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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.

22
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4answers
771 views

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 ...
21
votes
4answers
137k views

Leaving the oven door open for heat - bad idea?

I've heard before that it's a bad idea to use an oven to heat your house, because it's inefficient and carries the risk of carbon monoxide poisoning. But what about leaving the oven door open after I'...
16
votes
5answers
21k views

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 ...
15
votes
3answers
1k views

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 ...
15
votes
2answers
3k views

Propane vs. Electric vs. Heat Pump

Is there a relatively reliable way to figure out what energy source to go with when upgrading appliances? We need a new hot water heater, for starters. Our current one is propane. Options include ...
15
votes
1answer
138 views

Does transporting plastic offset the benefits of recycling it?

Apparently China has been processing about half the world's waste until this year, and most of that waste is transported over the ocean in large container ships. Recycling plastic uses less energy and ...
14
votes
3answers
2k views

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 ...
13
votes
6answers
4k views

What is the relationship between energy efficiency and sustainability?

What are the sound reasons (let's put aside the unsound reasons) why increasing energy efficiency takes us further down the road to sustainability? Are there real-world circumstances whereby ...
13
votes
1answer
78 views

Co-firing fossil fuels use in waste incineration

I know from shop talk among previous colleagues that waste incinerators often need natural gas to sustain firing. AFAIK this is mostly because mixed household wastes have a high moisture content, ...
12
votes
5answers
387 views

Lowering the heating thermostat at night: is it really worth it?

I've heard some very conflicting information regarding the effect of lowering the house heating thermostat at night. On one hand there are academic papers (such as Thermostat strategies impact on ...
12
votes
3answers
219 views

Options to suggest to landlord for cost savings via renewable energy?

I have a landlord who is very interested in saving money. I wanted to suggest options to her to help her save money while reducing environmental footsteps. However she is not motivated to save the ...
11
votes
3answers
825 views

Use waste heat of electrical appliances in place of traditional heating?

Does it make sense to keep electrical appliances turned on, or at least not turned off, during the winter as a partial replacement for traditional heating? I'm thinking in particular of computers, ...
11
votes
1answer
1k views

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 ...
11
votes
1answer
118 views

What are the sustainability issues in moving house?

We are moving house from one side of the UK to the other. The financial costs of doing so have raised the facetious question would it not be cheaper to sell everything here and buy it again, there? ...
10
votes
3answers
5k views

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 ...
10
votes
2answers
365 views

Should I take advantage of the higher heat pump COP during the warmest part of the day and “bank” heat in the house?

I am aware that heat pumps are able to move more heat into a building per unit of energy input (the "coefficient of performance" or COP) when the source (outside) temperature is higher. My question ...
9
votes
4answers
2k views

How to measure the energy output of a thermal solar hot water system?

I have a (thermal) solar hot water system with electric heating, and I'd like to be able to measure the amount of energy provided by just the solar heating. The system is set up like this: Water ...
9
votes
5answers
2k views

How can I measure the moisture content of my firewood to ensure good efficiency and clean burning?

It's clear that firewood that hasn't been well dried is more polluting and less energy efficient, hence the existence of various schemes to ensure firewood suppliers provide dry wood. Is there a way ...
9
votes
6answers
398 views

How can I use my own body as an energy source for greater environmental sustainability?

I've had the epiphany that my body is a living vessel of energy production (and consumption), just like all other energy sources and associated forms of consumption or re-allocation around me. My ...
9
votes
2answers
143 views

Does it make any difference to charge my electronic devices using an USB port?

I work with a computer and I was wondering if using its USB ports to charge the devices that I use the most (mostly my phone and my e-reader) while working as opposed to charging them using a normal ...
9
votes
1answer
825 views

Olive oil versus sunflower oil

I wondered what was the best, in one hand for the health (but I guess the question should be asked somewhere else, shouldn't it?) and in the other hand for the earth. Which one, if there is one, is ...
9
votes
1answer
128 views

Does it matter where I charge my device?

I have a number of small devices that can be charged in my car (using a charger that plugs into the car's electrical system and is powered by the car's gasoline engine) or my home (using electricity ...
9
votes
1answer
52 views

Are building certificates under EU Directive 2002/91/EC, such as EPC, Energieausweis, DPE, directly comparable between EU countries?

Implementing Directive 2002/91/EC, the UK have the Energy Performance Certificate (EPC), Belgium has the Energieprestatiecertificaat (EPC), Germany has Energieausweis, France has Diagnostic de ...
8
votes
3answers
2k views

What is the relationship between permaculture and sustainability?

What is the relationship between permaculture and sustainability? What are sound reasons why both urban and rural permaculture takes us further down the road to sustainability? Are there real-world ...
8
votes
1answer
178 views

Is the energy used to manufacture and install solar panels in proper balance with the energy output from them? [duplicate]

From mining/harvesting materials to altering them into useful manufacturing materials to making actual products, and then packaging them and shipping them to retail stores, or directly to customers, ...
8
votes
1answer
157 views

What can a smart thermostats and meters tell me about how to reduce my home energy consumption?

I'm considering a smart thermostat for my step-dad as a birthday gift. Here are some characteristics of the home: 3000 sq ft living with two people climate is arid with highs into the 100s (deg F) ...
8
votes
1answer
2k views

How much gas does it take to heat water from 15 to 60 degrees C?

There's a great answer about heating water with electricity, where anyone can easily get an idea how much would it cost to heat water just by applying one's price for kWh. I'm looking for the same ...
8
votes
1answer
2k views

Does repeatedly turning on and off an appliance tend to damage it?

