Share Your Home Electrification/Efficiency Improvements

My Nissan Leaf Forum

Help Support My Nissan Leaf Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Agree. This seems to (currently) mostly be a problem on a few days with some cool sunny spring weather, but can get worse as renewables become ever greater portions of the energy portfolio.

To improve the current situation, would hope to ultimately have home battery buffering/real peak shaving in a few years with up to the second real time spot market TOU grid communication to buy/sell electricity with the grid based on instantaneous grid demand.
 
We replaced all 35 windows and sliding glass doors with Hurricane rated high energy efficient doors and windows 35 windows and 25 feet of 8 foot tall sliding glass doors

3,100 sq ft living space single story house in Florida. Replaced the AC with a ultra high efficient Daikin Inverter with 3 zone system. 21 seer. The AC varies between 1.5 tons and 5 tons depending on heat load. It runs almost 20 hours a day. Blower CFM modulates between 500-1900 cfm and compressor also modulates. Temp in house stays within 0.4 degrees of set point anywhere in the house.

Replaced pool heater with high efficient 5 ton heat pump

Been driving a Nissan Leaf for over 4 years and a Hybrid for over 15 years.
 
iPlug said:
Agree. This seems to (currently) mostly be a problem on a few days with some cool sunny spring weather, but can get worse as renewables become ever greater portions of the energy portfolio.
Utilities, either because they own the generating assets or have contracts that mandate purchase, have a "baseload" of generation they will run and curtail other assets if not required. As a very general observation, PV and wind are being used to avoid spot purchases of peaker plant NG output. Outside of peak hours the grid is overwhelmingly supplying its "baseload" mix.

As I said earlier in an addendum, unless you know the specifics of your grid and its suppliers, self-consumption should be the default choice.
 
Flyct said:
...Replaced pool heater with high efficient 5 ton heat pump...
Excellent. Would be good to see more people do the same who heat their pools currently with electric resistance or NG.



SageBrush said:
Utilities, either because they own the generating assets or have contracts that mandate purchase, have a "baseload" of generation they will run and curtail other assets if not required. As a very general observation, PV and wind are being used to avoid spot purchases of peaker plant NG output. Outside of peak hours the grid is overwhelmingly supplying its "baseload" mix.

As I said earlier in an addendum, unless you know the specifics of your grid and its suppliers, self-consumption should be the default choice.
Concur. We do know our specifics.

Here is our PG&E portfolio as of most recently available 2017 data:

https://www.pge.com/pge_global/comm...bill/bill-inserts/2018/10-18_PowerContent.pdf

Only 2% market purchases and only 2% unspecified power.

On the hot summer afternoons like we have around these months with AC use blazing, can feel pretty confident all of our excess solar PV is offsetting peaker NG PG&E plants and would have a high spot market value during this time. Only 8 of our 43 PV panels are not on south or west facing roof slopes.

On the other side of the equation, the off peak energy we consume would be nearly carbon free Diablo Canyon nuclear, large hydroelectric, small hydroelectric, wind, geothermal, and biomass/waste. No coal base-load.

Agree the accounting probably does not work out so well for many others, particularly in states that use coal for baseload generation.
 
^^ That is a grid to be proud of in terms of carbon emissions. I'm jealous.

As for when to use the water heat pump, I think you are right for the summer.
The winter may be different
 
Our home is 30+ years old. , A/C units are 15+ years old and not so efficient. Windows are single pane. Size is ~3500 sq ft. We use (yearly average) 1000 kWh/month that is mainly for A/C cooling and charging my Leaf - obviously some appliances. The monthly usage is quite cyclical and varies by a factor of 2x in summer. All other major energy users are nat gas - common for a house this age, especially in Houston.

Our electricity supplier is Griddy that charges us $10/month to "sell" us energy at the ERCOT pricing - and passes along the transmission+add-ons at cost. I almost exclusively charge the Leaf early morning and use my programmable thermostat to "precool" the house later at night and early morning. I let the temperature rise from 73 degrees to 79 degrees in increments during the day and cool back down as we retire for the night.

Over a one year period, I've saved about $300 in electrical costs by using cheap energy at night (total bill approx $1200 for the year). If everyone in Houston were to do this, I'd guess that the energy cost differences during peak to off peak would likely disappear - would be self defeating, but a boon to the area grid!! BTW, the energy costs are usually 3.5 to 7 cents/kWh during peaks and 1.5 to 2 cents/kWh late at night during the summer as the grid becomes maxed out (7.5 cents currently). In fact, it is quite often 30 to 90 cents/kWh for short periods. I've seen it as high a $9/kWh (the max). I use both the Griddy app (very nice) and IFTTT alerts to call my wife if something out of the ordinary is going on. So far, not had to go above 79 degrees :mrgreen:

Caveat - kids are grown and gone! We don't have to air condition the outdoors anymore.
 
Two people, 2800 SF home in high desert of NM. It gets hot (but rarely over 100F) in the summer and humidity is low. Winter drops into the teens F
July we consumed 350 kWh for the house and two EVs.

I'm thinking about improving the house envelope so that we can add some moderate cooling in the summer and also use less NG in the winter heating season.
 
SageBrush said:
^^ That is a grid to be proud of in terms of carbon emissions. I'm jealous.

As for when to use the water heat pump, I think you are right for the summer.
The winter may be different

We will probably run the heat pump water heater during the daylight portion of the 21 hour off-peak winter window before the partial peak 5-8pm hours (no peak hours in winter). Things work out quite nicely as there is little if any solar flux from 5-8pm with early winter sunset time.

Further, ambient temperatures conveniently are highest during sunlit hours, which guarantees heat pump use during highest solar flux ensuring both highest energy transfer efficiency and maximal renewable energy use.

