Questions tagged [energy-efficiency]

Questions about ways to measure and improve the ability to get useful work out of devices that consume energy. This includes coal, oil and gas as well as electricity.

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66 views

Should the door be open or closed between two separate HVAC systems?

We recently built out an additional 600sqft theater room in our attic. It’s a big room with 14’ high vaulted ceiling. We live in Houston and room heat load is fairly high. We installed a 2-ton unit ...
30 votes
11 answers
7k views

Why are so many radiators installed beneath a window (at least in Germany)?

I live in Germany and I always wondered why the radiators in most apartments are installed right beneath a window. The pictures below show an example (this is an older building, but you see similar ...
0 votes
1 answer
100 views

Would a long refrigerant line reduce the efficiency of a heat pump?

I recently installed a multi split heat pump (air conditioner). One of the indoor units work pretty fine, the line set is about 8meters. The other unit, which is supposed to be even stronger but has a ...
3 votes
3 answers
185 views

Photovoltaic installation: does it make sense (or is possible at all) to get a bigger inverter than the power output of the installed panels?

We are going to install a PV in our offices. Our actual needs would be satisfied by an installation of about 4kW, so that ~16 panels of 250W. It's going to be a central-inverter, grid-connected ...
0 votes
1 answer
48 views

Home energy monitoring in split floor with one compressor

I have an odd situation where I live on a floor split in two and I want to split the electricity bill fairly with my floormate. I am looking at the home energy monitoring systems that have all the ...
0 votes
4 answers
22k views

Will adding a cool air return in the basement help with summer AC power usage?

Pretty much the title. I have a full basement. Part of it is unfinished and has the water heater, furnace, and washer / dryer. The other part (roughly 1/2 of the total space) is partially finished. It ...
0 votes
0 answers
27 views

Radiant Barrier: with or without Insulation?

Researching an attic radiant barrier for my old home has yielded two general classes of radiant barrier: simple films and then sandwiches of film/insulation/film. Is there really much benefit to ...
7 votes
4 answers
17k views

Is it a good idea to pay for an energy saving audit of my new home

We have a newly built home but I'm not at all confident in the builder's prowess when it comes to energy conservation. Is it worth hiring someone (like our energy provider or other specialized ...
2 votes
1 answer
65 views

increasing R-value for old vaulted ceiling

I have vaulted ceilings in the main living space. Internally there are 2x6 joists between the roof and the drywall and the insulation I am guessing is original from the 1960's so this section of roof ...
0 votes
2 answers
127 views

Is there a way to measure the output of a single HVAC vent?

As inspired by this previous question, is there a method or device used to measure the output of a single HVAC vent or the output of a single room? I'm imagining some sort of hood device that could ...
14 votes
3 answers
11k views

Are tankless water heaters worth it in cold climates?

I was thinking of switching over to a tankless water heater. A friend of mine said they are not good in colder climates since the water coming in is colder and takes longer to heat. Is this a valid ...
3 votes
3 answers
798 views

Is it more efficient to heat a room using an air conditioner (heat pump) when the windows are open?

In general, using an air-conditioner for heating is more efficient than a standard electric heater or radiator. But in our home, we keep the windows open all the time, in order to decrease the chance ...
-1 votes
1 answer
86 views

same-sized alternatives to F14T12 bulb

I have two bathroom light fixtures with very old magnetic ballasts and F14T12 fluorescent bulbs. These are, of course, a 1.5-inch diameter. I've been doing some bathroom renovations and I thought this ...
19 votes
7 answers
7k views

Why is my house energy efficient only in winter?

My electric utility company sent me a graph of my home's electricity usage over time as shown in the picture below. My home beats what the company considers as efficient homes in the neighborhood when ...
0 votes
1 answer
57 views

Using water cooler for CNC laser as residential heat pump

I want to save money on heating bills. Residential heat pump systems cost thousands of dollars, which I can't afford. I am considering using a heat pump marketed to chill water for cooling CNC lasers (...
2 votes
0 answers
34 views

Where can I find the efficiency of my heat pump with respect to temperature?

I can heat my house either with a standard gas heater, with a documented efficiency of 0.9, or with an heat pump, with a standardized coefficient of performance (Seasonal Coefficient of Performance) ...
7 votes
2 answers
2k views

(When) Does room messiness affect water heater efficiency?

