Changes in Building Regulations
The push to enhance energy efficiency in homes and reduce carbon emissions has led to significant changes in building regulations, especially in ROI, with similar changes expected for NI. Notably, by 2025, burning only fossil fuels for space and water heating will be entirely banned in ROI.
Alternative Heating Options
Thankfully, there are numerous alternatives available, including hybrid fossil/renewable systems that work effectively. To navigate the various options, it is advisable to consult with an energy expert who can assess factors such as insulation, airtightness levels, glazing, and ventilation system choices. These consultants not only perform the necessary calculations (Dwellings Energy Assessment Procedure in ROI and Standard Assessment Procedure in NI) but also offer advice on the best system based on your lifestyle and room usage.
Heat Loss Calculation
Using the plans provided by your designer, the energy assessor’s Heat Loss Calculation will determine the heat load required for each room and water heating. This calculation considers your preferred build method, target energy efficiency, and occupancy. You may need to adjust your insulation specifications (in the floor, walls, roof, or windows) to meet the minimum building regulations or other targets like the Passive House standard. Overheating calculations are now mandatory in ROI as well.
Discussing Heat Sources and Emitters
Once you know the heat requirement for each room, you can discuss your preferences for heat sources and emitters, weighing the pros and cons of each option. A highly insulated home might only require a small stove or spot radiators for colder days, while a less insulated home may need a full central heating system.
Heat Pumps
Heat pumps have become common in ROI new builds, as they satisfy both low energy and renewable requirements set by the building regulations. For those interested in the technical details, the Building Research Establishment (BRE) offers a heat pump comparison sheet.
Space Heating vs. Hot Water
Heat pumps are more efficient at providing space heating than hot water. This is because space heating operates efficiently at lower temperatures, whereas hot water needs a higher temperature, typically 65°C, to kill Legionella bacteria. Higher temperatures reduce heat pump efficiency, meaning fewer heat units are produced per electricity unit consumed.
System Sizing
The most common type of heat pump is air-to-water. In all cases, proper system sizing is crucial—the unit must be large enough to meet the demand calculated by your energy assessor for your specific home.
Solar Thermal Panels and Condensing Boilers
Solar thermal panels, which generate hot water only, can be paired with fossil fuel boilers. Condensing boilers, whether oil or gas-fueled, can also be used with photovoltaic solar panels to comply with the 2019 ROI building regulations. In NI, they can be installed as standalone units.
Biomass as a Heating Option
Biomass, including wood, remains a popular fuel choice for boilers, stoves, or even masonry heaters. For existing homes, grants are available in both NI and ROI.