Improve and Upgrade Your Home's Energy Efficiency

Many Irish homeowners are consciously making efforts to upgrade their homes to be more energy efficient and we're here to aid that cause for the greater good of our society. Energy-efficient homes rely less on unnecessary energy consumption, adopt the use of renewable energy sources, and cut down greenhouse gas emissions which ultimately result in lower utility bills and increased green energy savings for homeowners.

Other common 'efficiency actions' include replacing the energy-inefficient appliances with efficient ones which is prevalent in the retrograding of homes and businesses nationwide as we all strive to be more environmentally-conscious in 2021 and beyond.

Committing to energy efficiency improvement provides you with more sustainable living conditions and there are significant money-saving opportunities to those who embrace the full benefits of national energy grants and incentives on offer. While some home upgrades can prove expensive at the outset, the long-run benefits are worth it when your potential energy savings are calculated.

In this guide, we'll help you understand the meaning of an energy-efficient home. This guide will help you understand the key benefits and advantages of being energy efficient. We will explain different ways of upgrading your home to become more energy efficient and ideally, support you in playing your part in helping Ireland reach our ambitious sustainability targets in the years and decades ahead.

What is energy efficiency? 

Energy efficiency is simply the act of using less energy to perform the same task; within a domestic household context, this means a concerted effort to reduce energy consumption, with energy waste of any kind eliminated from our homes. 

With a bit of forethought and planning, any Irish home - no matter what year it was built in - can be made more energy efficient to the benefit of your back pocket and the environment.

With the Programme for Government promoting zero energy buildings and green living practices to help meet Ireland's 2030 emissions targets, modern Irish construction standards require greater energy efficiency in new builds, but older houses can also be upgraded to improve their respective energy performance. Currently there are over half a million Irish Homes that would benefit significantly from an energy upgrade and the most recent Retrofit Pilot Scheme launched by the SEAI is targeting a minimum B2 BER Rating, more realistic for older homes.

Of course, the people living in these homes can also be more energy-efficient through our actions, activities and mindsets. There are various factors which determine whether a home is energy efficient or not, falling under the following main areas:


An energy-efficient home should have a high energy rating. This means that a home should be properly insulated as well as airtight. It should have high-efficiency heating and cooling equipment that help to keep the utility bills low. Such a home should also be outfitted with low-flow accessories to lower water consumption and water heating costs. Those living in this home should keep the inside temperatures reasonable, manage electricity properly as well as buy energy-saving products such as LED bulbs and A rated appliances.

Conserve the Environment 

All the efficient features of an energy-saving home usually work together to lower energy consumption. Moreover, such a home is environmentally friendly. The sources of energy should reduce greenhouse gas emissions and also shrink the home's carbon footprint. Greenhouse gases have been at the forefront of climate change.

Successive Irish governments, prominent business organisations and sustainably-minded citizens and community groups have been championing the use of renewable energy sources in recent years, which entail low to zero greenhouse gas emissions. Hence, an energy-efficient home should conserve the environment and it's a responsibility of those within Irish society to develop a greater sense of awareness on how our activity affects the environment.

Comfortable and Healthy 

An energy-efficient home should be comfortable and healthy at all times. This home is warm in winter, and cool during the summer times and also free of drafts. The home is well ventilated and has excellent air quality. The house is never too humid or dry at any given time. Upgrading to this kind of a home can bring a lot of comfort to its residents.

Energy efficient, smart home owners ordinarily utilise a programmable thermostat to regulate their heating and cooling operations during the night and at times when they are away from home. Bord Gais Energy can help you to upgrade your home to an energy-efficient one and start reaping the benefits today.

A Home that Always Adds Value 

An energy-efficient home's fixtures and upgrades usually show the commitment to add resale value. Upgraded windows and doors, as well as highly efficient lighting and appliances, not only save a home's energy but also add value to it. Energy upgrades should also entail investing in renewable energy resources such as solar and wind that can pay off for years to come. Adopting the use of solar energy will save energy for a home, reduce emissions, and add significant value. The Government has committed to a Microgeneration scheme as part of  part of Ireland's Climate Action Plan stating that excess energy produced by households & businesses will be compensated with a Renewable Energy Feed In Tariff (REFIT) for every kilowatt of green energy currently sent back to the national grid. 

Being able to pocket an additional €400 per year through this initiative can make a sustainable home even more appealing to buyers if you’re ever intending to sell your home.. 

What is home insulation?

Energy-efficient homes are usually well insulated and sealed against any air leaks. Current Building Regulations and SEAI guidelines recommend a minimum of 300mm of insulation on  rafters above ceilings or 150/200mm of opencell insulation spray foam between rafters. Hidden cracks, such as those in attics and crawl spaces, can allow as much airflow as an open window can. This means that such cracks cause the heating and cooling systems to work harder to maintain the desired room temperatures. This increases the utility bills for a given home due to higher energy use. 

