What is
a Retrofit

Home retrofits

A guide to costs, grants, time frames and best ways to approach the project

A home energy retrofit involves carrying out a number of energy upgrade measures in one installation to achieve a warmer, more comfortable, energy efficient home with a BER rating of between B2 and A1. It involves upgrading your building fabric to current standards, improving your air tightness, installing a renewable heating system such as a heat pump and addressing the ventilation needs in your home.



  • Roof and attic insulation
  • Internal dry lining
  • New windows and doors
  • Airtightness
  • External wall and cavity insulation
  • Solar PV
  • Heat pump
  • Mechanical Ventilation


For homes built and occupied before:

  • 2011 for insulation and heating controls
  • 2011 for renewable systems
  • All homes must complete a minimum level of energy upgrades and achieve a minimum BER rating of B2


Works will be scheduled to commence once materials and subcontractors are lined up and will be completed from start to finish without disruption. The average upgrade is completed in two weeks but where more extensive works are involved the project could take longer.  The typical cost of energy upgrade works would be in the region of €30,000 – €40,000 depending on the floor area of the house. Houses that require external insulation or window replacement are likely to cost more. All works must be completed within the timeframe of the grant.

It’s a significant investment so grants are provided by the Government of Ireland through the Sustainable Energy Authority of Ireland (SEAI) to support you to do this. You can access a wider range of grants going through the One Stop Shop process than if you were to manage the project yourself.  Fixed amounts per measure are available for qualifying energy upgrade works.  Typical Grant amounts for whole house energy upgrades would range from circa €14,000 to €38,000 dependent on type of house and the energy upgrade measures being implemented.  Obviously the bigger the grant the more extensive the works are hence the greater the cost of works.

The Home Assessment report is charged at €595. This includes the cost of a Pre-Works BER Certificate for your house but this is fully refundable once you proceed with the proposed upgrades with Harte Home Retrofit

Where works proceed through the One Stop Shop process, One Stop Shop administration fees apply and are outlined in our bespoke house specific report for your home.



  • You live in an older house or have purchased an older house and it is undergoing wholesale renovation
  • Your home has an old inefficient boiler which needs replacing
  • Your home performs poorly and is in need of a whole house review
  • Your home’s indoor air quality is poor (evidenced by mold, dampness, unpleasant smells etc)
  • You will be spending more time at home and want to live in a warmer healthier home and optimise your heating costs.

Retrofit projects completed

BER Before: E1 – After: A3

The challenge: Bungalow built in 1977, 70mm cavity filled with wool, 200mm attic insulation and double-glazed windows and doors.  Heating is via a regular oil boiler with an open fire...

BER Before: G – After: A3

The challenge: Mass concrete architecturally designed house constructed in 1939 with single glazed aluminium windows.  Heating is via storage heaters with a stove in the living room and oil range...

BER Before: C3 – After: A3

The challenge: Dormer bungalow built in 2002 with conservatory with vaulted timber ceiling added in 2005.  There are double glazed timber windows with timber front and back doors and plastered...