Energy Class A DAB Pumps – What It Means and Why It's Worth It
Energy Class A DAB Pumps – What It Means and Why It Pays Off
When a customer is looking at a new circulation pump for heating, they will sooner or later come across the designation "energy class A" or "EEI ≤ 0.23". For many, this looks like another marketing gimmick, but in reality, it is one of the most important technical parameters that directly affect how much you will pay for electricity over the next fifteen years. This article will explain exactly what stands behind this designation, how energy class is measured, what it means in practice during the daily operation of the heating system, and why an investment in a class A pump really pays off – and much sooner than most people think.
What is the energy class and where does it come from
Energy classes are not a novelty for consumers – we know them from refrigerators, washing machines or air conditioners. For circulation pumps, they were introduced by the European Union through the ErP (Energy-related Products) regulation, specifically Commission Regulation No. 641/2009, later supplemented by Regulation 622/2012. These regulations stipulated that from January 2013, only pumps with an Energy Efficiency Index (EEI) less than or equal to 0.27 could be sold in Europe, and from August 2015 an even stricter limit of EEI ≤ 0.23 applies.
Pumps with EEI ≤ 0.23 are classified as energy class A – and this class is now the de facto standard for all new circulation pumps legally sold on the European market. DAB is one of the Italian brands that responded decisively to this transition and developed a range of pumps with special electronically commutated motors (EC motors), which achieve much lower consumption than old wet-rotor pumps with asynchronous motors.
What exactly does the EEI index express
EEI is not a simple power consumption figure. It is a dimensionless number that compares the actual consumption of a specific pump with the reference consumption of a hypothetical "reference pump" of the same size operating in a simulated heating cycle. The reference cycle includes various operating points – the pump does not run at full power all the time, but alternately at 100 %, 75 %, 50 % and 25 % load, with each point having a different weighting coefficient according to how long the pump typically runs in that mode during the real heating season.
Mathematically: EEI = (Pref / Phydr,ref) × correction factor, where Pref is the actual measured power consumption of the pump in the reference cycle and Phydr,ref is the hydraulic power of the reference pump. The lower the number, the better. Old three-speed pumps typically achieved EEI values of around 0.5–0.8. New pumps with EC motors – for example, the DAB EVOSTA2 or EVOTRON series – typically have EEI values of around 0.10–0.20, which is literally four to eight times better than their predecessors.
Why the old type of pump consumed so much electricity
To understand why class A is such a breakthrough, we need to look at what the old pumps suffered from. Classic circulation pumps with asynchronous motors operated at a fixed speed – or at most, at three fixed steps. The motor was dimensioned for the worst possible case: the coldest weather, maximum load, and the highest hydraulic resistance. In practice, this meant that the pump ran at maximum power even in September, when the boiler was just slightly heating hot water, or in mild winter, when a third of the capacity would have been sufficient.
A typical old pump for a family house had a power consumption of 40–100 W and ran for 4,000–6,000 hours per year (including hot water circulation during the heating season). Simply: 80 W × 5,000 h = 400 kWh per year. At an electricity price of 0.22 €/kWh, that is 88 € per year just for the circulation pump. Over fifteen years of operation, that is 1,320 €.
A modern class A EC pump has an average power consumption of 5–15 W in real operation. Let's assume an average of 10 W: 10 W × 5,000 h = 50 kWh per year. At the same electricity price, that is 11 € per year. Over fifteen years: 165 €. The difference compared to the old pump is more than 1,100 €. A new pump costs 120–250 €, so the investment pays for itself in one to two years.
Technology behind energy class A – EC motor and electronic regulation
The heart of every modern class A pump is an electronically commutated motor (EC, sometimes also called BLDC – Brushless DC). Unlike an asynchronous motor, which requires alternating current from the grid and whose speed is tied to the grid frequency (50 Hz), an EC motor is controlled by integrated electronics. The frequency of the rotor's power supply is adjusted according to the current need – the pump rotates exactly as fast as needed, no more.
Another key element is the pressure sensor built into the pump. The pump continuously measures the differential pressure at its output and compares it with the desired value. When a thermostatic valve in one room is closed and the hydraulic resistance of the system increases, the pump immediately reduces its speed. When the valve is opened and the system requires more flow, the pump speeds up. This entire regulation takes place automatically, several times per second, without user intervention.
Operating Modes of DAB Class A Pumps
DAB EVOSTA2 and EVOTRON series pumps offer several operating modes that directly affect electricity consumption and the hydraulic performance of the system:
- Constant pressure (ΔP-c): The pump maintains a constant differential pressure regardless of flow. Suitable for older systems without thermostatic valves, where the system resistance is relatively stable.
