The cost of solar has fallen rapidly over the years, from about $3.60 per watt in 2016 to about $2.80 per watt in 2020. Costs will continue to fall, however at the same time government rebates are falling as well. Now is as good a time as any to go solar.
There are many questions around cost that a homeowner will have. How much should I be paying for my system? Where should I save money and where should I spend a bit more for peace of mind? And lastly, is it actually worth it?
Different Costs in Different States
The average cost of solar does vary from state to state, but not by a huge amount. The table below shows average costs for a 6kW system in the different states, after the federal tax rebate (22%) is taken out. If we disregard Hawaii, the average prices range from $10,219 to $13,712. Certainly not a big enough variation to make solar financially valid in some states and not others.
|State||Final cost to customer for 6kW system|
|District of Columbia||$12,262|
Of course, these are average figures. A number of factors will influence the cost of an individual system.
The Size of the System
The size of the solar system will obviously have big effect on cost. So how big a system is good? The average size for a system is about 6kW: this is a good place to start. However, many homes might use much more energy and therefore a bigger system might be preferable.
A commonly used ‘rule-of-thumb’ is to use enough panels so that the energy output from the panels equals your energy use per day. You can calculate the energy use per day from your power bill.
The average energy used per day by a typical home in the US is about 29 kWh. For a house using this amount of energy, enough panels to produce 29 kWh per day of energy should be sufficient. However, if you have a huge house, with a heated pool, kids that take long showers and air-conditioning that operates frequently, your energy use per day might be 60 kWh. You might choose a system twice the size of the average system, at about twice the cost.
Of course, how many panels you need to produce the target amount of energy depends on a number of factors, most notably where you live (i.e., amount of sunshine), and which way the panels face (e.g. north, south, east or west). Your prospective installers should model this, hopefully with good software, and show you the energy output you can expect from different sized systems.
The amount of sunshine that will hit your solar panels changes significantly across the US.
Source: National Renewable Energy Laboratories (NREL)
If you live in Arizona you’re going to get about 6.2 kWh/m2 per day of sunshine. However up in Maine you’re only going to get about 3.7 kWh/m2 per day. So for a given amount of energy output, people in Maine will need to put up 1.7 times the number of panels compared to people in Arizona, at about 1.7 times the cost. The good news is that there are large expanses of the US that get very good sunshine, keeping system sizes and costs well under control.
The Type of Equipment
Equipment costs can be around half the total cost of the system (or more for premium gear) so the equipment you choose can greatly influence the total cost.
Nearly all of the equipment cost is made up of the solar panels and the inverter. The table below shows system costs for different types of panels.
|MANUFACTURER||COST PER WATT||PRICE RANGE (6KW SYSTEM)|
|Axitex||$2.58||$13,740 – $17,220|
|Boviet||$2.53||$15,180 – $15,180|
|Canadian Solar Inc.||$2.77||$14,400 – $18,840|
|CertainTeed Solar||$2.72||$15,360 – $17,280|
|Hanwha SolarOne||$2.80||$16,800 – $16,800|
|Heliene||$2.94||$15,180 – $20,100|
|Hyundai||$3.02||$14,880 – $21,360|
|JA Solar||$3.12||$17,040 – $20,400|
|Jinko Solar||$2.84||$14,760 – $19,320|
|KYOCERA Solar, Inc.||$5.00||$30,000 – $30,000|
|LG Solar||$2.76||$14,400 – $18,720|
|LONGi Solar||$3.00||$15,600 – $20,400|
|Mission Solar Energy||$2.54||$13,980 – $16,500|
|Panasonic||$2.84||$14,880 – $19,200|
|Peimar Group||$3.00||$15,780 – $20,220|
|Phono Solar||$2.93||$16,380 – $18,780|
|Q CELLS||$2.52||$12,600 – $17,640|
|REC||$2.91||$14,640 – $20,280|
|Risen||$2.34||$13,500 – $14,580|
|S-Energy||$3.21||$15,000 – $23,520|
|Silfab Solar||$2.79||$14,520 – $18,960|
|Solaria||$2.80||$14,820 – $18,780|
|SunPower Corporation||$3.30||$18,480 – $21,120|
|Talesun Solar Co.||$2.76||$14,220 – $18,900|
|Tesla||$2.74||$14,940 – $17,940|
|Trina Solar||$2.93||$15,960 – $19,200|
|Vikram Solar||$3.07||$15,840 – $21,000|
There is a large variation, from $5 per watt at the top end from Kyocera, down to $2.34 for Risen. However most of the panels range between about $2.50 and $3.00 per watt: not a huge range.
