Many Americans have been looking at the advantages of installing solar panels on their houses to lower electric bills and protect the environment. While these are important considerations, most solar roofs are unsightly, leading to slow adoption. To help solve this problem, electric car giant Tesla introduced the solar roof in 2016, with solar tiles nearly indistinguishable from standard roofing products.
But how much energy can a Tesla roof output? A 10kW Tesla solar roof can output between 11,000 kilowatt-hours (kWh) to 15,000 kWh of energy per year. Compared to the average U.S. home’s 10,972 kWh consumption of electricity use per year, the Tesla roof should be able to cover all of a home’s annual electricity needs.
Although the Tesla roof will likely meet your electric needs without you ever needing to draw on the city power grid, it is not always a guarantee. If you live in an area that does not receive much sunlight or are in a household that consumes more than the national average of electricity, then the Tesla roof output may need to be supplemented.
How the Tesla Roof Creates Energy
The concept of solar energy is foreign to many people. All they see are giant billboard-like panels on the top of people’s houses and think, “Surely it can’t be worth it.”
To alleviate these aesthetic concerns, Tesla created the solar roof. The Tesla solar roof consists of a series of photovoltaic roofing tiles, nearly indistinguishable from traditional roofing products, such as asphalt shingles or clay tiles, that capture the sun’s energy and convert it into electricity to power the house.
Solar energy solutions, whether traditional solar panels or Tesla’s innovative solar tiles, will be composed of photovoltaic (PV) cells. These PV cells capture sunlight and convert it into electricity. The electricity is used to either power the home directly or is stored in a Powerwall (basically a gigantic lithium-ion battery) to be used at a later time. Those homes with Tesla roofs are essentially “plugged in” whenever the sun is shining.
How Efficient is the Tesla Roof in Energy Output?
As most typical PV cells are between 1 to 10 cm in diameter and produce 1 or 2 watts of electricity, it can be seen that a lot of cells will be required to meet the energy needs of an entire house that consumes more than 10,000 kWh of electricity each year. A kWh is equal to the amount of energy required to keep a 1,000-watt appliance running for one hour (Source: OVO Energy).
How Much Energy is Needed for a Home?
To calculate the energy needs of a home, consider what it takes to power a light bulb. The most common lightbulb wattage is 60W, which means running this lightbulb for 16.66 hours would equal one kWh. Higher wattage appliances, such as microwaves and washing machines, will reach a kWh in a fraction of this time.
Therefore, to meet these energy demands, a combination of PV cells must work together in what is known as an array to help synergize the capture of sunlight. Tesla creates these arrays on each of its energy-producing solar tiles.
Solar Panel Output Efficiency
Traditional solar panels come in arrays of 60 PV cells capable of producing roughly 500 kWh of electricity per year. This would mean that 20 such solar panels are required to meet the energy needs of a home that consumes 10,000 kWh of power annually.
This usually means covering a sizable chunk of your roof with these cumbersome panels, which are about 5 feet by 3 feet in area. But how can the smaller, sleeker Tesla roofing tiles compare?
Tesla Roof Output Efficiency
For a typical Tesla solar tile of 44 inches by 16 inches in area, this helpful article found that the efficiency of a Tesla solar tile was 4.9%. Compared to the 4% efficiency of the first solar panels created in the 1950s, it can be seen that Tesla’s early iterations of the solar roof are more efficient than the earliest iterations of the solar panel. Nonetheless, the 4.9% efficiency is not equivalent to the 15-20% efficiency that modern solar panels get.
However, the 4.9% efficiency of Tesla solar tiles does not tell the whole story, as it looks at the entire area of the tile and not the actual energy-producing area.
Consider that each tile will come skirted in a plastic casing so that the tile can be attached to the roof. Suppose you knock 10% off the width and 33% off the height to account for these attachment protrusions. In that case, the solar module’s actual efficiency increases to 8.1%—an improvement, but still behind modern solar panels.