- Proportional pressure (ΔP-v): The desired pressure decreases linearly with decreasing flow. As valves close and flow decreases, the desired pressure also decreases. This is the most energy-efficient mode for systems with thermostatic valves – recommended for most new constructions and renovations.
- Automatic (Auto): The pump automatically monitors hydraulic conditions and switches between ΔP-c and ΔP-v depending on what is currently appropriate. Ideal for those who do not want to deal with manual settings.
- Night-time throttling: The option to program reduced performance at night, when the demand for heat is lower.
From practice, I know that most customers set the pump to "Auto" and never touch it again. And that is actually correct – EC regulation handles it better than most plumbers could set it manually.
Specific DAB Class A Products and Their Practical Features
Let's take a look at the specific products that currently represent energy class A in the DAB portfolio available in Slovakia.
DAB EVOSTA2 40-70/180 – The Foundation for a Family Home
EVOSTA2 is DAB's flagship product for the family home segment. The model 40-70/180 has hydraulic parameters: maximum head 7 m w.c., maximum flow 4.5 m³/h, construction length 180 mm, flanged connection G1½". Power consumption ranges from 3 to a maximum of 45 W depending on the operating point and selected mode. EEI = 0.20, which is well below the class A threshold.
For a family home with an area of 120–180 m² and either hydronic floor heating or radiators, the EVOSTA2 40-70/180 is a very well dimensioned choice. We recommend installing it with a mounting kit, which includes ball valves, an air vent, and seals – you can view the Mounting Kit for DAB.EVOSTA2 40-70/180, which is currently available at a discounted price. Mounting is an essential item during renovation, as most old pumps are mounted on BSP threads and the mounting must be replaced together with the pump.
For customers who are concerned about a dirty heating system (which is the case for most renovations of boiler systems from 2000–2010), there is the Mounting Kit for DAB.EVOSTA2 40-70/180 – FILTERBALL. This includes a ball valve with an integrated magnetic filter to capture metal impurities from the circulating water. These impurities (residual oxides from old steel piping, magnetite) are the main cause of premature bearing wear in the pump.
And for those who are worried about power outages during the winter – a real issue especially for boilers without gravity circulation – there is the Mounting Kit for DAB.EVOSTA2 40-70/180 + backup power supply. A backup power supply using a 12 V lead-acid battery can keep the pump running for several hours after a power outage. More information on this topic can be found in the article Backup Power Supply for DAB Pump – When and Why to Use It.
DAB EVOTRON 40/130 – Higher Level of Automation
The EVOTRON series is a technologically advanced variant with an EEI typically around 0.15 and extended options for connecting to smart home systems. DAB EVOTRON 40/130 has a construction length of 130 mm, a maximum head of 4 m w.c., and a flow rate up to 3.5 m³/h, making it a more compact model for smaller or lighter systems. It can communicate via a bus system and is capable of working in a coordinated network of multiple pumps.
For a comparison of both series in terms of applications, we recommend reading the article DAB EVOTRON vs EVOSTA2 – Which Pump to Choose.
DAB VA35/130 – For Smaller Installations
DAB VA35/130 is a model with parameters suitable for smaller apartment units or secondary circuits – for example, as a circulation pump for a hot water storage tank. With a construction length of 130 mm, its hydraulic parameters correspond to smaller installations. This model also meets the requirements of energy class A.
Practical Scenarios from Real Installations
Over many years of experience in field work, we repeatedly encounter several typical situations where replacing the pump with a class A model brought clearly measurable benefits.
Scenario 1: Family home built in 2005, natural gas boiler
Mr. Miroslav from the Trenčín area had the original Grundfos UPS 25-60 pump in his home (asynchronous, 3 speeds, power consumption at the highest speed 60 W). It ran all year round, as the boiler had a function for heating water via a storage tank and the pump was connected for continuous operation. Annual pump consumption: approximately 330 kWh. After replacing it with the DAB EVOSTA2 40-70/180, consumption dropped to an estimated 55 kWh per year. Savings of 275 kWh, which is about 60 € annually. The pump paid for itself in less than three years.
Scenario 2: New construction with floor heating
New houses with floor heating and a multi-loop distribution system are a typical environment where the "proportional pressure" mode (ΔP-v) excels. Closing individual loops via thermostatic heads causes dramatic changes in hydraulic resistance. An asynchronous pump in such a case runs constantly at full capacity, causing noise from the valves and the pump overheating. An EC pump of class A adapts immediately – reduced flow at night, when 4 out of 6 loops are closed, means the pump runs at 25% of its nominal power. The installer noted that the customer was "shocked" by the electricity bill after the season – it was 80–90% lower than with the old pump.
