Everything you need to know about retrofitting your home

Last month Electric Ireland and retrofit experts Tipperary Energy Agency announced a new joint venture called Electric Ireland SuperHomes, which aims to deliver up to 35,000 home retrofits over the coming years.

Home retrofits have become increasingly popular as homeowners look to lower their energy bills as well as their carbon footprint.

While certain retrofit measures are more costly than others in the short term, a wide range of grants and services are available for those homeowners looking to make green improvements, whether that's improving your home's insulation or upgrading your heating system.

In this episode we chat to David Flannery from Electric Ireland SuperHomes to discuss the new joint venture as well everything you need to know about retrofitting your home.

What exactly is retrofitting?

Retrofitting is when a substantial upgrade of a home is carried out through a combination of measures. It might mean an overhaul of an energy system that is inefficient and transforming it into a system that works.

We don’t often think about a home as being a system, but that’s precisely what it is. We generate heat in a home, we try to keep it in the house as much as possible and we have ventilation as well, which a house needs so it can breathe. 

A retrofit design combines these elements and takes them into account to provide an energy system that works together.

The non-energy benefits of a retrofit include warmth, comfort and healthy airflow throughout the house.

What’s the difference between a shallow and deep retrofit?

We’re more familiar with shallow retrofits in Ireland. Historically a shallow retrofit has been the predominant energy upgrade route that people have chosen.

Examples of this would include pumped cavity wall insulation, upgrading your attic insulation from 100mm to 300 mm, upgrading your oil or gas boiler, or adding heating control so that you can heat water upstairs and downstairs separately.

A deep retrofit goes further. We’re not talking about incremental improvements, we’re talking about dramatic improvements in terms of house performance, bills and carbon production.

Deep retrofits are entirely different and would be a once in a generation change. It’s about getting everything right at the same time, thinking about how things work together and designing your energy system for the house and how you use it.

Electric Ireland SuperHomes

Electric Ireland SuperHomes kicked off in 2017, even though it’s been around since 2015.

Focusing on bespoke, tailored designs for each house, SuperHomes has pioneered the retrofit model and refined it into something that works.

Each house has different needs. Even houses in a housing estate that were once the same would all be different now. Some will have extensions, converted attics, new boilers or new windows, and some won’t have upgraded at all. 

You’d need a separate retrofit design for each of those homes. 

Are Irish homes poorly insulated?

Irish homes are quite poorly insulated and even when we started insulating in the mid-1990s, insulation was treated with a little bit of suspicion.

We have a different climate from other countries and other countries have a history of insulation that is far more advanced than Ireland’s.

Ireland has improved a lot in terms of the shallow retrofit over the last number of years. There are now grants available from the SEAI, so there have been a lot of upgrades and the standard of new homes has improved considerably over the last number of years.

Take a look at this blog to see what energy efficiency grants the SEAI offers.

How can people tell if their home needs a retrofit?

Homeowners will know their home inside out, so usually they can tell you what part of the house is cold, what the bills are like, or if it’s draughty. They can talk to a retrofit expert to pinpoint exact problems.

Sometimes it can be difficult to find the cause of problems. An example of this is with box bedrooms. Many households say that the box bedroom is the coldest part of the house, no matter what they do.

The box bedroom tends to be right over the hallway and usually has no insulation underneath. In many cases, the bedroom door is old and has gaps at the edges, allowing a breeze to enter from the hallway. Most of the time the radiator in the box bedroom is the smallest in the house. 

This is where the fix comes in. If you get good and impartial advice that considers the features of the house, you should get a retrofit plan that’s cost-effective, sensible and addresses the issues in the house.

Solar photovoltaic (PV) panels

There are two solar panel options for people, which are solar thermal or solar photovoltaic.

The most compatible with a heat pump would be solar voltaic. Rather than the sunlight producing hot water, it’s producing electricity and feeds into your meter box. You can use that for anything and save you money.

For photovoltaic, you can put in a battery, which will store the excess that you’re not using if you’re not in the house. 

An element will spill onto the grid if it’s not being captured. There’s no fee or payment for that at the moment but in time the plan is to be paid for this excess.

Solar thermal panels

Solar thermal is going to provide you with lots of cheap hot water.

There will be more hot water produced at certain times of the year than others for obvious reasons and you have to be able to use that water.

Your return on investment will depend on how you use that water. For example, if you don’t use the hot water produced, because you keep your electric shower, you’re kind of doubling up on your costs and not availing of the savings you would get.

You need a bigger cylinder and need all the showers to run from it and it’s going to suit larger families, as they’ll save on the production of hot water.

How much are solar panels?

The cost of the solar thermal or photovoltaic could range from €2,500 - 5,000 depending on size.

The return on investment will depend on the extent of using the hot water for solar thermal. For photovoltaic, you’re talking €200-250 euro per year in savings. This means it’ll take around 12 years to earn back what you paid for the solar panels.

Does the panel always have to go on the roof of the house?

You can choose where you put it, but the more you do it in line with convention, the cheaper it’s going to be.

The obvious place is the roof if you have a good aspect. The southern aspect is going to be the best, but you could still do it on an East or West axis and split the panels in two to get morning and evening sun.

You can have panels on top of your shed. There aren't any significant planning issues, but there’d be more pipework, travel and distribution losses that way.

What is a heat pump?

With a heat pump you’re trying to extract as much free energy from the air as possible.

A conventional gas boiler would have an efficiency of around 90% or thereabouts, which sounds great if you think about it out of 100. However, a heat pump will have a performance that’s about 300-350% efficient. 

For every unit of energy that you use, you’re producing something called three comparable units in heating terms. 

A heat pump will keep the air in the house at a nice even temperature. At its most efficient, it will be around 21 degrees, it can go up to higher temperatures than that but it would be working hard and using more electricity.

