Random Notes

Tesla Solar Roof Install Journal

Notes and rants about my experiences with Tesla energy products: solar panels, roof, and Powerwall batteries.

FrozenChoco

Dec 31, 2020 • 19 min read

Sharing my experience with you, because there was little information when I started out going down this path and I wished I knew more.

Ordering and Pricing

Once you decided that you want solar roof for your house, ordering it could not be simpler. Everything is done via the Internet, and you just need to plug in a few numbers before Tesla figures out the size of your system and recommend Powerwall capacity for you.

I found that the number of batteries you can order without talking to a person is dependent on your electricity bill. I had experience with Powerwall from before, and it was wonderful once working. It definitely makes a difference as it stores solar energy for peak hour use, and I recommend considering them. Related, it is worth noting that my electricity company, PG&E, switched my rate plan to time-of-use as soon as my solar system is turned on, so now electricity cost is different depending on the season and time of day, making the battery very useful.

Additionally, if you install Powerwall at the same time you install solar roof, the cost is eligible for tax credits and some other rebates, such as the Self Generation Incentive Program. Be warned, however, Tesla is terrible at getting SGIP application done. My first project took a year, my second project still has no SGIP application code after a year. Other companies seem to be able to start the application process fairly early, but not Tesla. SGIP is a lot of money and will make your project cheaper, and Tesla is quick to tell you about "potential incentives." When I asked about the delay and lack of application code, all the incentives became "best effort only" without showing any effort; I can't even apply for SGIP on my own. Tesla support is just there to remind you that Tesla has "no financial obligation to you regarding the actual rebate and incentive amounts received. You agreed to pay the contract price in full regardless of the actual amount of rebates and incentives received." That is just saying "we don't care after you signed the contract," but with more words. Sigh.

Alternatives and Cost

I don't want to maintain links to them, but alternatives exist. Solar shingles are available from other vendors: Dow/RGS, Luma, SunTegra. Energy storage options include: LG Chem, Sonnen. I don't have experience with them, and my brief investigation lead me to believe some of them are better when you install them at the same time your house is built. Many cost less than Tesla products.

It'll take you decades to recover your investment; you won't be making money selling excess electricity from your solar system back to the grid. Tesla's financing terms is (I think) terrible and not very transparent. At least when I looked into it, they are only showing you monthly payment amount; after calculating the total cost, it worked out to around 30% interest in my case.

In addition to time-of-use energy bill to make things more confusing, my electricity company also has this True-Up billing that tracks your overall annual usage. If your solar system isn't generating electricity as much as you utilize annually (for example, your usage increased as you bought an electric car mid-year and now charge at home), you'll get a bill at end of the year to "reconcile" that difference and it may come as a shock. PG&E still changes monthly for gas, I still pay for electricity delivery charge monthly, so this True-Up billing seems to me an excuse to drown you in monthly paper reports so that you won't look closely when the bill comes?

Ultimately, to harness solar power you can just as easily install solar panels, which has many benefits including being much cheaper for a comparable system, having more competitive options, faster to install, and can be easily replaced. I have no idea how long solar roof from Tesla will last, it looks more pleasing the few times I pay attention to my roof but I rarely look at it. You have to decide if you really want solar shingles or panels considering the aesthetics and cost; either will both work with Powerwall batteries, which I think is the more important part.

Usage Patterns

You'll be generating energy close to what your system is sized for probably only during summer. For vast majority of the year, you'll be looking at half to a third of production. Meaning if your system is supposed to be sized at 15 kW, during the spring you'll probably get 10 kW and probably 8 kW at end of the year reported on mobile app. All of this is variable depending on where you are and the weather, but the point here is, you are likely not going to see the number you are purchasing.

It should still generate enough energy to cover your house during the day and charge Powerwalls for you, because you shared your bill as part of the ordering process and it is used to determine size of your system. During the pandemic when my kids attend schools online and I work from home, we are using less than 2 kWh during the day.

