Ten downlights swapped for $842, installed.

Ten downlights swapped from 50W halogen to LED is $842 including GST, fully installed - about $84 a light. Twenty is $1,573. The calculator on this page prices your exact number as you move the slider, with nothing to fill in.

A 50W halogen uses roughly ten times the power of the LED replacing it, and most of that becomes heat in your ceiling rather than light in the room. Ten of them running four hours a night is a meaningful part of a quarterly bill. The light is also better: modern LEDs are brighter, more even, and do not yellow as they age.

Usually. Most Australian halogen downlights use a 90mm cut-out and the LED replacements are made to match, so the ceiling is not disturbed. If yours are a different size the calculator asks, because a different cut-out changes the fitting and sometimes the work.

Not for a straightforward swap where the existing fittings are on plug bases - the work is done from below. Where old transformers are wired directly, new plug bases are fitted, which is included in the price the calculator shows.

Yes. The fittings we use are tri-colour, switchable between warm white, natural white and cool white at the fitting. Warm suits bedrooms and living rooms; cool suits kitchens, laundries and garages. You can set different rooms differently.

Yes, the fittings are dimmable. Whether your existing dimmer will drive them is the question - old dimmers built for halogen often will not work properly with LED, and the symptom is flicker or a limited range. We check on site and tell you if a dimmer needs changing before we start.

Ten lights is typically a half day. It is a clean job: the old fittings come out, the new ones go in, and the room is left as it was found.

The price per light falls as the number rises - ten works out about $84 each, twenty about $79 - because the setup and access are done once. If you are going to do it eventually, doing it in one visit is cheaper than two.

We work within 25 kilometres of our Cromer base, covering the Northern Beaches, both North Shores, the Northern Suburbs, the Sydney CBD, the Inner West and the Eastern Suburbs. Ring 0417 297 285 if you are not sure.