a consequence, greatly reduce the need for and capacity of mechanical systems.  The fabric first approach involves installing high levels of insulation at roof, wall and where possible, floor level, fitting highly energy efficient windows and doors, greatly improving the air tightness levels, reducing and where possible, eliminating any thermal bridges in the construction and eliminating the traditional, hole in the wall ventilation.


Although estimates vary as to the amount of actual heat lost through un-insulated walls, floors and roofs, everyone agrees that it is a huge amount of heat loss and if you wish to make energy improvements then this is an issue that must be addressed.

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Air Tightness and Ventilation

Another major source of heat loss is associated with poor air tightness levels and the provision of ventilation to the building.  Air tightness and ventilation losses can be measured using a blower door, in this test, heated air is forced out of the building and replaced with cold air from outside.

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Windows and Doors

Probably the single biggest heat loss area per M2 of a building is the windows and doors and typically they can lose three times more heat than an uninsulated wall so it was essential that we gave this element very special attention.

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Fabric First Approach and U-Values

As previously stated, we opted for a fabric first approach to our up-grade projects, aiming to make as many energy and heat loss improvements to the physical building as possible and as a consequence, greatly reduce the need for and capacity of mechanical systems.

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Central Heating and Hot Water

Following detailed heat loss calculations on each of the 9 up-graded homes we calculated the new heating and hot water needs for each one.  After extensive research we chose the new Daikin Altherma 3 Air to Water Heat Pump with either 6 or 8 Kilowatt systems being fitted in each of the 9 homes.

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Mechanical Heat Recovery Ventilation

As previously stated, we set out to make each of the homes very airtight, and remove all wall vents, open fires and extractor fans.  This was a very important part of the overall energy efficiency strategy but also left a situation where there was now very little air movement and no extraction.

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Photovoltaic Electricity Generation

The overall aim of this deep retrofit project was to dramatically reduce the energy demand from each of the homes and as a consequence, eliminate the use of on-site Fossil fuels and their associated carbon emissions.  As a result, all the appliances and systems used in these homes are powered electrically and to compliment the electrical energy demand, we installed Photovoltaic (PV) panels with battery storage.  PV panels which convert sunlight into electricity are normally mounted on the roof and in each of our homes we fitted systems that were between 3Kw and 5Kw in capacity.

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Other Measures

All homes were fitted with the latest energy saving LED lightbulbs and fittings, all the homeowners were encouraged to purchase the most energy efficient appliance and to use their electricity efficiently and at the right time of day, where possible.  Just one example of this is, many of the homeowners bought washing machines that were fitted with start-up timers so that they could be set to come on during the day when PV generation was most likely, regardless of whether they were at home or away.

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Post Up-Grade Performance Data

On completion of all works, each of the 9 homes were tested to establish their air tightness levels and new Building Energy Rating (BER) and the results were truly remarkable.  In the air tightness tests all the results were below our original target of 3.0M3/H/M2@50Pa, with the average coming in at just below 2.3M3/H/M2@50Pa.  Even more remarkably than this, all 9 of our homes achieved an A1 in the BER assessments.  An A1 rating is awarded to a home which is assessed as having an energy demand of below 25KwH/M2/Y

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If you are considering an energy up-grade of your home or business premises, why not call FloElen Construction on 087 7542450 and we will be delighted to call out to discuss your plans.  Our expert team provides a full service beginning with a free energy consultation, a full planning service and a team of very experienced construction professionals dedicated to completing your project to the highest standards.  We are an SEAI/NSAI registered contractor for all grant schemes and we guarantee a very a competitive quotation for your works.

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