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How to reduce your electricity bill during a heatwave
Mis à jour le
November 13, 2025
8
Min reading
Heat peak, heat wave, heatwave... so many terms that describe episodes of high temperatures.
What differentiates them? Their duration and their intensity.
Météo France defines a heatwave as a period of exceptional heat, during which temperatures exceed departmental thresholds for at least three days and three consecutive nights.
These phenomena have one thing in common: they cause a significant increase in electricity consumption, and therefore in the bill! While air conditioning is often singled out, it is not alone in the dock.
But why does the electricity bill skyrocket during a heatwave?
And above all, how can businesses stop this increase?
Light on the winning equation for not exploding the energy budget in summer.
Why does your electricity bill increase during a heatwave?
When we talk about the rise in electricity bills during a heatwave, the first instinct is to think of air conditioning. But other factors come into play, including tensions in the electricity market or inadequate supply contracts.
The rise in energy consumption during a heatwave
During heatwaves, electricity demand experiences spectacular peaks. At issue: theintensive use of refrigeration systems to maintain a minimum of thermal comfort. Air conditioning, ventilation and refrigeration equipment are running at full speed.
This phenomenon is amplified in poorly insulated or poorly ventilated buildings and through the use oflow-performance equipment.
According to RTE, the airconditioning alone increases national consumption by 700 to 1,100 MW per additional degree.
Other uses that are more invisible are also energy-intensive in summer.
Particularly sensitive to heat, data centers intensify their cooling. Behind the shutters closed, theartificial lighting also contributes to the increase in electricity demand.
Electricity contracts that are unsuited to summer needs
The electricity bill can increase if the contract is not adapted to the real needs of the company in summer.
During a heatwave, peak consumption can lead to overruns of the subscribed power. With penalties of several euros per hour, the bill can quickly rise in summer!
In addition, some contracts do not take into account seasonal variations, which complicates optimization in summer.
The increase in electricity prices during a heatwave
The heatwave sharply increases the demand for electricity, which often causes energy prices to soar. If the offer is struggling to keep up, tensions are emerging.
In summer, several factors can in fact: limit the capacity to generate electricity at the moment Where it is most in demand :
- One rollback Of nuclear production, when the temperature of watercourses exceeds regulatory thresholds and forces power plants to slow down (or shut down).
- One decline in wind power generation, in case of absence of wind.
- One decrease in hydroelectricity production, during a period of drought.
- One reduction in the energy efficiency of photovoltaic panels above 25°C.
When the nuclear and renewable energies no longer cover demand, producers are turning to imports. The use of gas or coal-fired power plants, which are more expensive to operate, directly increases the price of electricity.
Best practices to reduce electricity consumption in summer
With a few simple actions and investments (quickly paid for themselves), businesses can keep their electricity bills under control during heatwaves.
Optimize the air conditioning of your buildings
Air conditioning and ventilation are the second largest source of energy expenditure for businesses, after heating. They represent on average 25% of their electricity consumption.
According to ADEME, air conditioning is also responsible for 5% of greenhouse gas emissions from buildings in France.
Limiting its use is a priority to reduce both the electricity bill and the carbon footprint of businesses.
Several simple actions help to moderate the air conditioning, while ensuring a good level of comfort:
- Adjust the inside temperature at least at 26°C: every degree lower increases electricity consumption by 5 to 10%.
- Postpone the use of air conditioning : starting it from an outside temperature of 30°C and not 27°C divides energy consumption by three.
- Ventilate at night to naturally refresh the premises.
- Install sun protection on the windows (blinds, adjustable sunshades, solar films...)
- Prefer ceiling fans : they consume 50 times less energy than air conditioners.
- Improving thermal insulation buildings.
- Maintain air conditioners to avoid energy efficiency losses and leaks of highly polluting refrigerants.
Avoid passive overconsumption of energy
In summer, even with empty premises, some equipment operates as if in full activity, causing waste: non-stop ventilation, standby devices, useless lighting...
