Alternatives to the fan heater: Split air conditioning systems, infrared heaters & Co. The impending gas shortage is boosting the sale of fan heaters. The additional load could become a problem for the power grids. Techstage shows alternatives. 8:00 p.m. tech stage
The impending failure of Russian gas supplies is boosting sales of fan heaters. But the power grid is not designed for the mass use of such devices. Are there better alternatives?
In the middle of summer, people in this country buy fan heaters and other direct heating devices such as radiators, convectors and radiant heaters like crazy. The reason: after the imposition of Western sanctions because of the Ukraine war, Russia cut gas supplies to Europe. Only recently, the Russian state-owned company Gazprom reduced the flow through the Nord Stream 1 gas pipeline from 40 to 20 percent due to a missing turbine. If more gas does not flow through the pipeline soon, the storage tanks cannot be filled until winter – there is a risk of a gas bottleneck.
Not only that: According to the Federal Statistical Office , the share of natural gas in electricity generation in 2021 was 12.6 percent . The gas shortage could also lead to a bottleneck in power generation. Especially when the remaining three nuclear power plants are shut down towards the end of the year. In 2021, six nuclear power plants were still in operation, and their share of electricity generation was 12.6 percent – i.e. exactly as high as the share of gas in the electricity feed-in. For 2022, this proportion is likely to be lower, since three nuclear power plants were already shut down at the end of last year.
The tense supply situation with natural gas has led to high energy price increases. According to the Federal Statistical Office, natural gas was 235.6 percent more expensive in May 2022 than a year earlier. In June 2022, natural gas for industry cost 182.6 percent more than in June 2021, while the high price increases in the private sector have not yet fully arrived: the consumer price for natural gas in June 2022 was 60.7 percent higher than in the same month last year .
Mass use of fan heaters could lead to blackout
Direct heating devices such as radiators, radiant heaters and fan heaters are inexpensive and available for less than 20 euros. The VDE assumes that sales of the devices will continue to increase. Alarmed by the sale of over 600,000 fan heaters in the first half of the year, associations and municipal utilities are warning against using the devices. “We view the current development with some concern, as our power supply is not designed for such a simultaneous additional load ,” says Martin Kleimaier, head of the “Generation and storage of electrical energy” department of the Energy Technology Society in the VDE (VDE ETG) .. “Since the heaters are simply connected to a household socket, they cannot – in contrast to electric heat pumps or so-called night storage heaters – be switched off by the network operator in the event of imminent network overloads,” Kleimaier continues.
According to the experts, the risk of a blackout in areas where many fan heaters are used at the same time increases. “With such an additional load occurring at the same time, the overload protection can respond and thus lead to a power failure in the affected network areas,” says Hendrik Lens, deputy head of the Energy Technology Society (ETG) in the VDE. Restoring the power supply will then also be difficult. “If not as many affected customers as possible switch off their heaters manually, an attempt by the network operator to switch them on would immediately lead to them being switched off again.”
According to Gerald Linke, Chairman of the Board of the German Technical and Scientific Association for Gas and Water, there is no risk for private customers in winter due to a gas bottleneck . “Even if Russian gas no longer flows at all, around 19 million heating customers in Germany do not have to freeze in their homes. They are among the so-called protected customers and, like thermal power plants, social institutions and commercial and service companies, are supplied with a limited annual withdrawal throughout the winter. This is specified by the European legal framework and is anchored in the German Energy Industry Act.”
Frank Gröschl, head of technology and innovation management at DVGW , recommends: “However, it makes sense to start taking efficiency measures on the gas heating systems for the winter in the summer. Lowering the room temperature by one degree saves six percent of energy . By adapting the heating control to the actual user behavior, online control of radiator thermostats (see also Top 10: The best smart radiator thermostats 2022 and save heating costs with smart thermostats from 10 euros ) via app, hydraulic balancing of the heating system and much more are other fast-acting measures to increase efficiency and Consumption reduction possible. Ongoing maintenance on the gas heaters should take place before winter in order to identify and eliminate inefficiencies at an early stage. The fact that gas consumption has fallen by around 14 percent compared to the previous year shows that these measures are already beginning to take effect . There’s still something going on.”
Blackout protection: solar generator as an alternative power source for fan heaters, convectors, radiators and infrared heating
In order to protect the power grid from overload, users can also rely on particularly powerful solar generators (theme world) such as the Jackery Explorer 2000 Pro (test report) or the Bluetti AC200Max (test report) to operate a fan heater, radiator or infrared heater with a storage capacity of 2 kWh . If there is a blackout due to overloading of the power grid , these devices can of course not only be used to operate direct electrical heating. The devices supply a well-equipped home office with a computer, monitor and printer with a power consumption of 120 watts for a good 17 hours.
But even powerful solar generators don’t work miracles. The devices can operate a fan heater with 2000 watts for a maximum of one hour. Then the memory is empty. And while charging is possible within three hours in summer under favorable conditions with suitable solar panels, it should take significantly longer in the winter months. In addition, the blackout solution is not exactly cheap: you have to calculate around 2100 euros for a solar generator in this performance class alone. And for the matching 350-watt solar panels, 900 euros are due each, so that you get a total of around 5000 euros.
Simple fan heaters are already available for little money. As a rule, they offer a maximum output of 2000 watts , with which they heat the air electrically via a heating element and distribute it in the room using a fan. This happens relatively quickly, so that you can quickly heat a room up to a size of around 20 to 25 square meters.
A convector works in a similar way to a fan heater. The devices, which are available as standing or wall-mounted models, heat up the cold air via heating wires. But unlike fan heaters, convectors work without a fan. Instead, they use the thermal lift of the air to distribute the heat. Unlike fan heaters, they heat more selectively and it also takes longer for the heat to be distributed.
