A regional delivery truck needs a cooling plan based on its stops. An overnight sleeper-cab test does not describe a route with frequent door openings, short waiting periods and repeated transitions between driving and parking.

A current commercial-vehicle example

Volvo Trucks announced the start of new VNR production on 18 February 2026, positioning the truck for urban and regional delivery. The event highlights an application question for accessory buyers: which parts of a working day actually require stationary cabin cooling? It does not imply that an aftermarket Vethy unit has been approved for a VNR.

Collect a simple route record

For representative working days, record the start and end of each stop, whether the driver stays inside, approximate door-opening frequency, sun exposure and the available charging period afterward. Include depot waiting and loading queues, which may differ from customer delivery stops.

Group stops by practical need. A brief unoccupied stop may have a different comfort objective from a long occupied queue. A lunch break in an exposed cab may require more sustained cooling than several short deliveries. Set the required comfort outcome for each group before choosing a battery or AC model.

Test recovery as well as steady operation

During a representative trial, observe how quickly the occupied area returns to the agreed temperature after the normal door-opening pattern. Record energy consumed during the entire sequence. A low average demand with the doors closed may not predict performance during a busy distribution shift.

Also check the installation against the driver's work: entry and exit, visibility, overhead storage and access to controls. A system that is convenient in a sleeper cab can be awkward in a compact day cab.

Close the daily energy balance

Measure how much energy is restored during the actual driving and depot periods. The available charging opportunity depends on the installed electrical system and approved integration. A route can appear successful on the first day with a full battery but gradually lose reserve over repeated days.

Use the stop profile as the request-for-quotation attachment. Ask suppliers to explain the proposed electrical arrangement, expected limitations and commissioning checks for that exact duty cycle. This gives every bidder the same operating problem to solve and produces a more useful comparison than asking for a generic “truck AC” price.

Build the stop-profile sheet from real days

The stop profile is a table, one row per stop, filled from representative working days rather than from memory of a good week. Choose three to five days that include the heaviest delivery run, the longest depot wait and a typical Friday, because specification work must survive the worst normal day, not the average one. A sheet built this way becomes the single attachment that every supplier and installer works from.

Fill the sheet at the stops themselves, or reconstruct it the same evening with the driver. Estimates made days later blur short stops into long ones, and door-opening counts are the first casualty. The columns below cover what a cooling specification actually depends on; anything more elaborate tends to stop being filled in after the first week.

  1. Arrival time and departure time for each stop.
  2. Whether the driver stays in the cab, and for how much of the stop.
  3. Approximate number of door openings while parked.
  4. Whether the stop is in sun, shade or a covered dock.
  5. Whether the cab door stays open at the dock while the driver is away.
  6. Engine state during the stop and the reason it runs or does not.
  7. Cab temperature on arrival and the comfort target the driver actually needs.
  8. Time available for charging after the stop, and where that charging happens.
  9. The day type: heavy delivery run, quiet day, or the Friday pattern the fleet considers normal.

Review the completed sheet with the driver before using it. Drivers will correct things the sheet cannot see: which docks allow the engine to run, which queues tighten in the afternoon, which stops have shade in the morning but not at midday. Those corrections are the difference between a profile that describes the route and one that describes a route that almost exists.

Keep the seasonal variants together. A summer sheet and a winter sheet describe the same route with different weights: summer makes Class 3 brutal and stretches the charging arithmetic, while winter shifts attention to demisting and to how much battery the cold leaves for cooling at all. The specification is written against the summer sheet, but the winter sheet belongs in the same attachment, because it tells the supplier what the unit must survive rather than what it must achieve. Two pages, same columns, different weeks — that is the whole document.

Group the stops into comfort classes

Raw stop lists overwhelm a specification. Grouping turns them into four or five classes, each with its own comfort target, and the air-conditioning question becomes: which classes must be cooled, to what temperature, for how long? A unit sized for every class will be oversized and expensive; a unit sized for the wrong class will fail the driver exactly when the route is hardest.

  • Class 1 — brief unoccupied stops: the driver leaves the cab; the only goal is affordable recovery when work resumes. Cooling may be paused entirely.
  • Class 2 — short occupied stops: dispatch yards, short queues. Modest cooling that takes the edge off beats deep cooling that flattens the battery.
  • Class 3 — long occupied breaks: the lunch hour in an exposed cab. This class sets the sustained-capacity requirement and is usually the hardest.
  • Class 4 — depot and end-of-shift periods: longer dwell, often with charging available, where the battery reserve for the next morning is decided.

Expect routes that resist the four classes, and handle them the same way: give them their own class with its own target rather than forcing them into a neighbor. A regular customer whose dock stays open to the yard, a route leg with an unplanned wait that occurs twice a week, a loading pattern that holds the driver aboard for twenty unlisted minutes — these are real classes in disguise. Forcing them into Class 2 averages their demand away. The class list is right when every stop on the sheet maps to exactly one class and the driver recognizes the map at a glance.

