Solar panel types compared: what you can actually buy

If you look up panel types, you will find a tidy three-way comparison: monocrystalline, polycrystalline and thin-film. That framing is a little out of date. The market has narrowed a lot, and a homeowner requesting quotes today will see mostly one type. It is still worth knowing what the others are, because older systems, brochures and cheaper offers sometimes involve them.

The three families

Monocrystalline

Each cell is cut from a single crystal of silicon, which gives it a uniform dark appearance, often black or very dark blue. The pure crystal lets electrons flow with less resistance, so these panels convert more sunlight into power per square metre. Typical residential panels today are rated about 400 to 450 W, with efficiency around 20 to 23 percent. Cost per panel was once noticeably higher than the alternatives, but manufacturing scale has closed most of that gap.

Polycrystalline

Cells are made from melted silicon fragments, so the surface looks speckled blue with visible grain boundaries. Efficiency is somewhat lower, so you need more roof area for the same output. These panels were a common budget option a decade ago. Now most manufacturers have shifted their lines to monocrystalline, and a quote that includes polycrystalline today is often either old stock or a very price-led offer.

Thin-film

Thin-film technologies deposit a very thin layer of photovoltaic material onto glass, metal or plastic. They are lightweight, can be flexible, and tend to handle heat and partial shade gracefully. Their drawback for a house is lower efficiency per square metre. Thin-film is mainly used on large flat commercial roofs and ground-mounted installations where space is cheap and weight is limited. You may meet it in specialty products such as portable chargers or building-integrated roofing.

Side-by-side

Treat the efficiency figures as typical ranges. Specific products vary, and the datasheet for the exact model you are quoted is the document to check.

Why efficiency matters less than people think

Higher efficiency means more watts from the same space. If your roof is large and unshaded, you can reach any target by simply adding a panel or two, and a lower-efficiency model might cost less overall. If your roof is small, complicated or partly shaded, efficiency becomes a real advantage, because you cannot add panels that do not fit.

So ask a simple question: does the roof limit the system, or does the budget? If the roof does, efficiency earns its premium. If the budget does, compare cost per watt, covered in the price per watt article, rather than cost per panel.

Variations you will see on datasheets

Within monocrystalline there are sub-types, and the labels can be confusing. You may see references to half-cut cells, which reduce resistance losses and handle shade a bit better, or to bifacial panels, which can collect reflected light on the back and are mainly useful on ground mounts or flat roofs with a reflective surface. On a pitched house roof, the bifacial gain is usually small. Glass-on-glass construction is also becoming common, which can improve durability.

None of these terms should make or break a decision. What matters is that the panel is certified to recognised standards (look for a CSA mark or other accepted certification), that the dimensions fit your roof layout, and that the warranty terms are clear. The warranty guide explains the difference between product and performance coverage.

What about cold, heat and snow?

All silicon cells produce slightly more voltage when cold and slightly less when hot. The effect is described by a temperature coefficient on the datasheet, and a lower (less negative) figure means better behaviour in heat. For most Canadian homes the difference between panel types here is minor compared with day length, tilt and snow. If you are curious about reading these numbers, our efficiency and wattage guide shows how.

How to use this in a quote conversation

Do not worry about trying to out-expert the installer. A few questions go a long way.

• What is the rated wattage of each panel, and how many are in the design?
• What is the efficiency and the temperature coefficient on the datasheet?
• What is the product warranty and what is the performance warranty?
• Is the equipment certified for use in Canada?

If an installer is proposing a type you do not recognise, ask for the datasheet and a plain explanation of why it suits your roof. Panels are only one part of the system, so also look at the inverter choice, described in how solar panels work.

The short version

For a typical home, you will almost certainly be offered monocrystalline silicon and that is a sound choice. Polycrystalline is mostly a historical option and thin-film is for specialist or commercial settings. Spend your effort on warranties, installer quality and the roof itself. You can find more foundations in our solar basics hub.