Regulation and Settings of Attack Electric Electric Boiler: How to Save on Electricity?

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Regulation and setting of the Attack Electric electric boiler: how to save on electricity?

An electric boiler is in its essence a simple appliance – water, heating element, pump. But this apparent simplicity misleads many owners into setting it once and then forgetting about it. The result? The boiler runs at full power even when it is not necessary, the temperature in the house fluctuates, and the electricity bill is unnecessarily high. However, proper regulation can actually reduce consumption by 20 to 35 percent – without any construction intervention, just by intelligent setting.

In this article, we will look in detail at how the regulation of Attack Electric boilers works, what specific setting options are available, where people most often make mistakes and how to fix them. I am drawing from real practice – from dozens of customer situations where minor changes in the settings immediately showed savings on the bill.

Why regulation is crucial for electric heating?

With gas or wood-fired boilers, regulation is also important, but electricity is a more expensive energy carrier compared to gas – and this emphasizes every inefficiency. One kilowatt-hour of electrical energy typically costs you 0.18 to 0.25 € in 2024 (depending on the tariff and supplier). If the boiler unnecessarily heats water to 80 °C when 55 °C would be sufficient, it wastes energy every day. With a 15 kW boiler and 8 hours of daily operation, the difference in consumption between a well and poorly set system can easily be 10 to 20 kWh – that is 2 to 4 € per day, i.e. 60 to 120 € extra per month.

The good news is that the Attack Electric Excellent series boilers are equipped with a well-developed regulation system with an equitemperature regulation, programmable timer, stepped power and the possibility of connecting an external thermostat or smart regulator. All these tools together create the conditions for truly efficient operation – but only if you use them correctly.

Basic boiler settings – where to start?

Setting the maximum temperature of the heating water

The first and most influential parameter is the temperature of the heating water at the boiler outlet. Most customers whose system was set up by a previous heating engineer or electrician have the temperature set to 70–80 °C as the default maximum. This may be justified for old radiators with low performance, but in modern homes with floor heating or large panel radiators, it is a major mistake.

Practical recommendations by type of heating system:

Floor heating: maximum temperature 35–45 °C (ideal 38–42 °C)
Medium performance panel radiators (600–900 mm height): 50–60 °C is sufficient in most cases
Old cast iron fin radiators: 65–75 °C, higher temperatures are justified here
Combined system (floor + radiators): maximum 55 °C with a hydraulic separator and mixing valve for the UT circuit

Every 10 °C reduction in the temperature of the heating water means roughly a 6–8 % reduction in energy consumption. Moving from 75 °C to 55 °C thus saves you real 12–15 % just by this single change.

Setting the boiler hysteresis

Hysteresis is the temperature difference at which the boiler turns off and on again. If it is set too tightly (e.g. ±1 °C), the boiler turns on and off unnecessarily often – so-called short cycling. This wears out the heating elements, causes temperature shocks in the system and increases consumption.

The optimal hysteresis for Attack Electric electric boilers is in the range of 3–5 °C. This means that if you set the desired temperature to 55 °C, the boiler will turn off at 58 °C and turn on again at 52 °C. This prolongs the cycles and makes the system work more efficiently.

Equitemperature regulation – what it is and how to set it correctly?

Equitemperature regulation is a principle in which the boiler automatically adjusts the temperature of the heating water to the outside temperature. The logic is simple: the colder it is outside, the higher the water temperature the boiler prepares. And vice versa – in mild weather, a lower temperature is sufficient and the boiler consumes less energy.

The Attack Electric Excellent 15 kW and Attack Electric Excellent 24/22 kW series boilers have an input for an external temperature sensor, which allows exactly this type of regulation. If this sensor is not connected, the boiler regulates according to a fixed temperature – which is less efficient.

Equitemperature curve – how to set it?

The equitemperature curve determines what water temperature corresponds to what outside temperature. It is usually set with one parameter – the slope of the curve (sometimes referred to as the coefficient, steepness or curve number 1–9 or 1–20 depending on the manufacturer).

Basic rules for setting the slope of the heating curve:

Floor heating (low temperature): mild slope, typically a value of 0.5–0.8
Radiator system in a new building: medium slope, value 1.0–1.4
Old house with cast iron radiators: steeper slope, value 1.5–2.0
Poorly insulated house: maximum slope, value 2.0–2.5

Setting is done empirically – after the initial setting, observe for several days whether there is enough heat in the house even at the lowest outside temperatures. If yes and the house does not cool down, you can slightly reduce the slope. If the house is not heated sufficiently, increase the slope.

