jsBaYiJVl1
With our concerns about cost and climate, it has never been more important to improve our homes’ energy efficiency. When planning your project, it is important to think holistically to avoid unintended consequences and ensure that improvements perform as designed for you, your family’s and the wider societal benefits.
Insulating to reduce heat loss, or the “fabric first” approach, is the best way to begin your energy efficiency plan. Where possible, it is important to “join the dots”, so, for example, new floor insulation connects with wall insulation and attic insulation with wall. Care should be taken at windows as wall insulation needs to connect to your windows at the window reveal. Areas of uninsulated wall become cold bridges and the rate of heat loss increases through these gaps.
Insulation upgrades need to be considered with ventilation because the warmer we make our homes, the greater carry capacity our internal air has for moisture and some systems, particularly dry lining, can result in cold bridging. When this warm air meets a cold surface, moisture condenses and over time can result in mould, which is hard to get rid of. Insulation upgrades invariably make our home more airtight, which is a good thing, but apart from excess moisture there are also pollutants such as volatile organic compounds (VOCs) from furniture and paint, as well as off-gassing from cleaning products that it is important to vent out. Bottom line, it is crucial to ensure ventilation meets building regulation requirements and this extends beyond our bedrooms and living rooms to any space you don’t want to find mould or rot in.
As well as the traditional hole in the wall vents and trickle vents that come preinstalled in modern windows and doors, there are some more sophisticated and efficient solutions to providing clean air to your home. The problem with these traditional solutions is that you need to remember to open and close them. Demand controlled ventilation (DCV) use vents that open when they detect humidity and separately have fans to extract air from bathrooms and utility spaces. So, when your home is unoccupied, there’s no heat being lost.
Mechanical ventilation with heat recovery (MVHR) is a where the heat from stale air is transferred to the incoming fresh air, preheating it, and the incoming air can also be filtered for dust and pollen. It’s typically a fully ducted system with pipes to every room so can sometimes be tricky to install in retrofit, though there are some simpler recovery systems available, such as the Lunos system which uses individual wall-mounted fans installed in pairs, which alternate between air intake and extraction.
As our homes become more heavily insulated so it will become apparent that hot water production uses a lot of energy. The Building Energy Ratings were revised a few years ago and water use is now calculated as part of your home’s BER by the number and flow rate of taps and appliances.
Reducing demand through small adjustments to existing taps and recovering heat from showers and baths can be hugely impactful. Not all taps need to be high pressure apart from the kitchen sink and it’s inexpensive to retrofit as you don’t need to replace the tap. Kitchen and bathroom suppliers should be able to tell you the flow rates for the appliances they are selling you. Recovering heat from wastewater should also be considered as part of any refurbishment project, which works by taking the heat from water flowing down the drains to preheat incoming mains water.
The cost-of-living crisis has included significant inflation in construction costs. The Sustainable Energy Authority of Ireland (SEAI) grants play a role in tempering these costs. Perhaps more significantly, the SEAI maintains databases of registered contractors and conducts random checks on site. This helps ensure standards on site meet relevant building regulations standards as contractors can be penalised for mistakes and/or potentially de-listed from the register. Manufacturers of individual heating systems also keep registers or lists of contractors who have received training for that brand. Using one of these contractors can sometimes provide an extended warranty for your new boiler
or heat pump.
The energy we use to heat and light our homes is sometimes referred to as operational energy. The energy that is used to make the materials used in their construction is referred to as embodied energy. Our current standard of construction is energy and carbon intense. Concrete blocks, steel, glass, aluminium and even some types of insulation require significant amounts of energy and water to be produced.
The energy required to make the materials for 1m2 of new build construction or home extension is estimated to currently produce 1,400kg CO2, the equivalent of burning 600 litres of crude oil. It’s why existing buildings are such a valuable resource, and our built heritage is not only of huge cultural value but also an environmental one. So, no matter how energy efficient your home extension or refurbishment might be, it might never in your lifetime save the energy that was lost in making it! Simple changes in specification can reduce this figure so it’s worth asking the question of your designer.
It’s tragic in this context to see skips filled with material from home refurbishments that could have been reused elsewhere. Kitchen cabinets, bathroom suites, floorboards, joists, tiles, bricks, windows can all be reused intact. They can also be sold on for cash or at least given away on DoneDeal or equivalent. Some contractors might charge you extra to carefully dismantle rather than smash to bits, but with a little planning, it is possible to reduce a lot of landfill through sale or freecycle.
Recently, the Irish Green Building Council had set up a construction materials exchange scheme where new unused materials can be collected in an online database so they can be identified for reuse elsewhere. Currently, it is normal practice that these materials are skipped on site. Some studies have suggested that as much as 30 per cent of the materials that are delivered to a job end up in landfill. It’s a crazy amount of waste.
It can be daunting, confusing and frustrating keeping up with new technology, systems and building standards. However, the overriding principle is simple: it’s about conservation, of energy, of materials and our environment.
Illustration: Tara O’Brien
This feature originally appeared in the autumn/winter 2023 issue of IMAGE Interiors. Have you thought about becoming a subscriber? Find out more, and sign up here.