Car seat heating
An ice-cold driver's seat on a winter morning – it doesn't have to be that way. Car seat heating provides cosy warmth within minutes and noticeably increases the comfort of any vehicle. But which systems are available, what does retrofitting cost, how high is the power consumption and what must be considered during installation? In this comprehensive guide, we answer all the important questions about car seat heating. As an experienced online retailer for automotive electronics, Electronicx GmbH offers you expert advice and high-quality products – from heating mats to complete retrofit kits.
What is car seat heating and how does it work?
Car seat heating is an electrical heating system that is integrated into the seat or placed on top as a cushion. At its core are heating conductors – usually fine resistance wires or carbon fibre strips – that are incorporated into a thin mat. As soon as 12 volts of on-board voltage is applied, current flows through the conductors, they heat up and release the heat through the seat surface and backrest to the driver or passenger. Typical operating voltages are 12 V DC, the electrical resistance of the heating mat is 3–6 ohms depending on the version, resulting in a power consumption of 30 to 60 watts per seat.
Modern seat heaters are usually two-stage or continuously adjustable. At the low setting, less current flows and the temperature settles at around 30–35 °C; the high setting provides a pleasant 40–45 °C. A built-in temperature sensor or PTC thermistor ensures that the seat surface does not overheat – so the surface remains skin-friendly even during continuous operation. Safety is ensured by a 10 A or 15 A fuse in the circuit and often by an automatic switch-off after 20–30 minutes.
The different types of seat heating compared
Not all seat heating is the same. The following table shows the most common systems and their typical characteristics – from factory-installed heating to a simple plug-in cushion.
| Type of seat heating | Power consumption per seat | Heat-up time to 35 °C | Installation effort | Price range (material) |
|---|---|---|---|---|
| Factory-integrated heating | 40–60 W | 2–5 minutes | not applicable | orderable from factory |
| Retrofit heating mat (carbon fibre) | 35–55 W | 1–3 minutes | High (seat cover must be removed) | 50–120 € per seat |
| Retrofit heating mat (wire) | 40–60 W | 3–5 minutes | High (remove seat cover) | 30–80 € per seat |
| Heated seat cushion (seat pad) | 25–45 W | 2–4 minutes | Low (12 V socket) | 20–70 € |
Carbon fibre mats heat up particularly quickly and evenly, wire mats are somewhat cheaper but also more robust under mechanical stress. Heated seat cushions can be plugged in within seconds and are suitable for all vehicles without factory-fitted heating – ideal for hire cars or low-mileage users. Factory heating systems are usually integrated directly into the vehicle system and can hardly be retrofitted; subsequent installation is therefore limited to the last three variants mentioned.
Retrofitting seat heating – step by step
Retrofitting seat heating is one of the most popular comfort upgrades in the automotive sector. Modern universal heating mats can be installed in almost any vehicle seat – from small cars to SUVs. In our guide Retrofitting seat heating we show all the work steps in detail. Here are the most important points at a glance.
Requirements and vehicle check
Check whether your seat is suitable for heating mats at all. Seats with complex side airbags, seat occupancy sensors or climate-controlled upholstery require particular care. With leather seats and perforated covers, the mats must fit exactly. In principle, however, most commercially available car seats can be fitted with mats. Pay attention to the design: universal mat sets are available in sizes for driver and passenger seats as well as for the rear bench. The dimensions should match the seat surface and backrest dimensions – typical mat formats are 28 x 48 cm (seat surface) and 25 x 55 cm (backrest).
Heating mats or heated seat cushions?
Heating mats are placed under the original cover, remain invisible and offer the highest level of comfort. However, the installation effort is considerable: seat covers must be removed, mats fixed and cables routed to the outside. Heated seat cushions, on the other hand, are ready for use in minutes: place them on the seat, plug into the 12 V socket, done. The disadvantage: a loose cable lying around and somewhat lower heat output. For a permanent solution with an integrated switch, fixed retrofitting is the first choice.
Installation tools and materials
As a rule, you will need: a set of Torx and hex keys to release the seat mounting, upholstery pliers or spring hook pliers, side cutters, cable ties, crimping pliers, scotch locks or wire end ferrules, heat shrink tubing and a multimeter for checking voltage and wiring. The retrofit kit should contain: two heating mats (seat and backrest), a wiring harness with fuse holder (15 A), a switch panel (usually for two stages) and installation instructions. Make sure that the cable cross-section is at least 1.5 mm² to avoid voltage drops.