Scenario 3: Renovation of an old apartment building
In an apartment building from 1975 with a cast iron riser system, five old pumps were replaced during the renovation. Each of them had a power consumption of 100–120 W. After replacing them with EC pumps of class A, the total power consumption of all pumps dropped from around 550 W to less than 80 W. The annual savings for the apartment building exceeded 2,500 kWh, which is a visible item in the management statement when the electricity is billed collectively.
Noise and lifespan – further benefits of EC technology
Along with electricity savings, class A pumps offer additional, less obvious benefits. An EC motor is significantly quieter – an asynchronous motor generates electromagnetic noise tied to the frequency of the grid (50 Hz and its multiples), which manifests as an unpleasant buzzing that disturbs the quiet of a family home at night. An EC motor operates at various frequencies and is practically inaudible at low loads.
The lifespan of EC pumps is typically longer. This is partly because the motor heats up less (lower losses = lower winding temperature = longer insulation life), and also because the regulation prevents "hydraulic shocks" at full start-up, which were common with asynchronous motors at every switch-on. The stated average lifespan of new EC pumps is 20,000–40,000 hours compared to 15,000–20,000 hours for asynchronous motors.
To maintain maximum lifespan, regular maintenance is also important – bleeding air, checking the quality of the circulating water, and cleaning the filter (if installed). More on this topic in the article Cleaning and maintenance of DAB pumps – how to extend their lifespan.
How to recognize that your old pump needs to be replaced
If you have a pump at home that is older than 10–12 years, it is almost certain that it is not class A. Some simple signs that it is time for a replacement:
- The pump can be heard from other rooms – motor noise, as well as hydraulic noise (gurgling).
- Some radiators are cold, others are overheated – the pump cannot maintain flow.
- The pump has a power rating of 40 W or more on the label.
- It has no display or indicator – only a manual switch 1/2/3.
- There are visible deposits or corrosion on it.
In case of doubts, we recommend the article Common faults of DAB circulation pumps and their solutions, where diagnostic methods before replacement are also described.
Certification, labeling, and what to look for when purchasing
Every class A pump must have an energy label on the packaging similar to what we know from household appliances. On the label you will find:
- The value of EEI (the lower the better – the minimum for class A is EEI ≤ 0.23).
- The hydraulic power of the pump (reference flow and pressure).
- The maximum power consumption P1 in W.
- Annual energy consumption in kWh (calculated for a standard cycle – not the actual consumption in a specific installation, but a comparative indicator).
Note: since 2021, a new energy efficiency scale has been in effect for circulation pumps (as with other appliances), where the classes have shifted. What was previously class A may now be labeled as class B. Therefore, it is important to monitor the EEI value primarily, not just the letter class. All DAB pumps currently available on atria.sk meet EEI ≤ 0.23.
Return on investment – concrete numbers and calculation
Let's make a clear calculation for a typical situation of replacing an old pump in a family home:
Input assumptions:
- Old pump: asynchronous, power consumption 65 W, operation 5,500 h/year (including hot water heating)
- New DAB EVOSTA2 pump: average power consumption 10 W, same operation
- Electricity price: 0.22 €/kWh
- Price of the SET with DAB.EVOSTA2 40-70/180 including mounting: approx. 145 €
Annual electricity costs – old pump:
65 W × 5,500 h = 357.5 kWh × 0.22 € = 78.65 €/year
Annual electricity costs – new pump:
10 W × 5,500 h = 55 kWh × 0.22 € = 12.10 €/year
Annual savings: 78.65 – 12.10 = 66.55 €
Simple return on investment: 145 / 66.55 = 2.18 years
In other words: the pump pays for itself in less than two and a quarter years. The remaining twelve or more years of the pump's life you enjoy pure savings. Overall, over a 15-year lifespan, you save about 857 € on electricity – with an investment of 145 €. The ratio is almost 6:1.
If you want to know how to correctly choose the power and model for your specific home, I recommend reading the article What power of DAB pump do I need for my home.
Impact on CO₂ emissions and environmental aspect
This is not only about money. Every kWh of electricity saved means less CO₂ produced. In Slovakia, where electricity is generated from a combination of nuclear energy, renewable sources, and fossil fuels, the emission factor of the grid is around 200–250 g of CO₂ equivalent per kWh (depending on the year and mix). Saving 300 kWh of electricity per year on one pump corresponds to a reduction of about 60–75 kg of CO₂ per year – which is roughly equivalent to a car trip of 350–450 km.
