Introduction: why choosing Grundfos is the key to efficient heating and water management in 2026
In 2026, with energy prices settling at higher levels than ten years ago and European Union legislation continuing to push for lower energy demand in buildings, choosing a pump has become one of the most important decisions when building or renovating a house. A pump is not just a lump of iron with a motor; it is the heart of your heating system, a booster set for drinking water or an essential component for pumping rainwater out of the garden. If you choose the wrong model, you pay not only for higher electricity consumption but also for premature wear of the whole system, noise and frequent breakdowns.
Today we take a look at the world of Grundfos, the Swiss-Danish leader that has been setting the standards in water pumping for decades. Its products are synonymous with reliability, quiet running and advanced energy solutions. At ATRIA, however, we know that customers are often confused by the sheer number of types – from simple domestic pumps to high-output solar and industrial systems. This article is your comprehensive guide: it takes you through the whole range of core models, explains the differences between the individual series and helps you choose exactly what you need, without paying for features you will never use.
The article is divided into logical sections. First we explain how the different types of pump work (domestic, circulation, solar), then we look in detail at the specific models available in our range, analyse their technical parameters and go through practical application scenarios. At the end you will find an FAQ section and an overview of common installation mistakes.
Grundfos pumps by purpose: an overview of the categories
To choose a pump correctly, you first need to understand what job it has to do. Grundfos divides its products into several main groups, each with its own design and performance characteristics. In this chapter we go through these categories in detail.
1. Circulation pumps (domestic circulators)
This is the category that concerns almost every house with underfloor heating, radiators or hot water circuits. The job of these pumps is to keep hot water circulating constantly in a closed circuit. Without them the water in the pipes would cool down and the heating system would not work.
Circulation pumps are characterised by compact dimensions, low noise and the ability to work at high temperatures (up to 110 °C). Modern models such as the UPS or CRN series have integrated frequency converters that automatically adjust the motor speed to the needs of the system, saving up to 80 % of the energy used by old fixed-speed models.
2. Domestic and waste water pumps (Unilift series)
The UNILIFT series is designed for pumping water that may contain solid particles, sludge or dirt. These pumps are used to drain water from basements, swimming pools and flood sumps, or as pumps for water treatment (e.g. from biogas plants or septic tanks).
The KP designation in the model name (for example KP 150) refers to a specific size and output. These machines are robust, often made of cast iron or stainless steel, and are fitted with a scissor-type cutting system that breaks up larger debris to prevent blockages. They are true "workhorses" that are not afraid of tougher jobs.
3. Solar pumps
In the era of renewable energy sources, solar pumps are a key technology. They are used to pump water from wells and lakes or to feed solar collectors in hot water systems. The difference from ordinary pumps is that they are optimised for converting DC current (straight from photovoltaic panels) into mechanical work, or are designed to operate on the variable voltage that the sun supplies.
Grundfos solar pumps are exceptionally resistant to temperature changes and have special anti-corrosion surface treatments. Their output is directly proportional to the intensity of solar radiation, which means they pump at their maximum around midday and switch off in the evening.
Circulation pumps in detail: the UPS model series
When we talk about heating, we almost always come across the UPS series. This is the absolute standard in European households. Think of this pump as a "silent guardian" that makes sure you always have a warm floor and warm radiators at home, without you having to think about how it runs.
The GRUNDFOS UPS 25-30 is one of the most popular choices for smaller family houses and flats. Let us look at why this model is so popular and how it works.
Figure: Basic diagram of a circulation pump, which keeps the water moving in the heating circuit.
Why choose the UPS 25-30?
This model belongs to the "wet rotor" class. This means that the electric motor is completely immersed in the water it pumps. The advantages are obvious: the water acts both as a coolant for the motor and as a lubricant for the bearings. The result is extremely quiet running (often below 40 dB), which cannot be heard at all in a flat or bedroom, and a long, maintenance-free service life.
Technical parameters of the UPS 25-30:
- Noise level: Very low, ideal for indoor installations.
- Connection: Standard DN25 (1 inch) flanges, which match most common heating pipes.
- Maximum flow rate: Up to 4.5 m³/hour.
- Maximum pressure: 3.0 metres of water column (approx. 0.3 bar).
- Liquid temperature: From -10 °C to +110 °C.
- Energy efficiency: Class A (A+++ in the new labelling), which means minimal consumption.
