Interest in heat pumps is growing as more and more households seek a single solution for heating, cooling and hot water production. The ability for one system to serve several basic home needs sounds appealing, especially in new construction or major renovations.
However, a heat pump is not a device that is chosen solely based on the area of the house or a specific promotion. Its effectiveness depends on the condition of the building, heat losses, the heating installation, climatic conditions and the way the family uses the home.
Therefore, before considering specific home heat pumps, it is important to understand whether such a type of system is suitable for the specific property and what conditions must be met for it to work effectively.
Contents:
What kind of home is a heat pump suitable for?
Insulation is part of the system, even though it is not part of the machine
Why calculating by square footage alone is not enough
Underfloor heating, convectors or radiators
What we need to know about domestic hot water
Where to place the outdoor unit
Noise should be assessed according to location
When a heat pump may not be the first step
Questions to ask before an offer
How does a heat pump work?
In general, a heat pump extracts heat from the outside environment and transfers it to the building's heating system. In the most common solutions for homes, the source is the outside air, and the energy obtained is used to heat the water in the installation.
During the warmer months, some systems can also operate in reverse mode, removing heat from the home and assisting with cooling.
Thus, a properly built system can participate in:
- heating of premises;
- cooling in the summer;
- the provision of domestic hot water;
- working with underfloor heating;
- the power supply to water-cooled fan coil units;
- certain existing radiator systems.
It is important to note that the capabilities depend on the specific model and on the way the entire system is designed.
What kind of home is a heat pump suitable for?
A heat pump may be suitable for both a new house and an existing property, but the conditions are different.
In new-build projects, the system can be planned right from the start. This makes it possible to combine good insulation, low-temperature heating, a suitable boiler or buffer tank, and the correct positioning of the equipment.
In the case of an existing house, it is necessary to check whether the current installation is compatible with a heat pump and whether the building suffers from excessive heat loss.
The best conditions are usually found in homes with:
- good thermal insulation;
- high-quality windows and doors;
- limited uncontrolled heat loss;
- underfloor heating or suitable convector heaters;
- enough space for the internal components;
- a suitable location for the outdoor unit;
- a properly designed electrical installation.
This does not mean that an old house is automatically unsuitable. Rather, it means that, before making a choice, you should consider whether measures to improve energy efficiency are needed first.
Insulation is part of the system, even though it is not part of the machine
One of the most common mistakes is to expect a heat pump to compensate for all the building’s shortcomings. If the house loses a significant amount of heat through the roof, walls, windows or floor, any heating system will have to work harder.
This has an impact on:
- the required power;
- consumption;
- comfort;
- the time taken to reach the desired temperature;
- the total investment;
- the load on the equipment.
Before making a purchase, it is wise to assess the condition of the building envelope. Sometimes, a combination of improved insulation and a more accurately sized heat pump is a more sensible option than choosing an overly powerful system for an energy-inefficient house.
Why calculating by square footage alone is not enough
Two houses of the same size may have completely different heating requirements.
The following are important:
- the year and the construction method;
- the type and thickness of the insulation;
- the height of the rooms;
- the size and orientation of the windows;
- the region and typical winter temperatures;
- the number of external walls;
- heated and unheated areas;
- the desired temperature in the rooms;
- hot water consumption.
Therefore, the choice of capacity should be based on a calculation of heat losses, rather than simply on a guide table.
A system that is not powerful enough may have to run continuously under high load and may not provide the desired level of comfort in colder weather. An oversized system is not necessarily better either, as it may operate inefficiently under partial load and unnecessarily increase the initial investment.
Underfloor heating, convectors or radiators
Heat pumps generally operate most efficiently with systems that can heat rooms using water at a lower temperature.
Underfloor heating
Underfloor heating is often the preferred solution in new-build homes. It utilises a large heating surface area and can maintain a consistent temperature even at a relatively low water temperature.
The benefits include:
- even heat distribution;
- no visible radiators;
- good comfort;
- proper use of a heat pump.
However, it must be planned at the construction or major refurbishment stage, as it affects floor levels, floor coverings and the layout of the rooms.
Fan coils
Convector heaters can be used for heating and, with a suitable system, for cooling. They respond more quickly than underfloor heating and allow for more flexible control of individual rooms.
When cooling, provision must be made for proper condensate drainage and humidity control.
Existing radiators
It is possible to use existing radiators in certain cases, but it is necessary to check whether they can give off sufficient heat at the water temperature that the heat pump will supply.
A system designed for a high-temperature boiler cannot always be used as it is. Sometimes it is necessary to increase the number of radiators, replace them with suitable units or opt for a different type of solution.
That's why heating and cooling using a heat pump should be viewed as a complete system, rather than simply as the purchase of an outdoor and indoor unit.
Monoblock or split system
With air-to-water heat pumps, there are often two main types of configuration: monoblock and split.
Monoblock
In a monoblock system, the main components of the refrigeration circuit are housed in the outdoor unit. Water or a suitable heat transfer fluid usually circulates between the outdoor unit and the indoor installation.
The advantage is that the refrigeration circuit is factory-sealed. During installation, however, careful consideration must be given to protecting the external water connections against low temperatures and power cuts.
Split system
In a split-system configuration, the outdoor and indoor units are connected via a refrigerant. The indoor unit transfers energy to the water system.
This option restricts the water circuit from extending beyond the building, but requires the refrigeration unit to be installed by a qualified technician.
