Green Building Forum - MR16 halgoen replacements Wed, 23 Sep 2026 18:41:00 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299443#Comment_299443 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299443#Comment_299443 Sat, 31 Dec 2022 10:44:09 +0000 Rex
I have a low wattage MR16 dimmable halogen cable light with four bulbs that I would like to 'upgrade' to LED. When I last checked, it seems that it is necessary to exchange the transformer.

But all the numbers are confusing me and not sure what I should be looking for. Is it possible to just do a straight exchange, the same way if exchanged the 240v halogen downlights for LED bulb replacements? Or is it more complex then this?

Thanks]]> MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299461#Comment_299461 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299461#Comment_299461 Mon, 02 Jan 2023 11:24:56 +0000 Rex
The label on the light cover says Min 4x 20W Max 10 x 20W. The transformer has the attached info.

Does this mean that if I buy 4 LED MR16 lamps, the equivalent watts of each bulb must be greater than 20W?

Something like this: https://www.amazon.co.uk/AcornSolution-Equivalent-Replacement-Spotlight-120%C2%B0Beam/dp/B08MCHL83N/ref=sr_1_7?keywords=MR16%2BLED%2BBulbs&qid=1672658316&sr=8-7&th=1

Apart from the obvious 5W, the implication is that it is the 'equivalent' of 50W halogen; does this mean it is a direct replacement?

Thanks]]> MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299464#Comment_299464 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299464#Comment_299464 Mon, 02 Jan 2023 19:15:05 +0000 Artiglio MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299465#Comment_299465 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299465#Comment_299465 Mon, 02 Jan 2023 19:31:03 +0000 Peter_in_Hungary The LEDs you are contemplating are 5w but marketed as 50w equivalent halogen because although they only consume 5w they give out as much light as a 50w halogen. This equivalence has nothing to do with power consumption (= Watts) but light output. so your proposed swap to 5w LEDs won't draw enough power (only 20w) to be within the working parameters of your IKEA unit.

Light bulbs are marketed as equivalent (light output) to the old fashioned incandescent tungsten filament bulbs because old farts like me can't get our heads around the fact that 15w - 20w of LED bulbs is enough to light a room because we are stuck in a time warp of thinking 60w to 100w are needed as a minimum for a room, so the equivalents are just to help us.]]> MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299488#Comment_299488 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299488#Comment_299488 Wed, 04 Jan 2023 12:11:35 +0000 Rex
Or just exchange the transformer for an LED 'driver' that will run 4 x 5w bulbs. Only problem with an exchange, will it fit within the current housing?]]> MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299489#Comment_299489 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299489#Comment_299489 Wed, 04 Jan 2023 12:13:29 +0000 Rex MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299491#Comment_299491 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299491#Comment_299491 Wed, 04 Jan 2023 12:49:46 +0000 Peter_in_Hungary Posted By: RexSo I need 20W LED to get to the minimum transformer requirement?

No - You need 4 x 20w LEDs


Posted By: RexBut I assume that 4 x 20W LED will not save on my electricity costs when I current have 4 x 20W halogen?

Correct, no saving on electricity - but you will get much more light (about 200 Watts worth of halogen light if you believe the advert)

It is best to change the measurement used for light output. Watts was never a measurement of light, it is a measure of power used. Using it for light worked when all you had was incandescent bulbs and light output was in proportion to the Watts. Now there are several bulb technologies (LEDs, CFL, halogen and some legacy incandescent) you need a measure of light rather than power used.

The unit used is Lumen (shortened to lm) and you will see this on the bulb box along with the power used (W) the colour rendition of the bulb typically 2700k to 4000k) and the EU energy standard (A-G)

So you (and old farts like me) will have to stop thinking how many Watts I need to light a room but how many lumens I need.
Watts are just how much power you need to get the lumens you need and this varies with the bulb technology.]]> MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299496#Comment_299496 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299496#Comment_299496 Wed, 04 Jan 2023 14:42:04 +0000 Mike1
In which case you'd need to change the power supply / control gear or the entire fitting.]]> MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299498#Comment_299498 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299498#Comment_299498 Wed, 04 Jan 2023 14:48:52 +0000 borpin
Refused to use any transformers in my second build.]]> MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299502#Comment_299502 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299502#Comment_299502 Wed, 04 Jan 2023 18:50:22 +0000 philedge MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299514#Comment_299514 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299514#Comment_299514 Thu, 05 Jan 2023 11:54:52 +0000 Rex
Given that the fitting is one of those twin wire lights and the individual lamps have a metal fitting that punches through the insulation, fitting 240v bulbs is probably not the best idea.

So 4 x 5w LED MR16 bulbs and an LED driver (transformer) of around 30W should be OK? My slight concern is that I don't know the lumen value of the current 20W halogen, but if 5W LED is the equivalent of 50W halogen, everything will be much too bright.]]> MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299515#Comment_299515 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299515#Comment_299515 Thu, 05 Jan 2023 11:58:40 +0000 Rex
https://www.screwfix.com/p/lap-gu5-3-mr16-led-light-bulb-210lm-2w-5-pack/475pp

or

https://www.screwfix.com/p/lap-gu5-3-mr16-led-light-bulb-345lm-3-4w-5-pack/939pp

so a similar light level can be achieved.]]> MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299517#Comment_299517 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299517#Comment_299517 Thu, 05 Jan 2023 14:49:56 +0000 Peter_in_Hungary
Look at the lumen level produced by each respective bulb and ignore any marketing speak about being equivalent to any amount of Watts.

I had a look at a couple of halogen 20W bulbs and the lumens produced were 235 lm and 350 lm so say about 300 lm for a 20W halogen bulb, the LEDs you quote above are 210 lm and 345 lm with the 345 lm LEDs being dimmable. I would go for the 345 lm bulbs regardless of whether you use a dimmer or not. Generally bulb light output diminishes as they age so going for 210 lm might be a bit dim after some time.

As for the transformer - It is recommended that the transformer used is only run at 80% of its rated max. capacity. Less than 80% is OK but too much less if dimmer circuitry is involved may mean the dimmer won't work properly. So choose your bulbs and then choose a transformer to match the bulbs. If you go with the 4 x 3.4 W LEDs then I would get a 20W transformer but the 30W would also work but make sure that the Wattage of the bulbs is within the spec. of any dimmer circuitry.

BTW the halogen bulbs are producing about 15 lm / Watt whilst the LEDs are producing about 100 lm / Watt. About 6.6 times as much light / Watt which is why LEDs are so much better.]]> MR16 halgoen replacements https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299539#Comment_299539 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17683&Focus=299539#Comment_299539 Sat, 07 Jan 2023 13:14:45 +0000 Rex