In 2026, when every kilowatt hour is billed, this saving is crucial. A typical older pump can consume 150 W on average, whereas a modern UPS 25-30 in its optimum mode consumes only 30-40 W. Over five years of operation that will save you hundreds of euros.
Installation and settings
Installing the GRUNDFOS UPS 25-30 is relatively simple, but it does require precision. The pump must be mounted in a horizontal position, with the rotor shaft parallel to the floor. It is important that the pump is located on the boiler inlet or on the return pipe, where the water is still hot but not boiling. Before installation the system must be flushed clean, because sand or welding slag can damage the bearings.
The speed is set using the three manual switch positions on the side of the pump (position I, II, III). For most small family houses position II or III is sufficient. If you have long pipe runs or several floors, we recommend position III. Some newer versions can be controlled automatically by an external thermostat, although this is less common on the basic UPS models.
Pumping out water and dirt: the Unilift KP series
At the other end of the spectrum are models that do not look after clean water in radiators but deal with situations where water collects where it should not be. This is where the Unilift KP pumps come in. These machines are designed for pumping water from swimming pools, basements and flood sumps, or for pumping water containing solids.
The GRUNDFOS UNILIFT KP 150 A1 is a real "little rocket" in its class. It is intended for domestic use where water needs to be pumped out quickly, for example after a flooded basement or when emptying a swimming pool.
Figure: Grundfos Unilift KP 150 A1 - a robust pump for draining water from swimming pools and basements.
A closer look at the KP 150 A1
This model is fitted with a scissor-type cutting system that can break up small solids (leaves, small stones, textiles) that find their way into the water. This prevents the pump from clogging, which is a common problem with cheaper alternatives. The 10-metre cable (depending on the version) lets you place the pump deep in a sump or in a pool without needing extension leads.
Key features:
- Output: Capable of pumping up to 15 m³/hour at a maximum pressure of 5.5 metres.
- Pumping principle: Single-stage centrifugal pump with a cutting system.
- Service life: Long-term operation in harsh conditions.
- Control: Automatic float switch, which turns the pump on when the water reaches a certain level and turns it off when the sump is empty.
It is important to distinguish between the KP 150 and KP 250 models. The difference lies in the maximum flow rate and delivery head. The KP 150 is ideal for smaller volumes of water and shorter distances, while the KP 250 is intended for larger volumes and higher pressures.
When should you choose the KP 250 A1?
For cases where you need to pump out a large amount of water more quickly or lift it to a greater height, the GRUNDFOS UNILIFT KP 250 A1 is the better choice. This model has a higher output and can overcome greater hydraulic resistance. It is an ideal choice for professional firefighters, owners of large swimming pools or commercial premises where heavier loads are expected.
Figure: Grundfos Unilift KP 250 A1 - higher output for larger volumes of water and higher pressures.
When choosing between these two models, bear in mind that the KP 150 is often enough for an ordinary family house. The KP 250 is "surplus" output unless you have specific requirements for pumping speed or delivery head. You would be paying for output you may never use.
Solar pumps: the key to using the sun efficiently
For those investing in solar power systems or thermal collectors, having the right pump is essential. Solar pumps are designed to run directly from photovoltaic panels. This means their output depends on the intensity of solar radiation. When the sun shines, the pump runs at full output. When it is overcast, it slows down. This is a very important point, because ordinary pumps could burn out on a variable voltage or would be unable to start.
Grundfos offers a series of solar pumps that specialise in this task. Models from the Solar series are among the most popular.
GRUNDFOS Solar 25-120
This is one of the most powerful solar pumps in the range, suitable for larger solar systems. It is designed to provide sufficient flow and pressure to feed solar collectors or to pump water from wells for irrigation.
Figure: Grundfos Solar 25-120 - a powerful solar pump for larger systems.
Technical data and application:
- Suitability: Ideal for solar thermal systems and irrigation systems.
- Flexibility: Able to work with variable voltage and frequency.
- Economy: No additional electricity costs, only the initial investment in panels.
- Service life: Resistant to UV radiation and extreme temperatures.
The GRUNDFOS Solar 25-120 is often used in combination with photovoltaic panels with an output of at least 180 W (hence the 180 mm in some designations, although this refers to a length or reference parameter). It is an ideal solution for homeowners who want to maximise their energy independence.
