{"id":12604,"date":"2026-09-08T08:48:58","date_gmt":"2026-09-08T05:48:58","guid":{"rendered":"https:\/\/happyhome.ee\/useful\/ground-source-heat-pump-or-air-to-water\/"},"modified":"2026-10-20T16:10:44","modified_gmt":"2026-10-20T13:10:44","slug":"ground-source-heat-pump-or-air-to-water","status":"publish","type":"useful","link":"https:\/\/happyhome.ee\/en\/useful\/ground-source-heat-pump-or-air-to-water\/","title":{"rendered":"Home heating: what to know when choosing a heating system"},"content":{"rendered":"\n

In a well-functioning home, the heating system should be something you barely notice in everyday life. Rooms stay evenly warm, the system works quietly and efficiently, and there is no need to constantly adjust the temperature.<\/p>\n\n\n\n

Achieving this takes more than simply choosing a good heat pump. It is important to select a high-quality unit with the right capacity and efficiency for the specific house, design the underfloor heating carefully, and consider heating together with the building structure, ventilation, energy efficiency and, where needed, cooling.<\/p>\n\n\n\n

Happy Home houses use hydronic underfloor heating, while the heat source is selected according to the project and may be either ground-source heating or an air-to-water heat pump. Heating, ventilation and, where required, cooling are designed as one complete system for the specific house.<\/p>\n\n\n\n

The heating system is an important part of a home\u2019s overall energy efficiency, but the final result depends on the building as a whole. You can read more about how heating, ventilation, the building structure, windows and cooling work together in our article \u201cEnergy-efficient home: what really makes an A energy rating?\u201d<\/a><\/p>\n\n\n\n

The choice of heating system is also influenced by the energy performance calculation<\/h2>\n\n\n\n

Both ground-source heating and an air-to-water heat pump can heat a well-designed house comfortably and efficiently. The choice is influenced by the size and heat demand of the house, the possibilities offered by the plot, the technical solution, the investment and the energy-efficiency requirements in force at the time of design.<\/p>\n\n\n\n

The heating system plays an important role in the energy performance calculation, and the calculation methodology may, at a particular time, favour one type of heat pump over another in purely calculated terms. This is one reason why different solutions have been used in Happy Home houses at different times.<\/p>\n\n\n\n

In recent years, ground-source heating has been more common in our projects, whereas air-to-water systems were used more frequently before that. This does not mean that one technology has suddenly become inherently better or worse. Energy-efficiency requirements and the methodology used to calculate them have changed over time and will continue to evolve.<\/p>\n\n\n\n

It is also important to distinguish between the result of an energy calculation and actual annual energy consumption.<\/p>\n\n\n\n

The calculation is based on standardised conditions. In real life, however, the annual efficiency of a heat pump is affected by the weather and operating conditions of that particular year. With an air-to-water heat pump, the result is influenced by outdoor temperatures, the duration of cold periods and temperature fluctuations. With a horizontal ground loop, factors such as soil conditions, moisture, system load and winter conditions, including snow cover, also play a role.<\/p>\n\n\n\n

As a result, exactly the same house with exactly the same heating system may operate slightly more efficiently in one year than in another.<\/p>\n\n\n\n

\"Denmark
Denmark house<\/figcaption><\/figure>\n\n\n\n

Why do we use hydronic underfloor heating?<\/h2>\n\n\n\n

In Happy Home houses, heat is distributed through the rooms using hydronic underfloor heating.<\/p>\n\n\n\n

The large heating surface allows the system to operate with a relatively low water temperature. This works particularly well with heat pumps, because the lower the temperature the unit needs to produce, the more efficiently it can generally operate.<\/p>\n\n\n\n

There are also very practical advantages: the temperature is distributed evenly throughout the room, there is no need for visible radiators on the walls, and different rooms can be controlled separately.<\/p>\n\n\n\n

Underfloor heating is also a relatively slow-reacting system. The concrete floor stores heat and releases it gradually into the room, which means the system works best with stable settings rather than with frequent large temperature changes.<\/p>\n\n\n\n

Not every room necessarily needs heating<\/b><\/p>\n\n\n\n

Underfloor-heating circuits are planned according to the function of each room.<\/p>\n\n\n\n

Living rooms, bedrooms and bathrooms naturally require heating, but in some spaces the goal may be the opposite. A pantry, certain storage rooms or a separate walk-in glazed wine room, for example, may intentionally be kept cooler and may not need an underfloor-heating circuit at all.<\/p>\n\n\n\n

The circuits are connected to a manifold, and once the system is complete it is adjusted according to the design and the actual finishing materials used.<\/p>\n\n\n\n

The floor finish also matters. A thin mineral finish such as microcement conducts heat very effectively and can allow the underfloor heating to achieve the same room temperature with a lower water temperature. Parquet provides more insulation, but it is also perfectly suitable for underfloor heating \u2014 the system is simply adjusted to take the properties of the particular floor finish into account.<\/p>\n\n\n\n

