Questions tagged [energy-efficiency]
The percentage ratio of energy produced to energy supplied to a system; or a measure of minimum energy required relative to energy actually consumed; or a measure of relative energy consumed to provide the same energy service.
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How "eco" is the (3hr+) Eco mode on dishwashers
Our domestic dishwasher has an "Eco" mode that takes around 3.5 hours to run. I presume that the time includes lots of resting time to allow the contents to soak.
However, I find it very ...
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Measuring Home Heat Loss
I am interested in testing/measuring my house to see how leaky it is and how bad the insulation is. If my house is poorly sealed and insulated then I will know how to improve it and I can retest it ...
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Do switchable sockets left "on" use electricity if there's nothing plugged in?
My flat is fitted with switchable sockets as per below:
Please settle an argument a friend and I are having: if a socket is switched "on", is it wasting electricity if nothing is actually plugged ...
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Does air duct cleaning increase heating efficiency?
I recently moved into an older house with a natural gas-burning forced hot air furnace. There are no records of the ducts being cleaned, and based on the layer of black grime I can see, they are quite ...
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For Electric vehicles, HOW are miles per gallon equivalent (or L/100 Km) calculated, accounting for different sources of energy in the grid?
Could someone giver a clear and authoritative answer on HOW miles per gallon equivalent (or L/100 Km) are calculated for Battery electric Vehicles like Tesla Model 3 AWD long range? On the Electric ...
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Can I use a "normal" thermometer in a refrigerator?
My refrigerator has a rheostat that I want to turn up to save energy. I'm trying to figure out whether I need to get a dedicated refrigerator thermometer.
I have a digital and a mercury-based ...
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Is it inefficient to turn off the airconditioner for short durations of less than two hours?
I was recently recommended not to turn off the airconditioner (A/C) when leaving a room for two hours or less but instead to increase the temperature setting closer to the outside temperature. The ...
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Estimating real, overall efficiency of an air conditioning unit
I want to research into electrical consumption of air conditioning units. While trying to make a rough estimate of efficiency, found that the btu/h capacity of the specifications does not make sense ...
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What 'average' conditions are used to test the energy usage of freezers for a EU energy label?
I'm orienting myself on buying an extra (small) freezer on top of the limited amount of freezer space I already have in my fridge/freezer combination, so I can more easily cook and store fresh produce ...
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Biomass: Digestor/Reactor vs Gasifier Efficiency
When using biomass for energy, two popular options are reactors and gasifiers. The first uses anaerobic micro organisms to convert the biomass to fertilizer and a methane rich gas mixture. The second ...
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Are there toasters with a selector for one or two slices?
I noticed that all toasters I could find (even the ridiculously expensive ones, 300 Euro/dollars) toast both slots at the same time, instead of offering a selector one/two.
The closest I could find ...
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Are plastic cups more environmental friendly than ceramic mugs?
Many years ago I read that plastic cups, like this:
are more environmental friendly than ceramic mugs, like this:
This is rather counter-intuitive. If I remember correctly, I believe the argument ...
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Is it more energy efficient to ventilate a home with an HRV/ERV or “shock-ventilation”?
In a reasonably cold climate like Hamburg, Germany where the standard practice is to open all your windows in the winter for up to 20 minutes once a day to ventilate your home (Stoßlüften or “shock-...
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Most fuel efficient way to run AC in my car?
More of a curiosity question, but I'm trying to figure out the most fuel efficient way to run the AC in my car, assuming I must use AC. I already know when to open windows vs use AC, so I'm looking ...
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Why not use condensate from a split-unit air conditioner to improve cooling efficiency?
This is bugging me to the point that it almost enrages me.
A split-unit air conditioner would typically cause condensate to form in the indoor unit. This water can be simply drained with gravity ...
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Is PEX piping more energy efficient than copper?
My house has two bathrooms, with roughly the same distance of pipe from the water heater to each (see diagram below). One was added during a renovation and has PEX piping from the point where they ...