GRUNDFOS Solar 15-80
For smaller systems, for example small family houses with fewer collectors or for irrigating a smaller garden, the GRUNDFOS Solar 15-80 is more suitable.
Figure: Grundfos Solar 15-80 - a compact and economical solution for smaller solar systems.
This model is more compact and lighter, which makes installation easier. It is designed for a lower output but still delivers a reliable flow of water. Its advantage is that it is more affordable and uses less electricity, which matters with smaller photovoltaic systems.
GRUNDFOS Solar 25-40
Another interesting option is the GRUNDFOS Solar 25-40. This model sits somewhere between the versions above and is suitable for medium-sized systems. It offers a good balance between output and price.
A real-life example: a homeowner in Bratislava with 10 m² of solar collectors on the roof chose the Solar 25-40. The system works without any problems during the summer, when the sun shines regularly. Winter is the period when the solar pump does not run, which is acceptable in this case because the heating system is also supported by another heat source (a gas boiler).
Comparison table and selection by parameters
To give you a better idea of the differences between the individual models, we have prepared a clear table. It will help you quickly work out which pump suits your needs.
| Model | Type | Max. flow rate (m³/h) | Max. pressure (m) | Suitable for |
|---|---|---|---|---|
| UPS 25-30 | Circulation | ~4,5 | 3,0 | Small houses, flats, underfloor heating |
| Unilift KP 150 A1 | Waste water/Pool | ~15 | 5,5 | Basements, swimming pools, minor flooding |
| Unilift KP 250 A1 | Waste water/Pool | ~25 | 8,0+ | Large swimming pools, commercial premises, high delivery heads |
| Solar 25-120 | Solar | ~12 | 12,0 | Large solar systems, irrigation |
| Solar 15-80 | Solar | ~8 | 8,0 | Smaller solar systems, gardens |
| Solar 25-40 | Solar | ~10 | 4,0 | Medium-sized systems, AC power supply |
Real-life examples: how to choose a pump for your situation
Theory is all very well, but in practice we often come across specific situations. Let us look at a few real cases our customers have sent us and show how we helped them choose the right pump.
Case 1: Family house with underfloor heating
Situation: Mrs Nováková has a family house with a floor area of 150 m². She has underfloor heating and a gas boiler. She wanted to replace an old circulation pump that was very noisy and used a lot of electricity.
Solution: We suggested the GRUNDFOS UPS 25-30. Why? Because her system is small and does not need high pressure. The UPS 25-30 is quiet, economical and a perfect fit for applications like this. After installation the noise disappeared completely and her monthly energy bills fell by 20 %.
Case 2: Flooded basement
Situation: Mr Kováč had water in the basement of his house after a heavy storm. He needed a fast and effective pump to remove the water, which was a mixture of water and mud.
Solution: We recommended the GRUNDFOS UNILIFT KP 150 A1. This pump has a cutting system that can also cope with small debris. The cable was long enough for him to place the pump in the deepest part of the basement. The pump ran without interruption and the basement was dry within two hours.
Case 3: Solar water heating system
Situation: The company GreenEnergy installed solar collectors on the roof of a production hall. They need a pump that will pump water from the cylinder back to the collectors and run exclusively on solar power.
Solution: We chose the GRUNDFOS Solar 25-120. This model is designed to work with the variable voltage from photovoltaic panels. It is resistant to outdoor conditions and ensures a stable flow of water even in weaker sunshine.
Legislation and energy efficiency in 2026
In 2026 energy efficiency is still a live topic. The European Union has introduced stricter energy efficiency standards for electrical appliances, including pumps. These standards are partly implemented in Slovak legislation and also affect the market for heating equipment.
ErP Directive (Energy-related Products): This directive sets minimum energy efficiency requirements for products. Pumps that do not meet these requirements cannot be placed on the market. Grundfos is a leader in this field and all its modern models meet the highest criteria.
Energy class: When choosing a pump, focus on the energy class. The higher the class (A, A+, A++...), the lower the consumption. Modern pumps such as the UPS 25-30 are class A, which means they are very economical.
Subsidies and grants: In 2026 grants are still available for replacing old heating systems with new, energy-efficient ones. Installing a new Grundfos pump can be part of a project to insulate the house or replace the boiler, which allows you to obtain financial support. It is important to discuss these options with your designer or with the local authority.
