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Old 24-06-2019, 13:39   #1
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Shore power KW usage

We are fairly new boat owners. We have had our 45í MV in a marina since February this year. I just received our latest monthly electric bill from the marina for $172.00 stating a usage of 1727KW. This seems extremely high to me based on the amount of time we spend on the boat. We are weekend users so only on the boat for 2 1/2 days a week.
The boat is equipped with 5 ac units of which while we are on board 3 are running. When we leave all of the 120v ac power is turned off accept the battery charger and on a/c unit left on 75 degrees.
I am curious as to what others are seeing. For reference we are located near Galveston Tx., so it is hot and that one a/c unit rarely shuts off.

But in comparison to our 2500 sq/ft house that is poorly insulated running a 5 ton a/c unit 24/7 and a in ground swimming pool with pump and equip running 14 hrs/day our average monthly electricity consumption is only 1800 kw. I find it awfully hard to believe that this Boat consumes as much as a house when we only spend weekends on it.
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Old 24-06-2019, 13:52   #2
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Re: Shore power KW usage

Depends on the size of the air conditioner you leave on.


Math for an average (1200 watt) air conditioner that runs continuously:


30 days * 24 hours * 1.2 kw = 864 kwh


Plus a little for the pumps, the battery charger, and probably the fridge unless you shut that off too.
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Old 24-06-2019, 16:52   #3
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Re: Shore power KW usage

A house is usually much better insulated than a boat.
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Old 24-06-2019, 17:12   #4
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Re: Shore power KW usage

Iím not surprised! 75 in a poorly insulated boat afloat in 90 degree water takes a lot of power to maintain.
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Old 24-06-2019, 17:56   #5
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Re: Shore power KW usage

I believe itís mainly Solar heat gain.
I bet late afternoon you can lay your hand on the ceiling and feel warmth, the house has an attic and maybe some trees, boat sits in the sun and absorbs heat.
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Old 24-06-2019, 18:09   #6
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Re: Shore power KW usage

If we had that monthly electric bill for the boat, I'd be happy. Want to trade?
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Old 25-06-2019, 08:57   #7
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Re: Shore power KW usage

I have a 42' sailboat in Seabrook Texas that has one a/c on 78*F all the time (12000 btu) as well as one fridge. Boat has solar but my electric bill is usually $8 to $18 per month. About 200kw to 400 kw useage at $.071 per KW/hr. I lived aboard for a month and the bill was still under $30/month. What is the marina charging you per KW/hr?
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Old 25-06-2019, 09:03   #8
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Re: Shore power KW usage

Quote:
Originally Posted by TCM1968 View Post
I just received our latest monthly electric bill from the marina for $172.00 stating a usage of 1727KW. .
I know this doesn't answer your post, but wow, it would cost me twice as much for the same usage at the marina I'm at.
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Old 25-06-2019, 09:10   #9
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Re: Shore power KW usage

Check with the marina office as to how individual slip electric bills are computed. I've found marinas that simply take their total electric bill divided by the total KW usage BY ALL THE PEDESTALS to calculate a cost per KW then multiply that by the KW you use. This does not take into account how much electricity the marina uses and artificially increases the cost per KW. Slip holders end up in aggregate paying the entire marina electric bill. There's some (false) logic to this but in in reality, marina electricity not directly attributable to individual slips should be included in marina overhead and covered as part of the monthly slip rentals. In most states it is illegal to mark up electricity over what the actual individual meter cost is. Many electric companies offer an online bill cost calculator where you input the KW used and they tell you how much your bill will be. These calculators included taxes as well as a base fee just for having electricity available whether you use it or not. If you find that you bill would have been lower based on the utility companies calculator vs what the marina charged, gently point this out to the marina. The couple marinas where I've found this happening don't really realize they're breaking the law, and ended up changing their practices to more accurately compute slip bills.
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Old 25-06-2019, 09:11   #10
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Re: Shore power KW usage

I just double checked my 4 bedroom house usage since January 2017. Only one month did I exceed your listed amount. Most months between 800-1000 kwh. Summer between 1000-1500 kwh. Major electric usage in our house is Aircon.

I'm curious if that is a bill for one month or two? Are you able to see the meter readings?

I can't imagine that at Caribbean rates of $0.65-0.85 per kwh. $1000+ monthly electric bills. Crazy!!!! Of course this is hypothetical.

I'm very happy to rarely plug in and not pay marina's for power.
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Old 25-06-2019, 11:00   #11
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Re: Shore power KW usage

Quote:
Originally Posted by TCM1968
I just received our latest monthly electric bill from the marina for $172.00 stating a usage of 1727KW. .



Quote:
Originally Posted by wiekeith View Post
I know this doesn't answer your post, but wow, it would cost me twice as much for the same usage at the marina I'm at.

That would be over $480 in Hawaii!
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Old 25-06-2019, 11:02   #12
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Re: Shore power KW usage

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Originally Posted by Scubaseas View Post
I have a 42' sailboat in Seabrook Texas that has one a/c on 78*F all the time (12000 btu) as well as one fridge. Boat has solar but my electric bill is usually $8 to $18 per month. About 200kw to 400 kw useage at $.071 per KW/hr. I lived aboard for a month and the bill was still under $30/month. What is the marina charging you per KW/hr?
A one ton a/c uses 3.5 KW. X24x30x0.07=$176.40 You should advise the marina accordingly
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Old 25-06-2019, 17:37   #13
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Re: Shore power KW usage

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Originally Posted by ebs001 View Post
A one ton a/c uses 3.5 KW. X24x30x0.07=$176.40 You should advise the marina accordingly
Your calculations are based of the 1 ton a/c running at the lowest temp setting and at full load 24 hrs/day. From about 6pm to 10am which is 16 hours of the 24 it keeps up normally and cycles on and off. Itís only during the hottest hours of the day the it rarely cycles the compressor off. And like I said my 2500 sq/ft poorly insulated house with a 5 ton a/c running in the same climate and a 5hp swimming pool pump running 14 hours a day, electric water heater on always, my electric kw usage was the same this month as the boat. Last month my boat electric bill was only 70.00 . Something is fishy. I am going to install a kw meter on the boat and start comparing to the marina numbers.
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Old 25-06-2019, 17:41   #14
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Re: Shore power KW usage

Quote:
Originally Posted by Scubaseas View Post
I have a 42' sailboat in Seabrook Texas that has one a/c on 78*F all the time (12000 btu) as well as one fridge. Boat has solar but my electric bill is usually $8 to $18 per month. About 200kw to 400 kw useage at $.071 per KW/hr. I lived aboard for a month and the bill was still under $30/month. What is the marina charging you per KW/hr?
.10/kw is what they charged. And your numbers sound accurate to me and I believe mine should be at most a little over double yours.
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Old 25-06-2019, 17:49   #15
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Re: Shore power KW usage

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Originally Posted by TCM1968 View Post
.10/kw is what they charged. And your numbers sound accurate to me and I believe mine should be at most a little over double yours.

I agree. Note on hot days my boat is not cold. Really only the back 1/2 of the boat gets cooled. But I would think 1727kw is a bit much even for a bigger volume boat than mine. If it's any consolation 1727KW at my dive shop in the TCI would be over $1001.00.
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