June 2022

A deep retrofit takes a whole-house approach to energy in the home. This means simultaneously carrying out multiple energy upgrades to achieve a BER of A-rating.

In a deep retrofit or energy retrofit, the correct insulation levels are calculated by ‘modelling’ the house. This is done using specialist software called advanced DEAP (Dwelling Energy Assessment Procedure). This software determines how the proposed energy upgrades will perform over time. This analysis will provide you with a guide on the measures you need to take to achieve an A-rated home. These measures may include some or all of the following depending on the condition of your existing home.


Upgrading your insulation will reduce the heat loss in your home. Depending on your requirements, this may involve some or all of the following; wall insulation, roof insulation and floor insulation. Making sure your home is well insulated won’t just save you money on your heating bills. Still, it is critical to ensure your home is comfortable and your carbon footprint is reduced. When it comes to wall insulation, it’s always better to put the insulation on the outside, rather than the inside of the house.

With external insulation, you won’t have the disruption of works in your home, and you won’t lose any internal floor area. This is a more costly alternative to internal insulation, and rates vary across the country. When externally insulating, your windows should be repositioned outwards to avoid cold bridging. Your insulation contractor will provide a sill adapter to facilitate this. Unless your existing windows are modern and high performing, it is good to upgrade them when externally insulating.


Upgrading your windows to either double or triple glazing is a worthwhile investment. Not only will replacing your old windows with more energy-efficient glazing make a significant improvement to the comfort of your home, but also to contribute to reducing your heating bills.

Triple glazing is a more expensive option to double glazing, but the benefits are worth the additional cost and triple glazed windows are not that much more costly than high-performance double glazing. It’s worth taking your time when choosing windows. Do your research and buy the very best product you can afford.


A poorly designed heating system will result in rooms feeling cold even when well insulated. When it comes to heating systems, you should upgrade to a system based on the electricity you generate yourself. The typical heating system installed on a Deep Retrofit Project is an air-source heat pump. Unlike oil and gas heating systems which are 95% efficient, a heat pump is 100% efficient. For every 1 unit of electricity you put into your heat pump, you get about 3 or 4 units of heat out. Using electricity to power our heating makes good financial sense for us. It is by far the most environmentally friendly choice too.


Adequate ventilation is critical to creating a healthy environment in your home. When your house is poorly ventilated, installing energy-efficient windows can lead to condensation and mould. As part of a deep retrofit, you may need mechanical ventilation to maintain good indoor air quality.


For information about the retrofit scheme and the available grants in Ireland, visit the SEAI website. You’ll find all of the information about the deep retrofit grant scheme for 2022, the available grants, and a list of recommended BER assessors.


Denise O’Connor

Managing Director Optimise Design, B.Arch. RIAI RIBA
& Senator’s Expert Design Consultant
This blog post is sponsored, but the views expressed by the author are her own.

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