Count the stops per class from the sheet, then attach a number: minutes per day in each class, weighted by season. The class that dominates the summer sheet is the one the trial must test, and it is frequently Class 3 rather than the overnight-style Class 4 that sleeper-cab intuition suggests. Writing the per-class minutes into the specification prevents the most common sizing error, which is designing for a rest pattern this duty cycle does not have.

Class targets should be set with the drivers' representative, not for them. "Cool" means different things to a driver who steps in and out all day and one who sits through a queue; a target written as an agreed cab temperature per class turns later acceptance into measurement instead of negotiation.

Sizing questions specific to a compact day cab

Day cabs punish equipment that ignores them. There is no bunk to mount above, interior volume is smaller but the glass area is large, and the driver's working movements — entering, exiting, reaching for paperwork — pass the equipment all day. The questions below are the ones a day-cab specification must answer before a model is chosen, and every answer should come from the actual vehicle, not from a product sheet.

  • What roof structure and internal height are available, and does the chosen unit fit with its airflow clearances?
  • Where does condensate drain, and does the drain path survive a loaded wash or a pressure clean?
  • Can the driver reach the controls from the seat with a handshake, not by stretching?
  • Does the unit block visibility, beacon lines or any mirror the driver relies on?
  • What electrical access point does the body-builder use, and is it reachable for service?
  • How loud is the unit at a customer stop, where noise is noticed by other people?

The last two questions are easy to skip and expensive to rediscover. An access point hidden behind trim turns every service visit into an hour of disassembly, and a unit that hums through a quiet residential delivery window generates complaints no brochure anticipated. Ask the installer to demonstrate both on the trial vehicle: open the access point, then step away from the cab and listen.

Weight and roof loading complete the picture. A day-cab roof carries less than a sleeper's, and added mass high up changes handling at highway speed more than the same mass low down. Request the unit's fitted weight and confirm the roof structure against the chassis manufacturer's guidance for that cab, in writing, as part of the quotation rather than after delivery.

Before any order, ask for a physical fit on the trial vehicle. Cardboard templates and photographs hide more than they reveal; an hour with the actual unit held at the mounting position answers the height, drain, control reach and visibility questions at once, in front of the driver. Photograph the fit from the driver's seat and from outside, attach the photographs to the quotation file, and require the delivered installation to match them. This single visit resolves the disputes that would otherwise surface at handover, when the truck is already in service.

Mistakes when specifying cooling for multi-stop routes

Multi-stop specifications fail in repeating patterns. Each mistake below has the same root: borrowing a decision from a duty cycle the route does not have. Checking a draft against this list takes minutes and removes most of the reasons a first installation disappoints.

  • Sizing from overnight sleeper-cab figures. A delivery day cab cools through dozens of transitions, not one long rest; capacity and battery behavior must match the stop profile, not a bedtime scenario.
  • Testing only with the doors closed. Closed-door averages flatter any unit. The trial must reproduce the route's real door-opening pattern, including the two-minute gaps that dump the cooled air.
  • Ignoring the hot-soak morning start. The first recovery after a cab has baked in a yard all morning is the hardest task of the day; if the trial starts at a comfortable temperature, it hides exactly that.
  • Designing for the average summer day. The sheet should include the hottest normal day, and the acceptance test should use it; air-conditioning complaints arrive on the days above the average, never below it.
  • Letting the trial run one day. A full battery makes any route look fine on day one. The reserve question only appears across consecutive days, which is why the energy balance is checked weekly.
  • Judging noise from the workshop, not from the stop. A unit acceptable in a bay can be intrusive at a quiet residential delivery; measure it where the route actually puts the truck.

A quieter mistake is specifying the unit and treating installation as a detail. On a delivery truck, installation decisions — wiring route, protection, control placement, drain path — determine whether the same unit is convenient or chronic. Attach the installation requirements to the model specification in the same document, so no bidder can price one and improvise the other.

Track the reserve across a full working week

A single day cannot answer the battery question, because a full battery at the depot hides everything. The honest test closes the balance across a full working week: energy consumed by each comfort class, energy restored during driving and depot periods, and the reserve remaining each morning. If the reserve trends downward across the week, the route consumes more than it restores, and no specification language will fix that.

  1. Start Monday with the battery at its normal morning state, fully charged as the routine defines it.
  2. Log energy delivered to cooling, per class, each day.
  3. Log charging energy recovered during driving and depot periods.
  4. Record the reserve every morning before departure.
  5. Flag any day the reserve falls below the level the driver needs for confidence.
  6. Review the Friday reserve against Monday: flat is acceptable, declining is not.
  7. Repeat the week once in the hottest normal weather before the result is called final.

