Many people say that using full spectrum light bulbs has helped their Seasonal Affective Disorder or SAD. The full spectrum of light wavelengths emitted by these bulbs closely resembles summer sunlight, banishing Winter Blues.

What Are Full Spectrum Light Bulbs?

These bulbs give off light of many different wavelengths or frequencies, in the same way that the Sun does. We see the Sun's light as white, but if a narrow ray of light is passed through a prism, the white light splits up into its different wavelengths. The same happens in nature when we see a rainbow during a rain shower.

Conventional incandescent and ordinary compact fluorescent bulbs (CFL bulbs) do not give out all wavelengths of light, there are some important blue wavelengths missing from their light output.

Why Use Full Spectrum Light Bulbs?

Full spectrum bulbs give out similar light to that given out by SAD lights, but at a lower intensity. There is anecdotal evidence from many users who say that using these bulbs has improved their SAD and the low feelings that they experience in the winter.

Full spectrum bulbs cost slightly more than ordinary CFL bulbs, but they have similar energy efficiencies. The ordinary CFL bulbs do last longer.

Where Should You Use Full Spectrum Light Bulbs?

Given the extra cost and shorter life of these daylight bulbs you should experiment with one or two for one winter. Use them where you spend a lot of time, in front of the computer, perhaps. If your family is less moody and happier, then buy extra ones next winter.

Full spectrum, daylight, bulbs give a noticeably whiter light, that gives better color rendition. This is important to any painter or cross-stitch enthusiast. Using a daylight bulb in a studio extends the artist's day well into the evening.

Who Benefits From Full Spectrum Light Bulbs?

Nobody has claimed that full-spectrum lights are harmful. Everyone has at least a neutral comment on their effects, most people say they are beneficial. Check out the comments on Amazon and the only critical ones relate to the quality of the bulbs' manufacture.

Everyone seems to benefit in some way, though SAD sufferers really need a more intense light source or a SAD light box to improve their condition.

People say their teenaged daughters are made human again and that they smil in the mornings. It is worth trying just for that.

When Should You Use Full Spectrum Light Bulbs?

Where you live governs how many months of the year you should try out these daylight effect bulbs. If you live in Scandinavia or Canada you might need them for six months of the year. If you live in Britain or Ireland you might only benefit from using a full spectrum light source for four months of the year.

Given their extra purchase cost and shorter life, many users change their bulbs in spring and autumn. Switching to the full spectrum bulbs when they start feeling the Winter Blues hit.

How Do Full Spectrum Light Bulbs Work?

It seems that our eyes are sensitive to certain wavelengths of light, sending messages to the body's endocrine system to produce certain hormones when those light wavelengths are present.

Historically most humans spent many hours a day outside, so even in the winter most people had good light levels. It is only since the Industrial Revolution meant that most people live and work inside buildings that we have needed supplementary light sources through the winter months.

What Different Kinds of Full Spectrum Light Are Available?

Filament Bulbs

You can buy traditional incandescent bulbs still that give out a full spectrum. These use as much energy as an ordinary incandescent filament bulb, and have a very short life compared to CFLs. Filament daylight bulbs also give out a lot of heat, so it is uncomfortable to work very close to one.

CFL Bulbs

Compact fluorescent bulbs have the largest part of the daylight bulb market. They are available in many different shapes, with spiral tube bulbs being the most common. Some CFLs come with a diffuser fitted. They look like a large conventional bulb, with a frosted glass diffuser case hiding the coiled fluorescent tube inside. Daylight effect CFL bulbs use a similar low level of electricity to ordinary CFL bulbs. They give out some heat, but it is comfortable to work with one even at very close quarters.

Different Percentage of Solar Spectrum

Not all full spectrum bulbs are created equal. Some give a fuller range of light wavelengths than others. Cheaper bulbs might typically give out 85% of the light wavelengths that the Sun does. More expensive bulbs will give out 88% to 92% of the Sun's range of light.

Artists who need as accurate color rendition as possible should choose the bulbs that give the best approximation to the Sun's light.

Different Light Output

12, 18, 24 and 25 watt full spectrum daylight CFL bulbs are commonly available. These low wattage bulbs equate to 40W to100W incandescent bulbs in terms of light output. They will have a marginal effect at best on a SAD sufferer. 32Watt daylight bulbs usually give out enough light that most SAD sufferers say they notice an improvement if they work close to it for long enough. A 32W compact fluorescent bulb is roughly equivalent to a conventional 150W bulb.

Different Fittings

Full spectrum daylight bulbs and fluorescent tubes are available in the same range of fittings as ordinary bulbs and tubes.

Be careful when you buy a daylight bulb that it has the correct fitting, screw or bayonet, small screw or small bayonet, etc. European light fittings are conventionally for bayonet cap (BC) bulbs, but many lamps use the American style Edison Screw (ES) fittings.

You can replace any non-daylight bulb or tube with a full spectrum one because these are available to suit every fitting on the market

Different Purposes

You can find high power 100W CFL Daylight bulbs, equivalent to a 400W tungsten filament bulb. These are used in projectors and photographic darkrooms.

Be careful that the bulb you buy is designed to work at your supply voltage. US bulbs are designed for 110v, European bulbs are designed for 220v. Europeans might be tempted by the low priced daylight bulbs on US websites, but they will blow in two seconds in Europe.

ALZO 85W Joyous Light Full Spectrum CFL Light Bulb 5500K, 4250 Lumens, 120V, Daylight White Light, Extra Large
Amazon Price: $22.05 Buy Now
(price as of Nov 13, 2016)
A VERY bright bulb perfect for anyone who wants to relieve SAD symptoms, which is most of us.