What kind of heat pump do I need? How to choose the right type based on the size of your home

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On 20. January 2026

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Are you wondering which heat pump to choose for your home? The right choice depends not only on square meters, but mainly on heat loss, the desired heating water temperature, and the method of domestic hot water (DHW). We’ll briefly walk you through the factors that most influence your choice, so that the result is both cost-effective and comfortable.

The size of the house is a good guide, but the system’s temperature settings and the quality of the insulation are the main factors in determining the appropriate capacity and type. A new construction with underfloor heating is sized differently than an older home with radiators; space for the outdoor unit, noise levels, and the control method also make a difference. In the following steps, we’ll therefore clearly explain the choice between air-to-water, ground-to-water, monoblock, or split systems, and show you how to set the capacity range without unnecessary reserve.

How to Determine the Required Capacity for Your Home

When deciding which heat pump to choose, start by determining the home’s heat loss at its winter peak. Ideally, you’ll find this information in the building plans or energy certificate; if it’s missing, you can estimate it based on the type of construction and insulation, but it’s always better to rely on actual measurements and real-world operating conditions. When calculating annual heating costs, factor in whether the unit will also provide hot water—this adds short-term peaks that should be covered by a reasonable (not excessive) capacity reserve.

Equally important is the system’s temperature profile. Underfloor heating and modern radiators operating at a water temperature of 35–45 °C allow for lower output with higher efficiency; older radiators requiring 55–60 °C typically necessitate a higher nominal output or system adjustments (larger radiators, balancing, equithermal design).

Also consider the modulation range: the pump’s minimum output should be low enough to prevent cycling during transitional periods (frequent on-off cycling reduces both efficiency and comfort). A properly sized unit then runs for long, continuous periods, maintains a stable temperature, and saves energy without “chasing” the highest number on the nameplate.

Which heat pump to choose based on the heat source

Air/Water

The most common choice for single-family homes. Installation is quick, requires no excavation, and offers a good balance of price and performance.

Pros: easy installation, lower initial investment, wide range of models.

Cons: Performance and efficiency fluctuate more in freezing temperatures (defrosting, higher outlet temperature = lower efficiency).

Suitable when: you want a practical solution that doesn’t require digging on your property and you’re comfortable with a lower heating water temperature.

Ground/water (flat-plate collector or borehole)

A stable heat source with very quiet operation. A higher initial investment, but the most consistent efficiency throughout the season.

Pros: Stability even in freezing temperatures, quiet operation, long service life of the ground heat exchanger.

Cons: Requires land (collector) or boreholes, construction work and permits, higher price.

Suitable if: you prefer stability and low noise levels, and you have the space and budget for groundwork.

Water/water

A specific option where high-quality groundwater is available and permits have been granted.

Pros: Very consistent performance, quiet operation.

Cons: Complex permitting process, water quality and quantity, filtration maintenance.

Suitable when: the location and regulations allow it, and you want maximum stability.

Design: Monoblock vs. Split

In addition to the heat source, when choosing a heat pump, you also need to consider the unit’s design —that is, whether to choose a monoblock or a split system. The difference lies in where the refrigerant circuit is located and what connects the outdoor and indoor parts of the system.

Monoblock

The cooling circuit is enclosed within the outdoor unit; only heated water flows into the interior.

Advantages: simpler and faster installation; no need to handle refrigerant inside the building.

Risks/things to watch out for: protection against freezing of outdoor piping (antifreeze mixture, heat exchanger, electric cable heating for pipes), high-quality insulation of piping.

Choose this option if: you want a quick installation and can safely ensure the water is protected against freezing.

Split

The system consists of an outdoor unit and an indoor unit; refrigerant circulates between them.

Advantages: no heating water outside the building → lower risk of freezing, often better performance at low temperatures, more flexible internal connections.

Risks/things to watch out for: requires certified refrigeration installation (leak testing, vacuuming, refrigerant charging), precise penetrations, and insulation.

Choose this option if: you prefer freeze resistance and have an experienced installer/refrigeration technician available.

In practice: In most cases, split-type heat pumps are installed in older homes with radiator heating, while monoblock units are more commonly installed in new construction with underfloor heating. However, this is not a hard-and-fast rule—the required heating water temperature and the quality of installation are always the deciding factors.

Practical tips for both options

Consider the location: airflow, condensate/defrost drainage, vibrations, and noise levels affecting neighbors.

Check the modulation range: low minimum output = fewer cycling cycles during transitional periods.

Don’t forget about controls (equithermic control, DHW, zoning)—proper settings will have a greater impact on your bills than “rated” capacity.

Which heat pump to choose based on the location and noise level of the outdoor unit

Installation is also key to achieving good results. Position the outdoor unit so that it has unobstructed air intake and exhaust, a sturdy foundation with anti-vibration elements, and a proper condensate/defrost drain (so it doesn’t freeze on the sidewalk in winter). Consider noise levels in relation to bedrooms and neighbors; a night mode, proper exhaust orientation, and a reasonable distance from the building facade can help. For interior connections, ensure high-quality pipe insulation, short runs, and easy access for servicing. From

Conclusion: What kind of heat pump do I need?

When deciding which heat pump to choose, it’s best to base your decision on the actual conditions of your building—how well it retains heat in the winter, what heating water temperature the system naturally requires, and how you handle domestic hot water (DHW) production. Once you understand these factors, it will be easier to select a type and model that will operate quietly, efficiently, and without unnecessary excess capacity under your specific conditions over the long term.

Equally important is the careful installation and configuration of the system: the placement of the outdoor unit, high-quality insulation of the piping, circuit balancing, and proper control. It is precisely these details that determine whether the specifications on paper translate into real-world comfort. If, after reading this, you’re still wondering which heat pump is best for you, you can view the current selection of units and installation accessories on the Slovklima website.

FAQ

What kind of heat pump do I need based on the size of my house?

The size of the house is just a rough starting point. The key factors are heat loss (insulation, windows, ventilation, location) and whether you use underfloor heating or radiators.

Is it enough to choose based only on square meters?

Not exactly. Two houses with the same floor area can have completely different energy requirements, so it’s important to look at heat loss—or at least the quality of the building envelope.

When is an air-to-water system better, and when is a ground-to-water system better?

Air-to-water is the most common choice because installation is simpler and the initial investment is lower. Ground-to-water makes sense if you want stable performance even during severe frosts and have the conditions for drilling or installing a collector (but expect higher installation costs).

What is the difference between a monoblock and a split system?

A monoblock system has “everything” in the outdoor unit, and water flows into the house, so frost protection must be properly addressed. A split system has both an outdoor and an indoor unit, with refrigerant circulating between them, which can be an advantage when there is a risk of freezing and when water is involved.

Is it a good idea to keep some power “in reserve”?

Usually not. An oversized pump cycles more frequently, may be less efficient, and wears out faster. It is better to select the capacity based on actual needs and address the need for reserve capacity through proper system design.

What else should you check before buying to make sure it works without any problems?

Whether the system will also provide hot water, what temperatures you need for your radiators or underfloor heating, whether you have a suitable electrical connection, and where the unit can be installed in terms of noise and maintenance.