Alternatively, radiators can also be used for heating. Compared to fan heaters or convectors, however, the heating process takes longer. But they work silently and without drafts. In these devices, which are based on a normal radiator, electricity is usually used to heat thermal oil, the heat energy of which is dissipated via the ribbed outer surface. In contrast to the fan heater, which no longer emits any heat energy after it has been switched off, things look better with the radiator: they continue to heat up for a good hour.
With infrared heaters there is another way to heat a room without oil and gas. Similar to the sun, the heat output is greatest when an object is directly irradiated by the device’s infrared rays. The heated object or body stores heat up to three times longer than air and releases it back into the environment. As a result, infrared heaters are among the most efficient electric heaters.
So if you only use a room for a short time and want to heat it up quickly, you can use a fan heater or convector . However, if you want to heat an area permanently, it is better to use a radiator . Since the latter stir up less dust than fan heaters, they are more suitable for allergy sufferers. The same applies to infrared heaters, which work most efficiently compared to fan heaters, convectors and radiators.
In any case, the following applies: Electric heaters cause high costs if you do not produce the electricity yourself, for example via a photovoltaic system. According to the Federal Association of Energy and Water Industries (BDEW), the current electricity price is already 37.30 cents/kWh (as of July 2022). This means that a household with a consumption of 3,500 kWh per year pays around 1,300 euros in electricity costs. However, this is only an average price. Some electricity providers are already charging their customers prices of up to just under 60 cents/kWh .
Alternative heating options for homeowners
There are more heating options for homeowners than for renters or owners of an apartment to switch to alternative heating technologies. For example, you can often switch to pellets or wood. Split air conditioners , which are basically an air-to-air heat pump, are becoming increasingly popular . It is particularly flexible in relation to the room climate: it cools in summer and can be used as heating in winter. The devices extract heat from the ambient air and transport it away via the refrigerant, so that the room temperature drops. In winter you can reverse this process and use it to heat a room.
Particularly efficient devices are equipped with an inverter that automatically and continuously adjusts the speed of the compressor for temperature control. Compared to conventional on/off devices, split air conditioning systems with inverters save up to 30 percent energy. Inverter models reach the target temperature faster than conventional variants. And they work much more quietly.
To evaluate the effectiveness of split air conditioning systems or heat pumps, there is a so-called SCOP value. SCOP stands for Seasonal Coefficient of Performance and determines the annual performance factor of a heat pump within different operating states, which are weighted according to climate zones. With a SCOP of 4, for example, you get 4000 kWh of heating energy from 1000 kWh of electricity. Split air conditioners offer a SCOP of just over 4 to 5.1. This means that they achieve a similar level of efficiency as typical air-to-water heat pumps (SCOP 4.4-5.5). As with any heat pump, the operation of a split air conditioner depends on the outside temperatures. LG devices are suitable down to -10 degrees, Mitsubishi solutions work down to -15 degrees, while Daikin models even work down to -20 degrees.
Split air conditioners can be used as heating for an entire house. Andreas Schmitz, who works as a scientist in the field of mathematical optimization and AI and has a doctorate in engineering, reports this on his YouTube channel.
For Carsten Herbert, who works with his company Energie & Haus as a specialized engineering office in the field of energy-saving construction and renovation, split air conditioning systems are an efficient alternative to gas and oil heating.
Acquisition and operating costs of split air conditioning systems
Carsten Herbert examined in more detail whether the use of a split air conditioning system is worthwhile compared to a normal air-water heat pump. For his example calculation, he considers an older and poorly insulated house with a calorific value of 100 watts/m 2 . Such houses were built until about 1978. In the second case, he calculates the costs for a well-insulated house with a calorific value of 50 watts/m 2 . In both cases the living area is assumed to be 150 m 2 .
He carries out both model calculations on the basis of two multi-split air conditioning systems with six indoor units. Since these variants are more powerful than individual devices and the installation is more complex because several indoor devices have to be connected to them, you have to calculate around 1600 euros per kW. For individual devices, this value is significantly lower between 800 and 1400 euros. On top of that, you also have to add the maintenance costs. In the present case, these are 500 euros per year for split air-conditioning systems, while they are significantly lower for air-water heat pumps at 250 to 400 euros.
In total, the total costs of split air conditioning systems for a poorly insulated house in the model calculation are 29,000 euros. This means that the costs are similar to those for an air-to-water heat pump. However, there are also costs for hot water, which are included in air-to-water heat pumps, so that air-to-water heat pumps are more efficient overall in older, poorly insulated houses.
However, the situation is different for houses with good insulation and a calorific value of 50 watts/m 2 . In this case, the total cost is only 17,000 euros. Even with additional costs for hot water production, the split air conditioner works more economically than an air-to-water heat pump.
Conclusion
With high SCOP values of 4 to over 5, split air conditioning systems are an economically viable alternative for heating rooms for homeowners. The lower the heating load, the more economical the operation. They are also interesting for owners of photovoltaic systems, as they can use them to increase their own consumption of the electricity they produce themselves and thus obtain less expensive electricity from the grid from the electricity provider and thus reduce electricity costs.
Renters or condominium owners cannot easily use split air conditioners. This is because the community of owners must agree to this, which is rather difficult in practice. For them, there is no serious alternative to heating from oil and gas if they do not produce the electricity themselves, at least in part, for example using a balcony solar system in combination with a solar generator. Because with the currently rapidly increasing electricity costs, fan heaters, radiators, convectors and infrared heaters can quickly become a cost trap.
Our guide to reducing electricity costs with smart sockets and thermostats to save on heating costs shows other ways of saving energy costs .