Important practical note: many customers set the heating curve slope too steep at first to have "certainty". The result is that during the transitional period (spring, autumn) the boiler heats water to unnecessarily high temperatures, which is wasteful. It is better to start with a lower slope and gradually fine-tune it.

Stepwise power control – why 100% is not always right

Boilers Attack Electric Excellent 8/7.5 kW and the entire Excellent range operate with stepwise power control – they can switch on heating elements gradually (e.g. 1/3, 2/3, 3/3 power), which effectively regulates power without the need for a frequency inverter.

Sometimes customers think that "full power = best". This is not the case. If it is -5 °C outside and the house is well insulated, the boiler does not need to run at full 15 kW – it can easily maintain temperature with 5–8 kW. This extends operating cycles, reduces mechanical wear and the system runs more smoothly.

How to set the maximum power used:

In the boiler menu, look for the setting "maximum power" or "Max. step"
During the transitional period (September–November, March–April), reduce the maximum power to 60–70 % of the rated power
In the coldest months (December–February), keep full power available
If you have Attack Electric Easy 8 (a simpler model without heating curve control), compensate with at least an external programmable thermostat

Time programs and night temperature reduction

One of the most effective tools for saving energy is the time program. Excellent boilers have a built-in weekly scheduler, which allows setting different temperatures for different parts of the day and different days of the week. How to use it correctly?

Night reduction (damping)

During night hours (typically 22:00–6:00), it is not necessary to maintain the same temperature as during the day. Reducing the desired room temperature by 3–5 °C at night (or reducing the heating water temperature by 8–12 °C) saves real 8–12 % of consumption. This number may seem small, but with annual operation and a bill of 200 €/month, it is 16–24 € every month, that is 200–300 € annually.

Important warning: do not set the damping too deep (more than 5 °C below the daytime temperature) in poorly thermally insulated houses. The house may cool down so much that in the morning the boiler has to work at full power for several hours, which makes the energy balance not favorable. In well-insulated new buildings, a damping of 3–4 °C is ideal.

Damping during absence (workdays)

If you are at work during the day and the house is empty from 7:00 to 17:00, it makes sense to set damping also during the day. Set the temperature 4–6 °C lower and program the boiler to start heating one hour before your return home (e.g. from 16:00). The house will then warm up to a comfortable temperature without the boiler heating empty rooms all day.

Practical example: a family in a 140 m² house, boiler Attack Electric Excellent 15 kW. Before optimization: boiler at constant temperature 65 °C 24 hours a day, consumption about 3 200 kWh/month in January. After setting night damping to 57 °C (22:00–6:00) and day damping to 55 °C (8:00–15:30): consumption 2 480 kWh/month – saving 720 kWh, which at a price of 0.20 €/kWh represents 144 € monthly.

External thermostat and smart control

The built-in boiler control regulates the temperature of the heating water (so-called boiler control). But the actual air temperature in the rooms is controlled by the room thermostat – and this is exactly the component that determines comfort and efficiency. The boiler may have a water temperature of 60 °C set, but if the room thermostat detects that the living room is at 22 °C (the desired value), it signals the boiler to turn off.

Types of thermostats and their impact on savings

Simple bimetal thermostat: cheap, but inaccurate (deviation ±1.5–2 °C). Suitable only as a basic protection, not for efficient control.
Electronic programmable thermostat: accuracy ±0.2–0.5 °C, possibility of weekly program. Contributes well to savings, price 30–80 €.
Smart thermostat (Wi-Fi, Zigbee): control via app, geolocation (automatic temperature reduction when you leave the house), integration with weather. Price 80–200 €, return on investment in 1–2 years.
Thermostatic heads on radiators: allow setting different temperatures in individual rooms. Do not replace the room thermostat, but are a suitable complement.

Recommendation: even for the simpler model Attack Electric Easy 8, it is worth connecting at least a simple programmable thermostat. The boiler itself regulates only the water temperature, not the room air temperature.

Domestic hot water (DHW) preparation – how to avoid overpaying

If your Attack Electric boiler is also used for hot water preparation, this is another area where unnecessary costs can be hidden. A boiler that keeps water in a tank at 60 °C for 24 hours a day consumes energy at night, on weekends, and even when you are on vacation.

