Xavier Dubuisson, a consulting engineer who specializes in sustainable energy, is a self-confessed energy geek who lives and works from his family home 8km from Clonakilty, Co Cork. Since he and his wife, Susan O’Flaherty, bought their 200 sqm stone farmhouse in 2001, they have been gradually adapting and upgrading it for an expanding family and for energy efficiency.
“Every investment we made was the best that we could afford in energy efficiency,” says Xavier. They replaced their noisy, smelly and inefficient oil-fired range with a condensing oil boiler, installed rooftop solar thermal panels and two very good wood stoves (one in the kitchen/dining room, the other in the living room), insulated their attic very well and replaced light bulbs with CFL and then LED.
Five years ago they installed demand control ventilation (DCV) as part of a research project by the system manufacturer Aereco. DCV ensures airtight homes are adequately ventilated.
“The DCV is a lovely piece of kit. We have two dogs and a busy family and it manages the air quality very well in terms of moisture and smells!”
In 2016 they had achieved a C1 building energy rating (BER) but wanted to take their home a step further and move away from oil. “SuperHomes offered a great opportunity to do that,” says Xavier.
Tipperary Energy Agency, which manages the SuperHomes scheme, provided a good technical and financial rational for going ahead with the proposed changes, says Xavier. “They had a very good level of financial incentive and experience in delivering.”
The works proposed and carried out included:
• Upgrading the building fabric through improved insulation
• Air tightness measures
• Minor improvements in ventilation
• Removal of the oil boiler and replacement with an air source heat pump and controls.
• Installation of ground-mounted solar PV panels in the garden
It was too expensive to externally insulate the old stone walls but the cavity walls on the single story extension, which only had one inch of insulation, were pumped with polystyrene bead insulation.
“We replaced the front and back doors with passive house standard doors that reduce the heat loss from the glazing and are also much more airtight,” says Xavier.
Other air tightness measures undertaken included refitting and repairing seals and hinges on windows; improving the attic hatches with draught-sealant, hooks and insulation and sealing around where wiring and ducting penetrate the walls. As Xavier and Susan had already installed DCV, which is a requirement of SuperHomes, the main ventilation system did not need to be changed. The oil boiler was replaced with an air source heat pump. It produces lower temperatures over a more consistent basis than oil boilers and therefore may require larger radiators in some rooms. Tipperary Energy Agency carried out a full heat load design on the house and Xavier and Susan only needed to replace four radiators.
Now they still use their wood stoves but much less than they used to. They also opted for the Electric Ireland solar PV panel scheme to generate electricity. Given the poor orientation of their house roof the six panels totalling 1.5kW were ground-mounted in their garden. In retrospect they regret not gravelling under the panels as they now have to keep the grass mown around them. “Basically the PV panels feed electricity into the house and whenever there’s demand it’s used. Any excess electricity produced is dumped into the domestic hot water tank,” explains Xavier.
“This is a bit of overkill as we already have solar thermal panels that produce hot water. My plan for the next few years would be to get batteries [to store excess electricity] and then to invest in an electric car.” “The good thing about PV panels is that they make you think about energy as a household. Definitely this summer you were very happy to be putting on the washing machine [running on home-generated solar electricity],” says Xavier.
Overall he says SuperHomes Ireland has been a positive experience and has brought their home to an A3 BER.
The total cost was of the works, not including the solar electricity panels, was €18,205 including VAT. After the 35% SuperHomes grant Xavier and Susan paid €11,833 including VAT. “Certainly it’s very comfortable and has been a huge improvement. “The draughts are much lower and the temperature levels are much more stable. It’s much easier on the body and on the mind!”
Xavier says it’s fantastic not to be relying on oil. “I can’t remember how many times we ran out of oil and you’d be in the cold for a few days waiting for the delivery man to arrive and then there’d be a dirty mess getting things running again.”
“It’s particularly satisfying that a heat pump can deliver heat and comfort in an old house with minimal insulation like this,” he says.
You can register your interest for SuperHomes 2019 here