Ground-source or air-to-water?<\/h2>\n\n\n\n

Both can be very good solutions. The choice is determined mainly by the energy calculation for the particular house, the possibilities offered by the plot and the technical solution.<\/p>\n\n\n\n

Ground-source heating: horizontal ground loop or boreholes<\/b><\/p>\n\n\n\n

With a horizontal ground-source system, the collector loop is installed in the soil across the plot. This requires enough suitable open land, so the solution needs to be considered already when planning the house and the site.<\/p>\n\n\n\n

Existing mature trees can become a deciding factor. Trees cannot always simply be removed, nor is this necessarily permitted. Requirements to preserve mature vegetation may arise from planning conditions, design requirements or the characteristics of the specific plot, and removing trees may require a dendrological survey, a carefully defined felling plan and a permit. On some plots, felling outside the designated building area may be heavily restricted.<\/p>\n\n\n\n

In such cases, there may simply not be enough suitable space for a horizontal ground loop.<\/p>\n\n\n\n

An alternative is vertical boreholes, which require significantly less surface area.<\/p>\n\n\n\n

The cost difference can, however, be substantial. Depending on how many boreholes are required and how deep they need to be, a borehole-based ground-source system can cost several times more than a horizontal ground-loop solution.<\/p>\n\n\n\n

By contrast, for a medium-sized house, the initial investment for ground-source heating with a horizontal loop and an air-to-water heat pump is often in a fairly similar range.<\/p>\n\n\n\n

Air-to-water: no ground loop, but an outdoor unit<\/b><\/p>\n\n\n\n

An air-to-water heat pump takes heat from the outdoor air and therefore does not require a ground loop or boreholes.<\/p>\n\n\n\n

For a very small house, smaller and less expensive air-to-water units are also available, which can make the initial investment clearly lower.<\/p>\n\n\n\n

An air-to-water system does, however, introduce one element that ground-source heating does not have: the outdoor unit.<\/p>\n\n\n\n

Its location is determined during the design phase. The architectural appearance of the house, access for maintenance, noise, condensate drainage, free airflow and local authority requirements regarding placement and screening all need to be considered.<\/p>\n\n\n\n

The outdoor unit can be visually screened as part of the architecture, but it cannot simply be placed inside a closed unheated shed. During operation, the unit moves a large amount of air and needs sufficient free space around it.<\/p>\n\n\n\n

Which one operates more efficiently?<\/b><\/p>\n\n\n\n

One advantage of ground-source heating is the more stable temperature of the heat source. The operating conditions of an air-to-water heat pump change with the outdoor temperature, and its efficiency drops in very cold weather.<\/p>\n\n\n\n

The efficiency of a horizontal ground-source system is not completely constant either. It is affected by soil characteristics, moisture, the load placed on the ground loop and winter conditions, including snow cover.<\/p>\n\n\n\n

In practice, the client does not usually need to compare the technical specifications of dozens of different units. Once the appropriate type of heating system is clear from the project and the plot conditions, we select a high-quality unit suited to the requirements of that particular house.<\/p>\n\n\n\n

On some plots, both ground-source and air-to-water heating are realistic options. In other cases, the energy calculation, plot size, mature vegetation or other technical conditions already make the choice quite clear.<\/p>\n\n\n\n

\"Denmark
Denmark house in Viimsi<\/figcaption><\/figure>\n\n\n\n

The heating system is part of the technical whole of the house<\/h2>\n\n\n\n

A good heating unit alone cannot make a house energy-efficient. The lower the heat loss of the building, the less work the heating system needs to do.<\/p>\n\n\n\n

This is also where heat-recovery ventilation plays an important role.<\/p>\n\n\n\n

In winter, the ventilation system removes warm used air from the house and brings in fresh cold outdoor air. In a heat-recovery system, the two air streams pass through the heat exchanger in separate channels \u2014 the air itself does not mix, but much of the heat from the outgoing air is transferred to the incoming fresh air.<\/p>\n\n\n\n

This means that the fresh air entering the house is already preheated, so the heating system does not need to raise all incoming air from outdoor temperature to room temperature.<\/p>\n\n\n\n

For this reason, insulation, airtightness, ventilation and heating work together as one system. Happy Home also treats the building services as a complete technical whole.<\/p>\n\n\n\n

The location of technical equipment is resolved during design<\/h2>\n\n\n\n

Happy Home houses always have a deliberately planned area for technical equipment.<\/p>\n\n\n\n

In most cases, the house has a separate technical room. In some cases, the equipment can be located in a sufficiently spacious garage or storage room, but even then a dedicated area is reserved for it in the design.<\/p>\n\n\n\n