Sealing such air leaks and adding extra insulation to the outer walls and attic can prove to be a very cost-effective way to improve energy efficiency. Thus, insulation is the act of sealing air leaks, wall cracks, attics, crawlspaces, and other open spaces that could lead to higher energy consumption

Wall Insulation 

About 35% of a home's heat is usually lost via external walls. Any extent of insulation-related heat loss can essentially be eliminated by insulating the walls so that more heat is retained within a home. There are various ways of insulating a home's walls, such as a cavity, external, and internal wall insulation. The SEAI recommend a ‘Fabric First’ approach for creating a more energy efficient home and offer generous grants. These forms of insulation can be used on their own or in combination with a home's existing wall construction. Your building contractor or service provider will assess the best method and discuss this with you before your upgrade begins.

Cavity Wall Insulation 

Cavity wall insulation is an essentially easy and cost-effective first step to reduce heat loss in your home. If your home has cavity walls that are not insulated, or they are only partially insulated, it's advisable to completely insulate them. Insulation is usually pumped into the cavity to seal it.

A series of small holes are drilled in the wall, at regular intervals, on the outside of your home. The insulation is then pumped through these holes to cover the cavity. The holes are then filled in as well to match the rest of the wall. Cavity wall insulation ensures that heat is not lost through the cavities present on the walls. This is quite important when upgrading to an energy-efficient home. 

External Wall Insulation

For the solid block or concrete walls that have no cavity, external wall insulation is generally the most preferred option. This option can also be used in addition to cavity wall insulation to further improve the performance of a home's external walls. External wall insulation usually involves wrapping a layer of stable and rigid insulation around your home. External wall insulation also involves fixing a rigid insulation material on the walls and embedding a mesh into it to provide extra strength. Such insulation can also be covered with a render to provide weather resistance. 

Internal Wall Insulation 

You can apply internal wall insulation when your home has solid or cavity block walls. In this case, it means that external wall insulation is either not possible or it's not considered the best solution. This insulation process usually involves fixing insulation boards to the inside of the external walls and covering them with a distinct vapour control layer.

 The walls can also be covered with plasterboard, skim, and new painting to make the wall aesthetically appealing. Since boards are installed on the inside of a house, there will be a loss of space in the rooms. Internal wall insulation will help increase energy saving for your home. SEAI offers generous grants (i.e €6,000 for a detached house) for these upgrades and you may also qualify for Energy Credits. Further details are available at

Attic Insulation 

Your home's heat can be lost through the attic. When attic spaces are insulated, heat is kept below the ceiling and it circulates inside the rooms. Proper attic insulation is the best way to prevent heat losses in the winter and retain cool air in the summer.

If your home has an attic, a thick layer of insulating material, such as a blanket material, will be rolled out between and over ceiling joists. For large roof spaces spray foam insulation can be sprayed between rafters (roof uprights) once a suitable breeder card is fitted Spray foam can deliver greatly improved airtightness. Another technique involves the use of loose-fill insulation. Loose-fill insulation is great for insulating attics with very little headroom as well as multiple obstructions, such as vents and cross-beams. Loose-fill insulation can also be blown over existing insulation and can be available in fibreglass, cellulose, and mineral wool form. 

With new attic insulation, proper ventilation is required, reducing the risk of condensation build-up in the attic space, which, if left unchecked, can harm the effectiveness of your insulation and cause damage to the roof structure. It is also important to ensure that pipes and tanks are properly lagged to prevent freezing and leaks.

Heating and Cooling 

Normally, heating and cooling systems can be responsible for as much as half of the energy consumed in a given home. To maximise the energy efficiency of your home's heating and cooling systems, only use the system when necessary. It is good practice to change the air filters regularly and get the unit serviced as recommended by the manufacturer.

Conventional homes usually lose approximately 20% of the air that travels via the duct due to leaks and improper sealing. Regular system services can help avoid the 20% loss that takes place in conventional homes. Ducts should be sealed and insulated for increased efficiency and lower utility bills. 

New Home Planning 

When building a new home, it is good to incorporate energy efficiency in the initial planning and construction phases. Naturally, this is the best way to ensure your home is as energy efficient as possible upon completion, but of course, not all homeowners are in such a position. Common in new Irish builds, the passive solar energy design utilises the sun for lighting and heating purposes without incorporating mechanical devices. Embracing solar energy and adopting such designs can significantly cut your need for additional light and heat sources.

Install a Programmable (or Smart) Thermostat

Thermostats usually monitor temperature fluctuations and communicate with the heating and cooling systems. They tell when to turn on or off the temperature system. A good thermostat like Hive (our smart thermostat of choice for the Irish market), will eliminate broad swings in room temperatures and moderate the flow of heat efficiently and reliably to your preference.

A programmable thermostat will allow you to set the desired temperatures and the heating and cooling processes will take place automatically. A high-end electronic or smart thermostat may cost more than electromechanical thermostats, but it will offer better gains in the long run. Installing a programmable thermostat will help to upgrade your home to an energy-efficient one.

