The Background

In 2018, Irish architect and TV presenter Dermot Bannon purchased a small 1920s house in Drumcondra, Co. Dublin. At the time the original gas boiler in the house was not sufficient to heat the home and Dermot often found that there was frost on the windows in the morning and that the house wouldn’t retain the heat once the system was switched of.

The house’s G rating, marked it as the least energy efficient type of property on the market. This is typically usually due to poor insulation, inefficient windows and a lack of modern energy-saving features typical of older properties 

So in 2019, Dermot did a full retrofit, extention and renovation of his family home which included the installation of a Mitsubishi Electric Ecodan Air Source Heat Pump. 

Back in 2019, in order to obtain a grant from the SEAI, the house had to get to an A3 rating (currently in 2025, homes are required to have a BER of a B2 to qualify for a grant). Getting the house up from a G to an A3, was no small feat. However, through his own practice and his work with RTÉ’s Room to Improve, Dermot had been retrofitting a number of houses and knew that there were 3 key principals to a successful retrofit.

Dermot's Home

1. Insulation is key 

Dermot wrapped his extension around the original part of the house, which became an insulated barrier around the home. This made it a completely airtight building and prevented any warmth from leaking out or cold drafts from coming in.

 

2. Don’t forget ventilation 

Ventilation is a crucial part of any building, especially in retrofit projects where added insulation and airtightness can lead to poor indoor air quality and a stuffy atmosphere. Installing a mechanical heat recovery ventilation (MHRV) system can solve this problem. Fresh air is drawn in and pre-warmed by the outgoing stale air from bathrooms and kitchens, ensuring a constant supply of clean, comfortable air. This not only improves air quality but also helps reduce condensation and prevent mold growth.

 

3. The importance of a good heating system 

Dermot wanted the most efficient heating system on the market, which turned out to be a (Mitsubishi Electric) heat pump. He designed his home around this key feature, and incorporated underfloor heating downstairs and radiators upstairs.

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The Challenge

Dermot's biggest challenge that he faced when doing his home retrofit, was not knowing enough about heat pumps. He knew what they were, how they worked and the need to shift to a more sustainable solution for home heating but between the numerous different brands and the idiosyncrasies between them, Dermot found that he didn’t know where to begin. And so, he did what he always does when faced with an architectural problem - he went to the experts in the field and in this instance, it was plumbers. These are the professionals on building sites who install, service, and maintain heat pumps every day.

Being in regular contact with plumbers, Dermot conducted his own informal survey to discover which heat pump performed best. He asked practical questions like, “Which heat pumps are easiest to use?” and “Which offer the best efficiency?” But ultimately, it came down to one key question: “If you were installing a heat pump in your own home, which one would you choose?”

And it turned out that the Mitsubishi Electric Ecodan Heat Pump came out on top

 

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The Solution

Once the decision to install a Mitsubishi Electric Ecodan Heat Pump was made, based on recommendations from industry experts, Dermot got in touch with us. We met with him in 2019 to discuss his home in detail and ensure we could provide the most effective heating solution possible. After carrying out detailed calculations to assess the home’s heat requirements, we found that although a property of this size would typically require an 11kW heat pump, Dermot’s house was exceptionally well insulated. This allowed us to install a smaller unit instead. Opting for a smaller system made perfect sense as it's far more efficient to have a smaller unit running constantly rather than a larger one that is switching on and off.

After deciding on the unit to be installed, Dermot turned his attention to its location. For optimal efficiency, the outdoor unit requires a space with unobstructed airflow. Typically, homeowners choose to place their unit in the back garden, although, space permitting, it can also be installed at the front or side of the house. 

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Dermot’s back garden provided the perfect spot, allowing the outdoor unit to be positioned discreetly. With the addition of a cleverly placed plant, he was able to keep it well hidden from view so it blends seamlessly with the garden and can’t be seen from the house.

As part of the project, Dermot also availed of the SEAI’s grants to support his deep retrofit. The aim was to transform his home’s energy performance. Originally rated a G, the house achieved an A2 BER rating after the retrofit, comfortably exceeding the minimum A3 requirement at the time (now currently a B2). The Mitsubishi Electric Ecodan Heat Pump played a major role in reaching this level of efficiency, contributing significantly to the home’s outstanding overall performance.

Heat Pump Getting Cleaned

The Result

The results speak for themselves! The Ecodan heat pump takes care of everything: space heating, domestic hot water and maintaining a perfectly steady ambient temperature all year round. Dermot explains: “Nothing changes from July to December—the house feels the same”.

Gone are the days of hitting the boost button or turning on an emersion. The heat pump works quietly in the background, monitoring the house and adjusting automatically. “It keeps the house at a steady temperature,” Dermot says. So much so that even the family dog, who once would have search for the warmest locations in the home, like beside the oven, at the fireplace, by the radiator, will now sprawl anywhere.

Dermot's Heat Pump

It’s not just the heating that impresses. Dermot, an avid sea swimmer, recalls coming home to find the family lining up for showers after a swim. “I thought someone's going to have to sit and wait for 20 minutes until the water heats, but no". That was not a problem for the Ecodan heat pump which handled the 5 back to back showers that the Bannon family wanted with ease. There was enough hot water for everyone, as Dermot describes it, it feels like "we have infinite hot water.”

Ultimately, living with a heat pump is effortless. “If you’re asking me what it’s like to live with a heat pump,” Dermot states, “I don’t even know we live with a heat pump because we never have to do anything. We never have to control anything or switch anything on"

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The Conclusion

Dermot understood the concept a heat pump, the need to move toward more sustainable home heating and the importance of reducing reliance on fossil fuels. However, his biggest challenge was getting to grips with so many brands and the subtle differences between them. Dermot conducted his own survey amongst the plumbers that he was in contact with. That’s why we set up The Heating Hub; a place where Irish homeowners can get clear, reliable information on our heat pumps and ventilation systems, find answers to their FAQs and feel confident taking the first step in their own new build or retrofit project.

Dermot’s 1920s house has gone from the lowest efficiency rating (G) to the highest (A). The installation was seamless and the system has existed quietly in the background of Dermot’s life for 6 years; a silent partner that makes heating “invisible.”

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Now, the house stays at a constant, comfortable temperature thanks to his heat pump. When asked what he thinks the benefits of a Mitsubishi Electric Ecodan heat pump are, he listed them as:

  1. Easy to live with: It monitors the temperature of the house and it keeps it at the same temperature regardless of what month of the year it is
  2. Efficient: The Ecodan Heat Pump is keeping the house at the perfect temperature year-round.
  3. Future-proofed his home: The more renewable form of home heating, that is in line with our governments push for sustainable housing standards.
  4. Lowered his carbon emissions: The installation of a heat pump has helped in his goal to get the house free of fossil fuels.
  5. Service-backed: There is someone to talk to about servicing your system once a year. Mitsubishi Electric also have an incredible network of service providers around the country

In short, for Dermot, the heat pump isn’t just a heating system, it’s a reliable, sustainable and effortless part of daily life.

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