Electrical connection and fuse
The power supply is via the 12 V vehicle electrical system. The positive lead is connected directly to a permanent positive or ignition positive terminal (e.g. terminal 15) in the fuse box so that the seat heating only operates when the ignition is switched on. Use a separate fuse holder with 15 A – never work without fusing. The earth cable is screwed to a clean bodywork point. If two seats are heated, a relay is recommended to split the load across two circuits. The total current draw of two seat heaters on the highest setting can be up to 10 A (120 W) – this is not a problem for the alternator, but should not be operated for extended periods when stationary without the engine running, in order to protect the starter battery.
Power consumption and effects on the car battery
A single seat heating system draws about 3 to 5 amperes, i.e. 36–60 watts on the high setting. If both front seats are heated, this adds up to around 7–10 A (84–120 W). This is comparable to dipped headlights and is not a problem while driving, because the alternator supplies the current. It only becomes problematic when stationary with the engine switched off: a 60 Ah starter battery (e.g. a modern AGM battery, such as those stocked by Electronicx) can, on a full charge, theoretically operate a 5 A heater for about 12 hours until it is completely discharged. In practice, however, the battery should never be discharged below 50 % state of charge, so as not to jeopardise its service life. After just two hours of continuous operation without the engine running, at 10 A you would have consumed about 20 Ah – critical for batteries with low capacity or in winter. Therefore: only use seat heating with the engine running, or at most as a short-term source of warmth when stationary. Some systems have voltage monitoring that switches off automatically below 11.5 V.
Cost of seat heating: workshop vs. DIY
The pure material costs for a universal retrofit kit lie – depending on quality and scope of supply – between €40 and €150 for two seats. High-quality carbon mats with integrated thermostat and illuminated switches are around €80–120. Heated seat covers are available from as little as €20. Anyone who carries out the installation themselves saves the labour time. A specialist workshop usually charges 2–5 hours for fitting both front seats, which at an hourly rate of €80–120 quickly adds €300–600. DIY is quite possible with manual skill – but plan for a full day. Overall, for €150–250 you get a permanently integrated seat heating system that increases comfort and resale value.
Frequently asked questions (FAQ) about car seat heating
Can any seat heating system be retrofitted?
Yes, in principle almost all vehicles can be retrofitted with seat heating. However, with modern seats featuring complex sensor systems (occupancy detection, active head restraints) you should consult a specialist workshop. Make sure the mats are compatible with your seat covers.
How long does a seat heating system last?
With normal use and proper installation, high-quality heating mats often last 10 years and longer. Wire mats can break under heavy mechanical load; carbon fibre mats are more flexible and more durable. Heated covers with loose cables have a shorter service life if they are frequently kinked.
Is seat heating dangerous – can it catch fire?
Heating mats are extremely safe when correctly installed and fused. Thanks to built-in thermostats, the maximum surface temperature is below 45 °C. A 15 A fuse prevents overcurrents. With certified products, fires are practically impossible. Nevertheless, the heating system should not be damaged with pointed objects.
Does seat heating drain the starter battery?
Not while driving, as the alternator supplies the current. With the engine switched off, however, two hours of use at a high setting can draw around 20 Ah from a 60 Ah battery – depending on the battery's condition, this can lead to starting problems. Therefore: only operate with the engine running or with voltage monitoring.
Can I install the seat heating myself?
With good instructions and manual skill, self-installation is possible. You have to release the seat covers, position the mats and make the electrical connections. If you are unsure, the work should be carried out by a workshop. Electronicx supplies a detailed instruction manual with every set.
Which seat heating system is the best?
That depends on the intended use. For permanent, invisible warmth, carbon fibre heating mats are the first choice. They heat up extremely quickly and distribute the heat evenly. For quick, mobile use, heated covers are sufficient. Factory-fitted heating systems often offer several levels and are seamlessly integrated, but cannot be retrofitted cheaply.
Does seat heating wear out the battery faster?
Not under normal driving conditions. However, every additional electrical load increases the strain on the alternator and thus minimally increases fuel consumption (approx. 0.1 l/100 km per 100 W). An intact starter battery (e.g. an EFB or AGM battery) copes with the short loads without any problem.
Trust Electronicx – your address for car accessories
For years, Electronicx GmbH from Cleebronn has been a competent partner for automotive electronics, batteries and retrofit kits. Our range includes not only seat heating systems and high-quality heating mats, but also TPMS sensors and complete tyre pressure monitoring systems. We place great value on expert advice – by phone on +49 7135 7194106 or by email to [email protected].
Of course, we also deliver to other EU countries (shipping costs in accordance with our terms and conditions).
Electronicx GmbH | Managing Director: Andreas Emschanow | Hindenburgstr. 37A, 74389 Cleebronn, Germany | HRB 752730 Amtsgericht Stuttgart | VAT ID: DE300176428