Correct DHW strategy:

DHW heating timer: set the heating only for times when you actually need the water. For example, in the morning from 5:30–7:30 and in the afternoon from 16:00–19:00. In other times, the tank only maintains the temperature or does not heat at all (if the tank is well insulated, hot water can last 3–5 hours).
Off-peak tariff (NT): if you have a D02 or similar tariff with a low rate at night, set the main DHW heating exactly for night hours when electricity is cheaper.
Tank temperature: at least 55 °C for hygiene requirements (Legionella), up to 65–70 °C for normal operation. Higher temperature = higher heat loss from the tank.
Legionella program: once a week (e.g., on Friday night), set a one-time heating to 70 °C for 1 hour – this ensures hygiene safety without the tank running at 70 °C all the time.

For DHW preparation in an external tank, special accessories are available – TÚV module set (DHW preparation in an external tank). This set allows the boiler to be used not only for heating, but also for heating the hot water tank with the option of priority control – the boiler first heats DHW and then the heating circuit, or vice versa, according to the set priority. More on this topic can be found in the article TÚV module for electric boiler: how does DHW preparation in an external tank work?

Use of low tariff (NT) – night electricity

This is an area where savings can be set up very specifically. In Slovakia, there are available tariffs with a two-tier electricity price (VT – high tariff and NT – low tariff). Tariffs D02, D25, D26 and other combined tariffs allow you to pay 30–50 % less for electricity in NT compared to VT.

Practical settings for a system with storage:

If you have a storage tank (200–500 liters), set the boiler to primarily heat the water during NT (typically 22:00–6:00 and some daily windows)
Heat the tank to 70–75 °C at night, and during the day the boiler only tops up if needed
With a properly dimensioned tank (about 50 liters per 1 kW of boiler power), the boiler can run almost exclusively in NT during winter
This mode, however, requires a properly set HDO switch (mass remote control) and the selection of the correct tariff from your energy supplier

Calculation on a concrete example: 15 kW boiler, consumption 90 kWh/day. If 60 kWh are covered by NT (price 0.12 €/kWh) and 30 kWh by VT (price 0.22 €/kWh): total cost = 7.20 + 6.60 = 13.80 €/day. Without NT differentiation: 90 × 0.22 = 19.80 €/day. Saving: 6 €/day = 180 €/month.

Hydraulic balancing – a prerequisite for correct electric regulation

Even a perfectly set regulator and smart thermostat will fail if the hydraulic system is not correctly balanced. The most common problem: some radiators are over-pumped (too high flow, they quickly reach the temperature and the thermostat closes), others are under-pumped (too little flow, they never reach the desired temperature).

In such a case, the boiler cycles – runs briefly, then turns off, because the first radiators quickly reach the temperature, but distant rooms remain cold. The customer usually solves this by increasing the water temperature, which only worsens the situation.

Solution: hydraulic balancing of the system (regulating valves on each heating body set according to calculation or thermal camera). After balancing, the boiler works evenly, longer cycles, lower consumption. This topic is also related to installation – details can be found in the article Installation of Attack Electric boiler: procedure, requirements and connection.

Diagnosis and optimization – where to look to see if the boiler is working correctly

Modern Attack Electric Excellent boilers display a lot of operational data on the display. Learn how to read them:

Outlet temperature (Flow temp): current water temperature at the boiler outlet. It should correspond to the set value ± hysteresis.
Return temperature (Return temp): temperature of the water returning from the heating system. Delta T (difference between outlet and return) should be 10–20 °C for a radiator system and 5–10 °C for floor heating. If Delta T is too low (less than 5 °C), the flow is too high. If it is too high (more than 25 °C), the flow is too low.
Active power / active stage: how many heating elements/stages are active at that moment. If you see that the boiler is always running at maximum, something is wrong (underpowered, poor insulation, hydraulic problem).
Number of starts per hour: some boilers display or record this. More than 6–8 starts per hour indicates too small hysteresis or short cycling.

Most common setup errors that increase operating costs

Based on real experience with customers, here are the top 7 errors that increase the operation cost of an electric boiler:

Mistake #1: too high water temperature all year round – set temperature 75 °C even in April, when 45 °C would be enough
Mistake #2: disabled weather compensation – external sensor bought, but not installed or disconnected
Mistake #3: no night setback – boiler runs at the same temperature 24/7/365
Mistake #4: inappropriate electricity tariff – customer pays a single-rate tariff, although a dual-rate tariff would be more advantageous
Mistake #5: unbalanced hydraulic system – boiler compensates for hydraulic imbalance by increasing the temperature
Mistake #6: neglected maintenance – clogged filters, dirty water, unvented radiators – all increase consumption. More in the article Maintenance and service of Attack Electric boiler: what and when to check?
Mistake #7: too big or too small boiler – oversized boiler short cycles, undersized boiler runs full-time. About choosing the right power, read the article What power electric boiler do I need for my house?