Once you agree within your house on the temperature you like, you don’t really touch the thermostat after that and the temperature stays at this optimum level. If the house is well insulated, the heat pump will work very well.

Getting heat pump ready

The key thing to remember is that the home needs to be heat pump ready and there are strict criteria in place now for assessing whether a house is heat pump ready.

Essentially it looks at every fabric aspect of the home, such as windows and doors, walls of the attic, flooring, etc. There’s a value associated with each factor and when you put this through a heat loss indicator, you’ll come out with an overall figure.

The overall figure has to be below a certain amount and each element of your building fabric needs to perform to a minimum standard.

Once you achieve that, you know your house is heat pump ready and that the heat pump will work efficiently.

People can find out how efficient a heat pump would be in their own home by getting a heat pump technical assessment carried out. That will provide you with a pathway and will help you get to a standard you need to have a heat pump.

What is the cost of a heat pump?

The cost associated with a heat pump is also the cost associated with getting the home heat pump ready. If you look at a home built in 2010, it might not need much. It might need some insulation upgrades or wall cavity pumped. 

If you’re talking about a unit cost for the heat pump, it might be €10-13,000. There are grants available.

It’s more complicated for an older home or for homes that have extensions or attic conversions. You could be looking at anywhere between €40-70,000 for a house like that.

What are the savings with a heat pump?

The savings could be anywhere between 30-50%. 

There is funding there to help. The SEAI is incentivising plans to take a shallow retrofit to a deep retrofit.


The right insulation depends on what your wall type is. When you have a floor that’s concrete or a suspended floor, it’s not really something you’d want to insulate. You lose around 14% of your heat through the floor.

You should start focusing on the place that makes the most sense, which is the attic. When you assess the wall, you’ll see there are different wall types so there are different solutions.

You’ll have a hollow block or a solid wall. You’ll have to go internal or external. If you’re fortunate enough to have a cavity wall insulation with enough of a gap then pumping that is the most cost-effective way.

There are grants for insulation available of up to €6,000 for detached houses and €2,500 for internal insulation for smaller houses. There’s also grants or attic insulation as well.


We’re making a transfer over to renewable sources and soon there won’t be any gas boilers put into new houses.

There are improvements moving from a boiler to a condensing boiler. If it’s an old boiler, you might get 20-30% savings on that. For budget, this is what people may need to look at sometimes.

There are no grants for upgrading your boiler anymore, so it’s not incentivised. This is why people should perhaps consider a deep retrofit instead.

Airtightness and ventilation

Airtightness is crucial. If you insulate your home and there’s a draught going through, it will undo much of the positive work carried out.

We can measure this through an airtightness test, and that will vary from 7 or 8 air changes per hour to 13 or 14. Tackling that is important. Bringing this to 5 air changes per hour is comparable to a new home.

The last part is a ventilation system. You’ll have an active ventilation system that regulates the airflow through the house. It reacts to moisture and when moisture builds up, it switches on. It’s an intelligent ventilation system. This will minimise mould and odours in the home.

Those three essential elements - fabric, airtightness and ventilation - are the fundamentals of the SuperHomes package.

The process of a retrofit

A retrofit advisor, such as David, would be the first point of contact for anyone looking to retrofit their home. The advisor will give some general advice and look at the suitability of the person’s home to see if they’re eligible for the scheme.

You should receive a ballpark figure of what the costs could be.

Electric Ireland SuperHomes tries to create a process for people that shortens the retrofit journey, improves it and provides solutions and puts together a coherent, effective plan. Customers should be able to choose the type of measures they would like to implement.

If everything is satisfactory initially, you move onto a survey before bringing in a contractor and putting together a report with all the recommended measures, the grants available and the costs. That report will essentially contain a retrofit offer.

In general, how much is a deep retrofit?

While it does depend on the house, a typical house will cost around €50,000.

There is around €15-17,000 available in grants, so it brings the net cost down to somewhere in the region of €35,000.

That can vary and it can be less for a newer house. For an older or bigger house, it can be more than that.

Finance options

Retrofitting costs a lot of money and not everyone will have access to the funds right away. This is changing in Ireland and there’s a realisation there will need to be grant and financial support in place for people to avail of retrofitting.

You now can get a range of green loans for home improvements from banks and credit unions. You can put the savings you’re making on energy towards paying back these loans.

You can learn more about the various finance options available here and see what home improvement loans are available with our easy-to-use comparison tool.

If budgets are tight what can people do?

It’s always fabric first, so insulating the attic is a good step for those with a tight budget.

A good way to approach it is by looking at the pathway to a heat pump and the elements you have to tackle to put a heat pump in ten years down the road.

How can someone contact Electric Ireland SuperHomes?

The website, superhomes.ie, contains a lot of information and explains more about the retrofit process.

There’s good general information on heat pumps and other technology and there’s an expertise section there where you can find out more.

Lower your energy bills with bonkers.ie

Over time retrofitting your home will help lower household energy bills. However there are ways to immediately start saving today. With energy prices increasing, there’s never been a better time to consider switching energy supplier.

For those willing to switch, it’s possible to save up to 40% off standard rates for the first 12 months with some energy deals.

Here at bonkers.ie, you can use our energy comparison tool to compare the best deals today across all 14 energy suppliers nationwide.

Switching takes just a few minutes and you only need the following on hand to switch:

  • A GPRN number if switching gas and an MPRN number if switching electricity
  • A recent meter reading
  • A good estimate of how much energy you use
  • Some personal details

Read our helpful guide on what you need to switch suppliers for further information.

If you have any questions about retrofitting, let us know and we’d be happy to help! You can contact us on Facebook, Twitter and Instagram.

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