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Meta-campaigns for sustainable building management?
(Sorry if this is the wrong place to ask this. I considered politics--maybe that is better.)
I have seen various groups that try to set up small campaigns targeted at individual organizations to ...
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Should I worry about the minimum mark on our kettle?
Our electric kettle for boiling water for tea or coffee has what looks like a minimum mark at 0.8 litres (though on closer inspection it says “mini” rather than “min”!). I try to save energy by ...
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Do solar panels generate more electricity in hot or cold climate?
Do solar panels generate more electricity in hot or cold climate? Who is right (sorry for the messiness, I currently don't know how to take a long screenshot)?
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Renewables vs Fossil Fuel Cost Comparisons, without Subsidies
They said that Solar and Wind are now cheaper than fossil fuels. One of the primary reasons is subsidies and new technologies. Does anyone know the comparison research using No Subsidies. If we ...
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Do SSDs have a lower environmental impact compared to HDDs?
In this question on Super User they say that Solid-State Drives (SSDs) use much less power than traditional Hard Disk Drives (HDDs). I read some internet posts and research articles that backup this ...
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Lowest energy use per passenger-km, electric bicycle or electric unicycle?
Which uses less electrical energy per passenger-km (pkm) travelled?
Electric bicycle (with a single rider)
Electric unicycle (aka. self-balancing personal transporter)
I have heard that a standard ...
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Shall I boil water with a water boiler (cooker) or with a pot?
I know that when making tea it uses less energy when heating the water when using a water boiler(cooker), than when using an electrical plate. A water boiler is directly heating the water, while a ...
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What is the most efficient setting on my oil-filled radiator?
I have an oil-filled radiator with three heat intensities:
Low (900W)
Medium (1100W)
High (2000W)
Given the radiator has a thermostat, what is the most efficient heat setting to use?
My goal is to ...
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What type of solar panels to use for a house of 50 m2 and 3000 kW of consumption?
I am beginning to acquire knowledge to assemble my first self-consumption solar kit and I have been investigating what kind of solar panels I should use for a house of approximately 50 m2 with a ...
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Radiative Cooling for Residential
I've seen a lot of references to films which radiate heat from an underlying surface out into space. For example:
http://radi-cool.com/
https://arpa-e.energy.gov/technologies/projects/passive-...
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Why is the Energy Guide efficiency rating of my air conditioner so much lower than the specification?
Now that my partner and I are working from home indefinitely, we decided to install central air conditioning. We got quotes for a unit with a 17 SEER efficiency rating, and ultimately picked this one. ...
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How feasible would a gas-powered electric-engine based car be?
Would an electric motorized vehicle work if there was a small gas-powered generator to power it instead of batteries?
EDIT: The original Chevy Volt was going to have a gas generator to charge the ...
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How to ensure you are using efficient chargers for cell phones, laptop computers, and other electronic devices?
I recently asked a question regarding a sustainable way to generate white noise. I received a wonderfully helpful comment from Móż (thank you!) in which Móż recommended ensuring that the power source ...
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Is human energy efficient?
I spent 2 weeks traveling on my bicycle, and usually I was very hungry.. Since I ate a lot of food, I asked to myself if maybe a train (dividing cost between all passenger) was more green than me!
I ...
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How feasible is a city with no cars and no streets?
Saudi prince, Mohammand bin Salman, announced a future city spread in 170km with no cars and no street. But any place to meet daily needs like schools, medicine and office will not take more than 5 ...
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How to keep my tankless water heater safe in a cold room?
I have a room in my apartment that can sometimes get around 40°F (4°C), and that's where my new tankless water heater is stored. Should I take any special precautions to keep my pipes from freezing or ...
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How to test accuracy of my Kill-A-Watt or similar device?
I have a used Kill-A-Watt power meter and want to see how accurate it is. In my "conventional" middle-class USA apartment, am I likely to have any electricity-consuming devices that I could ...