Adapt the operation of the equipment to the real occupancy rate is a simple way to reduce the electricity bill. For example, this involves:
- La intelligent programming air conditioning and ventilation systems according to the schedules of attendance.
- La Power off equipment in empty offices, including computers that generate heat.
- THEadjusting the lighting to real needs, with the installation of presence detectors.
Excess consumption in the middle of summer?
The Pilott energy monitoring platform allows you to monitor your consumption station by post and to detect drifts. At the end of the day, a detailed energy management of your equipment for optimized uses in real time.
Learn more about Pilott
Involve employees in simple actions
Controlling energy consumption also requires the involvement of each employee.
Turning off the lights, unplugging the equipment, lowering the blinds or avoiding the night before are simple but effective actions. Repeated throughout the company, they can really bring down the electricity bill.
One regular awareness-raising among teams, with internal displays and campaigns, anchors these best practices in daily life.
Adapting energy supply contracts to summer needs
Adapting electricity supply contracts to the real needs of the company helps to reduce the bill.
Les Horoseasonal contracts, which distinguish between high and low season periods, offer a more advantageous rate between April and October. Thanks to the“off-peak hours” option, the company can take advantage of low-cost time slots to operate its most energy-consuming equipment.
THEoptimization of the subscribed power is also an area to be explored in order to limit overpower and financial penalties.
I want to optimize my contract
With Sirenergies, identify the contract best suited to your consumption profile and optimize your uses to take full advantage of off-season rates and off-peak hours.
Make an appointment with a SirEnergies expert
Self-consume your electricity
Self-consumption its own renewable electricity generates substantial savings on the electricity bill, in the order of 20% to 40%.
The financial impact is immediate in summer when the photovoltaic panels reach a peak of production.
With self-consumption, the company also protects itself against rising electricity prices during a heatwave.
In the long term, investing in photovoltaic panels is always a win, with a estimated return on investment between 5 and 10 years.
The choice of efficient technologies to limit the financial impact of the heatwave
In addition to simple actions, investing in efficient equipment improves comfort while greatly reducing electricity consumption.
Install or upgrade air conditioning systems
To replace aging air conditioning or invest in an efficient system, many solutions exist, starting with the heat pump (PARK), which has become a must.
But other innovative technologies are helping to reduce the excessive use of cooling systems, such as:
- The variable refrigerant flow system (VRV/VRF): this system automatically adjusts the quantity of refrigerant to the thermal needs of each zone. It heats or cools each space in a personalized way.
- The free-cooling system : this system takes advantage of the natural freshness of the outside air to cool the building.
Others more sustainable solutions can be considered as the use of soil freshness (geothermal heat pump or climate sink), bio-air conditioning or evaporative air freshener (RAE), solar air conditioning, “cool roofing” or even reflective materials.
Storing the cold in an offset
Cold storage makes it possible to produce cold during off-peak hours, when electricity costs less, and to use it later, during peak hours or in case of high heat.
For a self-consuming company, refrigeration can also be produced at the time of a peak in photovoltaic production.
Cold is stored as thermal energy (often in the form of ice or ice water) in insulated tanks or tanks.
This system smoothes consumption, limits power calls and reduces the electricity bill, while securing the cold chain.
Use intelligent control systems
Connected sensors and intelligent systems optimize the energy management of tertiary and industrial buildings. They not only make it possible to monitor consumption, but also to control equipment according to real needs and summer constraints.
For example, the smart thermostats regulate the indoor temperature according to the schedules, the occupancy of the premises or the weather forecasts. Associated with presence detectors, they avoid air conditioning empty rooms. For their part, the televariators adapt the lighting to the use.
In a smart building, equipment can be managed automatically. This involves a BMS (technical building management) or a GTC (centralized technical management). These systems control lighting, air conditioning, ventilation or blinds. They are based on data such as temperature, sunlight, CO₂ levels or presence in the premises.
