I promised a thread on indoor lighting bulbs. First things first, this an over simplified internet thread for people who know little about bulbs. I used to test bulbs and this is what I think you need to know to make better bulb purchases. This is thread 1, I'll do 2 later.

Electrical terminology you should know:
- Watts (W): Power. Figure will be on the box
- Watt-hour (Wh): Amount of energy consumed. Is <Watts*No of hours you've used your bulb for>
- Kilowatt-hour (kWh): What you get billed for by the grid provider (KPLC). Is <Watt-hour/1000>

Electricity Tariff: How much a kWh (which is what we call a *unit*) costs for you:

In Kenya electricity tariff for domestic consumers comes in 2 levels:
1. 0-100 units - 10KES per unit
3. 101 and above - 15.8KES per unit

The real figure is... things vary. From my bills:

July 2020:

No of Tokens (NoT) - 227.73 units

Token cost
2277.31/NoT = 10 KES/unit

Total cost
3500/NoT = 15.37 KES/unit

Levies cost
(3500-2277.31)/NoT = 5.37 KES/unit

August 2020:

No of Tokens (NoT) - 258.38 units

Token cost
2583.84/NoT = 10 KES/unit

Total cost
4000/NoT = 15.48 KES/unit

Levies cost
(4000-2583.84)/NoT = 5.48 KES/unit

September 2020:

No of Tokens (NoT) - 155.55 units

Token cost
2457.77/NoT = 15.8 KES/unit

Total cost
3500/NoT = 22.5 KES/unit

Levies cost
(3500-2457.77)/NoT = 6.7 KES/unit

Summary: July, Aug, Sept

Token cost: 10, 10, 15.8

Total cost: 15.37, 15.48, 22.5

Levies cost: 5.37, 5.48, 6.7

And this is only if you buy directly from KPLC. Merchants can be more expensive. And most won't give you a breakdown like the one you get from KPLC.

For the sake of this thread, let's assume the total cost is 24 - it's an average used by the energy industry. Unsure where it came from.

Calculating how much your bulbs cost to run with different watts as examples:

Scenario 100W - 1 bulb
W: 100
Time: 4AM-8AM then 5PM-11PM - 10 hours
Wh: 100*10 - 1000
Units: 1000Wh/1000 - 1kWh
Cost per day - 1*24 = 24
For 30 days - 720
For 12 months - 8,640
For 3 years - 25,940

Scenario 50 W - 1 bulb
Cost per day - 0.5*24 = 12
For 30 days - 360
For 12 months - 4,320
For 3 years - 12,960

Scenario 11W - 1 bulb
Cost per day - 0.11*24 = 2.64
For 30 days - 79.2
For 12 months - 950.4
For 3 years - 2,851.2

Scenario 8W - 1 bulb
Cost per day - 0.11*24 = 2.64
For 30 days - 57.6
For 12 months - 691.2
For 3 years - 2,073.6

Scenario 6W - 1 bulb
Cost per day - 0.08*24 = 2.64
For 30 days - 43.2
For 12 months - 518.4
For 3 years - 1,555.2

Scenario 4W - 1 bulb
Cost per day - 0.04*24 = 0.96
For 30 days - 28.8
For 12 months - 345.6
For 3 years - 1,036.8

To explain 10 hours: Most houses in Kenya aren't built with natural light in mind so 1 or 2 bulbs stay on for long

The other bulbs might be on for less hours.

10 hours a day for 30days for 12 months = 3600 hours per year

- The 4W GLS I have is 15,000 hours - 4 years 2 months
- The 14W CFL I have is 8000 hours - 2 years 2.5 months
- The 11W CFL I have is 6000 hours - 1 years 8 months

3 hours a day for 30days for 12 months = 1080 hours per year

- The 4W GLS I have is 15,000 hours - 13 years 3 months
- The 14W CFL I have is 8000 hours - 7 years 1 month
- The 11W CFL I have is 6000 hours - 5 years 2 months

Numbers' summary:
- Buy lower wattage bulbs. The money adds up
- Use longer hour bulbs for areas where lights stay on for longer. Doesn't hurt to do it everywhere though
- Less hours reduce the cost so do the math. Either way, the lower the wattage, the less the running cost

Bulb fittings:
Pin type. Most household lighting bulbs in Kenya will be that type
Screw type. Your microwave and fridge will probably use this type of bulb. Between E10 and E14
Always check especially for LED bulbs. I've absentmindedly bought screw types for lighting

You can get a *screw to pin type adapter* if you bought an expensive LED bulb that you're now attached to, electrical shops sell them. A shop in village market that sells them so I buy them there.

I'll talk about bulb technologies, costs and characteristics in the next thread.

Hopefully tomorrow. If not - in time I will. Check my pinned tweet for other electrical threads.