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Published on September 1st, 2020 | by Paul Fosse

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My Plan To Save $170,000 In Energy Costs Over 35 Years Using Efficiency & Tesla Solar

September 1st, 2020 by  


In this article, I’ll show my 35 year plan (which I started in 2010) to save a lot on energy costs and reduce my carbon footprint. I want to be clear that I didn’t come up with this plan all at once. I’ve been adding in new steps every couple years. I had no idea (until today) that the savings would amount to so much money! Most of the savings are from efficiency and only about $14,000 of the $169,000 is from the solar installation I plan to install.

I plan to save electricity from energy efficiency, downsizing my living space, and installing Tesla solar to generate electricity

Energy Efficiency

The first area that I worked on was eliminating the use of propane for heating. My builder had installed propane appliances in 2003 and I never thought much about it until 2010. We had a historically cold winter in Florida, and when I got my January propane bill, it was $591, which was in addition to my $235 electric bill, for a total of $826. I was not going to take this.

After determining that I was stuck with the propane company my community had a contract with, I went to Walmart to buy a few space heaters and told my family they could each have one to keep warm be we wouldn’t be using any more propane for heating. Space heaters (and mini split and multi-zone air conditioners) let you only heat or cool the room you are in. I wasn’t going to spend $5,000 replacing my air conditioner/heater until it quit working, but I wasn’t going to use the gas heater anymore. The gas heater was also troublesome and needed maintenance and repairs every year (those savings aren’t even in the $169,000).  

The next major energy hog I had was a 50 inch Zenith plasma TV that was on 18 hours a day using 500 watts of electricity and dissipating it in heat. This increased my air conditioning costs noticeably. I should have replaced it earlier, but I finally did when that TV failed and I didn’t attempt to fix it. Instead, I replaced it with a much more efficient television, reducing my bill about $30 a month.

The third thing that I did to improve the energy efficiency of my house was replace my air conditioners with high-efficiency all-electric units, cutting my costs about $40 a month and letting my family use whole house heat for the 3 weeks a year you now need it in Florida, but by then they were used to the space heaters.

The next way I improved the energy efficiency of my house was by replacing all the lights with florescent lights. LED lights are now cheap enough to use, but they were very expensive 5 years ago. This only cut my bill by $10 or so. 

When my pool pump failed, I replaced it with a smaller, more efficient unit and set it to run only a few hours a day, saving about $20 a month. 

I didn’t find a smart thermostat would save much for our family (I have one now that came with my new home). Since we are home most of the time, we can’t comfortably set the temperature any higher to save energy. You can also use it to pre-cool your home to take advantage Time of Use (TOU) utility rates if your utility has them. My utility’s TOU rates are only a bit lower and they don’t allow them to be used with solar net metering. As the Duck Curve comes to Florida, I expect the utility will allow or even mandate TOU pricing. We do set it a little higher in the afternoon. We also bought an electric car (2012 Nissan Leaf, then 2018 Tesla Model 3) and a plug-in hybrid Ford C-Max Energi that together use about $30 a month in electricity.

I did not add insulation to my house, because I already had very good modern insulation. But many people will find they can get substantial energy savings from insulation, weatherstripping, or other modifications to their home to improve efficiency.

CleanTechnica has written extensively on home energy efficiency. Check on some of the articles here to get other ideas!

All of these efficiency changes reduced my energy costs from about $400 a month to about $300 a month. A good start, but I have a long ways to go!

In a year or two, I will replace my inefficient water heater with a hybrid heat pump model that is 4 times as efficient. The payback on these water heaters is only about 3 years! I could also use a heat exchanger to use the waste heat from my air conditioner, but I had one of those in my last 2 homes and I found them somewhat troublesome. I expect Tesla to announce a version of its Octovalve that will help make an air conditioner/heater/hot water heater/refrigerator/freezer optimize all the hot and cold areas of your home, but that may not come out for a while. 

Downsizing

I wrote the article linked here on why we need less space in the modern era — because so many of our belongings have moved into the virtual world. In this second article on the topic, I wrote that I moved from a 3800 square foot home to a 2300 square foot townhome. Not only is the number of square feet about 60% of what it was, the new home has 9 foot ceilings instead of 12 foot ceilings, further reducing the cubic feet that need to be heated or cooled. In addition, a townhome will have one or more common walls with neighbors, which even will further reduce energy costs.

Moving to the new townhome reduced my energy costs from about $300 a month to about $85 a month, but that is still more than the $15 a month I’m looking for.

Solar

Tesla rooftop solar

It’s important to take the preceding steps — increasing energy efficient and right sizing your home size for the space you need — before you install solar. The reason it’s important is that after doing that you may find that you only need a system half the size. If you buy a big solar system and then you do the energy efficiency upgrades, you may be producing way more power than you can use in a year. Most utilities don’t pay you much money for overproduction on a yearly basis. While net metering, where available, typically pays you retail electricity rates for overproduction of electricity, that is used within a given time period, often a year.