Adopting an energy management tool
To sustainably optimize your energy consumption, it is essential to have a clear, precise and real-time vision of its uses.
Energy management tools make it possible to monitor, analyze and manage your consumption with precision, by identifying waste and optimization levers.
Did you know that?
With Pilott, Anticipate consumption peaks and adjust your uses during off-peak hours.
A true energy dashboard, Pilott centralizes your data, facilitates decision-making and helps you control your costs.
To conclude...
A heatwave is not inevitable for your energy budget.
The implementation of simple actions and efficient equipment allows businesses to better withstand heatwaves. They also serve as sustainable optimization levers for their energy transition.
Better adjusted contracts, rational air conditioning, smart buildings, smart buildings, self-consumption or even real-time energy management: the solutions are numerous, accessible and adaptable to your budget.
Adopting a proactive approach means not only reducing your electricity bill, but also increasing energy efficiency and strengthening the resilience of your company in the face of climate hazards.
What if, instead of suffering the heat, you took back control of your energy? Sirenergies accompanies you to transform the heatwave into an opportunity.
Take the first step towards optimization
In a few clicks, organize an exchange with one of our experts.
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The answers to your questions
Why change energy suppliers?
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Changing suppliers can allow you to benefit from more competitive prices, adapted services or better contractual conditions. Thanks to sourcing, change is happening without interruption of supply.
Comment réduire la puissance souscrite de son compteur ?
En analysant votre courbe de charge pour identifier la puissance réelle appelée, puis en demandant un ajustement à votre fournisseur ou via un expert en énergie.
What is the difference between €/MWh and kWh?
The €/MWh is a price unit used in wholesale markets, while kWh is the unit visible on your bills.
Quelles sont les nouvelles obligations pour le Décret Tertiaire et l'Audit Énergétique ?
Le calendrier 2026 impose deux échéances majeures :
- la déclaration des consommations 2025 sur la plateforme OPERAT avant le 30 septembre
- la réalisation d'un audit énergétique avant le 11 octobre pour toutes les entreprises consommant plus de 2,75 GWh/an.
Pour simplifier ces démarches, vous pouvez centraliser vos données de consommation avec la plateforme Pilott de Sirenergies, garantissant ainsi la conformité de vos rapports réglementaires.
What are the energy challenges of the agricultural sector?
Farms must deal with high seasonal needs (greenhouse heating, irrigation, storage) and high volatility of prizes. Controlling these costs is essential to maintain profitability and secure the business.
Quel est le nouveau record 2025 d'exportation d'électricité de la France ?
En 2025, la France a atteint un solde exportateur net de 92,3 TWh, battant le précédent record de 2024 (89 TWh).
Pourquoi mon contrat est-il en kVA et ma consommation en kWh ?
Le kVA mesure la capacité maximale que votre compteur peut supporter à un instant T, tandis que le kWh mesure la quantité d'énergie consommée sur une durée.
L'hydroélectricité est-elle une énergie "propre" ?
Oui, elle est considérée comme une énergie renouvelable à faibles émissions de gaz à effet de serre.
De plus, l'eau ne subit aucune transformation chimique durant le cycle de production et réintègre son milieu naturel en aval.
Cependant, la construction de barrages nécessite des mesures pour protéger les écosystèmes (débit minimum, passes à poissons).
What are the customer reviews on bellenergie Business's customer service?
In 2025, the supplier had a NPS (Net Promoter Score) of +16 and a note of 4,17/5.
Satisfaction is based on a “zero solicitation” model and 100% in-house customer service in Toulon, guaranteeing proximity and responsiveness that cannot be found with major historical suppliers.
How to optimize taxes and contributions?
Tertiary companies are concerned by taxes such as TICFE or TICGN. Sirenergies checks the accuracy of invoices, identifies possible exemptions, and helps correct errors to sustainably reduce costs.
Qu'est-ce qui remplace l'ARENH en 2026 pour les entreprises ?
