Remote work during a heatwave raises a very practical question: is it better to pay more for electricity to work from home, or book an air-conditioned coworking space? Since May 2026, a succession of intense heat episodes has brought this choice back to the forefront, especially in homes that are difficult to cool.

To decide between the options for remote work during a heatwave, two cost items must be separated. The first is measurable: the electricity used by air conditioning. The second is much harder to quantify: the drop in productivity when heat worsens working conditions. Yet no available figures make it possible to assign a reliable average cost to this loss of productivity. The right approach is therefore not to invent a figure, but to calculate the level of loss from which coworking starts to become worthwhile.

How much does an air-conditioned day of remote work cost?

The regulated electricity rate used for May 2026 is €0.2016 per kWh, excluding the subscription. Consumption varies greatly depending on the type of air conditioner. A portable monobloc unit is rated at between 2.0 and 2.5 kWh per hour, while an A+++ inverter split system uses between 0.5 and 0.8 kWh per hour.

Over an eight-hour day, the calculation is simple. A portable air conditioner would use between 16 and 20 kWh, or about €3.23 to €4.03 of electricity. A highly efficient split system would use between 4 and 6.4 kWh, or about €0.81 to €1.29. These amounts include neither the electricity subscription, which is already paid for the home, nor other household uses.

Other orders of magnitude show how much the result varies with the appliance and usage pattern: an A++ split system used five hours a day for thirty days is estimated at €24.19 per month, while a low-end portable air conditioner used eight hours a day can reach around €64 per month. In southern France, intensive air-conditioning use for a household of four can bring the total to €150 per month, with an announced bill increase of 15 to 25% during periods of intense heat.

To compare with coworking, let us deliberately take the least favorable home scenario among the hourly consumption figures given: €4.03 for eight hours of portable air conditioning. This gives coworking every chance in the calculation.

Is coworking cheaper than air conditioning at home?

In 2026, a one-off day in a coworking space generally costs €15 to €30 outside Paris and €25 to €50 in Paris. Compared with a maximum electricity cost of about €4.03 for eight hours of portable air conditioning, the conclusion is clear: on energy cost alone, staying at home remains cheaper.

The same conclusion applies to a monthly subscription. Open-space prices recorded for six major cities are €400 in Paris, €262 in Lyon, €203 in Marseille, €284 in Bordeaux, €190 in Toulouse and €229 in Lille. If each subscription were divided by €4.03, it would take about:

  • 99 days of home air conditioning in Paris to equal €400;
  • 65 days in Lyon to equal €262;
  • 50 days in Marseille to equal €203;
  • 70 days in Bordeaux to equal €284;
  • 47 days in Toulouse to equal €190;
  • 57 days in Lille to equal €229.

This theoretical threshold exceeds one month in all six cases. In other words, a coworking subscription purchased only to save on air conditioning is not cost-effective. The calculation changes only if the heat causes enough loss of time, concentration or ability to work for that loss to have an economic value greater than the additional cost of coworking.

The real break-even point: what is your lost productivity worth?

The useful formula is: coworking cost per heatwave day – home air-conditioning cost = minimum daily productivity loss from which coworking becomes worthwhile.

Suppose a monthly subscription is purchased only to get through several heatwave days. Keeping the high home scenario of €4.03 per day, here is the minimum productivity loss that would need to be avoided each day to recoup the subscription.

With 10 heatwave days

  • Paris: about €35.97 per day;
  • Lyon: €22.17;
  • Marseille: €16.27;
  • Bordeaux: €24.37;
  • Toulouse: €14.97;
  • Lille: €18.87.

With 15 heatwave days

  • Paris: about €22.63 per day;
  • Lyon: €13.43;
  • Marseille: €9.50;
  • Bordeaux: €14.90;
  • Toulouse: €8.63;
  • Lille: €11.23.

With 20 heatwave days

  • Paris: about €15.97 per day;
  • Lyon: €9.07;
  • Marseille: €6.12;
  • Bordeaux: €10.17;
  • Toulouse: €5.47;
  • Lille: €7.42.

This calculation turns an impression into a decision. In Toulouse, for example, twenty very hot days reduce the extra cost of the subscription to about €5.47 per day after deducting home air conditioning. In Paris, the same reasoning still leaves almost €15.97 to justify each day.

Coworking does not become worthwhile because home air conditioning is expensive; it becomes worthwhile when the extra comfort prevents a loss of work whose value exceeds the additional cost.

Which cities are easiest to make cost-effective?

Based solely on the economic criterion of coworking prices, Toulouse and Marseille have the lowest thresholds among the six cities compared, ahead of Lille and Lyon. Bordeaux is more expensive, while Paris is by far the hardest to recoup. This ranking does not mean that these cities will experience more or less heat.

Indeed, no available figures provide the number of heatwave days forecast in 2026 for each city, nor a comparable measure of poorly insulated housing stock that would allow a ranking combining climate, insulation and coworking. Claiming that a given city will have exactly 10, 15 or 20 heatwave days would therefore amount to inventing a forecast.

The most robust method is to use these scenarios as a personal reference grid. If your city experiences ten very hot days, use the corresponding line. If the period extends to fifteen or twenty days, the coworking cost per useful day falls mechanically. Then compare this extra cost with the real value of the work you believe you lose at home.

A three-question guide

  • What equipment do you use? An efficient split system can cost less than €1.30 over eight hours, while a portable air conditioner can exceed €4.
  • How many days will you actually use coworking? The higher this number, the more the monthly subscription is spread across many days.
  • What is a degraded workday worth? This is the only factor that can tip the calculation, but it must come from your own situation because there is no reliable average figure.

For an employee who is properly set up and productive at home, home will almost always remain the cheapest solution if only direct expenses are compared. For someone working in a very hot home and losing a significant part of the day, coworking can become rational well before the electricity bill makes it necessary. The threshold is therefore not only climatic: it is above all economic and personal.