Updated September 2026 · By Marcus Reid, The Driver Gear
35L vs 45L cooler for a sleeper cab: which size should you buy? (2026)
The short answer: a 35L cooler holds 3–4 days of food for one driver and fits almost any sleeper — it is the right size for most solo drivers. A 45L holds 5–7 days and suits team drivers or week-long hauls, but needs a bigger footprint. The 10-litre gap is about two extra days of food, not a power problem: both sizes draw roughly the same overnight.
Research-based. We did not test these hands-on. Scores come from published specs and driver reviews. This guide contains affiliate links to Amazon.ca. As an Amazon Associate I earn from qualifying purchases. Prices are approximate, in CAD, and change often — check the live listing before you buy.
Our pick
Dometic CFX5 35 — 18/20
provisional · specs + reviews
35 litres, freezing down to −22°C, about 1.1 Ah/h average draw, and a 5-year warranty. The 35L that fits nearly any sleeper cab — the right size for most solo drivers.
Quick picks
Two sizes, two winners
Both picks are compressor coolers — the only type worth buying for a truck. For the wider field, see our full 12V cooler buying guide.
Best 35L
Dometic CFX5 35
35L · −22°C · 19 kg. Premium build, app control, 5-year warranty — the benchmark 35-litre cooler.
- Score: 18/20 provisional · specs + reviews
- Capacity: 35L (about 50 cans)
- Avg draw: about 1.1 Ah/h at 12V
Best 45L value
Alpicool CF45
45L · −20°C · 13.6 kg. Ten extra litres for less than half the Dometic’s price.
- Score: 15/20 provisional · specs + reviews
- Capacity: 45L (about 60 cans)
- Avg draw: about 1 Ah/h at 12V
Buyer’s guide
What 10 litres actually means
Cooler sizes sound abstract until you translate them into days of food. As a rule of thumb for one driver eating real meals:
35 litres ≈ 3–4 days. About 50 cans of space, which in practice means breakfast, lunch, and dinner ingredients plus drinks for a standard 2–4 day run, with room to spare. This covers most company-driver routes where you pass a grocery store every few days.
45 litres ≈ 5–7 days. Ten extra litres is roughly two more days of food — the difference between restocking mid-week and doing one big shop. This is the size for owner-operators on long hauls, team drivers feeding two people, or anyone who parks far from stores.
The honest decision rule: if you restock every 2–3 days, buy 35L and enjoy the smaller footprint. If you regularly go 5+ days between grocery stops, buy 45L. Buying bigger “just in case” costs you floor space every single day for capacity you use twice a month.
Fit check
Will it fit your sleeper?
Both sizes are long, low boxes — but check your floor space before ordering. The Dometic CFX5 35 measures 69.4 × 39.8 × 40.7 cm; the Alpicool CF45 is 69 × 34.5 × 46.2 cm. Similar length, but the 45L stands about 5 cm taller.
Measure three things: the floor footprint where it will live, the lid clearance above it (top-opening lids need roughly 40 cm of swing space), and the door or hatch it must pass through on the way in. A cooler that fits the sleeper but not the door is a return waiting to happen.
Give the compressor air. Compressor coolers vent heat from their sides — do not wedge one tight against a wall or bury it under bedding. A few centimetres of clearance on the vent side keeps it efficient and quiet. And strap it down: a 13–19 kg box becomes a projectile in a hard brake.
Power
Does the bigger one drain your battery faster?
Barely — and not where it matters. Both picks are rated around 45W, and once a compressor cooler reaches its set temperature, the compressor cycles on and off. Average overnight draw lands near 1 Ah/h at 12V for either size. The 45L works slightly harder on the first cooldown, then the two are close.
Size for food, not for power. The battery question that actually matters is whether your truck batteries survive the night at all — run your own numbers in our 12V cooler battery-drain calculator, and read how long a 12V cooler really lasts overnight before blaming the cooler’s size.
The picks in detail
Two coolers, compared honestly
Scores are provisional — based on published specs and buyer reviews, not hands-on testing.