Depending on how much power you reserve for emergency, during the evenings and at nights you'll be getting power from Powerwall batteries. Some numbers:

Each battery is supposed to have 13 kW of storage capacity and peak output at 7 kW. If you have more than one battery, they can work together, expanding your storage and peak output. Let's say you set your reserve at 20%, each battery will give you about 10 kW.
If your house uses 2 kWh constantly, 10 kW will power your house for 5 hours. However, you are probably cooking dinner in the evenings, or turning on AC when it is hot out, and that'll push utilization up to 4 kWh. Of course, when everyone is sleeping, your home will hopefully use less energy.
To charge a car using 240V at 32A, giving a little less than 30 miles per hour of charging, I am looking at 10 kWh. If I charge during the day when sun is up, solar energy will be used to charge and whatever remains of the 10 kWh will come from batteries.
Since each battery's peak output is below what car charging drains, if you want to charge without sourcing from the grid, you'll need more than one battery or solar to make up 3 kWh.
Remember that sun isn't fully up in the morning yet, it will take power to cook breakfast.
Turning on air conditioning is probably 2.5 kWh, and varies depending on size of your house.

I think what this means for most people is that:

If a car is charging overnight, and you drive 60 miles a day, you probably will not use power from the grid if you have 3 batteries.
If you drive 100 miles a day, you'll source maybe 30 minutes of power from the grid with 3 batteries.
If you are not charging a car overnight, one battery is probably sufficient.
Charging your car during the day is more economical, since you make hardly any profit from selling energy back to your utility company (PG&E sells you energy at $0.33+ per kWh, but will give you approximately $0.04 per kWh, its too complicated for me since the numbers change depend on the time of day, but if you want to do the math yourself, it is documented on-line).

How Long Does It Take?

By now I've done both solar panels and roof with Tesla. Despite the estimates on Tesla's website and what your advisors may be telling you, actual time between placing order till operational system is much longer; my installations both took half-a-year to complete. If you are including the time to get rebates, it is at least a year-long struggle. The long delays are fairly consistent even though my installations were years apart; probably this is a fundamental issue with how Tesla operates. My second installation would have taken longer, had I not learned from my previous experience and was contacting PG&E myself to figure out missing documents. Once I received permission to operate, Tesla equipment has been trouble-free; after frustrating delays, Tesla will eventually get you there. Ask your friends and neighbors if they used other vendors or technology, and decide for yourself whether Tesla's brand, technology, and mobile app is important to you. I think the industry still has room to grow and there isn't a vendor that is clearly superior to others.

Preparations

You'll be asked to sign several documents, as well as uploading a lot of pictures to prepare for installation. I think this generally give Tesla an idea of viability and the company will send a technician to perform site survey, who will go on the the roof, into the attics, and generally be taking similar pictures for documentation.

Powerwall cannot be installed within 3 feet of your gas meter, and you generally want them and the inverter to be on the same wall as your main panel. If that is not possible the electrician will put in work to route everything for you, so not being able to accommodate all that equipment on the same wall isn't really a problem. However, electrician may have to route around other things like garage door motors. If you don't mind batteries sitting on the floor they can be stacked, but that will not be possible if they are mounted on the wall with ground clearance. Powerwall units can be mounted indoors or outdoors, the on/off switch is exposed.

Tesla will take care of the permits and most of the paperwork. Inspector may want to count how many smoke detectors you have in your home, and generally check if the rest of the house is up to building code.

Sub Panel and Backup

There is a sub panel where all the breakers are, and you get to decide which breaker is backed by battery. Alternatively, the electrician may just decide to put the entire house on battery backup and they'll add a sub panel near your main panel instead of adding another one by the old sub panel. Definitely ask about the backup everything option. I feel it is less work: fewer breakers technicians have to reroute, therefore take less time for installation, and that translates to shorter duration without power.

When power is cut, it takes a second for battery backup to kick in and it is not seamless. You want to put your Internet router and modem on a separate uninterrupted power supply battery to buffer that one second. With important equipment on UPS, lights will flicker when your neighborhood loses power, but everything will continue working normally for you.

I learned this from the technician that each breaker has two wires that are best "balanced." If not it could make your Powerwall shuts down randomly and it took a day for technicians to do that. On that note, there are different versions of Powerwall and it isn't clear to me why Tesla would install the older version that:

wouldn't work with the mobile app,
turns off in the evenings on its own, and
generally is useless because it cannot be programmed.

It's not like you have a choice or there is a pricing difference (A). So you definitely want to check and make sure you got Powerwall 2 that can be monitored and controlled from Tesla mobile app.

Roof Tear Down

There is no other way around it. To make way for solar roof, your existing roof is coming down. Tesla subcontracts this work out to folks that normally performs roof installations.

