Solar kits vs buying the parts: which one actually saves you money
Two ways to buy the same system
A kit is a system somebody else specified, boxed at one price. A parts list is the same system with the specifying left to you.
The kit is not a rip-off and the parts list is not automatically cheaper. They are different trades, and which one is right depends on something specific about you rather than on which one is better.
What a kit is genuinely good at
It removes the compatibility question, which is the one that costs real money when you get it wrong. Somebody has already checked that the controller talks to the battery, that the inverter's PV input window suits the array, and that the wire is heavy enough for the run.
Nothing is missing. The MC4s, the fuse holder, the lugs, the right crimp — the small parts that turn a Saturday into a Wednesday when one of them is absent.
It is one decision. If you are building a small system and you would rather spend the weekend mounting than specifying, that has real value and it is not a lesser way to buy.
What it costs you, and it is mostly not price
The sizing is somebody's average, not your site. A kit is specified for a generic load, a generic latitude and a generic winter. Yours is not generic. An Alberta off-grid system carries November to February as its binding constraint, and a kit sized against a national average is short exactly when you need it.
The weakest part is usually the one you would have upgraded. Kits are assembled to a price, and the margin comes out of whichever line the buyer is least likely to scrutinise — typically the controller, the wire gauge or the protection hardware.
It is hard to grow. Off-grid systems grow. If the kit's inverter has no headroom, the second battery rack means replacing the inverter, and you have paid twice for the expensive part.
Nobody can tell you why anything in it was chosen, which is the part that bites at year three when a component fails and you are trying to work out what will replace it.
What a parts list costs you
Honesty cuts both ways here.
Six decisions instead of one, and each one has a wrong answer. Panel and string configuration. Controller or hybrid inverter. Battery voltage and chemistry. Wire gauge for the actual run. Fusing and disconnect ratings. Mounting for the actual roof or ground.
Something will be missing the first time. It is almost always a connector, a lug or a fuse holder, and it is almost always discovered at 4pm Sunday.
You own the compatibility question. If the battery does not close-loop with the inverter you chose, that is yours.
Side by side
| Kit | Parts list | |
|---|---|---|
| Compatibility | Checked for you | Yours to check |
| Small parts | All in the box | Something is usually missing the first time |
| Decisions | One | Six: strings, controller or hybrid, battery, wire gauge, fusing, mounting |
| Sizing | A generic load and winter | Your site and your winter |
| Weakest part | Often the controller, wire or protection | Whatever you choose |
| Growing it later | Hard if the inverter has no headroom | Planned in |
| Why each part is there | Nobody can say | You can |
| Best for | A small, fixed system you want running by the weekend | Off-grid, a system that will grow, or one going in front of an inspector |
Which one you are
Take the kit if the system is small, fixed in scope, and you want to be mounting by the weekend. A cabin with four panels, a small bank and lights does not need six decisions made about it.
Take the parts list if any of these is true. You are off-grid, because the winter deficit is a site-specific problem and a generic kit does not solve it. You expect the system to grow. You already know what you want in one or two positions and want to choose it. Or it is going in front of an inspector, and you want to be able to say why each part is there.
And take the parts list if you are the kind of person who is going to take the kit apart anyway. Some people are. You know if you are one.
What a good parts list looks like
Every line is a category plus the spec that constrains the choice, not a brand and a model number. A list that names one seller's part numbers is a kit with extra steps: it makes you depend on somebody's recommendation being right for a site they haven't seen. A line that says the fuse has to be Class-T, rated to the conductor's ampacity, with an interrupt rating above what the bank can deliver tells you what to filter on, and you can buy it from us or from anybody.
And a good list ends with the decisions it can't make for you, named as decisions rather than left as gaps.
Bring your list to the counter Browse charge controllers
Checked on 12 September 2026.
Parts for this guide
See all Charge Controllers
Got a question about your build?
Bring the model number, a photo of the label or your parts list to the counter, or send it to us. The hard ones go to the licensed electricians on Solar YYC's crews, who've done 2,000+ projects in Alberta.
Ask us something