When nobody is watching the TV, my practice is to turn it off, so as to save electricity, even if I know that someone will want to watch it in the next 10 minutes. However, it is claimed that turning ...
8
votes
2answers
181 views

More sustainable pick-me-up: can of coke or cup of tea/coffee?

Question: which has a greater embodied energy: a cup of tea/coffee or a can of Coke (or Pepsi, or other caffeinated soft drink) -- or maybe some other stimulating drink? I have made some estimates of ...
8
votes
1answer
141 views

What would be the most sustainable biomass source for (100%) ethanol production?

So I have read that sugar (cane) is way more efficient than corn, (and that Brazil leads the way in taking initiative to actually bother with this advance in biofuels sustainability), and that, based ...
7
votes
5answers
344 views

Practical and cheap ways to get warm at home this winter?

Since winter is near, can someone suggest some practical ways to get warm at home without spending too much in gas or electricity? Also for every solution, please add if it can be done homemade and ...
7
votes
2answers
266 views

Anything similar to GravityLight that can be readily purchased?

Ever since it was first mentioned in a popular news site, I've always been interested in GravityLight. But I've never been able to go to a store or a site and just buy it. Is there anything vaguely ...
7
votes
3answers
4k views

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 ...
7
votes
2answers
142 views

What are the incentives for energy companies promoting energy efficiency?

My hydro (electricity) bills always contain helpful hints on conserving energy: do laundry runs in the wee hours, favor LED over incandescent bulbs, etc. I'm sure many at the big-energy corporate ...
7
votes
1answer
120 views

Have spray-on solar cells hit the market yet? What other lightweight cell can I use for unusual shapes?

I read in a couple of places that researchers at Sheffield University have made spray-on perovskite cells at efficiencies of 11%. I was interested in this because it is lightweight and could fit more ...
7
votes
2answers
196 views

Which is more “meter” efficient? I would like my utility bill to significantly cheaper

I live in a 3 bedroom, two bath, large den, kitchen, attached garage Patio home. I live alone except for when my kids are in from college which is rare. I am hot natured so I keep my electric heating ...
7
votes
1answer
403 views

Why isn't STES (Seasonal thermal energy storage) more popular?

I don't understand why STES - or more specifically BTES (Borehole thermal energy storage) - isn't more popular. I understand that is has a high implementation cost; excavation, drilling, evacuated ...
7
votes
1answer
93 views

How much energy would U.S save if all public illumination use LED?

How much megawatts U.S could save if they used LED for public illumination? Bonus : The math for China which is another big energy consumer in the world. And the math for the humanity as whole. ...
6
votes
4answers
2k views

Which is more energy efficient? Heating ten 1L water separately or one 10L water directly

Just like the title said. In my house, we are very heavy tea drinkers. So my mother tends to boil a lot of water every day. She usually does this with a small amount of water (1-2L) every time she ...
6
votes
1answer
147 views

cost of energy for old crt vs new flatscreen

My parents recently moved and are going through throwing out and replacing a lot of their furniture. They have 3 large old fashioned crt televisions that are quite heavy, and I'm considering ...
6
votes
3answers
6k views

How can I estimate the gas usage of a pilot light?

Can anyone provide a method to estimate the gas flow rate to sustain a pilot light, using just the apparent size (flame width and length) and reasonable assumptions for things like gas line pressure? ...
6
votes
2answers
212 views

Water heater vs stovetop: most efficient way to heat water using natural gas?

When I am going to boil a pot of water for cooking, will the total energy consumption be less if I start with hot water from the tap? A few considerations: Both the water heater and the stove burn ...
6
votes
1answer
166 views

MVHR no longer the ventilation of choice in some Nordic countries?

We've covered Mechanical Ventilation with Heat Recovery (MVHR) before here, and it's been the ventilation method of choice for Passivhaus buildings for many years. But I heard something interesting ...
6
votes
2answers
4k views

How much power does an Electric Airpot use while on standby?

We have just brought a Buffalo K711 4.25L Electric Airpot that is great for my wife as she is disabled and can find a kettle hard to pour. I was expecting it to be well insulated, however its sides ...
6
votes
1answer
74 views

Is it possible to calculate energy efficiency of a flat by knowing how much energy was consumed for heating?

During 6 days my heating system consumed 11,4 m3 of natural gas keeping its temperature at 20 degrees of Celsius. No human or other energy source (except for refrigerator) was inside the flat at that ...
5
votes
2answers
3k views

Which is more energy efficient, a washing machine express wash, or normal?

My electric washing machine has an express wash button (they seem a common feature) that reduces the washing time by a lot. My first thought would be that using it would save energy because of the ...
5
votes
1answer
365 views

Electrical usage data logging with wireless data transfer

Does anyone know of a wireless energy usage capture device, that one can attach to an appliance and find out the energy usage? I know that there are certain energy monitors that do the job to some ...
5
votes
3answers
549 views

Best way to store vegetables in the fridge

What is the best way to store fruits and vegetables in the fridge? I currently use plastic food containers like those in this picture, of different sizes. 1) Is it better in terms of energy ...
5
votes
2answers
605 views

What is investment/outcome ratio for wind energy in terms of energy (EROEI)?

Merchants say that I can have 1 watt of energy per every $1.5 invested. Yet, I have heard from people "from the business" that the installation alone (forget mining the ores and smelting the parts) ...
5
votes
2answers
71 views

What exactly is Potential Induced Degradation in PV panels?

Can someone explain Potential Induced Degradation? I've been looking over the internet but a lot of the explanations go into too much detail.