The cheapest option may not always be the best. Choosing a Tier-1 panel is a good place to start and there are certainly many of these that are well priced. The warranty is very important: it’s no use getting cheap panels if their warranty periods are short and things go wrong. At least 10 years manufacturers’ warranty (preferably 15) and 25 year performance warranty are reasonably common.
Inverters have historically been the bugbear of solar systems, i.e., the bit that causes the most problems. This is where it may really not pay to get the cheapest option. There is a considerable variation in price across inverters. An entry level 5 kW inverter might cost as little as $500, while a premium quality inverter might be $1,500 or higher.
European inverters have historically been the best quality however premium Chinese brands have certainly closed the gap in recent times. Again, warranty is very important, as is the presence of a local office to service any warranty claims. A decent inverter should have a 10 year warranty. Also, questioning a bunch of installers and wholesalers can give you a great idea of failure rates amongst the different brands.
Installation costs are the other major costs with a solar installation, i.e., the price the installers charge to actually put the panels up, put the inverter in, wire the system together and look after all the paperwork with the relevant electricity authorities.
A lot of installers don’t break down the different costs in their quotes: if you are curious you should ask for a cost breakdown.
Installation costs can vary a lot. Again it is a good idea to be wary of cheap offerings. There are lots of ways to cut corners and save time and money on an installation, however doing this can cause problems down the track, including safety issues, and can affect the aesthetics of your installation.
Installers with a long history and lots of good recommendations from previous customers are a good bet, even if they are not the cheapest. Spending a few extra hundred dollars on your system doesn’t affect the economics that much, and may certainly be worth the extra peace of mind.
Is it Worth the Cost?
To answer this question, we’ve modelled two residences, one in sunny Arizona, which has a 12.5c/kWh feed in tariff, and the other in not-so-sunny Maine, which has no feed in tariff. So close to best-case and worst-case scenarios. The table below shows the assumptions made in the model, and the payback period for each case. The payback period is the amount of time it takes to pay off the initial investment from savings in power bills.
|Electricity tariff (c/kWh)||10.85||13.44|
|Internal use of solar %||40%||40%|
|System size for 30 kWh per day||6||14|
|Savings per year||$1,188||$1,472|
|Payback period (years)||10.5||21.3|
As expected, people in Arizona can get away with a much smaller and cheaper system size than people in Maine, less than half in fact. In Maine it’s going to take about 21 years to pay back the investment. That will leave 4 years on the solar cell performance warranty to make money. Not a fantastic investment, but as pretty much a worst-case scenario in the US, you’re not losing money and actually making a bit while helping the environment.
Things are certainly much better in sunny Arizona, where you can pay off a system in just over 10 years and then have about 15 years to make money.
The feed in tariff is a very important factor in the finances and one in which the US is behind other leading nations in solar. Only around 7 states have a feed in tariff. Contrast this to Australia, where every state has a feed in tariff, and government subsidies are higher, so that homeowners can pay off systems in 3-4 years. This is something that governments in the US could revisit. After all, it seems only right that people get paid for power they are putting back into the grid.
There are certainly many factors that customers should be aware of when it comes to the cost of a solar power system. System size, equipment, and installation labour are the major costs. However, cheaper is not always better and for peace of mind an extra investment could be worth it.
We’ve shown that even in a poor location such as Maine, solar will pay for itself plus a bit more. For most of the US, with more sun and with some states having feed in tariffs, solar is a great investment.
In most parts of the US the answer is yes. People in states like Arizona will pay off their systems faster than people in the northern states, however in most states people will do significantly better than break even.
Costs vary depending on what size system you need, where you are located, which equipment you select. An average 6kW system should cost around $11,000 after the federal government rebate is taken out.
Almost certainly not. Poor quality installation and poor quality inverters, in particular, will only create problems and headaches down the line. Systems are still very profitable paying extra for quality installers and equipment.
This very much depends on where you live. In the sunnier states, payback times of 10 years are possible, leaving about 15 years to make money. At the other end of the scale, in the most northern states it might take 20 years to pay off the investment, leaving about 5 years to make money.