Heating Film Running Costs in Ireland: How Much Does It Cost to Run?

Heating film running costs depend on the heated floor area, system output, electricity tariff, heat loss of the room and the amount of time the thermostat calls for heat. Therefore, two rooms using the same heating film can have very different electricity costs.

The maximum electrical output shown on a heating system does not mean that it will consume that amount of electricity continuously throughout the day. Once the room reaches the selected temperature, the thermostat switches the system off and activates it again only when more heat is required.

In this guide, we explain how to calculate heating film running costs, provide practical examples for different room sizes and show which factors have the greatest effect on electricity consumption in an Irish home.

What Determines Heating Film Running Costs?

The running cost of heating film cannot be calculated from the room size alone. Several factors determine how much electricity the system will use.

The most important factors include:

• the usable heated floor area,
• the output of the heating film in watts per square metre,
• the electricity price per kilowatt-hour,
• the heat loss of the room,
• the insulation beneath and around the room,
• the selected room temperature,
• the daily heating schedule,
• the outdoor temperature,
• the thermal resistance of the floor covering,
• the accuracy and programming of the thermostat.

For example, a well-insulated bedroom maintained at 19°C for a few hours each evening will normally require less energy than a poorly insulated living room maintained at 23°C throughout the day.

Consequently, the same heating film product can produce different running costs in different properties.

How Do You Calculate the Running Cost?

You can calculate the maximum hourly electricity cost using three pieces of information:

1. the heated floor area in square metres,
2. the heating film output in watts per square metre,
3. your electricity tariff in euro per kilowatt-hour.

Worked Example: 10 m² at 80 W/m²

A 10 m² heated area using 80 W/m² heating film has a maximum connected output of:

10 m² × 80 W/m² = 800 W, or 0.8 kW.

At an illustrative electricity price of €0.35 per kWh, the maximum cost for one full hour of operation would be:

0.8 kW × €0.35 = €0.28 per hour.

However, this example does not mean that the system will consume €0.28 every hour of the day. The thermostat will normally cycle the heating on and off after the room reaches the selected temperature.

Example Hourly Heating Film Running Costs

The following table uses an illustrative electricity rate of €0.35 per kWh. It shows the maximum cost while the heating operates continuously at full output.

Your actual tariff may be higher or lower. Therefore, use the unit price shown on your current electricity bill when calculating your own project.

These figures represent the theoretical maximum consumption while every part of the system operates at full output. In normal thermostat-controlled use, the system may operate for only part of each hour after the room has warmed.

Example Daily and Monthly Costs

To estimate a daily or monthly cost, multiply the maximum hourly cost by the number of equivalent full-power operating hours.

The following examples assume the system uses the equivalent of four full-power hours per day and an illustrative electricity rate of €0.35 per kWh.

Why Actual Monthly Costs May Be Different

These figures are examples rather than guaranteed bills. A room may require fewer or more than four equivalent full-power hours depending on its heat loss, insulation, temperature setting and weather conditions.

For instance, a system may run continuously while warming a cold room and then operate intermittently to maintain the temperature.

Does Heating Film Run at Full Power All Day?

No. A correctly controlled heating film system does not normally operate continuously once the room reaches its target temperature.

During the initial warm-up period, the thermostat may call for continuous heat. However, after the room and floor reach the selected temperature, the controller switches the system on and off as required.

The operating cycle depends on:

• how quickly the room loses heat,
• the difference between indoor and outdoor temperature,
• the insulation level,
• the selected thermostat temperature,
• the position of the thermostat and floor sensor,
• the floor covering and underlay,
• air leakage and ventilation.

Therefore, connected electrical power and actual electricity consumption are not the same thing.

For example, a 2.8 kW system has the capacity to consume 2.8 kWh if it operates continuously for one hour. If the thermostat calls for heat for only 30 minutes during that hour, the system consumes approximately half that amount.

How Does Heating Film Output Affect the Cost?

Heating film is available in different output levels. A higher wattage system has a greater maximum electrical demand per square metre.

However, choosing a lower wattage product does not automatically guarantee a lower final bill.

If a low-output system cannot provide enough heat for the room, it may operate for longer periods and still fail to maintain the required temperature. Conversely, a correctly sized higher-output system may warm the room faster and then cycle off.

The correct output should be selected according to:

• the calculated heat loss of the room,
• the available heated floor area,
• the level of insulation,
• the intended floor covering,
• whether the system is the primary or supplementary heat source,
• the manufacturer’s technical requirements.

For this reason, do not select heating film based only on the lowest wattage or lowest theoretical hourly cost. The system must first be capable of meeting the room’s heating requirement.

How Important Is Insulation?

Insulation is one of the most important factors affecting heating film running costs.

A well-insulated room retains heat for longer. As a result, the thermostat can switch the heating off for longer periods after the target temperature has been reached.

