A newbie over here, learning all about this stuff, so this might be a silly question to some, but I’m wondering if this calculator which I found on a website works.
If not, how do you recommend one calculate it? Basically, a rectangle bedroom, 2.85x1.9x2 (meters) recommends me 1073 Lumens OR 8 Watts, which seems about right. I’ve actually just purchased a 810 lumen, 8watt bulb which I think is just about right (4000k) and I’m wondering if the calculator is reliable or what people recommend?
The rooms in your country are smaller than what most newer American homes would be. I used your figures with 2.85m and 1.9m for the floor and 2m height. That gives 57 square feet (10 square meters) for the floor area. Both of the smaller bedrooms in my home are 108 square feet and the calculator recommends 3011 lumens or 23W. I think 800 lumens from a single source would be a bit anemic for your bedroom. If you look at the diagram at the calculation site the light comes from four different lamps evenly arranged in the room and away from the corners. It looks as though they used four “can lights” in the ceiling for this calculation. If you are using a single lamp with one bulb, I doubt it would give enough even illumination for the room.
When I converted my home to LEDs a couple of years ago I didn’t bother with a calculator. One of the smaller bedrooms is used as a home office of sorts. It has a desk with a lamp overhead and there are two other ceiling lamps illuminating the room itself. I don’t remember how many lumens would be from each lamp because they were homemade units built from LED strip lights. They are on two separate switches, one for the ceiling lamp over the desk and the other for the general illumination. All of my rooms have multiple ceiling light sources that put light over the work areas. Only the living room has floor and table lamps. There are two table lamps and two floor lamps in the living room and it has a ceiling lamp put in by the builder too.
I’m not sure what bulbs are available where you are but I didn’t use any bulbs sold by my local home improvement stores. They were expensive and totally inadequate compared to what I could buy from overseas vendors. I particularly like a bulb called a “corn bulb” which has the LEDs arranged like kernels of corn and on the top of the bulb. You can get them in much higher intensities than the typical American sourced bulb and far cheaper to boot. Many of mine came from Banggood (often cited here for buying flashlights) www.banggood.com but also from Chinese sellers on eBay. You have to be careful to order bulbs that match the voltage in your country. The ones I bought are good for 85-240V AC. Here’s a typical 12W bulb in warm white (2800 – 3200 kelvin) for $2.21 shipped to the US https://www.ebay.com/itm/12W-E27-36LED-SMD-5730-LED-Corn-Bulb-w-Cover-Warm-Cold-White-Light-ED/172475923232?hash=item28285dbb20:m:mpn9X6KP1WcSbJJKPvBjz7w I used cold white for most rooms in my home but I see a lot of people here who prefer warm white. Cold white is brighter for the same number of watts and I just like it better. In either case they beat out fluorescent lights or incandescent lights.
Well quite true, however my room is the smallest in my home. I live in a flat (apartment in American English) in London, so hence the size. Without going into history too much, we’re kind of limited to space over here, so it comes either a lot of cost or location, such as moving out of the centre of the city.
Interesting, I never considered these things at all. The issue is the building is old so back when they created these flats from the original building, it was not actually thought of, I presume. So if I were to add a secondary light source, it would be a bit of work or I would have some trunking sticking out because the ceiling is concrete, not drywall or some sorts.
I wonder if the trunking or doing LED Strip lights is a pay off to far superior lighting in my bedroom though, so I can get the correct lighting and split it between the sources so it’s not so bright in one angle of the room, because even the light source right now is at a slight corner rather than even one side of the room.
I was actually thinking that 800 lumens and 4000k would be just about right, and not too bright as to cause strain as I don’t necessarily want it to be an office level brightness, because it’s a bedroom.
Yup, I am also looking overseas. I’ve just ordered my first set and I’ll see from there, based on the results I get. banggood.com looks similar to aliexpress.com, hehe, but I’ll check it out thanks.
I’m sick of warm white (2700k), it seems like everything is yellow or creamy and it just bothers me now, it doesn’t feel warm, but outdated feel, maybe it’s the lumens being even low that’s spoiled it for me, but I’ll test things out to be sure. Oh and I once had a bright light bulb, which I guess was high kelvin and did not have a lamp shade, so it kind of strained me. Trying to avoid both issues from now on.
Actually 5.4 m^2. Seems you calculated metric volume(which would be 10.8 m^3) instead of floor area. :GRAD:
[offtopic]Your 100 sqftish rooms are also 10 square meterish rooms. I'm lazy and often use very rough conversion factors to understand figures presented in alien(to me) systems or to explain to someone who's not familiar with the system I grew up with. So a 100 m^2 apartment becomes a one thousand sqft apartment in my speech if I were to discuss housing size with an American, or I think of a 2500 lb small compact car as a 1250 kilogram car. Neither are correct, but pretty close. Figuring this out first helps me immediately spot significant mistakes in scale when actually calculating something. But this presents me a problem, too. Ask me how many grams is a pound, and my guess of 454 grams is probably pretty close, but ask me how many kilograms a stone is and my best guess is "maybe 8-13 kilos", and ounces, guessing "a bit more than 30 grams, probably". For a grain, I'm gonna have to do some math first as a I very well know that 8 g bullets are about 123-125 gr, but other than that no clue apart from "it's really tiny". When memorizing exact conversion factors is not needed on an everyday basis, I end up just googling them when necessary in turn resulting in not recalling them very well.[/offtopic]
I agree. In fact, my preference for general lighting in a bedroom is way dimmer than that: At the moment I'm happy with a single 120-lumen bulb, and my bedroom is around 10 m^2 with a height of about 2.5 meters. Obviously this level of illumination is not suitable for reading etc, but I have table lamp for that use and rarely read anything from paper in bed.
Bedroom lighting is really more about personal preference than office room lighting: a very well lit office suits almost everyone, while a many people will disagree on a given bedroom's lighting, no matter how much work went into it - at least unless it is a very adjustable and sophisticated system.
Oh, color temperature is important too, and warm LED household bulbs often have a horrible tint.
The common opinion (with scientific backing) is that warm light is preferable before going to sleep and/or when waking up for a moment - if there is need for light. More than that I believe it's a matter of preference too - bedroom light color temperature is probably one of the least causes for sleeping and falling asleep difficulties and disorders.
My bedroom light has a very low/warm CT, but I don't know if that has any benefit compared to regular 2700k warm. Just feels nice.