1. Establish heat loss
SEAI states that sufficiently low heat loss is crucial for efficient performance. For the individual grant route, many homes built before 2007 need a technical assessment unless a valid BER records an eligible Heat Loss Indicator. The current individual-grant page describes an HLI threshold of 2.3 W/(K·m²) for the relevant self-declaration route. Programme rules differ, so use the current SEAI guidance.
2. Inspect the fabric before specifying equipment
Record attic, wall and floor insulation, window performance, draughts, ventilation and moisture defects. Insulation should not conceal unresolved damp, ventilation or building-condition problems. The assessment should identify upgrades needed before or alongside the heating system.
3. Size emitters room by room
Existing radiators may have been selected for boiler flow temperatures. Ask for each room's design heat loss and the proposed radiator output at the heat pump's design flow temperature. “The radiators look large” is not a calculation.
4. Resolve hot-water design
Confirm cylinder size, recovery time, immersion or backup arrangement, household peak demand and space. A combi boiler replacement often changes the hot-water arrangement substantially.
5. Check electrical capacity
The designer and electrician should confirm supply capacity, protective devices, cable routes, isolators and any backup heater demand. Do not assume a consumer-unit upgrade is or is not required before inspection.
6. Choose outdoor location carefully
- Manufacturer clearances and airflow.
- Condensate and defrost-water drainage.
- Noise at your windows and neighbouring properties.
- Access for cleaning and service.
- Exposure to salt air, flooding or physical damage.
7. Define commissioning and handover
The contract should identify who commissions the system, sets the weather-compensation curve, balances emitters and explains controls. Request design data, commissioning sheets, electrical certification, grant documents, safety file, manuals and warranties.
Readiness evidence pack
- Current BER and advisory report.
- Technical assessment where required.
- Room-by-room heat-loss calculation.
- Emitter schedule at design temperatures.
- Electrical assessment.
- Equipment location plan.
- Itemised quotation and exclusions.
- Commissioning and aftercare responsibilities.
Next, compare complete project costs or review heat pump versus oil boiler.