What exactly is a heat pump?

A heat pump is a heating appliance that takes ambient heat from our natural surroundings, then using some electricity, increases that heat to usable temperatures through a compressor and refrigerant. This is the same technology that your fridge uses, except in reverse. For each unit of electricity that is used, a good quality heat pump can create 4.5-5.5 units of heat. This is called the Coefficient of Performance (COP). Because the original heat that is used is natural and from our environment, a heat pump is a renewable technology.

Does it work with radiators?

Yes, a heat pump can work with radiators as well as underfloor heating but it’s very important to choose your heat pump carefully. It’s best to use low temperature radiators where possible but some of the better-quality heat pumps on the market can effectively heat normal steel radiators too.

Does it heat my water too?

Yes, absolutely! You need to be a little bit careful here though. Every heat pump will say that they heat water HOWEVER, many heat pumps use a standard electric heater to boost the water temperature to 60 – 65°C. Only a select few of the top heat pumps can heat water using the “heat pump” itself and without the electric heater. This is hugely important as it will make a big difference to the running cost of your heat pump.

How does a heat pump work?

The heating cycle of a heat pump works by taking heat in from the ground, air or body of water outside, warming it up further, and transferring this heat to a building’s heat emitters (radiators, heat exchangers, underfloor pipes) to increase the indoor air temperature and create a comfortable living environment for building occupants. To offer a more technical explanation, this is the following process:

  1. Liquid refrigerant absorbs heat from the collector (outside) and the liquid turns to gas.
  2. The refrigerant gas then travels to a compressor (in the heat pump) where it is “compressed” rising the pressure of the gas and in turn, increasing its temperature.
  3. The hot gas flows through the condenser exchanger where it meets cooler fluid coming from the building heat emitter(s) and thus heats it as it travels back to the building. The refrigerant condense back to a liquid as it cools.
  4. The cooled liquid refrigerant then flows back through a valve which reduces its pressure in order to cool it down further and the whole cycle repeats.

Note: this is the basic process of a heat pump. Advanced heat pump units in particular introduce other stages to increase temperatures even further.

What does 'Air-to-Water' (A2W) mean?

This refers to a heat pump that sources its energy from “air” and then puts it into “water”. This usually refers to the air outside your home and the water that’s in your heating system, e.g., underfloor heating pipework. An air-to-water heat pump is also correctly known as an “air-source” heat pump.

What does 'Geothermal' mean?

A geothermal heat pump is one that takes its energy from the earth or a body of water. Collector pipework is buried in the earth around your home and circulates to collect the heat energy from this earth. This pipework can be laid horizontally or vertically (borehole) or a body of water such as a river or lake can be used. A geothermal heat pump is also correctly known as a “ground-source” heat pump.

Do I need a huge garden?

Well, no. But we’ll answer this in two parts.

An air-to-water heat pump is a piece of equipment (a lot like an external oil boiler) that sits on your footpath or in your garden and is then piped to indoors and that’s it. A monobloc version (the most common in Ireland presently) has all the heat pump components built into the outdoor unit with only your DHW cylinder and some controls inside.

A geothermal heat pump can be vertical or horizontal. A vertical geothermal heat pump is where a hole is drilled into the earth (a lot like drilling a well) and the collector pipework goes into this hole. It’s then piped to indoors and that’s it. This method doesn’t take up much space in your garden, however you need sufficient access for a drilling rig (large truck).

A horizontal geothermal heat pump required a coil of pipe to be buried around 1.5metres deep around your garden. So, this is the one where a large garden is required and has to be dug up. For this reason, this type of heat pump is most suitable for new builds and/or dwellings that sit on large sites.

Do heat pumps work in Ireland?

Yes, absolutely. Not only that, but they can work very efficiently in Ireland as we have a moderate climate and we rarely experience extremely low temperatures. That said, most heat pumps can operate in temperatures as low as round -20°C (air temperature). Furthermore, the technology has been around for nearly 200 years. And it’s the same technology that’s in your home’s fridge and freezer, only in Ireland, we generally need it for heat, so it works in reverse.

