Solar panels on a garden room

The planning rules

• Panels on the roof of a building within the curtilage of a house are covered by Class 2(c).
• They must sit at least 50 cm from the edge of the roof.
• On a flat roof, no more than 50 cm above the roof; on a pitched roof, no more than 15 cm.
• Panels on walls aren't exempt.
• If they cause hazardous glint or glare, they must be covered or removed until it's fixed.

The panels don't change the garden room's own height limit, but tilted frames on a flat roof add height, so keep the whole thing within the limit. See roof and height limits.

Is it worth it?

• Roof size: after the 50 cm setback, a 4 × 3 m roof leaves room for only a few panels.
• Orientation and shade: south-facing, unshaded roofs work best. Gardens are often shaded by trees and the house.
• When you use power: a garden office used in daylight hours makes good use of solar.
• The house roof first: if the house roof has space, panels there are usually simpler and closer to the inverter.

Connecting to the house

A registered electrician must design and connect the system. Panels on a garden room typically feed back to the house through a DC or AC cable alongside the room's power supply. Plan this before the trench is closed: an extra duct is cheap at that stage. See electrics.

Grants

SEAI's solar PV grant is aimed at homes and has rules on when the home was built and occupied. Whether panels on an outbuilding connected to the house qualify isn't spelled out, so check with SEAI or a registered installer. See grants.