lighting costs (is my math correct?)

[lost_at_sea]

Can someone tell me if i'm out to lunch on the operational costs of my lighting fixture?  I've recently seen my utility bill increase by 100% and i'm trying to account for what's going on.

2x250 w MH's for 6hrs/day (30 days * 6hrs * 0.5KW * 0.065$/kwh) = $5.85
2x54w T5's for 11hrs/day (30 * 11 * 0.108KW * 0.065$/kwh) = $1.26

The total KWH's used in my condo are around 1000KWH per month, this seems insanely high.

Thanks!!

[HomerJ]

Here is my usage for the past year.  1500 sq.ft house with a SPA outside.  (Dark blue is current year, light blue is last year)

[attachment deleted by admin]

[JetJumper]

2x250 w MH's for 6hrs/day (30 days * 6hrs * 0.5KW * 0.065$/kwh) = $5.85
2x54w T5's for 11hrs/day (30 * 11 * 0.108KW * 0.065$/kwh) = $1.26

Change your 0.065/kwh to about 0.12~/khw and you are good.

If you want to factor in the distribution charges and any other fees.. it works out to about 12-13c/kwh

[cdylnicki]

Electricity costs in Ottawa as per Hydro Ottawa 2010-05-01:

on-peak - 9.9cents /kWh
Mid-peak - 8.9 cents /kwh
off-peak - 5.3 cents /kWh

*in 168-hour week, only 30/40 hours are on-peak times.*

It may be worth it to change your lighting so they are on during the evening to early mornings.

[JetJumper]

Electricity costs in Ottawa as per Hydro Ottawa 2010-05-01:

on-peak - 9.9cents /kWh
Mid-peak - 8.9 cents /kwh
off-peak - 5.3 cents /kWh

*in 168-hour week, only 30/40 hours are on-peak times.*

It may be worth it to change your lighting so they are on during the evening to early mornings.

This is only if you have been switched to Time of Use.  A lot of people have still not be transitioned.

On top of those prices you listed however add another 5.5-6.5cents /kwh due to distribution / admin fees.  So the on-peak is really 15-16ishcents/kwh.

[JD]

It is easiest to take your total bill and divide it by your KWh's. This is the best overall average cost per KWh.
If you are on Time of Use billing, changing your lighting routine can save you some money.