Why am I paying for AC when I use DC ?

self ^ | June 20, 2026 | knarf, Tessla and Edison

[knarf]

I'm not smart enough to analyze this correctly, but most of my house is operating low voltage items . . . TV's, lap tops and a ton of smaller lights and stuff that all have those little black boxes for plugs.

[EVO X]

The excess daytime solar power from houses could be used to charge EVs parked at workplaces and shopping centers.

I think that fantasy is over with. Sure there will high speed chargers around in big box store parking lots, but the stores lease the space..

[em2vn]

A step down transformer in you appliance steps down the house voltage to a very low voltage before it reaches a rectifier in your appliance that converts AC to DC. AC voltage can be transmitted over long distances far more easily and cost effectively than can DC. You do not have anything to complain about. You are paying far less for electricity than if DC was being piped to your home.

[bobbo666]

All of those special and mis-named fees are there to dodge most states’ laws about not passing new taxes without the state assembly voting for it.

Fees = taxes. But, if the politicos admitted they were a tax then the dumb bastids who sit on their butts instead of voting might actually practice some measure of democracy — like voting. So, the politicos repackage the taxes as fees and permit utilities to put them on your bill.

[Dr. Sivana]

Pennsylvania in the winter sounds in a mobile home could be pretty pricey. You never say what your electricity bill is, so I cannot judge how high it is. I take it you do not use air conditioning?

[cymbeline]

“Can someone explain all this to me ?” (why AC is sent to your house rather than DC)

The answer is that AC can easily be converted to higher and lower voltages. That is huge because much more electric energy (watts) can be sent over a given wire diameter when it is sent at a high voltage.

Thus, the transmission lines use a high voltage. It is reduced to 220/110 volts when delivered to your house because, for one thing, the lower voltage is safer.

California has a major transmission line that sends DC. That’s because DC utilizes the transmission lines more efficiently because it is a steady current. AC, on the other hand, oscillates between zero and the operating voltage. At the zero points, for instance, there is absolutely no energy being transmitted.

Converting the AC to DC and back to AC is complex but worth it for that particular transmission line.

[wafflehouse]

you are paying for energy, AC is how it gets to you. you are changing it to DC on the fly (plugin bricks or whatever). maybe what you should do is see how much power you are using with something like a kill-a-watt meter. you might be surprised at how much electricity certain things are using

[fruser1]

You have to compare actual power usage, not the dollar amount of the bill. Localities change rates and taxes annually. You may actually use less, but pay more because of increased rates.

[eastexsteve]

You’re paying for watts per hour. Whether it’s AC or DC makes no difference. Actually you’re costing yourself a bit of overhead because it takes extra energy to convert that AC coming in to DC for your RV.

[ridesthemiles]

I AM METERED. MY USAGE IS EASY TO SEE ON MY BILL & FOLLOW IT THRU THE MONTHS.

I HAVE CEILING FANS THAT RUN ALL SUMMER. NO AC.
MY PROPANE FURNACE RUNS ALL WINTER.
I HAVE ELECTRIC CLOTHES DRYER-—BUT ONLY 1 IN HOUSEHOLD MEANS LAUNDRY ABOUT EVERY 2 WEEKS.
PROPANE COOKING & HOT WATER. DISHWASHER.
ELECTRIC FENCING FOR LIVESTOCK-—OVER 2 1/2 MILES OF HOT WIRE USES VERY LITTLE POWER-—FENCE ‘PULSES’-CLICK-CLICK-CLICK, ETC.
HAVE 2 REF-FREEZERS—2 UPRIGHT FREEZERS- MULTIPLE TV’S—
DO NOT USE HAIR DRYER OR “CURLING IRON”.

HAVE LAPTOP & HP PRINTER & MULTIPLE DESK CALCULATORS.
GARAGE/SHOP IS 220 AND HAS FLUORESCENT LIGHTING..6 UNITS.

POWER BILL RUNS UNDER AVERAGE OF $80 A MONTH OVER ENTIRE YEAR.ABOUT 16 CENTS A KILOWATT HOUR. RURAL N NEVADA HIGH DESERT. NO COMPLAINTS YET.

INCOMING DATA CENTERS MAY CHANGE THAT.

[ridesthemiles]

DUE TO MY NEAR-SIGHTEDNESS-—I HAVE 100 WATT LIGHT BULBS EVERYWHERE

[ridesthemiles]

I ALSO USE A CROCK POT FOR COOKING MEAT FOR MEALS. POT RUNS ALL DAY-—LOW & SLOW—_GREAT PORK SHOULDER ROASTS====MMMMMM.
AT LEAST 3 TIMES A MONTH. COOK UP ABOUT 10 CHICKEN THIGHS AT ONCE & FREEZE FOR FUTURE USE.

[central_va]

Even though there is a meter I don’t think the power company bothers with it anymore. They just charge what they want.

[Georgia Girl 2]

We have a 38 ft RV on our rural property. When we are not there which is most of the time we disconnect the electric plug from the pole. I get a monthly electric bill for at least $32 per month. There is a minimum charge just for having the electricity on the property.