Summary: how much can you really save?

If you systematically apply all recommendations from this article, it is a combined effect of multiple measures. Here is a realistic savings table for a typical family house of 130–150 m² with a 12–15 kW boiler:

Measure	Savings (%)	Savings (€/month)*
Reducing water temperature by 15 °C (where possible)	10–15 %	20–35 €
Weather compensation (external sensor)	8–12 %	16–28 €
Night setback 4 °C (8 hours)	8–12 %	16–28 €
Day setback (empty house, 7 hours)	6–10 %	12–24 €
Use of NT tariff (50 % consumption in NT)	15–25 %	30–60 €
Hydraulic balancing of the system	5–10 %	10–24 €
Total effect (not a simple sum, as some effects overlap)	25–40 %	50–120 €

*Calculation based on an average monthly heating bill of 240 € during the heating season.

Most Frequently Asked Questions (FAQ)

Can I set up the Attack Electric boiler completely by myself, or do I need a service technician?

Most user settings – water temperature, hysteresis, time programs, night setback – can be set by yourself via the boiler display and user manual. Service settings (equithermal curve, sensor configuration, pump settings) are in a protected service menu level and it is recommended to set them during installation together with the installation technician. Hydraulic balancing of the system also requires a professional. More about typical errors can be found in the article Common faults of Attack Electric electric boilers and how to solve them.

Is it worth investing in a smart thermostat if I have an Attack Electric Excellent?

Yes, even though the Excellent boiler has a built-in regulator, a smart thermostat adds geolocation (automatic temperature reduction when leaving the house), more precise room temperature regulation (not just boiler water), and convenient control via an app. The payback period for an average house is 1–2 years. Recommended models compatible with Attack Electric boilers: thermostat with OpenTherm interface or a simple contactless switch (both connection types are available).

What is the correct water temperature for floor heating with Attack Electric?

For floor heating, the rule of low temperature applies – typically 35–42 °C at the boiler outlet. Higher temperatures are not needed for floor heating and are actually harmful – the floor overheats, comfort decreases, and you consume more energy. If you have a combination of floor heating and radiators, a hydraulic separator (with a mixing valve for the floor heating circuit) is necessary so that radiators can receive a higher temperature (e.g. 55 °C) and the floor a lower one (38 °C) from one boiler.

Is it worth adding a hot water storage tank to an electric boiler?

Yes, especially if you are using or planning to use a two-rate tariff (NT/VT). A 300–500 liter tank allows the boiler to work intensively during the cheaper night tariff and only top up or not work at all during the day. The payback period for this investment (a 400-liter tank costs 500–900 €) with the correct tariff configuration is 2–4 years. The tank also reduces the number of boiler starts, which extends its lifespan.

How can I find out whether the boiler is working efficiently or wasting energy unnecessarily?

Monitor three indicators: 1) delta T (difference between output and return) – should be 10–20 °C for radiators, 2) number of starts per hour – ideally less than 4–6, 3) the percentage of time the boiler is running at maximum power – if it is more than 80 % of the time even during transitional periods, the boiler is either undersized or there is a problem with the house insulation or hydraulics. You can read these values directly from the boiler display or (in some models) download the operation history.

What to do if the boiler keeps the room cold, while others are warm?

This is a classic sign of an unbalanced hydraulic system, a blocked valve, or an air-locked radiator. Procedure: 1) bleed the radiator (bleed valve at the end of the radiator body), 2) check whether the thermostatic head is not blocked (after long inactivity, it may get stuck – remove the head and manually push the valve), 3) if the problem persists, call a technician for hydraulic balancing. Increasing the boiler temperature as a compensation for a problematic radiator is the most expensive solution.

Conclusion: regulation is an investment with immediate return

Proper regulation of an electric boiler is not a one-time action, but a continuous process. Once a year (ideally before each heating season), check the settings, compare the consumption with the previous year, and adjust the equithermal curve or time programs according to new conditions (new window insulation, an extension, or a change in the number of residents in the house).

If you are unsure about choosing a specific model, I recommend reading other articles in the Knowledge Center: Attack Electric Excellent vs. Easy: what are the differences and which one to choose? or How to choose an Attack Electric boiler: power, model and accessories. A well-chosen boiler with an optimally set regulation is the foundation for many years of comfortable and economical heating.

Do you have a question about this topic?

Having trouble making a decision or dealing with a specific situation in your home? Write to us – we are happy to help.