L'ARENH est remplacé par le VNU (Versement Nucléaire Universel), un mécanisme de redistribution des revenus excédentaires d'EDF en cas de prix très élevés, et par les CAPN, des contrats long terme pour les gros industriels.
What are the electricity offers offered by bellenergie Business?
The range E @sy is available in four pricing structures to adapt to each risk profile:
- E @sy Fixed: 100% budget visibility without variation.
- E @sy Click: Smoothed price thanks to staggered purchases on the markets.
- E @sy Block + Spot: A mix between a secure base and a portion indexed to daily prices.
- E @sy Sport: A 100% dynamic offer to take advantage of downside opportunities in real time.
How to optimize the taxes and contributions of a community?
Communities are subject to taxes such as TICFE or TICGN. Sirenergies analyzes invoices, identifies exemption possibilities and fixes possible errors to reduce the tax burden.
Quand faut-il renégocier son contrat d'électricité professionnel pour 2026 ?
Idéalement entre 6 et 12 mois avant l'échéance, de préférence au printemps ou au début de l'été lorsque la demande est plus faible.
How do I read an electricity or gas bill?
One invoice consists of several elements: consumption, supplier share, taxes and contributions. The analysis of each line makes it possible to identify possible errors and to check the consistency with the signed contract.
Pourquoi l'humain est-il le premier levier de la performance énergétique ?
Même le bâtiment le plus moderne et le mieux isolé perd son efficacité si ses usages sont inadaptés. La technologie et les normes ne suffisent pas : la transition énergétique est avant tout une transformation humaine.
Derrière chaque kilowattheure consommé se cache une habitude.
Un collaborateur sensibilisé comprend qu'ouvrir une fenêtre alors que le chauffage est allumé ou laisser un ordinateur en veille consomme de l'énergie inutilement. En replaçant l'humain au centre de la stratégie de gestion de l'énergie, l'entreprise s'assure que ses équipements performants sont utilisés de manière optimale, garantissant ainsi une rentabilité durable et un impact environnemental réduit.
How do I get a tax exemption?
Some businesses may obtain a partial or total exemption from the TICFE or the TICGN, depending on their activity and energy intensity. The support of an expert makes it possible to identify the eligibility criteria and to put together the file.
What are the main taxes applicable?
Among the taxes include TICFE, TICGN, CTA, CJA and TURPE. They represent a significant part of the bill and vary according to consumption profiles. Understanding them well is essential to optimize costs.
Is Bellenergie Business electricity really green?
Yes. The supplier guarantees an offer 100% renewable via the official Guarantees of Origin (GO) mechanism.
For the most demanding companies, the offer GREENVOLT+ ensures very low carbon intensity electricity, sourced exclusively from independent French producers (hydraulic, wind, solar).
What are the consequences of overpowering?
Exceeding capacity leads to financial penalties and can impact the size of the contract. Adjust the correctly subscribed power makes it possible to avoid these additional costs.
Which taxes are particularly relevant for farms?
Farms are subject to taxes such as TICFE or TICGN. Sirenergies verifies their application, identifies cases of exemption and accompanies the procedures to reduce the tax burden.
Who can benefit from optimizing invoices and taxes?
All businesses, from SMEs to large organizations, can benefit from this service. Les local authorities also find it a lever to better control their budgets.
What are the concrete benefits for tertiary companies?
Les profits include a direct reduction in bills, strengthened budgetary forecasting and better control of consumption. Businesses gain visibility and efficiency thanks to adapted tools.
Comment réduire ma facture si les prix du marché sont volatils ?
En 2026, les principaux leviers sont : la renégociation de votre contrat de fourniture au bon moment, l'optimisation de votre tarif d'acheminement (TURPE), la vérification de votre éligibilité aux taux réduits de taxes (Accise), et la réduction de votre consommation (efficacité énergétique, autoconsommation).
What are the challenges for tertiary companies?