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Is an air to water heat pump appropriate to keep a hot tub at temperature throughout the year?
Is an air to water heat pump appropriate to keep a hot tub at temperature throughout the year? The hot tub will run 24 hours a day, seven days a week, covered when not in use.
Presumably if the ...
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How does the EPA estimate annual power consumption for refrigerators?
I'm trying to get a simplified idea of how the EPA estimates annual power consumption for refrigerators, e.g. here. There are a number of reasons why I want to know this, but there are three big ones:
...
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Will this work to prevent my pipes from freezing?
I live in an apartment in the US midwest, and during the winter my pipes freeze unless I trickle my faucet. I think that the point at which it freezes is in a difficult-to-access exterior wall on the ...
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What form of electrical lighting has the smallest energy-footprint?
We all know that when it comes to household electrical lighting, LED lights consume the least amount of energy for a given amount of light, followed by fluorescent tubes, halogens, and Edison-age ...
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Is it practical to use an infrared space heater along with a heat pump system?
We live in a house that has a heat pump system, for AC and heat, with a second-stage heating coil for aux/emergency heat. It frequently gets down to below 30 degrees in our climate, at which point ...
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How much coil do I need to heat a given length of pipe (as a function of x,y,z)?
I'm imagining heating some water pipes using heating coils similar to these. Under various conditions, would I need to apply almost continuous lengths of heating coil to the entire length of pipe? Or ...
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Efficiently freezing an ice pack once per 48 hours
Question: What are some good electricity-efficient ways to cool an ice pack down to ~5 degrees C once every 48 hours?
Background: I am in a warm climate and connected to the grid in a US city. I don't ...
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Keep my hands warm while working on a laptop?
I want to keep my hands warm(er) while working on a laptop in a cold room. Would it make sense to take a polar fleece blanket, fold it in half, sew together the two edges that are perpendicular to the ...
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How much energy costs do portable solar panels save in a house?
Our Houston area HOA does not allow roof top solar panels and I doubt they would survive our hurricanes too. I discovered NRG Energy sells these portable solar panels under their goal zero brand.
If ...
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Why do the best energy star freezers have higher capacity and lower rated power consumption than the best refrigerators?
The title says it all; I'm looking for any qualitative information that can help me.
Freezers: https://www.energystar.gov/productfinder/product/certified-residential-freezers/details/2255167
...
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Help me safely mod my freezer
I want to connect my freezer to an external thermostat like this to maintain a higher temperature than it otherwise could. Are there any thermostats or other control devices that would keep the ...
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Can I insulate my refrigerator to improve efficiency?
Any "reasonable" methods would be appreciated. I have heard that this can be done but I'm dubious that it would do much. Maybe if I put polyethylene on the right bits?
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Most energy-efficient way to keep my pipes from freezing without tearing up walls/floor?
I live in a second-floor apartment in the US Midwest. For a few weeks per year, I have found that I need to turn on the baseboard heater in my kitchen in order to prevent the pipes in the kitchen and ...
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Most efficient cheap heating system for small apartment in the US midwest?
I live in the US Midwest and am looking to upgrade from my current old baseboard heaters to a more energy-efficient solution. Any ideas?
I am already well advanced on a parallel project of home ...
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How do I find an efficient AC-DC converter for low-power applications?
My understanding is that AC-to-DC converters each have their own "sweet spot" in which they achieve their rated or advertised maximum efficiency. I want something with maximum efficiency at ...
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Help me estimate my annual refrigerator power consumption from this data sheet?
I am shopping for refrigerators and looking at this model. Feel free to let me know if that's stupid.
But my main question is this: I'm trying to come up with a moderately conservative power ...
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Should I turn off my Gas Water Heater if I will be gone for 3 days?
I have a gas water heater. If I go out of town for a week during warm months, I've been told that I will save energy if I turn the heater off before I leave.
Would that still be true if I was going to ...
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