Confirm the charging side against the vehicle's installed electrical system and its approved integration limits, not against hope. Some electrical arrangements deliver little at idle or during short hauls, which makes the depot window the only real recharge — and depots have queues of their own. If the arithmetic only closes with ideal charging, the route needs either a different charging routine or a different comfort expectation for one of the classes, and it is better to learn that from the sheet than from drivers in August.

Present the week's balance as a small table in the trial report: per-class consumption, charging recovered, morning reserves. This one table usually decides the project, because it converts the vague worry about batteries into five numbers everyone can see.

Give the table to the people who will live with it, not only to the buyer. A dispatcher reading declining reserves will immediately name the depot window that could be protected; a driver reading the same table will name the class where the target is unrealistically strict. Neither insight appears in a technical report written for procurement. The table is also the artifact that survives staff changes, which matters more than it sounds: the person who commissioned the trial often moves on before the second truck is ordered.

Turn the profile into an RFQ and a handover test

The stop-profile sheet, the class targets and the weekly balance table are exactly what a request for quotation needs. Attach all three and ask every bidder the same questions: which comfort classes the proposed unit covers, what electrical arrangement it assumes, what limitations the bidder sees in this duty cycle, and which commissioning checks will be performed. Comparable inputs produce comparable prices; a generic request produces offers that differ mainly in optimism.

  • Each class from the sheet, with its agreed temperature target and daily minutes.
  • The door-opening pattern of the heaviest day, so trial conditions are fixed in advance.
  • The electrical constraints of the vehicle, from its approved documentation.
  • The required handover evidence: commissioning record, fitted weight, drain and access details.
  • The noise expectation at customer stops, stated as a condition the handover test will check.
  • The seasonal sheets, so the bidder sizes for summer and confirms survival in winter.

Define the handover test while the truck is still at the trial stage, and reuse it unchanged at delivery. It should walk the heaviest day: start from a hot-soaked cab, run the real stop pattern, and confirm each class reaches its target within the trial's measured times. The driver who helped build the sheet should sign it. A handover defined this way makes the acceptance mechanical — the unit either reproduces the trial's numbers or the installer returns before the invoice is paid.

Keep the sheet alive after handover. Routes change with the season and with customers, and a profile that no longer matches the route will quietly mis-size every future repair or replacement. One page, updated twice a year, keeps the specification honest for as long as the truck works.

For fleets comparing several bids, add one more attachment: a short description of what the truck does not need. Stating that the route has no overnight rest, that the driver goes home each night and that the depot offers a defined charging window removes whole product categories from the conversation. Bidders then compete on the duty cycle that exists. The same description protects the fleet from an upsell built on a sleeper-cab assumption, which is the most common way a delivery-truck project ends up paying for capability the route will never use.

Next step

Compare the available configurations in the Vethy product catalog, then request the current model-specific documentation before selecting a unit.

Sources and method

Frequently asked questions

How do I size a parking air conditioner for a regional delivery day cab?

Size it from minutes per comfort class rather than from cab volume alone. Build a stop profile from three to five representative days, group the stops into classes, and total the daily minutes the driver actually needs cooling in an occupied cab. The longest occupied class, usually a lunch break in an exposed cab, sets the sustained requirement. Then check that requirement against the energy the vehicle can restore during driving and depot periods across a full week, because a unit that meets the temperature target but empties the battery is not correctly sized for the route.

Do frequent door openings make parking AC useless on delivery routes?

They change what the system must do, but they do not make it useless. Each opening dumps cooled air and loads the unit just as it is recovering, so a closed-door test flatters performance and a multi-stop route punishes it. The practical approach is to accept a different target per stop class: maintain comfort through short occupied stops and allow the cab to drift during brief unoccupied ones. Reproduce the real door pattern in the trial, and judge the unit on recovery within the minutes the route actually allows.

Can the battery recharge enough between delivery stops?

Only measurement answers this. Charging opportunity depends on the installed electrical system and its approved integration, and on how much driving and depot time the route really provides. Short hauls with long queues may restore very little, leaving the depot window as the sole recharge. Track morning reserve across five consecutive days: a flat reserve is acceptable, a declining one means the route consumes more than it restores. If the balance closes only under ideal charging, adjust the charging routine or the comfort target for one class.

What should a route trial prove before a fleet buys more units?

It should prove three things: each comfort class reaches its agreed target under the real door-opening pattern, the weekly energy balance stays flat including the hot-soak morning start, and the installation does not interfere with entry, exit, visibility or overhead storage. Add the driver's written sign-off, the commissioning record and the fitted weight. A trial that reproduces the heaviest normal day and survives five days of reserve tracking gives the fleet evidence it can scale; anything shorter tests the equipment on a route the truck does not drive.