Tertiary companies must manage their energy costs while guaranteeing the comfort of users (offices, shops, services). Consumption is often linked to heating, air conditioning and lighting, which requires precise monitoring to avoid budgetary excesses.
What is energy sourcing?
Sourcing consists in identifying and analysing the offers of several electricity and gas suppliers. This approach makes it possible to obtain contracts adapted to the consumption profile and budgetary constraints of the company.
Qu'est-ce que le cosinus phi
C'est l'indicateur d'efficacité d'un appareil électrique ; il représente le ratio entre la puissance active (utile) et la puissance apparente (totale).
Pourquoi la France a-t-elle exporté un volume record d'électricité en 2025 ?
Ce record de 92,3 TWh s'explique par la conjonction de trois facteurs :
- Le redressement du parc nucléaire : Après les problèmes de corrosion sous contrainte de 2022, la production nucléaire a retrouvé une forte disponibilité (373 TWh).
- L'essor des renouvelables : Une capacité installée en hausse (solaire et éolien) et une production hydraulique solide.
- Une consommation intérieure atone : La demande française reste inférieure de 6 % à la moyenne historique, créant un surplus massif disponible pour nos voisins.
Comment mobiliser les collaborateurs autour d'un projet de sobriété énergétique ?
La réussite d'un projet collectif énergie repose sur trois piliers fondamentaux :
- La visibilité : On ne gère bien que ce que l'on mesure. Partager les données de consommation via des outils comme l'application Pilott donne un sens concret aux efforts fournis.
- L'incarnation : Nommer des ambassadeurs énergie internes permet de diffuser les bonnes pratiques par l'exemple et de lever les freins opérationnels propres à chaque métier.
- La gamification : Transformer la contrainte en défi (challenges inter-services, concours de l'équipe la plus sobre) crée une dynamique positive et renforce la cohésion d'équipe autour des enjeux RSE.
Comment l'eau est-elle transformée en électricité ?
Le processus repose sur l'utilisation de la force de l'eau (énergie cinétique) issue des courants, des chutes d'eau ou des dénivelés. Le fonctionnement suit trois étapes clés :
- Le barrage retient l'eau et l'oriente vers des conduites.
- La pression de l'eau fait tourner une turbine, créant de l'énergie mécanique.
- Une génératrice (alternateur) transforme cette énergie mécanique en électricité, laquelle est ensuite adaptée par un transformateur pour le réseau
Le prix de l'électricité va-t-il baisser en 2026 ?
Pas nécessairement sur votre facture finale. Si les prix de gros (le prix de l'énergie brute) ont baissé, les coûts d'acheminement (TURPE) et certaines taxes augmentent, compensant souvent la baisse de la part énergie.
Qu'est-ce qui remplace l'ARENH depuis le 1er janvier 2026 ?
Le dispositif ARENH a laissé place au VNU (Versement Nucléaire Universel).
Ce changement structurel expose davantage les entreprises aux prix de gros, rendant la gestion des risques plus complexe qu'auparavant.
Il devient alors indispensable de définir une stratégie d'achat d'électricité avec Sirenergies pour lisser l'impact de la volatilité des marchés sur votre budget.
What are the energy challenges for manufacturers?
Industrial companies consume large volumes of energy for their production processes. They have to deal with the volatility of prizes, multi-site management and specific taxes. Controlling costs is essential to remain competitive.
What taxes are particularly relevant to manufacturers?
The industry is concerned by TICFE, TICGN and other contributions that may represent an important part of invoices. Sirenergies identifies cases of exemption and accompanies the procedures to benefit from them.
Quel est l'impact de ces exportations sur le prix de l'électricité pour les entreprises ?
L'abondance de production française tire les prix du marché de gros vers le bas.
En vertu du mécanisme de l'Ordre de Mérite (Merit Order), les centrales les moins coûteuses (nucléaire, renouvelables) couvrent la demande plus souvent, évinçant les centrales à gaz ou charbon plus onéreuses.