If your current roof is covered in Terracotta roofing tiles, there may not be anything under them. Apparently it is okay when my house was built in the 70's to not even put moisture barriers under tiles. In this case, Tesla will charge you 10% more to install additional plywood boards and underlayment. You'll find out via an e-mail that asks you to accept a new agreement (B).

If there is swimming pool anywhere near your roof, there is going to be stuff floating on the surface after the tear down. Generally speaking areas in your backyard is going to be covered with saw dust and stuff that came off from the roof. You can ask ahead of time if anything was going into the pool and the answer would be, that they won't be dumping materials from your old roof in there. Still, it would have been nice if they can put a temporary cover over it. You will probably find nails in the pool, best fish them out so they won't stain.

If you have one of those solar pool heater panels that pumps cold water up to your roof, Tesla will ask you to remove them. I found out after weeks of trying to find someone who can remove and dispose those panels, that this isn't really necessary (C). You cannot keep and reuse them, but the tear down contractors will remove them for you provided there is no water in the pipes.

The gutters will come off when tear down happens, and despite Tesla informing me that new gutters must be installed, the roofing contractor asked me if I intend to keep the old ones. This is going to be a recurring theme working with Tesla, that one group doesn't really talk to another, and they don't communicate well with subcontractors either (D). The thing about gutters is that some of them apparently don't work well with solar roof, or rather roofers haven't figured out how to work with solar roof. It is another project that you need to schedule, and cost that you'll have to budget for.

Installation and Power Outage

Solar roof installation is supposed to take 4 days. For a while, with the number of people working on-site it does seem possible. However, after 2 days, the number of folks working on the project decreased dramatically.

Powerwall installation took 2 days but it almost seems like it could have been done in one day, if they had more time to commission the batteries.

I think Tesla is terrible at giving you estimates and keeping you updated with progress. The project leads on-site have no visibility into schedule for other groups, and strangely I've had different leads for the roof installation: the first two seems to be keeping pulse on the project, but the next one was just, "I don't know if it'll be done tomorrow." Not the kind of confidence-inspiring words you want to hear from a lead. Tell your customer what you do know or figure out the answer! Additionally, why wouldn't Tesla tell people at ground zero when the electricians are going to show up? I was elated when the last team stayed and finished the installation and overall it took 2 weeks.

At some point during installation electricians will shut off power to your home so they can work on the main panel. With shelter-in-place mandates this affects school for my kids and my work. If you only need Internet and have laptops, you can possibly back up the modem and router on a portable battery, then work with your laptop. Other devices will probably drain the portable battery too quickly for you to keep working. Power was out for roughly half day. It is worth noting that some devices at home don't like power being cut off suddenly: servers, video game consoles that enter low-power state, desktop computers in general. You want to turn them off ahead of time and keep them off, so that when power is restored they won't create a surge all powering up at the same time.

Contractor will need to charge their power tools, so many that will trip your circuit breaker. Best figure out which room you don't mind suddenly losing power for, that doesn't have equipment plugged in requiring power constantly. It isn't difficult to flip the breaker, but you simply will not be aware unless you are monitoring closely. External plugs probably share breakers of the adjacent room on other side of the wall.

Post-Installation Issues

Just because the tiles are installed doesn't mean you can use your solar system. Tesla lead that finished installation showed me that all streams are generating power, although there isn't anyway to see if installed system is really generating the amount of power you ordered. Plus it depends on time of day and weather, so the best you can see is that system is working.

Interestingly, for my previous solar installation Tesla had this table listing guaranteed annual energy generation targets that, if installed system failed to generate the minimum Tesla was supposed to cut a check for the difference. I didn't see anything similar this time around. Anyway, after months of drama I was just glad that the system works.

The site clean-up took a few more days, following the standard operating procedure of over-promising and under-delivering. Although the clean-up crew seems to have made an attempt to take everything with them, they still managed to leave some plastic, a bucket, and a few souvenirs. You want to sweep your driveway carefully for: metal shards, loose screws of various sizes (I found many from 1/2 to 3 inches), pins and wire segments of sorts (lower gauge almost like nails).