During the design stage, we determine the locations of:<\/p>\n\n\n\n

    \n\n
  • the heating unit;<\/li>\n\n\n
  • the domestic hot-water tank;<\/li>\n\n\n
  • the ventilation unit;<\/li>\n\n\n
  • the underfloor-heating manifolds;<\/li>\n\n\n
  • the necessary pipework and connections;<\/li>\n\n\n
  • the space required for maintenance.<\/li>\n\n<\/ul>\n\n\n\n

    This allows us to check already during the planning stage that all technical equipment fits logically into the house without unexpectedly taking space away from another function later.<\/p>\n\n\n\n

    For domestic hot water, we generally use a sufficiently sized hot-water tank that provides a comfortable reserve for normal detached-house use.<\/p>\n\n\n\n

    \"Japan
    Japan house in Veskim\u00f6ldre<\/figcaption><\/figure>\n\n\n\n

    A fireplace can complement the main heating system<\/h2>\n\n\n\n

    A heat pump does not, of course, rule out having a fireplace.<\/p>\n\n\n\n

    Different types of fireplace can be incorporated into a Happy Home house if the client wishes. The fireplace may use solid fuel or another solution, it may be heat-storing or non-heat-storing, and it can also be combined with a masonry heat-storage wall (a masonry heat-storage wall must be built by a suitably qualified stove and fireplace specialist).<\/p>\n\n\n\n

    In the energy-efficiency calculation, a fireplace is generally not treated as the main heating system of the house. The primary heating solution is therefore designed independently of whether or not the client chooses to add a fireplace.<\/p>\n\n\n\n

    The role of the fireplace is usually supplemental heat, everyday comfort and atmosphere.<\/p>\n\n\n\n

    Ground-source heating can also be used for cooling<\/h2>\n\n\n\n

    One additional possibility with ground-source heating is to use the lower temperature of the ground to cool the house in summer.<\/p>\n\n\n\n

    With so-called passive cooling, the cool temperature of the ground is used to remove excess heat from the building. Because the compressor does not need to produce cooling in the same way as in conventional active cooling, this can be a very energy-efficient way to cool the house.<\/p>\n\n\n\n

    However, having ground-source heating does not automatically mean that cooling is included. Using the system for cooling requires additional components and equipment, which also means an additional cost.<\/p>\n\n\n\n

    There are several ways to solve this technically. Cooling can, for example, be connected to the hydronic system, but in Happy Home houses we also often use separate ceiling-mounted cooling units, either in addition to or instead of this solution.<\/p>\n\n\n\n

    Their advantage is faster response and convenient room-by-room control \u2014 cooling can be directed precisely to the bedroom or living space where it is needed at that moment.<\/p>\n\n\n\n

    Some projects use both: ground-source cooling as well as separate cooling units.<\/p>\n\n\n\n

    \"Denmark
    Denmark house<\/figcaption><\/figure>\n\n\n\n

    A good heating system is a well-designed whole<\/h2>\n\n\n\n

    When choosing a heating system, the important thing is that the unit has the right capacity and good efficiency for the particular house, and that the complete heating design is properly resolved \u2014 from the heat source and underfloor-heating circuits to the technical room, controls and final system settings.<\/p>\n\n\n\n

    Both ground-source and air-to-water heating can be excellent solutions. The choice for a particular house is shaped by the energy calculation, the plot, technical possibilities, investment and the client\u2019s preferences.<\/p>\n\n\n\n

    Once installed, even a good system needs to be commissioned correctly: the underfloor-heating circuits are balanced, flow rates are adjusted, and the room controls are checked to make sure they correspond to the design and actual use.<\/p>\n\n\n\n

    A well-designed heating system is ultimately almost unnoticeable: the house feels comfortably warm, the system operates efficiently, and the homeowner does not need to constantly think about how it is working.<\/p>\n","protected":false},"author":2,"featured_media":15824,"template":"","valitud":[],"useful_category":[],"class_list":["post-12604","useful","type-useful","status-publish","has-post-thumbnail","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/happyhome.ee\/en\/wp-json\/wp\/v2\/useful\/12604","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/happyhome.ee\/en\/wp-json\/wp\/v2\/useful"}],"about":[{"href":"https:\/\/happyhome.ee\/en\/wp-json\/wp\/v2\/types\/useful"}],"author":[{"embeddable":true,"href":"https:\/\/happyhome.ee\/en\/wp-json\/wp\/v2\/users\/2"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/happyhome.ee\/en\/wp-json\/wp\/v2\/media\/15824"}],"wp:attachment":[{"href":"https:\/\/happyhome.ee\/en\/wp-json\/wp\/v2\/media?parent=12604"}],"wp:term":[{"taxonomy":"valitud","embeddable":true,"href":"https:\/\/happyhome.ee\/en\/wp-json\/wp\/v2\/valitud?post=12604"},{"taxonomy":"useful_category","embeddable":true,"href":"https:\/\/happyhome.ee\/en\/wp-json\/wp\/v2\/useful_category?post=12604"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}