There is no single best option. The choice depends on the building, the distances involved, the climate, the installation site and maintenance preferences.
What we need to know about domestic hot water
If the heat pump is also to provide hot water for the home, a suitable water storage tank must be provided.
The following factors are taken into account when selecting it:
- the number of people in the household;
- taking a shower or a bath;
- peak consumption hours;
- the required volume;
- temperature conditions;
- recovery time;
- the presence of an additional heater;
- programmes for periodically raising the temperature.
A heat pump does not mean an unlimited supply of hot water. The tank capacity and settings must be tailored to the family’s actual habits.
Is a buffer tank needed?
A buffer tank can help ensure the system runs smoothly, but whether one is needed and its size depend on the specific installation.
It may be useful for:
- ensuring the necessary water supply;
- limiting excessive switching on and off;
- better control of multiple heating circuits;
- striking a balance between production and consumption;
- to assist the defrosting processes in certain systems.
This is not a component that should be added mechanically to every project. The solution must form part of the plumbing layout drawn up for that particular house.
Where to place the outdoor unit
The location of the outdoor unit affects its operation, noise levels, access for servicing and the drainage of water during defrosting.
A good position should ensure:
- free airflow;
- sufficient clearances;
- a solid foundation;
- protection against snow build-up;
- adequate drainage;
- access for servicing;
- a reasonable distance from bedrooms and neighbouring properties.
It is not a good idea to enclose the body in a narrow recess or decorative structure that obstructs airflow. Nor should water from defrosting be allowed to collect on a walkway where it might freeze.
Noise should be assessed according to location
The catalogue figures are important, but the perception of noise also depends on the installation and the surrounding environment.
A hard surface, a corner between walls or an enclosed courtyard can reflect sound. Vibrations can also be transmitted to the structure if the foundation has not been laid correctly.
Before installation, it is advisable to consider the following:
- the distance to windows;
- proximity to bedrooms;
- its position in relation to neighbouring properties;
- the need for anti-vibration components;
- the nature of the surrounding surfaces.
How climate affects choices
A heat pump extracts energy from the outside air, which is why its performance varies with the outside temperature.
At lower temperatures, the available heating capacity usually decreases and the amount of electricity required increases. The outdoor unit also goes through defrost cycles under certain conditions.
It is therefore necessary to examine the data for the specific model at temperatures typical of the region, rather than just the rated values under more favourable conditions.
A house in an area with colder winters may require a different approach to that for a home in a milder climate.
The electrical installation
Before making a purchase, you should check whether the electrical installation is capable of supporting the system.
The following are important:
- the required power supply;
- single-phase or three-phase configuration;
- defences;
- the power of the auxiliary heater;
- the other major energy consumers in the home;
- the available connected capacity.
This check must be carried out in advance, not after the equipment has been delivered. Otherwise, you might end up with a brilliant machine and an electrical system that reacts to it as if it were a personal insult.
Zone management
A larger house often has rooms with different purposes and different patterns of use. Bedrooms, the living room, the study and the guest rooms do not always need to be kept at the same temperature.
Zone control can improve comfort, but it must take into account the minimum required water flow rate and the heat pump’s operating mode.
It is not enough simply for all loops to be closed independently. The control system must form part of the overall design so as not to compromise the stability of the system.
How are costs estimated?
The exact future expenditure cannot be determined on the basis of a single advertising coefficient alone.
It depends on:
- the house’s heat loss;
- outdoor temperatures;
- the desired indoor temperature;
- the water temperature in the system;
- domestic hot water consumption;
- settings;
- the method of control;
- the price of electricity;
- household habits.
It is more useful to compare scenarios based on the building’s calculated annual energy requirement than to promise the same bill for every home.
When a heat pump may not be the first step
There are cases where other issues need to be resolved first:
- the house is not sufficiently insulated;
- the window frames are badly damaged;
- the existing system requires a very high temperature;
- there is no suitable place for the equipment;
- the power supply is insufficient;
- The owner has no plans to make the necessary changes to the system.
In such a situation, the most sensible approach may be a step-by-step one: first, minimising losses; then, adapting the system; and only then selecting a heat pump.
Questions to ask before an offer
Before accepting an offer, ask for clarification on the following points:
- Has a calculation been carried out to determine the heat losses?
- At what outside temperature is the power setting selected?
- What water temperature will be required?
- Are the existing radiators suitable?
- How will domestic hot water be supplied?
- Is a buffer vessel required?
- What is the control system?
- Is there an additional source of heat?
- Where will the outdoor and indoor equipment be located?
- What do installation, commissioning and warranty servicing involve?
- What preventative measures are needed?
- Who will be responsible for the overall operation of the system?
The clearer the answers are, the lower the risk that individual components may be sound, but the system as a whole may not perform as expected.
Conclusion
A heat pump can be an effective solution for heating, cooling and hot water, but the outcome depends on much more than just the choice of a particular make or capacity.
Good insulation, correct sizing, suitable radiators, the hydraulic layout, the electrical supply and professional installation are all part of a single whole.
The best approach is to first assess the home and the family’s habits, and then select the equipment. This way, the end user can approach a partner or installation company with clearer requirements and look for a solution that is genuinely suitable for their home.
At crystalbgr.com Various heat pump solutions can be considered, which can subsequently be sourced through the company’s partner network.