[Colorado Doug]

Yours is the best explanation thus-far into the thread. I would only expand it a little bit to say that it would require massive amounts of copper and other conductors to carry low voltage DC electricity throughout the grid and it’s also more difficult to change voltages with DC, for instance if one wants to change 12 volts to 5 volts AC, all you need is a simple transformer, not so with straight DC due to the monotonic nature of the turns ratio. With AC it’s a simple matter to carry 225,000 volts across long distances and then step it back down to 220 volts at the end of the line for home use. As norwaypinesavage mentioned, the amperage goes way down when energy is sent at 225,000 volts but the wattage stays approximately the same. The amperage goes up as the voltage comes back down. That is how you can get 150 amps out of a 20 amp circuit when using a welder or battery booster. Think of it like a water hose. High voltage is like when you use a small hose nozzle, it squirts a long ways but not as much volume. When you use a fat hose with no nozzle, you get a lot more water but it does not shoot very far.

[ansel12]

“””””I HAVE 100 WATT LIGHT BULBS EVERYWHERE”””””

I’m a bright lighting nut, kitchen, bathroom, work areas, reading.
I have used these for years they are bright 100 watt light, produce little heat, and use about 14 watts, use can also use splitters to greatly increase the light where you want to and I think the “daylight” version makes for the clearest lighting for seeing clearly (aka 5000 kelvin=”daylight”).

Great Value A19 LED Light Bulbs, 100 Watts Eqv, Daylight, General Purpose, 9yr, Medium Base, 12 pack $23.97 $2.00/ea
https://www.walmart.com/ip/GV-100W-9YR-DL-12PK/17347700525

To really light up an area use 3 to 5 bulbs by using a splitter, 3 of those LED bulbs in your overhead light fixture is only 42 watts for instance.
https://www.walmart.com/search?q=bulb+splitter

[knarf]

Yeah, I cited them in my post

[knarf]

I thought Tesla was experimenting to send AC through the earth . . . ?

[faucetman]

ALL of your 12 volt DC run from an AC converter.

[Tell It Right]

To charge EVs at home typically means using fossil fuel-supplied electricity.

Agreed. However, in mine and my wife's case, our EV is usually charged with solar because my wife's retired and I'm quasi-retired. When I work it's usually at home. In other words, usually the EV is charged during the day.

Like FReeper JAKraig stated, it requires some project engineering or it'll cost you more than it saves you. Comment #32 details steps I took to make mine save me.

Another step I took was to have two charging circuits for the EV (dryer outlet circuits). One charging circuit is constantly powered, but not always free (like virtually all circuits in the house). The other charging circuit is intermittently powered -- only when my home battery stack is charged at least 70%. That circuit isn't always on, but when it's on it's always free (almost always). The idea is that 70% charge in my battery stack is almost always plenty of charge to power the home through the night without pulling from the grid. When we come home with the EV, if we have plenty of range left in the EV battery, we plug it into the intermittent charger. It may or may not get charge, and if charging it may or may not charge all the way to 80% (the recommended top charge state for local driving). And sometimes the EV stays parked (and plugged in) until the sun comes out the next day enough to charge the home battery stack to 70% (or whatever I configure the inverters to) and resume charging the EV. Of course, if we come home with the EV with low charge we plug in the constantly powered charger (definitely charge the EV, but may or may not add to the power bill).

Another thing is my water heater has a heat pump built in the top of it to heat the water tank. It runs at only 380W, but can take hours (if I have guests staying over I switch the water heater to use normal heat strips like a normal electric water heater, using 4kW). The 50-gal water tank is large enough for my wife and I to take back-to-back showers, and with our kids grown and moved out, we don't care if it takes hours to reheat the tank. While it's reheating the tank, the water heater's heat pump runs and pulls air in from the attic (often very hot -- a free heat source). Thus, the water heater doesn't have to run as long to find enough heat energy for the water tank. Also, the water heater outputs free cold air as a byproduct. During the warm half of the year, I duct that free cold air into an intake duct of my home HVAC. Thus, my home variable speed heat pump can stay in one of the lower speeds for a few extra hours each day thanks to the free cold air coming from the water heater.

The variable speed heat pump saves me money. The hybrid water heater saves me money. But the two work together to be better than the sum of their parts. (Project engineering)

I charge my EV at a slow speed (5.6kW). When my total load of my home with whatever appliances running at any point in time is less than 18kW, it's within the threshold of AC power that my solar inverters can provide and, thus, they don't have to pull power from the grid (assuming I have solar and/or battery power, which is always DC power). If most of the time the variable speed heat pump is in a low power, while the water heater uses low power, while the EV is charging at one of the slower settings, I'm almost always within the 18kW limit even if we're running another appliance (i.e. clothes dryer or electric stove and oven). (Project engineering)

Charging my EV is like adding a major appliance to my power load. Except that usually my EV can be charged only when there's free solar power. This is because the EV has its own battery that gets about 230 mile range (when charged to 80%, driving local driving speeds). We drive on average 1,500 miles per month on home charged miles alone (18K miles per year). That's 50 miles per day. If we come home in the EV and it's raining, usually it's no problem waiting for a sunny day if it comes in a couple of days (unless we drove a lot extra one of those days). The two-charger circuit system detailed above means it happens without us putting much thought into it. So the solar system saves me money, the EV saves me on gasoline cost, and the two work better than the sum of their parts. (Project engineering)

[Merrick]

No - I meant Tesla was wrong about tgransmitting power through the air instead of via transmission wires. I thought in context that was clear, since I also said DC CANNOT be transmitted through the air - which Tesla knew - and I was talking not about the argument between DC and AC but the argument between through-wire and through-air transmission.

Like I said up front. There is more than one question hanging in the original question and I chose two aspects of it.