Finally, you can't turn on your system until after PG&E did its inspection and gives you permission to operate. This is weeks-long waiting for someone to come to "take a look". I also had the unfortunate experience of waiting with Tesla representative for PG&E inspector for an hour. Tesla representative then called PG&E to find out what happened to the scheduled inspection, was only then told that "management called all inspectors in for a meeting, and so no inspection will be happening on that day." This is how much PG&E doesn't care about its customers and the level of service it provides. Without any notice it just breaks its commitments, and couldn't be bothered to cancel or reschedule appointments.

What about the battery while waiting for inspector to show up, you asked? That is a good question. I was told not to keep the battery charge above 10%.

Before Tesla people pack up and leave, you want to make sure they are done commissioning your system, which allows you to see your battery charge level and hopefully demonstrate that solar system is able to change the batteries and support your home using the Tesla mobile app. After comparing a few days of readings, mobile app tells me daily discharge is 3%. Once your system is commissioned and you can see the charge level, you can configure system to be in "stand by" with "storm watch" disabled. In this configuration Powerwall will not send energy to your home, but it won't draw power from the grid to recharge either. Then you just check periodically to see if you must recharge the battery manually, either by turning on the inverters for a short time (ask your electrician how and where to do that), or configure the batteries to pull power from grid. It would have been more ideal if the system could be in a maintenance mode before inspection, not send power to the grid, and manage the health of Powerwall for you. But it doesn't so you need to work out a plan while you wait for permission of operate. Update: looks like there is now a new "Self-Consumption Only" mode that will prevent energy from going to the grid until you have permission to operate. I am not able to verify this and don't know about its limitations and requirements, but it'll be great not to have to keep your system dormant while you wait for paperwork and inspection to complete.

Why does it take so long to get an inspection? Another good question that I have no answer to. You'd think Tesla will tell you that scheduling is done, and it is up to city and PG&E people to decide they can't drag their feet anymore. You'd also think it is in Tesla's interest to schedule this inspection quickly, since Tesla gets paid after inspection. But you'd be wrong (E). In my experience, it was 4 weeks of waiting; no one replied to my queries, and just one day I was told that inspection is happening the next day! More importantly, do not turn on your system and send energy to the grid, because you will get charged for the energy you back-fed, as if you used all that electricity. Permission to operate comes after PG&E inspection and the paperwork for interconnect is done; another 4 weeks.

With everything working there is just this issue about the small black square device you are supposed to plug in. Normally, it facilitates monitoring and reporting of your overall system. However, the new gateway next to your batteries can connect to Internet directly on its own, so the black gateway device is not necessary at all; you'll be able to see and control your system in mobile app just fine. What happens if you don't plug it in? Tesla will send you e-mail and text messages every two weeks saying your system stopped communicating to your monitoring device. Isn't Tesla getting real-time data from another source that Tesla installed and provisioned? Why not pool the data together? Why must Tesla expose and remind customers of this embarrassing issue that it can address server-side every two weeks? Are the internal organizations communicating via confused homing pigeons? That must be one the reasons why Tesla is having trouble getting the cost down, to keep the pigeons fed and insured.

Frustrating Experience Overall

The immediate positive experience with the ordering simplicity is replaced with a lot of frustration as I worked with Tesla. It all went downhill after placing my order. Of course it wasn't all Tesla's fault; they could blame sub-contractors or PG&E, but they shouldn't. Tesla is the one getting paid, and should have been managing expectations from the beginning and keeping up with communications. A large part of my frustration comes from Tesla representatives telling me one thing but something else ends up happening.

Too often I had Tesla visitors show up unannounced because they are scheduled to do some work, to meet some other people involved in the installation, or to receive/drop off equipment. Too many times I was asked if I was given some equipment, that I had never heard of or received whatever it was. Then the poor Tesla visitors would be stuck in the situation explaining to me why work is delayed because someone or something is missing.

The technicians that came to perform the installs were great. They answer questions and know that they are doing, some of them will even try to get corporate office and representatives from out-of-state to do work for you. Get all your questions answered while they are around.

The customer service people that you talk to on the phone, however, are not the most responsive nor most knowledgeable. One of them openly questioned my ability to read, much to my surprise. Calls ended up in voice mail often, and rarely do I get a callback. E-mails are often ignored, or you may get a reply after 6 weeks. I don't think these people really work for you, and I wish some of them would at least read the questions before pasting some generic response. At one point, to get Tesla to replace the broken Powerwall unit, I was calling Nevada every few days; every time is a different person, who'd spend time reading what must be a tome of notes, then tell me they'll call me back but never did. Not every representative is like this, of course, and some of them really put in the effort to provide customer service; but they are few and far in between, many of them wasted a lot of my time that I'll never get back.