If we expand this: in Europe, there are an estimated 120 million circulation pumps. If all were replaced with class A pumps, 23 TWh of electricity would be saved annually. This is the total annual output of several large power plants. The ErP regulation was one of the most effective regulatory measures of the EU in terms of energy savings.
Installation and what you need to know before replacement
Replacing a pump is a relatively simple task – it can be done by a skilled DIY enthusiast or an installer within an hour. Important points:
- Center distance: Most commonly 130 mm or 180 mm between flanges. Measure your existing pump before ordering. Most new DAB pumps are 180 mm, some are 130 mm.
- Connection diameter: Most commonly G1¼" or G1½" – check the existing piping or purchase a new set with piping included.
- Pump orientation: DAB EVOSTA2 and EVOTRON can operate in all positions – horizontal, vertical, or angled. The only condition is that the shaft must not be vertical, i.e., the rotor must not stand on the motor (a horizontal or angled shaft is acceptable).
- Depressurization after installation: A new pump must be depressurized after filling – most DAB pumps have a vent screw on the cover.
A detailed step-by-step replacement procedure can be found in the article Installing a DAB circulation pump step by step.
Most frequently asked questions (FAQ)
Is a class A pump really that efficient, or is it just a marketing claim?
It is really efficient, and it is not just marketing – it is a technical reality verified by measurements according to the EN 16297 standard. The difference between an asynchronous and an EC pump has been measured multiple times directly on site using a wattmeter: the average power consumption of an old pump is 55–80 W, while a new EC pump consumes 8–15 W under the same thermal load. A 70–85% saving is realistically achievable.
Can I connect a DAB class A pump to any boiler?
Yes. DAB EC pumps are designed for standard 230 V AC, 50 Hz power supply – exactly the same as asynchronous pumps. They do not require special wiring. Some modern condensing boilers have an input for external pump control (PWM or 0–10 V), which allows for even finer coordination, but this is not necessary for basic functionality.
How long does it take for the replacement with a class A pump to pay for itself?
For a typical family home, the simple payback period is 1.5 to 3 years, depending on the electricity price, the pump's operating intensity, and the installation cost. With self-installation (without an installer) and an electricity price above 0.20 €/kWh, the pump pays for itself in less than 2 years. If you pay an installer, add 30–80 € for labor to the cost.
Is it necessary to replace the pump if the current one is still working?
From a purely economic perspective: yes, if it is more than 10–12 years old. The electricity saved will more than cover the new installation cost, and in addition, the aging of an asynchronous pump causes a drop in efficiency (burned insulation, worn bearings, decreasing magnetic field voltage). A 15-year-old pump likely consumes 20–30% more electricity than when it was new. Combined with the fact that a class A EC pump has 8× lower power consumption than a new asynchronous pump, the savings are dramatic.
What does it mean when the manufacturer states "EEI ≤ 0.23" – is this a guaranteed value?
Yes, it is a guaranteed upper limit. The manufacturer is required to prove the EEI value with a certified measurement and is responsible for ensuring that no unit of this class exceeds this value. In practice, most DAB pumps achieve an EEI of 0.15–0.21, significantly below the 0.23 limit.
Is it worth buying a set with piping, or is the pump alone sufficient?
We always recommend a set with piping for renovations. Old piping often has damaged seals, corroded or brittle threads, and incorrect dimensions. A new set ensures tightness and correct hydraulic connection. If the system is dirty (typical for houses older than 10 years), consider a set with an integrated filter – the article DAB pump with or without filter – is the filterball set worth it? discusses this decision in more detail.
Conclusion: energy class A is the minimum today, not a bonus
Energy class A for circulation pumps is not a premium addition or luxury – it is today the legal minimum for any pump sold in the EU. Even within this class, there are differences: pumps with EEI 0.20–0.22 are less efficient than those with EEI 0.12–0.16. When choosing a pump, it is therefore worth looking at the specific EEI value on the label, not just the letter class.
An investment in a modern DAB EC pump – whether it is a DAB.EVOSTA2 40-70/180 set for a typical family home, or a DAB EVOTRON 40/130 for smaller systems – pays for itself in less than three years, and for the next twelve or more years, you will enjoy clean savings. Add to that lower noise, longer lifespan, automatic hydraulic regulation, and peace of mind without worries about power outages and the availability of a backup power source.
A comprehensive overview of how to choose the right DAB pump for your home can be found in the article How to choose a DAB circulation pump for heating, where all selection parameters are summarized, including sizing, series selection, and system compatibility.
Do you have a question about this topic?
Are you unsure or dealing with a specific situation in your home? Write to us – we are happy to help.