I have what I think of as a "standard US electric standby water heater." I will update this when I know the model; I am out of town right now. It is located in a cold, cluttered closet in a ...
1 vote
2 answers
128 views

Most efficient heating system @ ~41° N

I'm researching building a home on a property I just bought. Water is plentiful but there is little or no chance of getting municipal services such as natural gas or electricity. However I have open ...
2 votes
3 answers
191 views

How to track energy usage per zone?

I have an old oil boiler with 4 zones, individual zone pumps. I'm trying to track heat usage on a per-zone basis. Would it be possible to simply track how often each zone pump runs and apply their ...
4 votes
1 answer
93 views

How do the old and new (post-2021) EU energy labels for LED light bulbs compare?

One of my light bulbs recently failed, for the first time in a few years, and I had to go buy a replacement. Usually I try to look for the ones with the best EU energy label rating, since not only do ...
0 votes
2 answers
231 views

Why does G23 energy-saving lamps need ballast, LED type as well?

IKEA Lival desktop lamp (like this) uses a huge adapter plugging into power-socket, which should be a ballast/transmitter. The lamp uses a G23 bulb from e.g. OSARAM DULUX S11 W. I feel it is very ...
2 votes
2 answers
182 views

If I live in the US Southwest, would a heat pump or conventional dryer use less energy?

Suppose I live in Poway, CA (weather), where temperatures are roughly between 50 and 90 F throughout the year and relative humidity is generally between 40 and 60%. With climate change the highs have ...
2 votes
0 answers
106 views

What is the optimal number of solar panels for my house?

Just had a solar power tech stop by. With the orientation of our house and the solar load, our property (house + workshop) can support roughly 41 panels. Each panel provides 370 W (max)...which ...
0 votes
4 answers
1k views

Weatherstripping for inswing exterior door with clearance problems. Clearance door sweep?

How would you weatherstrip this gap under an inswing exterior door? The door threshold is not very high, and the door already drags a bit on the interior carpet, so many styles of door threshold are ...
24 votes
8 answers
6k views

How to find electric device(s) driving a high electric bill?

The cabin electric bill came and I gave it what I thought would be a cursory glance and it looked unusually high. Not just for this cabin, but in my experience with our houses. Our main house is a ...
2 votes
5 answers
5k views

110v vs 220v Mini Split Efficiency

I am under the impression that, as a general rule, 110v heating and cooling options are inherently not very efficient. So I was surprised to find a 110v mini split shopping around with a fairly decent ...
1 vote
3 answers
106 views

Is there a low-e alternative to double-pane gas-filled window panes?

I spoke with a local glass retailer and he said instead of using double-pane gas filled windows, I could instead use a 3-layer sandwich of, say, 1/8", 1/4", 1/8" panes to achieve the ...
1 vote
3 answers
180 views

Why is Condenser energy guide rating different from advertised?

I'm installing a Carrier 24APB6 which has advertised up to 17 SEER. The seller tells me it is a 16 SEER unit but the yellow Energy Guide sticker on the condenser gives it a SEER rating of 14 on a 13-...
2 votes
2 answers
240 views

What is a good exterior wall composition for a wood frame house with pine chink siding in a moderate climate?

I'm designing a house for myself that will be built in northern Georgia (USA). The climate is moderate, with lows in the 20's during the coldest part of winter. The house will be framed with 2x6's, ...
32 votes
9 answers
7k views

Can I gain AC efficiency by spraying condensate water on the outdoor coils?

Recently, I was working from the basement and I noticed tonnes of condensate water going down the drain, and thought I might re-use it to improve the efficiency of my home AC system. So I put a ...
9 votes
16 answers
68k views

Would putting a sprinkler on my roof help cool my home?

Anyone ever put a sprinkler on your roof to help out your A/C on unusually hot days? Just wondering if it helps.
3 votes
2 answers
118 views

How could I insulate a thin hot roof and bring it to current Southern CA code?

So we started an exterior remodel today, and found that our roof construction is way more mickey mouse than I thought it was. Our house has vaulted 2nd floor ceilings through most of the 2nd floor ...
24 votes
13 answers
5k views

Do smart or programmable thermostats actually save money?

I am looking at replacing all the thermostats in my house. I have hot water baseboard heat and forced air A/C. Each room's baseboard heat is controlled by a thermostat in that room. I tend to prefer ...
0 votes
2 answers
807 views

Why does the well pump continuously draw large current?