Technical depth: why the pump curve and the system resistance curve matter
It happens very often that a customer buys a pump on the basis of the maximum parameters given in the table (maximum flow rate or maximum pressure), only to find in practice that the system does not work as expected. The reason is a failure to understand the principle of the pump performance curve. Every pump has its own curve, which shows how its performance changes depending on the pressure it has to overcome.
Put simply: when all the valves in the system are open, the pump reaches its maximum flow rate, but the pressure will be zero. Conversely, if the valves are fully closed, the pressure reaches its maximum but the flow rate is zero. The actual duty point lies where this curve intersects the characteristic of your pipework system (the resistance curve). If you have long pipe runs, many bends or narrow fittings, your system has high hydraulic resistance. In that case you should choose a pump with a curve that is "higher" and "steeper", so that it maintains sufficient pressure even at a lower flow rate. Conversely, for short, wide pipes a pump with a flatter curve is enough.
The effect of water temperature on density and viscosity
Another factor that is often ignored not only by lay people but sometimes by amateur installers too is the temperature of the pumped liquid. Pump curves are calibrated for water at a temperature of approximately 20 °C. As the temperature rises, the density of water and its viscosity fall. This means that at higher temperatures (for example 80-90 °C in older heating systems) the pump will move slightly more volume, but its ability to generate pressure may differ slightly.
On the other hand, if you are working with water containing antifreeze (a frost-resistant fluid), the situation changes dramatically. Antifreeze is considerably more viscous (thicker) than water. If you run an ordinary circulation pump on a system full of antifreeze without any adjustment, the pump will have to expend far more energy to overcome friction inside the pipework. The result is a drop in flow rate of as much as 30 – 40 % and higher electricity consumption. That is why accurate pump sizing is critical in systems with antifreeze, often taking into account the correction factors given in the Grundfos data sheets.
Intelligent control electronics: from manual switches to automation
We have already mentioned the UPS series, but the modern market offers far more than three-position switches. Today Grundfos dominates the field of intelligent solutions that are changing the way pumps are controlled. These systems are not just about switching on and off, but about constantly adapting to the needs of the building.
The CRN and CRI series: solutions for larger buildings and commercial use
While the UPS is the king of small houses, the CRN and CRI series serve larger residential complexes, hotel restaurants and industrial premises. These are vertical multistage pumps that can generate high pressures (up to tens of metres of water column) in a compact design.
The key difference here is the use of frequency converters (VSD - Variable Speed Drives). Models such as the Grundfos CRN 3-16 or CRI 3-17 have integrated control that automatically keeps the pressure in the system constant, regardless of how many valves are open at any given moment. If you open one tap in the kitchen and another in the shower, the system immediately increases the motor speed to keep the pressure stable. When the taps are closed, the speed drops to a minimum, saving energy and extending the life of the mechanical parts.
This solution is the absolute standard for booster sets (domestic drinking water pumps). Instead of traditional diaphragm vessels, which constantly inflate and deflate and cause "knocking" in the pipes, an intelligent pump regulates the flow of water smoothly. The result is perfectly quiet running, constant pressure even with several outlets in use at once and electricity savings of up to 50 % compared with old relay-controlled booster sets.
The GRUNDFOS GO app and remote control
For the most advanced users there is Grundfos GO technology. This is an app that lets you monitor and control your pumps from a smartphone. If you have pumps installed with a GS base or the appropriate modules, you can see in real time:
- The current flow rate and pressure in the system.
- Energy consumption in kWh.
- Historical operating data for recent months.
- Warning messages about possible faults (e.g. motor overheating, dry running, blocked rotor).
This function is extremely useful for building managers or owners of holiday properties. If something goes wrong, you receive an alert before the system fails completely. You can also change the pump settings remotely without having to visit the property in person, which saves time and the cost of a service call-out.
Installation details and safety features that must not be missing
A good pump is half the battle, but correct installation is the other half, and it decides how long the pump will last. Many problems arise not only from choosing the wrong model but from failing to follow the installation procedures.
Critical points when installing circulation pumps
When installing circulation pumps (such as the UPS), it is absolutely essential to follow these rules:
- Protective mesh and filter: A threaded strainer (a so-called "dirt trap") must always be fitted upstream of the pump inlet. It catches welding slag, sand and other debris left in the system after the boiler or radiators were installed. Without this filter the pump bearings wear out quickly and the rotor seizes. The filter should be cleaned at least once a year.
