BER Target and Heating System in Ireland — Match the Heat Pump to the Fabric
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BER target drives the heating system spec in Ireland. BER A2: 6 kW heat pump + average fabric + airtightness 3–5. BER A1: 6 kW heat pump + MVHR + 6 kWp solar + airtightness 1–2 m³/m²·hr. Passive House: 6 kW heat pump + MVHR + 8 kWp solar + airtightness ≤0.6. Sizing: 6 kW for a fabric-first 150 m² house (wall 0.13, roof 0.13, floor 0.13). 9 kW for less insulated. Oversize wastes money. Match the heat pump to the fabric, not the other way around. A 9 kW heat pump in a fabric-first house runs short cycles and is less efficient. The BER assessor calculates the heat load from the floor area, the U-values, and the airtightness. Engineer sizes the heat pump based on the heat load.
TL;DR
BER target drives the heating system spec. A2: 6 kW heat pump. A1: 6 kW + MVHR + 6 kWp solar + airtightness 1–2. Passive House: 6 kW + MVHR + 8 kWp solar + airtightness ≤0.6.
Sizing: 6 kW for a fabric-first 150 m² house. 9 kW for less insulated. Oversize wastes money.
Match the heat pump to the fabric, not the other way around. A 9 kW heat pump in a fabric-first house runs short cycles and is less efficient.
When this matters most
You're at design stage and need to match the heating system to the BER target.
When this doesn't apply
The heating system is commissioned.
Frequently asked questions
What size heat pump do I need for BER A1?
6 kW for a fabric-first 150 m² house (wall 0.13, roof 0.13, airtightness 1–2). 9 kW for less insulated. Engineer sizes based on the heat load calculation.
What heating system do I need for Passive House?
6 kW heat pump + MVHR + 8 kWp solar + airtightness ≤0.6 m³/m²·hr. The whole system is designed around the airtightness and the fabric.
What is a fabric-first design?
A design that prioritises insulation, airtightness, and thermal bridges over the heating system. A fabric-first house needs a smaller, cheaper heat pump and runs it more efficiently.
Sources
SEAI, BER and DEAP guidance. https://www.seai.ie/
Frequently asked questions
What size heat pump do I need for BER A1?
6 kW for a fabric-first 150 m² house (wall 0.13, roof 0.13, airtightness 1–2). 9 kW for less insulated. Engineer sizes based on the heat load calculation.
What heating system do I need for Passive House?
6 kW heat pump + MVHR + 8 kWp solar + airtightness ≤0.6 m³/m²·hr. The whole system is designed around the airtightness and the fabric.
What is a fabric-first design?
A design that prioritises insulation, airtightness, and thermal bridges over the heating system. A fabric-first house needs a smaller, cheaper heat pump and runs it more efficiently.