Cela multiplie les épisodes de prix bas, voire négatifs, sur le marché spot.
What are the PP1 and PP2 alert days?
These are signals sent by RTE during periods of tension on the electrical network. The Sirenergies tool informs you in real time to anticipate your uses.
Why launch an energy tender?
Un appel d’offres permet de mettre en concurrence plusieurs fournisseurs d’électricité et de gaz afin d’obtenir des conditions contractuelles optimisées. C’est une démarche transparente qui permet de choisir l’offre la plus adaptée aux besoins budgétaires et techniques de l’organisation.
What is the point of following Spot & Forward prices?
This makes it possible to choose the right time to contract, secure your budgets and anticipate increases.
Quel est l'impact réel de la rénovation de l'éclairage public ?
C'est le levier le plus rapide pour obtenir des résultats visibles. L'éclairage représente environ 40 % de la consommation d'électricité d'une commune.
Passer au LED avec pilotage intelligent permet de réduire la facture de 50 à 80 %, avec un retour sur investissement (ROI) rapide, souvent estimé à 2 ou 3 ans.
Pourquoi le kVA est-il crucial pour les entreprises ?
Parce que la puissance souscrite en kVA détermine le prix de l'abonnement et que tout dépassement peut entraîner des surcoûts importants.
What are the advantages of sourcing?
Sourcing offers better visibility on the market and promotes the selection of competitive contracts. It helps to reduce the risks associated with price volatility and to optimize the energy budget.
How to properly define your subscribed power?
The subscribed power must be calculated according to the consumption profile and uses (heating, industrial processes, tertiary equipment). One fine analysis makes it possible to ensure the adequacy between real need and contract.
Quelle est la différence concrète entre le transport et la distribution d'électricité ?
Le transport (RTE) correspond aux "autoroutes" de l’électricité. Il s’agit de transporter de très grandes quantités d'énergie sur de longues distances, depuis les centrales de production (nucléaires, barrages, parcs éoliens offshore) vers les régions de consommation.
La distribution (Enedis) s'apparente aux "routes départementales" et aux rues. Elle récupère l'électricité à la sortie du réseau de transport pour la livrer directement chez le client final, en abaissant la tension pour qu'elle soit utilisable par vos appareils.
Comment financer les travaux communaux sans augmenter la taxe foncière ?
Plusieurs leviers existent pour préserver la fiscalité locale :
- Les CEE (Certificats d’Économie d’Énergie) : Un financement privé majeur pour l'efficacité énergétique.
- L'optimisation de l'achat d'énergie : Choisir des contrats adaptés (prix fixes, indexés ou groupés) pour dégager des marges de manœuvre dès la première année.
- Les aides publiques : Mobiliser le Fonds Vert, le FEDER ou le Fonds Chaleur.
The answers to your questions
How do I read an electricity or gas bill?
One invoice consists of several elements: consumption, supplier share, taxes and contributions. The analysis of each line makes it possible to identify possible errors and to check the consistency with the signed contract.
How to filter news by theme (gas, electricity, etc.)?
Use the category filters in the section: Gas, Electricity, Green Energy, Environment, budget, Energy market to target relevant topics.
How to optimize your contracts when you are an SME?
Sirenergies supports SMEs in the renegotiation of contracts, the choice of the most suitable suppliers and the adjustment of the contracted power. The objective is to secure prices while avoiding unnecessary penalties.
How to optimize the taxes and contributions of a community?
Communities are subject to taxes such as TICFE or TICGN. Sirenergies analyzes invoices, identifies exemption possibilities and fixes possible errors to reduce the tax burden.
Who can benefit from optimizing invoices and taxes?
All businesses, from SMEs to large organizations, can benefit from this service. Les local authorities also find it a lever to better control their budgets.
What does the simulation of electricity bills allow?
It generates a budget forecast per delivery point, by comparing your actual consumption with your bills.