In contrast, a poorly insulated room may lose heat through:

• external walls,
• the roof or ceiling,
• the floor,
• older windows and doors,
• uncontrolled air leakage,
• uninsulated structural elements.

In addition, suitable insulation beneath the heating film reduces unnecessary heat transfer into the structural subfloor.

Nevertheless, floor insulation alone cannot compensate for major heat loss through the rest of the building. The room should be considered as a complete thermal system.

How Does the Heated Floor Area Affect the Cost?

A larger heated area requires a higher total connected output. Nevertheless, you should not reduce the heated area without considering the required room output.

Heating film should normally be planned across the available open floor area, excluding locations beneath permanently fixed objects or places where heat could become trapped.

These excluded areas may include:

• fitted kitchen units,
• permanently fixed wardrobes,
• baths and shower trays,
• heavy furniture without suitable clearance,
• other permanently covered floor areas.

For this reason, the remaining usable heated area must provide enough output to cover the calculated heat loss of the room.

For example, a 20 m² room may contain only 13 m² of usable open floor after permanent furniture and fittings are excluded. The heating calculation should use the 13 m² heated area rather than the full room size.

How Can a Thermostat Reduce Energy Use?

A properly programmed thermostat prevents the heating film from operating when heat is not required.

Depending on the model, a thermostat may provide:

• weekly heating schedules,
• separate weekday and weekend programmes,
• room-temperature control,
• floor-temperature limits,
• Wi-Fi or mobile application control,
• holiday settings,
• open-window detection,
• energy-use information.

Instead of maintaining the same temperature throughout the day, users can schedule heating around actual room use.

For example, a bedroom may require heating in the morning and evening but not during working hours. A home office may require the opposite schedule.

As a result, individual room control avoids heating the entire property when only one area is occupied.

How Does the Electricity Tariff Affect the Cost?

In practice, the electricity unit price directly affects heating film running costs. The same system will cost more to operate on a higher tariff.

When estimating the cost, check the price per kilowatt-hour shown on your electricity bill. Do not use the total bill divided by total consumption, because standing charges, taxes and other fees may be included.

Some electricity plans provide different rates according to the time of day. Where suitable, a heating schedule may take advantage of lower-cost periods.

However, the lowest unit rate should not be the only consideration. Review:

• day and night rates,
• peak-time rates,
• standing charges,
• contract duration,
• discount expiry dates,
• smart-meter tariff conditions.

Therefore, always use your own current electricity tariff when preparing an accurate project estimate.

How Can You Reduce Heating Film Running Costs?

Good system design and sensible control can reduce unnecessary electricity consumption without sacrificing comfort.

Improve the Building Insulation

Reducing heat loss allows the room to retain warmth for longer. Consequently, this decreases the amount of time the heating system needs to operate.

Use Suitable Insulation Beneath the Film

Correct floor insulation helps direct useful heat upwards rather than into the structural subfloor.

Choose the Correct System Output

The system should match the calculated room heat loss and available heated floor area. An incorrectly sized system may operate inefficiently or fail to achieve the required comfort level.

Use Individual Room Controls

Separate thermostats allow users to heat occupied rooms without operating systems in areas that are not currently required.

Create a Heating Schedule

Programme the thermostat around the times when each room is occupied. In addition, avoid maintaining a high temperature continuously when the property is empty.

Avoid Excessive Temperature Settings

Increasing the target temperature increases the amount of heat the building must retain. Therefore, select a comfortable temperature rather than automatically using the highest setting.

Use Compatible Flooring and Underlay

Materials with excessive thermal resistance can slow heat transfer. For this reason, confirm that both the floor covering and underlay are approved for electric underfloor heating.

Keep Sensors and Thermostats Correctly Positioned

Poor sensor placement may produce inaccurate temperature readings and unnecessary operation.

Is Heating Film Economical for Irish Homes?

Heating film can be a practical heating solution for many Irish homes. However, its running cost depends on the condition of the property and the way the system is used.

It may be particularly suitable for:

• well-insulated apartments,
• renovated bedrooms,
• living rooms with compatible floating floors,
• home offices,
• extensions,
• attic conversions,
• garden rooms,
• energy-efficient new builds.

By contrast, older properties with substantial heat loss may require insulation improvements before electric underfloor heating can operate economically.

Therefore, the best way to assess a project is to complete a room-by-room heat loss calculation and compare the result with the available heated floor area.

Frequently Asked Questions

Heating Film Running Costs: Summary

Heating film running costs depend on more than the product wattage. Room heat loss, insulation, heated floor area, thermostat programming, temperature settings and electricity tariffs all influence the final result.

The connected output allows you to calculate the maximum hourly cost. Nevertheless, the thermostat normally reduces actual consumption by switching the system off once the room reaches the selected temperature.

For the most reliable estimate, complete a heat-loss calculation, measure the usable heated floor area and use the current electricity price from your own tariff.