Install an Energy Efficient Water Heater or Heat Pump

Water heating is a significant energy expense for many Irish homes, accounting for approximately 12% of your monthly utility bill on standard supply contracts from your energy service provider. Energy-efficient water heaters are therefore necessary for your home if it has to upgrade. There are several water heaters in the market with varying types of fuel.

The first is a storage water heater which contains a big tank where the water is heated. 

The second, more sustainable solution is a tankless water heater which heats water as it passes via a circuit, thus eliminating the need to use a tank. Tankless water heaters are more energy-efficient than the conventional storage water heaters. 

There are heat pumps that essentially move heat from one location to another instead of merely generating it. Such kinds of heat pumps are about 2-3 times more efficient than the ones that just generate heat. 

For solar water heaters, the active heaters are more efficient than the passive ones. Tankless coil water heaters are known to be most efficient during the cold months.

Upgrade Windows and Doors

Replacing your windows might be an expensive upfront cost, but it will result in an immediate energy saving experience as well as improved comfort. If you can't afford to acquire the best windows, consider choosing a more affordable option on the market that is not as good as the best quality available but improves your home Depending on the age and condition of your window frames you could consider a glazing only upgrades, this would entail removing existing glass and replacing it with the latest Low-emissivity (Low E) glass which has special coatings and gas filled units that are very effective for retaining heat with little or no decoration afterwards.

As a budget option, you can tape a clear plastic sheet on the inside of the window frame to diminish any present drafts.

It is also possible to install insulating window shades that can protect against cold drafts and heatwaves. If you're more concerned with heat coming into your house than going out, you can apply reflective films on the windows facing the sun. 

It is also important to consider how windows operate because some offer better air tightness than others. Awning, hopper, and casement windows usually entail low air leak rates. Fixed windows generally fall under this category but they are not very suitable for places where ventilation is a key consideration.

A significant amount of heat is usually lost due to poorly insulated core. For doors, the most efficient ones have steel frames with a foam insulation core. Steel doors are cost-effective as well as safe and greatly reduce actual consumption levels in a home.

Another option would be to choose an energy-efficient fibreglass door. This means that you have to look for doors which have labels that indicate their energy efficiency status.

Sliding doors usually have higher air leakage rates even when weatherstripping methods are applied. 

Generally, hinged doors are more efficient than sliding doors, but if you happen to prefer sliding doors to protect your home from the elements, choose the ones with metal frames and a thermal break for maximum efficiency. A thermal break is a plastic insulator between the exterior and interior parts of the frame.

The Programme for Government and the Climate Action Plan set ambitious goals to reduce greenhouse gas emissions from buildings, including our homes, with targets to retrofit 500,000 homes to a Building Energy Rating (BER) of B2 and to install 400,000 heat pumps in existing buildings over the next 10 years.

These targets represent a very significant increase in both the volume and depth of retrofit activity required. A half million homes equates to almost 30% of all residential buildings in Ireland.

What is a BER certificate?

In Ireland, a Building Energy Rating (BER) certificate indicates your home's energy performance on a standardised national scale. A comprehensive assessment of your home's energy efficiency, the BER cert rates the energy performance of your home on a scale of A-G, with each grade consisting of separate compliance guidelines. 

Homes that are A-rated are the most efficient and will essentially tend towards having the lowest energy bills. G-rated homes are the least energy-efficient and usually have high energy bills. It’s good to get a BER certificate to help you monitor the level of your home's energy efficiency.

The Sustainable Energy Authority of Ireland (SEAI) usually calculates BER via the energy use of space, hot water heating, ventilation, home appliances, and lighting. The number of people likely to occupy the building under consideration is also looked into. BER assessments are usually undertaken by SEAI registered BER assessors, a list of which can be found on

Export and earn with Bord Gáis Energy 

Customers of Bord Gáis Energy are now entitled to a payment for any electricity exported to the national grid.

We are offering our customers, both business and homeowners, 18.5 cent per kWh for any excess electricity that they are microgenerating and exporting to the electricity grid under our Microgen Export Plan. This rate will be offered to both metered and eligible deemed* customers.


  • To receive a payment, you’ll need to agree to our Microgen Export Plan T&Cs
  • If you were a Bord Gáis Energy customer on February 15th 2022 (date of legislation) and microgenerating at that time, your payment will be back-dated.
  • If you joined us after February 15th 2022, payments will be back-dated to when you became an eligible customer. 
  • All payments will be based on the data provided to us by ESB Networks.  
  • Once you’ve exported for 6 months, payment will be made as a credit on your electricity bill. We started making our first payments from March 2023.
  • If you’re eligible for a smart meter, you’ll need to have one installed to qualify for a payment.

* Deemed customers are customers who are not eligible under the National Smart Metering Program to have a smart meter installed.  In this case, your export amount will be calculated (deemed) using a pre-determined formula.

Mother holding infant son beside solar panels.

Bord Gáis Energy are supporting our customers take-up of microgeneration technologies and move towards net zero. 

Sign up for a microgeneration plan

You can now switch to a microgen plan by signing into your online account. 

Sign in now and choose to receive a payment for exporting your surplus energy to the grid. Terms and conditions apply.