- Air lock and expansion vessel: The system must have a correctly positioned expansion vessel and air vents. If air builds up in the system, the pump will "cavitate" (work in a gaseous environment), which leads to overheating, noise and rapid destruction of the motor. The system must be bled before the pump is started.
- Water level and direction of flow: The pump must always be filled with water before it is started. The direction of water flow must match the arrows on the pump body. Installing it against the direction of flow causes immediate damage to the impeller blades and loss of pressure.
- Vibration isolation: Although modern Grundfos pumps are very quiet, vibrations can be transmitted when they are installed on solid concrete floors or metal beams. It is advisable to use flexible couplings or anti-vibration pads to stop vibrations spreading through the whole building, which could cause plaster to crack or discomfort for the occupants.
Safety features on drainage pumps
With Unilift KP pumps, the setting of the float switch is critical. The float determines when the pump switches on and off. If it is set incorrectly, the pump may switch on and off frequently (so-called "cycling"), which drastically shortens the life of the motor. The correct setting means that the pump switches on when the water level is high enough and switches off when the sump is almost empty, leaving a small reserve of water to prevent air being drawn in.
Another important element is <
Frequently asked questions (FAQ)
1. How long does a Grundfos pump last?
Grundfos pumps are known for their long service life. With correct installation and maintenance they can be used for 10 to 15 years. UPS circulation pumps often last more than 15 years, while Unilift drainage pumps can last 5 to 10 years depending on how intensively they are used and the quality of the water being pumped.
2. Can I use an ordinary pump on a solar system?
It is not recommended. Ordinary pumps are not designed for the variable voltage and frequency supplied by solar panels. The motor could be damaged or the pump might be unable to start. Solar pumps have special electronics that adapt to changing conditions.
3. How often does the pump need cleaning?
UPS circulation pumps are not usually cleaned if the system is clean. We recommend checking their condition once every 2-3 years and cleaning the filters if necessary. Unilift drainage pumps need cleaning more often, especially if they pump dirty water. After each season or after use in dirty water, it is advisable to clean the pump and check the cutting system.
4. Can the pump be installed vertically?
It depends on the type of pump. Most circulation pumps (such as the UPS) are installed horizontally. Some models, however, can also be installed vertically if the design allows it and the manufacturer permits it. Unilift drainage pumps are designed for submersible installation, so they can be placed in various orientations, but always in accordance with the instructions.
5. What is the difference between the UPS 25-30 and the UPS 25-60?
The difference lies in the maximum pressure. The UPS 25-30 has a maximum pressure of 3 metres, while the UPS 25-60 has a maximum pressure of 6 metres. Higher pressure is needed for larger systems or to overcome greater height differences. For an ordinary family house the UPS 25-30 is sufficient.
6. Can I use the pump for pumping chemicals?
It depends on the type of pump and the material it is made of. Most standard Grundfos pumps are intended for pumping water. For chemicals you need to use special pumps made of stainless steel or plastic that are resistant to corrosion. Never use ordinary pumps for chemicals, as they could be damaged.
Conclusion: investing in quality pays off
Choosing the right pump is a decision that will affect your home for years to come. Grundfos offers a wide range of products that meet the highest standards of quality and efficiency. Whether you need a quiet circulation pump for your underfloor heating, a robust waste water pump for your basement or an efficient solar pump for your green energy system, Grundfos has the right solution.
At ATRIA we stock the complete range of these products and our specialists are ready to advise you. Do not hesitate to contact us if you have any questions or need help choosing. The right pump is the key to comfortable and economical living.
Remember that cheaper alternatives may look tempting at first glance, but the long-term costs of repair, replacement and higher energy consumption can be far greater. Grundfos is an investment that pays for itself in savings and peace of mind.
Appendix: a graphical guide to choosing a pump
To finish, here is a simple chart that will help you visualise the process of choosing a pump by type of application.
Chart: A quick overview of pump selection by type of application. Blue indicates the categories, green the resulting models.
We hope this article has helped you understand the world of Grundfos pumps better and that you have chosen the right solution for your needs. If you have any further questions, do not hesitate to contact us. We look forward to working with you!
Do you have a question about this topic?
Can't decide, or dealing with a specific situation in your home? Write to us - we will be happy to advise.