Finally, when you consider that these protrusions will be concealed once the installation is complete, with each tile abutting snugly up to its neighbor, then the tile’s surface area can be reduced even further, as the final exposed surface of the tile will consist mainly of the energy-producing PV module. Once an additional 20% off the height and 10% off the width is calculated for this consideration, the efficiency of the Tesla solar tile jumps to 10%.
Are Solar Panels or the Tesla Roof More Efficient?
Even at a 10% rating for energy production, Tesla roof tiles do not output energy as effectively as modern solar panels. If true energy production is the primary goal, then the homeowner will be better off with traditional solar panels.
However, if aesthetics is highly valued, then the Tesla roof is the better option, as even at the lower efficiency rating, it has still been shown to meet the energy needs of average homes.
Homeowners may also want to wait for a later iteration of the Tesla roof, as efficiency is sure to improve once Tesla gets better at incorporating PV cells into its trendy designs, as it has reported struggling with incorporating the technology into the clay tile look to date.
Balancing Output Efficiency and Cost with the Tesla Roof
When a solar panel or Tesla tile is exposed to sunlight, it will do one of two things:
- Reflect the sunlight
- Capture the sunlight and convert it into energy
The higher the efficiency, the higher the rate at which sunlight is captured; this is directly related to cost, as it will require more of an inefficient product to meet a home’s energy needs.
This is where the comparison between traditional solar panels and a Tesla roof gets interesting. While solar panels are more efficient than Tesla tiles—which means fewer units will need to be purchased to meet the home’s energy needs—even a few solar panels sitting on the top of a house will be unsightly.
On the other hand, Tesla tiles are indistinguishable from the rest of the roof, meaning that even if significantly more tiles need to be used, it will not detract from the home’s aesthetics. The problem is that this can get costly.
Cost of the Tesla Roof
Tesla has stated that the cost to install its solar roof is $21.85 per square foot; this means that for a home needing 2,000 square feet of roofing, a Tesla roof’s total cost will be about $44,000.
While this is much more expensive than replacing a roof with traditional roofing products (which will usually cost between $10,000 to $20,000), Tesla maintains that for a home with an average electric bill of $200 per month, the cost of the Tesla roof will recoup itself in under 20 years—well short of the 30-year guaranteed lifespan of the product.
However, the cost of the Tesla roof is tenuous, with some homeowners reporting that they paid nearly $35 per square foot for the roof, making the final cost of their Tesla roof close to $100,000.
Costs of Solar vs. Non-Solar Tesla Roof Tiles
A Tesla roof is not composed entirely of solar tiles. It will be a combination of solar tiles mixed with non-solar tiles. There is no difference in appearance between those tiles that produce energy and those tiles that do not.
A typical Tesla roof will consist of 30-40% solar tiles, with the remainder being identical non-solar tiles. The solar tiles cost is approximately $54 per square foot, with the cost of the non-solar tiles being $14 per square foot. Therefore, the total cost of the Tesla roof averages out somewhere in between.
As Tesla’s solar tiles are about half as efficient as traditional solar panels, it will require roughly two solar tiles for every solar panel to meet extra energy demands. If you are in a large house or a house with increased energy needs, it can get very expensive to play catch-up when installing a Tesla roof. Even though there will be no difference in aesthetics, paying for more of the $54 per square foot tiles can cause the final bill to skyrocket.
How to Make the Tesla Roof Output Meet Your Needs
While it has been established that a Tesla roof will not be as efficient at converting sunlight to electricity as traditional solar panels, it is also reasonable to think that a Tesla roof could very well meet your energy output needs. The following are some ways to ensure that you are satisfied with your Tesla roof installation and final output:
Use the Tesla Roof as a Supplement
While the goal of most contemporary homeowners is to create a net-zero energy-efficient building (one that does not pull from the nonrenewable energy grid and/or sends renewable energy back to the grid to replace that used from nonrenewable sources), you may simply be satisfied to use a Tesla roof as a stylish supplement to your energy needs.
If you have a large, sprawling house, and the up-front cost of installing a Tesla roof that will cover all of your property’s energy demands is prohibitive, you may elect to have a standard Tesla roof do what it can while pulling from the city’s grid to make up the deficit, creating a type of “hybrid” energy set-up for your home.