Some More Frustrating Experience

(A) My initial Powerwall unit didn't work at night. During the day there is solar, so who in their right mind would want to pay for battery backup that only works during the day? Took nearly a year of troubleshooting and calling to fix this when Tesla had finally replaced Powerwall, inverter, and something else. This is something I had already paid in full, but for a year I didn't get what I paid for.

(B) When Tesla sends you an updated agreement after the site survey, read the new agreement carefully. For me, not only was there additional costs associated with roof preparation (10% increase and not part of previous agreement), the cost for the roof installation (few dollars) and Powerwall (few thousand dollars), as well as the overall system size changed (slightly smaller). It is really bad form to change these numbers after both parties already signed agreement months ago, because it alienates your customer and erodes trust. I think it is shady.

(C) When Tesla sent a message saying that I must remove the solar pool heating panels from the roof, it was just weeks before tear down was going start. I frantically contacted about a dozen vendors online and finally one of them questioned why I wanted this done. I was told that most roofers will just remove them for you if you are not putting them back (you cannot reuse them anyway, since they'll be blocking the solar shingles). I then tried to confirm with Tesla via both text and e-mail whether I can just cut and drain the pipes without completely removing the panels. At this point the representative still says I must remove solar pool heating panels, and pasted exactly the same instruction from before. Turned out all I needed to do is cut the pipes near the eaves, put caps near the T junction of the pool pump that sends water up the roof, all for 10% of the cost of getting someone to take down and dispose the panels. But it is too easy to say just that; instead you wade through paragraphs of poorly written requirements and ambiguous wording telling you something else.

(D) It seems like Tesla is organized into silos that really cannot communicate with each other and don't talk to the subcontractors. That in order to get some answers it is impossible to just talk to one person. Not sure if it was because my broken Powerwall issue got escalated, or if solar roof is still a product that representatives are not trained to deal with, or maybe there are just normally that many individuals assigned to reach out to other people in the organizations for... something. But it sure is annoying to have to listen to the music and recordings while you are holding on the phone, or always explaining things one more time. I think a lot of this can be done through e-mail, but Tesla would rather record your conversation with their representatives, than to answer your e-mails and commit to making things right. If you got to speak to the representatives enough times you'll realized most of them don't know what they are talking about; you really want to talk to the people that actually do the work but you cannot do that directly.

(E) I was getting impatient and annoyed that, weeks after installation completed I still cannot use solar. As it turned out, there was a number I could call for someone at my utility company to check if paperwork has been filed. Even though my installation had passed city inspection, and Tesla already took money for the whole project, they didn't file interconnect request. Permission to operate was never going to show up until Tesla files interconnect request online. If you use PG&E, that number is listed under Solar Customer Service Center on this Contact Us page. Even after receiving notice that the forms are submitted, it is important to check with PG&E if any document is missing. You signed an authorization for Tesla to be your representative, and Tesla has all the agreements and documents, there is nothing you can do when something is missing. I think Tesla should only get paid when customer receives permission to operate, because this is not right: I paid Tesla for solar and battery, but there is unfinished paper work even after passing inspection, I had to follow up to make sure paperwork is done, and it'll take months for me to get to use what I paid for.

Why put e-mail address on Tesla's website when it is clearly not the way Tesla wants to be contacted? Why assume that when a customer sends you e-mails, they don't expect any replies? Why is there a limit to the voice mail box, so when you cannot leave messages, you must spend time waiting in queue to talk to a representative who often doesn't have the answer? With higher cost than other solar shingles or batteries, Tesla should put in more effort, do much better at servicing their customers, and not left their customers with more questions than answers. I want to support and see Tesla be successful because I think its mission is admirable. Every time I support Tesla, however, I am left questioning my decisions. I know (hoped) eventually it'll probably work out, but getting there is definitely a long character-building experience, one that I didn't enjoy going through.

If you made it this far, I thank you for reading. I don't want to dissuade you if you are considering Tesla products; hopefully the experience I shared gave you things to expect and plan, for solar products from any company you are considering working with. I wish you good luck achieving more energy independence, and hope your experience is much better with far fewer issues.