Glossary

BER (Building Energy Rating) · Better Energy Homes Scheme · Breather membrane · Cavity wall insulation · Class 63 · EPS · ESB Networks service alteration · External wall insulation (the wrap) · HLI (Heat Loss Indicator) · Internal wall insulation (dry lining) · Mineral wool · MPRN · One Stop Shop · Post-works BER · Render (acrylic, silicone) · SEAI-registered contractor · Second wall measure · Section 5 declaration · Traditional Homes Pilot · U-value · Whole-surface solution

BER (Building Energy Rating)

A rating of a home's energy performance from A1 (most efficient) to G, given by an SEAI-registered BER assessor. External wall insulation usually improves it.

Better Energy Homes Scheme

SEAI's scheme of individual home energy grants, including the wall insulation grants.

Breather membrane

A weather membrane fixed to a timber frame or behind cladding. Also called house wrap in the building trade. It isn't insulation.

Cavity wall insulation

Insulation pumped into the gap between the two leaves of a cavity wall, usually bonded bead.

Class 63

The planning exemption for external wall insulation to a house, in force from 27 July 2026 (S.I. No. 341 of 2026). Up to 150 mm, not onto a public road, in keeping with the house and its neighbours.

EPS

Expanded polystyrene, the usual white insulation board in external wall insulation.

ESB Networks service alteration

A change to how the electricity cable meets the house. SEAI says you may need one for external wall insulation.

External wall insulation (the wrap)

Insulation boards fixed to the outside of the walls and finished with a reinforced render. SEAI's grant is €8,000 for a detached house down to €3,000 for an apartment.

HLI (Heat Loss Indicator)

A figure on the BER that shows how fast the home loses heat. For the heat pump grant, SEAI accepts a valid BER with an HLI of 2.3 W/K/m² or less instead of a technical assessment.

Internal wall insulation (dry lining)

Insulated boards fixed to the inside face of external walls. Rooms lose a little space.

Mineral wool

Insulation made from stone or glass fibre. Non-combustible, and costs more than EPS as a board.

MPRN

Meter Point Reference Number: the 11-digit number on your electricity bill. SEAI uses it to identify the home and to see which grants it has had.

One Stop Shop

An SEAI-registered company that manages a home energy upgrade and the grant application for you. The grant is taken off your price up front instead of being paid to you after.

Post-works BER

The BER done after grant-funded work. It's one of the steps before SEAI pays the grant.

Render (acrylic, silicone)

The finish coat over the insulation. Acrylic is the lower-cost option; silicone costs more and is sold as self-cleaning.

SEAI-registered contractor

A contractor on SEAI's register for the type of work. For the grant, the contractor must be registered for external wall insulation.

Second wall measure

SEAI's rule that lets a home that had a cavity or internal wall grant apply for another wall measure. After cavity: internal or external. After internal: external only. After external: none.

Section 5 declaration

A formal decision from your planning authority on whether specific works need planning permission or are exempted development.

Traditional Homes Pilot

SEAI's pilot scheme for traditional homes, typically pre-1940 solid brick or stone. These homes can't get wall insulation grants under Better Energy Homes.

U-value

How fast heat passes through a wall, roof or window, in W/m²K. The lower the number, the less heat escapes.

Whole-surface solution

SEAI's requirement that every external wall of the home is fully insulated. Partial insulation isn't eligible.