Would love to see reports of PG&E grid energy mix by source and time and day of year to see detailed curtailment patterns to know how best to further play this game for environmental impact. Good to hear similarly minded folks at least as interested in such things.

A bigger issue for us in winter is heat pump ducted air usage to warm the house, especially during the colder nights. No sunlight then and a cost reasonable residential battery solution yet awaits. Would like to see exactly what our PG&E grid is up to with energy input sources and renewable curtailments, if any, during that time. Best I can surmise, non-carbon sources would still be very high at this time.

Grid solar inputs would be relatively low that time of year, so don’t imagine much in the way of needing curtailments there. Not sure if they ramp down NG inputs for electricity generation then since houses aren’t running AC, rather burning NG directly to stay warm instead of a few heat pump folks like our household who actually don’t decrease their winter electricity use.
 
iPlug said:
Would love to see reports of PG&E grid energy mix by source and time and day of year to see detailed curtailment patterns to know how best to further play this game for environmental impact.
-
Exactly



We will probably run the heat pump water heater during the daylight portion of the 21 hour off-peak winter window before the partial peak 5-8pm hours (no peak hours in winter). Things work out quite nicely as there is little if any Solar flux from 5-8pm with early winter sunset time.
-
I had the same thought
 
I don't use natural gas.
That's why I got the forced air coal furnace to do the lion's share of home heating in the winter.
 
Oilpan4 said:
I don't use natural gas.
That's why I got the forced air coal furnace to do the lion's share of home heating in the winter.
Looks like some are going in different directions on the “electrification/efficiency improvements” ;)
 
Out of curiosity, have you calculated how many therms or kWh or other units of energy in coal you use annually with your forced air coal furnace?
 
iPlug said:
Out of curiosity, have you calculated how many therms or kWh or other units of energy in coal you use annually with your forced air coal furnace?
I'll chime in since Oil-y will not have a clue


You are asking about AFUE -- the ratio of usable heat divided by heat content. In older furnaces the AFUE was ~ 55%; modern, expensive models ($4,000 - $6,000) have AFUE in the 80 -85% range.

A good heat pump costs $1,500 - $2,000 and when run wisely has a yearly COP of ~ 4. Coupled with DIY PV at two cents a kWh, one can heat or cool for a cost of ~ 0.5 cents a kWh, often without extensive ducting losses.

Coal is more complicated because the dry heat content can vary from 3.5 - 7.0 kWh a Kg, compounded by the furnace AFUE.
It can be as low as 3.5*0.6 = 2.1 kWh a Kg,
Or as much as 7*0.85 = 6 kWh a Kg

To match a heat pump fuel costs (before considering duct losses of the furnace), the low heat coal with a low efficiency furnace has to be no more expensive than 1 cent a Kg
To match a heat pump fuel costs, high heat coal with an efficient furnace and no ducting losses, the coal has to be no more expensive than 3 cents a Kg

I have no idea how much retail coal costs in NM but power plants pay 2 - 5 cents a Kg. Perhaps 2 - 3x retail ?
 
I've completed the following over an eight-year time period:
Added blown-in insulation to the walls and attic of an old house.
Removed baseboard heaters, and added ductless mini-split heat pump
Added solar panels
Removed 30 year-old electric water heater and installed Navien high efficiency tankless water heater
Replaced old windows
Replaced refrigerator with a more efficient model

It's important to note that none of the above changes made a big dent in our electric bill.
The #1 thing that reduced our electric bill by over 60% in the winter was to add a direct vent natural gas heater. It's a small house, so we can heat with just the one heater, usually. Instead of $250-300 a month in the winter, we are now looking at $110 (including charging the leaf). My gas bill is only $40-$50 a month with the new heater.

My Solar City solar panels from 7 years ago are a joke. We barely generate any energy from those, even in the middle of the summer with a lot of direct sunlight.

I'm going to replace the back door and re-frame next. There are a lot of gaps where cold air can get in, and my band-aid fixes haven't worked very well so far.
 
SageBrush said:
I'll chime in...
Very informative. Thanks.

I don’t agree with many of his viewpoints/philosophies, sometimes math as well, but see his input as overall valuable, sharing information and know how and even if disagreeing, cross checking ourselves and others hopefully learning something the process.
 
Tortoisehead77 said:
I'm going to replace the back door and re-frame next. There are a lot of gaps where cold air can get in, and my band-aid fixes haven't worked very well so far.
-
I contend that fixing air leaks is job #1 for any home. The thing is though, if you do a good job then job #2 is a heat exchanger to have good air quality.
 
Maybe get HERS testing for air leaks.

That was included when I upgraded our ducted central air heating system to a heat pump last year. We’re pretty air tight, but an informative excercise.

Not sure how much that costs a la carte but it was cool to identify leaking areas with real pressure/volume data.
 
iPlug said:
Maybe get HERS testing for air leaks.
I'm actually waiting for a couple of home energy auditors to give me price quotes so I'll report back.
It seems like the standard service is ID of air leaks by air pressure testing and IR photos. I'm looking for an engineer who can model my home for an energy refit that balances home envelope improvement with installation of mini-splits and a HX.

We'll see how it goes. I personally plan to avoid HERS or any other certification. They are complicated and cumbersome, and mostly serve the rebate/subsidy industry. I'm not saying that they are inaccurate, but that they are rather expensive because they are bureaucratic.
 
FLIR makes a nice IR camera that attaches to a smart phone. It yields very high quality data IMO and costs about $300. Just an FYI for those who are considering IR analysis of insulation performance. I think our local 'tool library' actually rents them although I have my own personal unit since it is such a cool (and useful) appliance.
 
Back
Top