Best 35L
Dometic CFX5 35
The benchmark portable fridge: vacuum-insulated panels, a variable-speed compressor that sips power, and the longest warranty in the business. This is the 35L everything else gets measured against.
provisional · specs + reviews
- Why it wins
- Benchmark efficiency: the variable-speed compressor averages about 1.1 Ah/h at 12V in warm conditions — the lowest draw per litre in this size class, per Dometic’s published test figures.
- App control that matters: Bluetooth and WiFi monitoring with energy-consumption tracking and lid-open alerts — genuinely useful, not a gimmick.
- 5-year warranty: two to five times the coverage of budget brands. This is a buy-it-for-a-decade purchase.
- 3-stage battery protection: guards your truck batteries with adjustable cutoff levels.
- Watch out for
- The price: roughly two-and-a-half times the Alpicool. You are paying for efficiency, warranty, and brand reliability — worth it only if you keep it for years.
- Heavier than the bigger Alpicool: 19 kg empty. The insulation and build quality weigh something.
- Single zone: one compartment, one temperature. No separate freezer section.
Prices change often — the live Amazon.ca listing shows the current price.
Best 45L value
Alpicool CF45
Ten more litres than the Dometic for less than half the money. The CF45 is the value way to carry a full week of food — lighter than the smaller Dometic, with the same 12/24V flexibility.
provisional · specs + reviews
- Why it scores well
- Capacity per dollar: 45 litres at less than half the Dometic’s price — the cheapest honest way to get a week of food on board.
- Lighter than the smaller Dometic: about 13.6 kg empty, despite holding 10 litres more.
- ECO/MAX modes: ECO sips power on mild days; MAX pulls down fast when you load warm groceries.
- Basket and LED light included: the small usability touches are all here.
- Watch out for
- Thinner insulation than premium brands: it works harder in summer heat — fine in a cab, but expect longer compressor cycles on 35°C days.
- Shorter warranty: typically 1 year versus Dometic’s 5. Budget for that in the value math.
- Freezes to −20°C, not −22°C: irrelevant for food, but the Dometic edges it on paper.
Prices change often — the live Amazon.ca listing shows the current price.
How this guide was made. We compared 35L and 45L compressor coolers available to Canadian buyers using manufacturer specifications and published buyer-review aggregates as of September 2026. Research-based. We did not test these hands-on. Scores come from published specs and driver reviews. Scores are our own, out of 20. Prices were approximate at research time and will change — the Amazon link shows the current price.
The verdict
Buy the 35L Dometic CFX5 35 if you run solo and restock every few days — it fits any sleeper, sips power, and the 5-year warranty makes it a decade purchase. Buy the 45L Alpicool CF45 if you need a week of food on board or drive team — the extra 10 litres costs almost nothing in overnight power and far less in money. Either way, buy compressor: a thermoelectric cooler cannot freeze and struggles in summer heat, which is exactly when you need it most.
FAQ
Cooler size questions, answered
Is a 35L cooler big enough for a truck driver?
For one driver, yes — 35 litres holds roughly 3–4 days of real meals plus drinks. If your runs stretch past 4 days between grocery stops, or you drive team, step up to 45L.
Does a 45L cooler drain the truck battery faster than a 35L?
Only slightly, and only on the first cooldown. Overnight, both sizes cycle at roughly 1 Ah/h at 12V. Run your own numbers in our 12V cooler battery-drain calculator rather than guessing.
Compressor or thermoelectric for a sleeper cab?
Compressor, every time. Thermoelectric coolers cannot freeze, cool only ~20°C below ambient, and draw power constantly. A compressor cooler cycles on and off and actually freezes. See our thermoelectric vs compressor comparison for the full breakdown.
Will a 12V compressor cooler work in a Canadian winter?
Yes — cold ambient air makes a compressor’s job easier, not harder. The winter challenge is keeping the cooler’s electronics and your batteries warm, not cooling the food. Read our −40°C winter reality check before January.