Make sure you add a little electrical capacity to account for electric vehicles that you plan to purchase but don’t own now. In most places, you can’t reduce your bill to zero, because of the connection fee charged by your utility. In most communities, you are not allowed to go off grid. As long as net metering is allowed by your utility, you don’t really want to go off grid anyway, since net metering allows you to use the utility as a giant battery for free.

One significant advantage of getting solar in a place that has occasional long power outages, like Florida from hurricanes or California because of wildfires, is that it provides you a way to produce electricity when the grid is down for a few days or a few weeks without the high monetary and environmental costs of a natural gas or diesel generator (as long as the system is set up in a way that allows that). Those natural gas or diesel generators add maintenance costs and no other benefits when a hurricane or wildfire doesn’t hit your area. The solar more than pays for itself. Most solar systems, including Tesla’s, require you to have a battery system in order to run the solar when the grid is down. A safety switch so that your solar system doesn’t back-feed the grid when it is down is also required, since feeding the grid when line workers are repairing the lines could injure or kill them. 

Tesla solar offers a consistent price per kilowatt of capacity nationwide. Even though the price for the capacity is consistent nationwide, two things that aren’t consistent are:

1. Your solar potential, which is based not just on how sunny or cloudy your location is, but also: if there are trees or other obstructions that shade it during parts of the day; the orientation of your roof; and your latitude, which determines how much air sun has to fight through to get to your solar panel. Tesla solar simplifies all of that by giving you an estimated kilowatt-hour per day production for the company’s four standard system sizes — small, medium, large, and extra large.

Go to Google Project Sunroof to learn more about your roof’s potential. You will notice Tesla’s pricing on small systems is about 40% less than Google’s estimates and about 34% less on extra large systems. If you have shading on the part of your roof you are using for solar part of the day, you may want to have Tesla (or another installer) install power optimizers or micro inverters. Both will keep shade on some panels from hurting the production of other panels.

2. The second major variable is your cost per kilowatt-hour of electricity where you live. Some places, like Hawaii, have rates above 30 cents per kilowatt-hour and good solar potential, so will have the fastest payback. Many other states that have electricity costs around 20 cents a kilowatt hour will also have very fast payback. Electricity rates are below 10 cents a kilowatt-hour in my city, so I need to have good solar potential to keep the payback time reasonable.

Since I live in a new townhouse, I’m waiting for a year to see if I have any roof issues (which are covered under warranty for one year) before I have anyone mount panels to my roof, which would void my roof warranty. I will have my energy use so low (even with an electric car) that Tesla’s smallest system (4 kWh capacity), costing only $6,068 after incentives, should zero out my energy use. At my other house, I was looking at a $40,000 system to produce the power I used. This new option has the added benefit that the cost is reasonable enough that I won’t need to take out a loan and add interest costs! Look at the table below. The year I get solar, my energy cost is only a couple thousand dollars more than my annual cost was a few years ago, and only about a thousand more than what my costs would be if I do nothing.

Conclusion

Everyone’s journey will be different, but I wrote this to give you an idea of how much a month you could save by combining energy efficiency, downsizing, and solar over a long period of time.

In the table above, I used my actual cost of propane and electricity for the years up to 2019, and projections after that. I went out 25 years, because that is the life of the solar panels. I got the cost of solar from Tesla’s website and the price of a hybrid water heater installed by finding a local ad. I compared my actual (before 2019) and expected (from 2020 to 2045) monthly costs of electricity and propane and one-time costs for solar and a hybrid water heater to doing nothing to reduce my costs. I assumed electricity costs will rise 2% a year, which is conservative for such forecasts, but my assumption could be high or low.

When I install Tesla solar panels and a hybrid water heater next year, I will have cut my monthly costs from over $400 at my peak to the minimum $15 connection fee my utility charges to be connected to the grid, or 96%, and I will have reduced my ongoing heating and cooling carbon footprint to almost nothing! Please tell me in the comments if this inspires you to look for ways to improve your own energy use!

If you decide to order Tesla solar panels or a Tesla Solar Roof, use a friend’s referral code for $100 off either solar panels or a solar roof! If you don’t have any friends with a Tesla, use mine: https://ts.la/paul92237 
 


 


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About the Author

A Software engineer for over 30 years, first developing EDI software, then developing data warehouse systems. Along the way, I've also had the chance to help start a software consulting firm and do portfolio management. In 2010, I took an interest in electric cars because gas was getting expensive. In 2015, I started reading CleanTechnica and took an interest in solar, mainly because it was a threat to my oil and gas investments. Follow me on Twitter @atj721 Tesla investor. Tesla referral code: https://ts.la/paul92237



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