We brought a 1950s house to A3 standard, hosue is about 110m2:
- Replace old gas boiler with condensing combi boiler, removing hot water storage tank - ballpark €5k
- All new windows and patio door to rear (double on rear (south facing), tripple on front (north facing and busy road) - ballpark €7,000 (6 windows & french door includung two large bay windows)
- New composite front door - ballpark €3,500
- Replace all lights with LEDs - pretty insignificant cost
- Replace heating controls to smart system with smart TRVs in each room - ballpark €500 (self install - you may get a grant for this but installation costs are very high).
- Attic insulation to modern spec - ballpark €1,200 (€800 after grant)
- Externally insulate front elevation and half of rear elevation (modern extension on ground floor level) - ballpark €7,000 (€4,000 after grant)
- 2.5kW solar PV - ballpark €2,500 (after grant)
- Self install of demand controlled ventilation system - €500, this will be a lot more if you get this instlaled professionally
These are the direct costs to to the BER improvement, we undertook all of those over the course of 3-5 years, in tandem with other decoration and renovation works.