While the Tesla roof may not provide all of the energy required, it will significantly reduce your monthly electric bill and help your home achieve greater sustainability.
If you are like most people and want your Tesla roof to cover all of your home’s electric needs, you must get scientific to figure out how much energy your home will require. This includes everything from scrupulously monitoring all past utility bills to figuring out exactly how many kWh of electricity each of your appliances is consuming on a typical month.
In conjunction with this, you will need to look at the weather history of the area you live in. While there is no way to predict the yearly forecast with 100% accuracy, homes in sunny areas such as Arizona, Colorado, and California will get more average sunlight than comparatively cloudy areas such as Ohio and New York, with cloudy regions requiring a higher percentage of solar tiles to meet the energy needs of a home.
Make Concurrent Renovations
To ensure that your Tesla roof helps you reach net-zero energy-efficient status, it is essential to look into some concurrent home renovations that will help reduce your home’s energy needs.
A great place to start is through a blower door test. This will help you identify leaks in the building envelope that can cause your heating and air conditioning to work overtime. If you do not want to invest in a blower door test, some general renovations that can help your home reduce its energy consumption include:
- Doing a traditional service of all HVAC ducts and making sure the filters are regularly replaced
- Installing new windows that have better seals against air transfer and allow natural light to circulate more freely through your home
- Including high-quality poly-iso insulation in the walls and ceiling to help regulate interior temperatures without the need for heat or air conditioning
- Energy Star certified appliances for the kitchen and laundry room
Take Advantage of Tesla’s Smart Home Features
The investment in a Tesla roof likely means that you are doing what it takes to live a sustainable lifestyle. As a result, the day-to-day behaviors that reduce energy consumption, such as turning off lights when not in use, not leaving televisions running when you leave the house for an errand, and zone heating the house to make sure that only the areas of the home currently in use are climate controlled, should be a priority for you.
Fortunately, the Tesla roof comes with several features that make it compatible with a smart home—a home that has its lighting, heating, and electronics controlled from a smartphone or computer.
Through your Tesla roof’s smart home features, you can see how much energy is being produced by the solar panels, how much energy your home is currently consuming, and how much electricity is stored in the Powerwall.
Tesla Powerwall Output Capacity
Many people wonder what solar-powered homes do for electricity when the sun is not shining. Tesla solves this problem with its innovative Powerwall. The Tesla Powerwall is a rechargeable lithium-ion battery meant for energy storage. Whenever a home is not actively using electricity for daily functions, it is stored in the Powerwall to be used when the sun goes down or is insufficient to meet current energy demands.
The most recent iteration of the Tesla Powerwall is the Powerwall 2. It has a cost of $6,500 and has a storage capacity of 13.5 kWh. It can provide 5 kW of continuous energy flow, with a peak of 7 kW.
While these figures may seem low, it takes only 500 W (or .5 kW) to run an average washing machine for an hour, so it is very reasonable to think that a home running off the Tesla Powerwall 2 overnight will have plenty of energy in reserve to meet its needs until the sun rises the next morning.
Electric car giant Tesla is helping contemporary homeowners power their homes sustainably and in style. Through its innovative solar roofing tiles, a Tesla roof can be installed that is nearly indistinguishable from more traditionally roofed houses. This has been getting people to adopt solar power for their homes, as the unsightly nature of traditional solar panels was unattractive to many consumers.
While a Tesla roof cannot convert sunlight into electricity as efficiently as traditional solar panels, there is every reason to believe that a Tesla roof will be enough to meet the energy needs of your home. Most Tesla roofs will produce upwards of 15,000 kWh of electricity per year, which surpasses the average home use of 10,972 kWh annually, making the comparative inefficiency of Tesla tiles mostly moot.
Tesla roofs can be installed to meet the energy needs of higher-consuming homes, but the cost is currently steep. Therefore, using the Tesla roof as a supplement, making some concurrent renovations, and capitalizing on Tesla’s smart home features are some great ways to get the most out of this innovative roof and make your home as sustainable as possible with the output available.