Skip to main content

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.

Filter by
Sorted by
Tagged with
4 votes
0 answers
43 views

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 ...
Cheeseminer's user avatar
3 votes
0 answers
35 views

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 ...
Jake's user avatar
  • 131
1 vote
2 answers
66 views

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 ...
Sanjay Biswas's user avatar
4 votes
1 answer
66 views

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 ...
HRSE's user avatar
  • 143
0 votes
1 answer
32 views

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 ...
javert's user avatar
  • 123
2 votes
0 answers
33 views

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 ...
Tinkeringbell's user avatar
3 votes
0 answers
50 views

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 ...
FarO's user avatar
  • 429
3 votes
2 answers
386 views

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 ...
Louis Somers's user avatar
4 votes
3 answers
560 views

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-...
statueuphemism's user avatar
1 vote
0 answers
104 views

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 ...
LShaver's user avatar
  • 11.9k
2 votes
1 answer
36 views

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 ...
capet's user avatar
  • 743
-3 votes
1 answer
124 views

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)?
Sergey Zolotarev's user avatar
4 votes
0 answers
91 views

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-...
Dark Falcon's user avatar
2 votes
1 answer
1k views

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 ...
mattsmith5's user avatar
1 vote
2 answers
374 views

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. ...
LShaver's user avatar
  • 11.9k
1 vote
1 answer
124 views

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 ...
ciudadanoxx's user avatar
7 votes
3 answers
956 views

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 ...
THelper's user avatar
  • 14.5k
6 votes
2 answers
121 views

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 ...
End Antisemitic Hate's user avatar
6 votes
3 answers
236 views

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 ...
Francesco Pagani's user avatar
2 votes
3 answers
153 views

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 ...
PD Pro's user avatar
  • 303
4 votes
1 answer
133 views

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 ...
capet's user avatar
  • 743
1 vote
2 answers
73 views

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 ...
capet's user avatar
  • 743
0 votes
1 answer
40 views

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 ...
capet's user avatar
  • 743
1 vote
1 answer
44 views

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 ...
capet's user avatar
  • 743
1 vote
1 answer
66 views

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 ...
capet's user avatar
  • 743
2 votes
1 answer
61 views

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?
capet's user avatar
  • 743
1 vote
3 answers
184 views

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 ...
capet's user avatar
  • 743
3 votes
1 answer
53 views

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 ...
capet's user avatar
  • 743
2 votes
1 answer
76 views

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 ...
capet's user avatar
  • 743
3 votes
1 answer
223 views

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 ...
capet's user avatar
  • 743
2 votes
0 answers
41 views

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 ...
capet's user avatar
  • 743
2 votes
1 answer
53 views

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: ...
capet's user avatar
  • 743
0 votes
1 answer
42 views

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 ...
capet's user avatar
  • 743
2 votes
1 answer
99 views

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 ...
capet's user avatar
  • 743
2 votes
1 answer
459 views

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 ...
capet's user avatar
  • 743
1 vote
1 answer
2k views

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 ...
capet's user avatar
  • 743
5 votes
1 answer
66 views

What will happen if I leave my freezer off most of the time?

I only use my freezer to freeze ice packs, which I only use about an hour every two days. Because of this, I plan to turn my freezer off (or to the hottest setting) most of the time, and then reduce ...
capet's user avatar
  • 743
2 votes
2 answers
75 views

How to get a small volume of freezer capacity with high efficiency and low cost?

I have a big refrigerator/freezer and barely use any of the space. I also don't necessarily need to keep things cold all the time, as I mostly use it to freeze ice packs and extend the freshness of ...
capet's user avatar
  • 743
3 votes
2 answers
10k views

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 ...
Duncan Jones's user avatar
3 votes
2 answers
2k views

How much more efficient is boiling water with a lid?

I sometimes end up boiling water in a pot without putting a lid on top because I can't find the lid. How much energy is wasted when bringing water to a boil without in a pot without a lid? Or ...
Nic's user avatar
  • 2,899
2 votes
2 answers
198 views

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 ...
Nic's user avatar
  • 2,899
2 votes
3 answers
102 views

How can I conserve energy and water in my bathroom? [closed]

I am interested in energy conservation and would like some simple tips on ways I can reduce my water and energy use in the bathroom in particular, as I feel that this is the place that I use the most ...
Max Brown's user avatar
5 votes
2 answers
202 views

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 ...
WhiskeyHammer's user avatar
3 votes
1 answer
53 views

Why is there no energy star certification for portable or box fans?

Why are there no energy star certifications for portable fans? From what I understand no portable electric heaters have the certification because using a portable heater is not efficient at all. ...
Agriculturist's user avatar
0 votes
1 answer
81 views

Is there any case where plant farming is more eco friendly than raising livestock?

I am looking for an example or a case with arguments that would justify converting cattle ranches into plant farms (e.g., wheat, apple, or anything non-meat). The advantages should be in a more ...
user101464's user avatar
4 votes
1 answer
92 views

Is this discrepancy between energy label and measured values reasonable?

My fridge is a Haier A3FE835CGJE and is rated A+++ (Europe, 2017), with about 200 litres volume, half of which for the freezer. It is a "no frost" model which does not require defrosting. The ...
FarO's user avatar
  • 429
4 votes
3 answers
94 views

How to reduce energy usage of a window air conditioner?

In the summer, we use a window air conditioner in our bedroom to be able to sleep comfortably at night. It takes a while to cool, and I know it uses quite a bit of energy. Here are a few steps we take ...
LShaver's user avatar
  • 11.9k
3 votes
1 answer
68 views

Costs of transportation

I assume that it makes sense to ask for the energy costs of transportation of different goods per weight and volumetric mass density, depending on the means of transportation (truck, train, ship, etc.)...
Hans-Peter Stricker's user avatar
3 votes
1 answer
109 views

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 ...
Cath's user avatar
  • 31
0 votes
2 answers
3k views

What level of light intensity (lumens) do you need across a solar panel in order to obtain 15% energy efficiency?

What level of light intensity (lumens) do you need across a solar panel in order to obtain an incident-light to energy-output efficiency of 15%?
stephencarlsbad's user avatar