You may be able to find the size of the fitting printed somewhere on the socket. If your bulb has a twist-and-lock fitting with two prongs on the bottom, it’s most likely a 240-volt GU10 bulb, and generally has a 50mm fitting. These can usually be switched for LED bulbs without replacing any parts. [2] X Research source If the bulb has 2 sharp pins and pushes into the fitting, it is likely a low-voltage MR11 or MR16 bulb. These 12-volt bulbs require a transformer if you’re using them in place of a halogen bulb.

Since LED bulbs use far less power than halogen bulbs, they will not have the same wattage rating. However, most LED bulbs list their equivalent wattage on the packaging. If you can’t find the information on the packaging, you can estimate the equivalent wattage. LED bulbs generally use about 10% of the power of their halogen counterparts, so a 5-6 watt LED would be roughly equivalent to a 50 watt halogen bulb. [4] X Research source

If your downlights are used to light a workspace area, you will probably need higher lumens. If your downlights create soft ambient lighting in a gallery space, you might prefer lower lumens.

In the home, these lights are popular in living and bedroom areas.

These are often used in kitchens and bathrooms.

To replace the dimmer switch, turn off the power to the switch, then unscrew the switch plate and remove it. Pull the switch out of the electrical box and remove the wires, then reattach the wires to the new dimmer switch. Push the new switch into the electrical box and replace the switch plate. [8] X Research source

If you’re not sure which breaker controls the light, have someone else stand in the room and turn off various breakers until the second person tells you that the light has gone off. To be extra safe, double-check that the circuit is off with a simple circuit tester. [10] X Expert Source Barry ZakarHandyman Expert Interview. 16 July 2020.

Although some types of bulbs require a short amount of time to warm up, LED bulbs work instantly, just like halogen bulbs.

If you’re not sure which breaker switch controls the light, try turning them off at the box one by one until the light in the room goes off.

While it’s safe to throw halogen bulbs in with your regular garbage, compact fluorescent lights (CFLs) and fluorescent tubes contain mercury and should be treated like hazardous waste. If you have any of these you need to dispose of, check to see if there is a drop-off location in your area where you can take light bulbs that contain mercury.

You may need to go into your attic to access the transformer.

If the transformer lists a range, it is an electronic one (20 and 70 in the picture). The bottom number is the minimum load required for the transformer to function, and the top number is the maximum allowable. If there is only one number, the total power consumption of your bulbs on the transformer should be below the transformer maximum load rating and the transformer will be an iron core one. Being much more efficient, your LED bulbs individually will fall well below the transformer’s maximum power range. However, if your LED bulbs do not work or not work reliably on the halogen transformer, you will have an electronic version rather than the old iron core. If you are not dimming on the circuit, it is possible to wire multiple LEDs in parallel and doing so achieve the minimum load rating of an electronic transformer. Add up the Wattage (in VA or Watts) of each bulb to find out the total power. This is a way to reuse electronic halogen transformers. Rewiring by an electrician might be an option. E. g. , a room with 4 halogen transformers/light combinations could be rewired to 1 transformer with 4 LEDs.

If you’re not sure which wire is live and which one is neutral, use a voltage tester to test each side. The neutral wire will not have a reading, and the live one will have one.

Make sure if you have more than one bulb on the circuit that you do not exceed the maximum volt load for the new transformer.