Review of 35w 4700k CFL bulb (and comparing to a 20w bulb)

Review : 35w CFL spiral bulb from Long Life Lamp Company (color temp 4700k)
Cost  : around £6/$10 on amazon

Conclusion : Any CFL under 30w is probably pointless in my opinion. Not enough lumens/brightness (which would seem to most often be the most important thing). For a CFL (compact fluorescent lightbulb) I would go only for 35w or above. This is a 'cool white' at 4700k color temp, which is a nice 'white' light. Instant start. Quite big but the 'starting point' when choosing a CFL bulb in my opinion. A good buy

Marks : 8/10
Marks per value : 9/10


35w CFL spiral bulb 4700k color temp from Long Life Lamp Company :
This was the cheapest '35w' CFL I could see on Amazon. It's meant to be equivalent lumens of a 175w incandescent bulb, which is probably around correct or perhaps slightly less at around 150w bulb. We should now be talking lumens mostly, when talking about bulbs, as lumens is the brightness. Although of course you want to know wattage so you know how much power it uses. Mine is a 'bayonet' fitting, but you can get 'screw' fitting type.

Things to note when buying a CFL bulb :
The lumens/brightness (many don't say yet, but soon it will be the norm)
The wattage : e.g. 35w
The fitting type : bayonet ? screw ? you can also buy an adapter to fit either
The shape : This bulb is 'spiral' which is probably the best choice for me at the moment
The size : Be careful because at +35w the CFL bulbs can get very long. This one is 16.5cm
The color temp : 2700k is meant to be same as 'warm' (yellowish) incandescent bulb. Higher color temps are 'whiter/cooler'. Maybe even a blue-white.
Use with dimmer switch ? I'm not sure CFL's can be used with dimmer switches.

How many lumens for this bulb ? : The box doesn't say.

Instant start ? : Pretty much. Perhaps 90% power straight away then the rest follows in within 5 seconds. It's also flicker free.

Can you use with a dimmer switch ? : No

4700k color temp : This is described as 'cool' white, which is about right. It's not 'warm' (yellowish) like a 2700k. I think it's nice color. Some may fell it's too cold. Perhaps it depends where you are lighting. I have seen quite a few 'color temps' now. I think 2700k is the standard 'warm' type, and the higher it goes, the more 'white' it gets.

20w CFL 2700k

35w CFL 4700k

Size : CFL bulbs above 35w can get a bit big (like 20cm long). This one is 16.5cm long and 6cm wide. Not too big but getting around the maximum I would consider for a CFL bulb. I would like to try 42 CFL bulbs but they seem too big at the moment.

Comparing 35w 4700k CFL to a 20w 2700k CFL bulb :
I took some pictures and videos comparing a 35w to a 20w. As can be seen, there is no comparison in lumens, and the 20w takes a while to brighten up too (but even then is too dull). The fact is that anything under 30w for a CFL is probably very dull (just not enough lumens) and not fit for much. I'm not even sure about 30w CFL as a starting point. Until they get the lumens up, I would suggest 35w as a CFL starting point. Also I didn't like the 'yellowish' color temp of the 2700k. The 20w takes time to brighten up but still is not decent enough at 'full lumens'.

Amazon USA search : CFL bulb 30w-49w
Amazon UK search : CFL bulb 35w

Summary : 35w is a good starting point for a CFL bulb, though they are usually a bit big. But if you want decent 'brightness' (lumens), you will need to start here (or at least 30w).  I am still unsure of the 4700k color temp (after all, it is basically a fluorescent lamp and the color temp looks the type they use in prisons) but it is growing on me. 20w CFLs are a waste of time.

35w CFL 4700k bulb

35w CFL 4700k bulb