Air-to-Water Heat Pump Installation

The air-to-water heat pump is the most popular type of heat pump in Latvian private homes. It combines high seasonal efficiency, relatively reasonable installation costs and broad compatibility with existing radiator and underfloor heating systems. This page covers the key questions about air-to-water heat pump installation — from the operating principle to maintenance after commissioning.

What is an air-to-water heat pump

An air-to-water heat pump absorbs heat from outdoor air, even at low temperatures, and transfers it to the heating water via a compressor and heat exchanger. Unlike air-to-air systems, which heat air directly in rooms, an air-to-water heat pump heats water that circulates in radiators, underfloor heating or a hot water storage tank.

This is one of the reasons air-to-water heat pumps have become the first choice for Latvian households — it integrates into the existing water-based heating system without needing to change it significantly. It also provides hot water for domestic use, which many homeowners value highly when switching from gas or wood boilers.

Modern units maintain high efficiency down to outdoor temperatures of –20°C, so Latvia's climate conditions pose no difficulties. This is an important factor when choosing a heat pump as a primary or supplementary heat source.

Suitability

Air-to-water heat pump installation is suitable for private and detached homes with water-based heating — whether radiators, underfloor heating or hybrid systems. It is also suitable for new builds, where water-based heating with a low flow temperature is already planned at the design stage.

It is not suitable for apartments with central heating or homes without a water-based heating system — in these cases it is better to choose an air-to-air heat pump, which heats air directly in the rooms and does not require hydraulic work. Likewise, it is not worthwhile to install a water-based heat pump in homes with direct electric heating and no existing pipe system — the investment would be too large relative to the benefit.

During the site visit, the specialist assesses the condition of the existing pipework, flow rate options and circulation pump compatibility, so that installation proceeds without additional complications.

Radiators or underfloor heating

An air-to-water heat pump is most effective in combination with underfloor heating. Floor heating operates at low flow temperatures — usually 25–35°C — which allows the unit to reach maximum seasonal efficiency (SCOP). This directly translates into lower electricity consumption and lower heating costs.

Radiator systems are not excluded. Existing radiators can be integrated with a heat pump, but several aspects need to be considered. A heat pump operates at a 35–50°C flow temperature, which is lower than traditional gas or wood boilers (70–80°C). As a result, existing radiators may not release enough heat — especially compact panel or cast-iron models.

In these cases it may be necessary to increase the radiating surface — by replacing radiators with larger panel models or adding extra heat-emitting surfaces. Alternatively, a hybrid system can be considered, where underfloor heating provides the base heat for the home while radiators remain as an additional zone upstairs.

System preparation also includes installing suitable mixing valves and thermostatic controllers that separate zones with different flow temperatures. This is also why air-to-water heat pump installation takes longer than an air-to-air system — the hydraulic work must be carried out carefully and according to the project.

Monobloc or split

Air-to-water heat pumps are available in two main designs — monobloc and split type. The choice affects both installation complexity and cost.

In a monobloc system all components — compressor, heat exchangers, expansion valve and controls — are located in a single outdoor housing. Installation is simpler, since only heating water circulates in the pipes between the outdoor unit and the house, not refrigerant. This reduces the risk of leaks and simplifies maintenance. A monobloc is often the more advantageous choice if the utility room is smaller and you want a shorter installation time.

In a split system the outdoor and indoor units are separate, connected by refrigerant pipes. The indoor unit usually contains the hydraulic group and heat exchanger, allowing more flexible placement of the unit in the utility room. Split is more flexible in cases where the outdoor unit location is far from the house or in situations with different floor levels, but installation requires a certified F-gas specialist for refrigerant charging and leak testing.

Installation process

Air-to-water heat pump installation proceeds step by step, and the quality of each stage directly affects the unit's longevity and efficiency. Here are the main stages to plan for before work begins.

Cost factors

Air-to-water heat pump installation in Latvia indicatively costs from €5,000 to €12,000, though the final price varies and depends on several factors. The main one is the unit's capacity and brand — a typical 6–10 kW air-to-water heat pump costs from €4,000 to €8,000 depending on the manufacturer and functionality.

In addition to the unit itself, installation includes purchasing and installing a buffer tank, a hot water boiler with a heat exchanger, circulation pumps, three-way valves and pipes. If existing pipe replacement or additional underfloor heating installation is needed, costs increase. Rebuilding the electrical wiring or a capacity increase from the grid operator also affects the overall total.

To clearly understand all cost items and compare different systems, see our detailed price page. There you will also find pointers on available support mechanisms and differences in complexity between systems.

Maintenance and upkeep

After the unit is commissioned, regular maintenance is essential to ensure high efficiency and preserve the manufacturer's warranty. Most manufacturers require at least one maintenance visit per year — usually before the heating season.

During standard maintenance, the specialist checks and cleans filters, controls the refrigerant pressure and seal condition, checks the hydraulic system pressure and expansion tank, and sets optimal heating curves to match changing needs. The check also covers condensate drainage and frost protection, allowing potential problems to be spotted early.

Regular maintenance reduces the risk of unexpected breakdowns and extends the unit's service life. We can also help you arrange maintenance — simply submit a request and we will contact you to arrange a suitable time.