How to Save on Energy Bills — A Room-by-Room Checklist

On “on” the blower never stops, so a motor sized to push heat around the house spends most of the day pushing room-temperature air around it instead. On “auto” it runs with the burner. A modern ECM blower draws well under half a PSC one and makes this row smaller, not zero — and a fan left on “on” through summer costs this again while the burner is cold.

Furnace running cost→

Resistance strips buy one unit of heat per unit of electricity; the compressor buys three. A thermostat switched to “emergency heat” in January and left there runs the expensive one all winter, and nothing about the house feels different, which is why it goes unnoticed until the bill arrives. Check the thermostat is on “heat” rather than “emergency” or “aux”, and if the strips are engaging on mild days, the system needs a technician rather than a setting.

Heat pump running cost→

This counts the cooling season only. DOE's figure covers heating as well, so an electrically heated house saves it twice over — and a programmable or smart thermostat is what turns it from a resolution into a schedule. Note what is not claimed here: the widely repeated “each degree saves 3%” has no source we could find, so it does not appear on this site.

Central AC running cost→

A fan cools people, not rooms, so it earns nothing in an empty room — the break-even figure above is the bar, and an hour a day is roughly four times it. Whether your house clears that bar depends on your house, which is why this row's saving is an assumption about comfort rather than a property of the hardware. Turn fans off when you leave.

Ceiling fan running cost→

Every other row in this room put together does not come close, and this one is a plug. A pre-2010 fridge kept in the garage for drinks costs more than every cooking appliance in the kitchen combined, and in a hot garage it costs about 30% more again, because the compressor is fighting the room as well as the food. If you genuinely need the capacity, a current model at half the consumption pays for itself; if you need it for six weeks a year, unplug it for the other forty-six.

Refrigerator running cost→

An oven's cost is dominated by heating the box, not the food: the preheat alone is 0.50 kWh before anything goes in. A microwave heats the food and nothing else, which is why it wins by roughly ten to one on a reheat and why the gap closes on a long bake, where the box is doing useful work the whole time.

Microwave running cost→

The wash is identical either way — what you are switching off is a resistance element that bakes the last of the water off the dishes after the cycle has finished. Crack the door instead and they air-dry in the residual heat. Rinse aid makes the difference invisible by breaking the surface tension so water sheets off rather than beading.

Dishwasher running cost→

Heat leaks in through the insulation in proportion to the temperature difference across it, so a freezer holding 0°F inside works harder the hotter the room is. In a northern garage the winter months more than repay the summer ones and the annual factor comes out below 1 — the penalty is a hot-climate problem, not a garage problem. Either way, leave the coils room to breathe.

Chest freezer running cost→

This row is on the list because it is small, and because most pages like this one would round it up until it wasn't. Two self-clean cycles a year cost about what a load of laundry does. Skip them if you like, but do not expect the bill to notice — the reason to avoid the cycle is the smoke and the strain on the door latch, not the electricity.

Electric oven running cost→

A heat pump dryer recycles its own heat instead of blowing it out of the wall, and needs no vent. It saves about half rather than the two-thirds its nameplate implies, because it runs a longer cycle to get there — read the watts column against the cycle column before believing any dryer's headline figure. Worth it when the old machine dies; not worth killing a working one for.

Dryer types compared→

The dryer is the most expensive thing in the laundry room by a distance, because evaporating water is expensive and a rack does it for nothing. Two loads a week is a modest target — towels and bedding, the loads that take longest anyway. Dryer balls help the loads you do run by separating them so the air gets through; they do not replace the rack.

Dryer running cost→

The drum motor costs the same at every temperature — what the dial changes is how much of the fill gets lifted from the tap to the wash temperature. That makes this row a straight function of how many gallons your machine fills with: on a pre-2011 agitator filling with 15 gallons the same switch is worth 334 kWh a year. Detergents formulated for cold water clean as well at tap temperature; reserve hot for genuinely soiled loads.

Washing machine running cost→

A half load is not half a wash. An auto-sensing machine weighs the load and fills to suit, but the fill has a floor around 55% of a full one — the drum has to be wetted and the pump kept fed — and the motor runs its whole cycle regardless. On an older machine with a manual water-level dial there is no floor at all: left on “large” it fills to large for three socks.

Cost per load by load size→

The hours you play are not what a gaming PC costs. Idle is where it lives, and a machine that never sleeps is a permanent hundred-watt load in a spare room. Sleep is worth more per year than a cheaper graphics card, and it is one setting. Check the power plan has not been set to “never”, which is a common side effect of the tuning advice on gaming forums.

Gaming PC running cost→

A laptop is built around a battery, so every part of it is designed to sip; a tower is built around a wall socket and behaves accordingly. Docking the laptop to the big monitor gives back part of the saving — the panel is the panel whichever box drives it — but the tower's idle draw is the bulk of the gap and that goes away entirely.

Laptop vs desktop cost→

A set-top box has no off switch worth the name: the anchor DVR draws 30 W watching and 27 W not watching, so it behaves like a device that is simply never off. Only the hours nobody is recording can be reclaimed, which is what makes this a schedule rather than a habit. A box you keep for a channel you watch twice a month is worth cancelling outright.

Cable box running cost→

Sleep suspends to RAM and wakes in a second or two, so there is nothing to trade off. Blanking the display alone is the smaller half of the same setting — worth 29 kWh a year on its own — and it is included in the figure here rather than counted twice. Set the display to sleep after five minutes and the machine after fifteen.

Desktop computer running cost→

Here for scale, and as a warning about the genre. Modern televisions are regulated down to a watt or two asleep, so the standby glow that every energy-saving list tells you to hunt down is worth roughly one takeaway coffee a year. The set-top box beside it is worth five times as much. Spend the evening on the rows at the top of the table instead.

TV running cost→

Only worth this if your bulbs are still incandescent — at 93 kWh a year per bulb the swap pays for itself in months, but a house that switched years ago has already banked it and there is nothing left here. Start with the fixtures that burn longest rather than the ones that are easiest to reach; an LED lasts about 25 times as long, so the ladder comes out once.

LED vs incandescent cost→

Priced as LEDs, so it does not double-count the swap above. These are the fixtures nobody owns — the porch light, the garage, the stairwell — and the ones most likely to be running at noon. A dusk-to-dawn sensor costs less than a bulb and removes the decision. If they are still incandescent, this row is worth nearly seven times as much, and it belongs at the top of your list rather than the bottom of ours.

Cost to leave a light on→

Water heating is priced by the gallon and by the degree, so cutting flow by 40% cuts the energy by the same share — and unlike turning the tank down, this genuinely reduces the heat you draw rather than shifting where it comes from. Shorter showers do exactly the same arithmetic for nothing. The stated assumption is that showers take half a household's hot water; scale the row up or down if yours are longer or shorter than that.

Water heater running cost→

Standby loss is the entire difference between a tank and a tankless heater — both put the same energy into the water, and only one of them keeps sixty gallons hot around the clock waiting for you. Insulation attacks that directly and costs an afternoon. Skip it on a modern tank already foamed at the factory; the label or a hand on the side will tell you which you have.

Tank vs tankless standby→

Most lists get this row wrong by a factor of five, and it is worth knowing why. Turning the tank down does not cut what your showers use: you mix to the same temperature either way, so a hotter tank just means fewer hot gallons and more cold blended in. The heat reaching the person in the shower is identical. What actually falls is standby — the heat leaking out of the jacket while nobody is drawing anything — and that scales with how far above the room the tank is held. Real, smaller than advertised, and it also stops the tap scalding.

Water heating arithmetic→