The pump is a submersible type around 100ft down. It is rated at 1.5 HP ~ 1.1 KW and is around 3 yes old. The manufacturer's spec sheet mentions a full load current of 9.2 A. 1.1KW/230 gives me a ...
0 votes
5 answers
76k views

Unplugging vs running an empty refrigerator

We have a community Pea Patch that has 2 older refrigerators that are empty 5 days a week and used to store produce on 2 of those days. Does it take less energy to leave them running for those 5 days,...
1 vote
0 answers
38 views

How can heat pump water heaters be more efficient when they just use heat from heated space? [duplicate]

I understand the principle of heat pumps, and it makes sense that a heat pump / AC split system is more efficient then for example resistive heating for heating a house. In this case, the heat pump ...
11 votes
8 answers
83k views

Does lowering the blower speed of a forced-air furnace lower its efficiency?

My gas furnace has two options for the blower speed: MED, and MED-HI. It had been set on the higher speed, but that was too harsh, so I lowered it to the slower speed. Does that have any impact on the ...
2 votes
2 answers
76 views

Is there any considerable advantage to a forced air-to-air heat exchanger over just cleverly positioned positive pressure forced air intake?

This is from a typical North Western European housing perspective where most (older) buildings will not have forced air/AC/heat pumps etc. for various reasons, and most houses are only heated using ...
2 votes
2 answers
122 views

Replacing 2 hot water heaters with 1

I've recently purchased a home that has two hot water heaters - one at each end of the house. One in the garage, one in a closet. They're both showing their age, and both cost quite a bit to operate. ...
2 votes
1 answer
58 views

Determine highest "carbon reduced per dollar spent" option for reducing pollution generated by home?

I've been talking with friends and coworkers about how I can reduce the amount of pollution generated by my house (heating the air, heating the water, cooking the food, etc.) Everybody has a ...
1 vote
1 answer
61 views

Would down-stuffed curtains stop heat loss through windows?

My home has some very big 6 ft by 8 ft windows likely a big source of heat loss and is contributing to high heat bills. It would be too expensive to replace them with modern vinyl windows and the ...
8 votes
3 answers
50k views

Why are almost all of my house's HVAC floor registers placed near exterior windows?

My current house is a single story built over a crawlspace and all the HVAC registers are in the floor. In all of the larger rooms, at least one (and usually more) register was placed near an exterior ...
0 votes
1 answer
411 views

Run mini-split heat pump heads at different temperatures

I vaguely remember the contractor who did maintenance on our ductless heat pumps two summers ago telling us not to set the thermostats of the two small heads that share an outdoor unit to different ...
0 votes
3 answers
49 views

Letting a thermostat regulate temperature, or do it myself? [closed]

I always hear people say that it is more efficient to let a thermostat regulate the room temperature. Well, I do not have a thermostat, but I have an electric heater with on internal one. Not a exact ...
0 votes
2 answers
258 views

California Title 24 implications for bypassing ballasts in my 4-pin (GX24Q) fixtures

I've gotten fed up with the recessed 4-pin GX24Q fixtures in my kitchen that were required by California Title 24, after removing a burned out (and relatively expensive) CFL, cracking it in the ...
0 votes
3 answers
2k views

Why don't heat pumps run for a bit BEFORE starting the air circulation fan?

I'd like to think I understand how heat pumps work decently well. My home has one plus electric heat, which I try not to resort to because heat pump is more efficient, if slower. When a traditional ...
1 vote
2 answers
84 views

Removing excess HVAC ductwork for efficiency

I have central ac in my home and at some point the kitchen was redone, blocking an existing vent permanently. The flex HVAC ductwork leading to the vent (probably 8 feet of it) is still there. Should ...
0 votes
3 answers
190 views

Do plugged in chargers always use up energy? [closed]

I always make sure that all chargers with no device attached (mostly laptop and phone chargers) are unplugged so that they don't use up electricity. I guess it used to be a reasonable approach. I was ...
1 vote
0 answers
62 views

How best to capture and move the heat from oil furnace stove pipe more efficiently throughout room

In my basement the stove pipe that goes from the oil furnace to the chimney is always hot, so I feel like I should be capturing this extra heat and moving it about the basement. How do I keep this ...
5 votes
7 answers
11k views

Air sealing a whole house fan

I have a whole house fan installed in my house from the previous owners. I love the fan, as it lets me cool down the house quickly in the evening -- or after I fill the house with smoke from ...

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