Smart Thermostats: Climate Protection or an Expensive Compulsory Purchase?

What begins as a climate-protection measure could become an expensive compulsory purchase for many people.

Greater control over heating, lower energy use and reduced CO₂: that is the political promise. Yet the proposal to make connected thermostats mandatory in every room raises a question that matters far more to many homeowners and tenants: who will pay for it all, and will the investment actually pay off?

What is behind the requirement for smart thermostats?

France has already made its position clear: by 2030, connected thermostats must be fitted to every radiator in a great many homes. Similar debates are under way in Germany, driven by climate targets, rising energy prices and the aim of managing consumption more effectively.

The political reasoning initially appears plausible. Digitally controlling each individual heat source makes it possible to set temperatures room by room, adapt heating schedules, review consumption data and reduce energy use. Conventional twist thermostats respond slowly and offer little visibility, whereas smart models promise greater efficiency.

“The idea: set precisely, room by room, when and how much heating is needed – and reduce heating costs over the long term.”

Using an app, wireless hub or smart-home system, residents can, for example:

• set a separate temperature for every room;
• tailor heating times to their daily routine;
• turn down the heating while away from home;
• analyse consumption data and identify “energy-hungry rooms”.

It is precisely this added value that governments cite to justify the requirement. Behaviour-based savings are considered cheaper than funding insulation or replacement heating systems everywhere.

The costly downside: funding disappears, but the bill remains

France illustrates how quickly a measure that makes sense in principle can turn into a financial trap. The state was originally meant to subsidise the purchase and installation of connected thermostats. Following widespread cases of fraud, however, the government withdrew that support.

As a result, households are left to cover the entire bill. The costs can be substantial:

Number of radiators	Average cost per thermostat	Total cost per home
2	approx. €300	approx. €600
4	approx. €300	approx. €1,200
6	approx. €300	approx. €1,800

A typical flat with four radiators would cost around €1,200. For larger flats or houses with more radiators, the amount quickly rises to levels that are especially difficult for households on tighter budgets to afford.

Who could be exempt from the smart thermostat requirement – and who could not

The French rules provide for several exemptions, which could also serve as a model for other countries. No requirement applies there to:

• buildings heated mainly by a wood-burning stove;
• cases in which the investment is not expected to pay for itself within ten years.

The aim is to avoid forcing people to alter heating systems that offer little technical potential for savings or are used only infrequently. For most households with conventional radiators and central heating, though, the obligation would still apply.

“Anyone using ordinary radiators and central heating will, in many cases, be unable to argue their way out of the requirement.”

Political criticism: “regulatory overreach” and intrusion into everyday life

Opposition to the requirement comes not only from consumer groups, but also from economists and politicians. Critics refer to “regulatory overreach” and warn that the state is intervening ever more deeply in how private homes are equipped – from the type of heating system right down to the thermostat on each individual radiator.

The fact that the state sets the rules while increasingly withdrawing from the costs is particularly contentious. Grant schemes are being cut back, while obligations remain in place or are even tightened. Many citizens consequently feel abandoned.

Regulatory costs add up for homeowners and tenants

A requirement for smart thermostats would not arrive in isolation. Costly rules concerning buildings and energy are already piling up, from insulation standards and new heating regulations to refurbishment obligations. In France, for instance, many residential developments must already prepare a so-called multi-year plan for forthcoming modernisation work. Comparable discussions are taking place in Germany in connection with the Building Energy Act and climate-protection requirements.

For homeowners, this means that no sooner has one refurbishment been completed than the next rule is on the horizon. Ultimately, the costs are borne either directly by the owner or indirectly by tenants through higher service charges and rents.

• Smart thermostats
• Insulation measures
• Heating-system replacement
• Mandatory assessments and energy performance certificates
• Modernisation levies in rented buildings

Consumer organisations warn that this accumulation of individual measures places a particular burden on low- and middle-income households. Often, the only options are to take on debt or postpone urgently needed repairs in order to finance new obligations.

Do the devices really save as much as promised?

On paper, the calculation is appealing: heating rooms according to actual need can, according to estimates, cut energy consumption by 10 to 30 percent. In practice, however, the result depends heavily on the starting point.

Several factors determine the real saving:

• Have residents already heated consciously, or have radiators constantly been running at full output?
• Is the home well insulated, or does much of the heat escape through walls and windows?
• Are the thermostat functions actually used consistently?
• How high will energy prices be in the coming years?

People who have already heated economically will often achieve only a small additional benefit. In poorly insulated older buildings, some of the saving quite literally disappears through the walls. And if residents ignore the app after the first few weeks, little of the theoretical potential remains.

“Smart thermostats only achieve their full saving potential when technology, building standards and user behaviour work together.”

What households should consider if a requirement is introduced

Although the precise rules vary from country to country, anyone expecting a future requirement or already considering an upgrade should clarify several points in advance.

• Take stock: How many radiators are there, which valves are installed, and how old is the heating system?
• Assess the system choice: Individual wireless thermostats, a central gateway or integration with an existing smart home: depending on the property, one option may be cheaper and simpler.
• Calculate the payback period: What will the devices and installation cost, and what realistic annual saving could be achieved at current energy prices?
• Clarify the tenancy position: In rented homes, the owner makes the decision. Tenants should discuss early on whether and how costs will be shared.
• Keep data protection in mind: Many systems collect detailed usage data. Anyone who values privacy should examine this carefully before buying.

Opportunities and risks of connected heating technology

Beyond the political dispute, smart thermostats offer genuine advantages. They make energy consumption more visible, simplify needs-based heating and can support both comfort and the climate, for example through setback programmes when nobody is home. In apartment buildings, data can also help faults to be identified more quickly.

At the same time, new dependencies arise: on wireless networks, apps, cloud services and manufacturers that must provide updates. Those who rely entirely on connected controls may, in the event of failures, be left without heating or only able to use their devices in a limited way.

There is also a social issue. Technical requirements costing several hundred or even several thousand euros hit people with limited means harder than well-off homeowners. Without fair funding, there is a growing risk that climate protection will be seen as a luxury for the affluent – further reducing public acceptance.

Policymakers therefore face a twofold challenge: making sensible use of the saving potential offered by smart technology without financially overwhelming households, and designing rules so that investments genuinely pay off rather than simply becoming another costly tick-box on a long list of obligations.