HOWEVER, not all heat pumps work as well as others. Our climate is moderate but in wintertime, night temperatures can be quite low. If the air temperature is -10°C and your home needs heat up to 21°C (and 65°C for hot water), you need a heat pump that, not only can reach these temperatures, but can do so efficiently and without costing the earth in electricity. That’s where a high-performance, which will have more advanced technology, can far out-perform market incumbents and standard “run of the mill” heat pumps. This means huge, long-term cost savings for you.

Do I need a boiler as well as a heat pump?

No. A heat pump will generally be capable of taking care of all your heating needs HOWEVER it is very important that the correct heat pump is fitted and that it’s correctly designed and sized. That said, it’s absolutely possible to have a boiler working in conjunction with a heat pump and sometimes this might make sense e.g., on larger projects or where sudden demands might occur.

If I want to fit a heat pump, must I replace the whole heating system?

No, it’s not necessary to do this in most cases. We undertake a bespoke assessment of every property and can help you decide what to retain and what to replace. Because we prefer to specify heat pumps that can achieve higher water temperatures than standard heat pumps, we can often retain existing heating distribution systems, whilst retaining a high performance. We always seek to minimise disruption in your home but we must ensure high performance of the heat pump to maximise your return on your investment.

I want to upgrade my heating system, but I'm overwhelmed by the technology options that are available. What should I do?

You need to get some help from a professional. We are more than happy to talk you through some options, but you might see us as biased (we’re not, but we can see how you might think we would be 😊). An independent, registered BER Assessor is usually good bet for impartial advice but be aware that he/she might have vested interests in a particular brand as well so it’s always good to get more than one opinion. There are some key data figures to keep an eye on and we can help you to identify those if you wish to get in touch.

Are there grants available?

Yes, but for retrofit and commercial use only. There is a very attractive grant available from the Sustainable Energy Authority of Ireland (SEAI) for retrofitting a heat pump into a dwelling built before 2011. A heat pump technical assessment is required to determine the Heat Loss Indicator (HLI) of the dwelling (this looks at where heat can be lost through the fabric of the building) and only dwellings that meet a required standard are considered. This may mean that some energy retrofit works are required, to improve the HLI, before the dwelling becomes eligible for the grant. There are also attractive installation grants available for commercial premises.

Who is the SEAI?

SEAI is an acronym for Sustainable Energy Authority of Ireland. This is Ireland’s government’s body that is tasked with making Ireland’s energy more sustainable, secure, affordable, and clean. This means carrying out a lot of research, compiling data and encouraging the Irish people to make changes that are sustainable, make energy savings, reduce the use of fossil fuels and make decisions that will have a positive impact on our environment. The SEAI administer all of the energy related grants that the Irish Government make available. See more at www.seai.ie.

Can I purchase a heat pump from you and install it myself or have my plumber install it?

All heat pumps should be installed by competent professionals only. The installation of heat pump requires a combination of a competent plumber and a registered electrical contractor. It would also be likely to entail some building works. So, the answer is yes, but strictly noting the above. All heat pumps must be commissioned by a competent technician who has the suitable qualifications and has undergone specific training with the heat pump manufacturer. Generally (not always), this cannot be done by your own installation team. We commission ALL heat pumps that we supply which validates the product warranty and ensures that your heat pump is programmed and set up correctly to ensure that it works as efficiently as possible and to prolong its life.

What is a "monobloc"?

“Monobloc” is the name given to a standalone air to water heat pump, where all the heat pump components are situated within a single outdoor unit (excluding the control element, which will be inside). This is hugely advantageous in that all the refrigerant gas is contained within the outdoor unit and only hydraulic liquid (brine) travels between inside and outside. This means that installation is more straight-forward and does not require special refrigerant gas expertise.

Prior to the popularity of monobloc units, “split” systems were widely used where the heat pump components were “split” between inside and outside, with refrigerant gas running between.

What is EVI technology?

EVI technology is the software program, combined with the use of a “flash tank”, that allows an air to water heat pump to produce extremely high water temperature, even with extremely cold outdoor temperatures. This allows domestic hot water production and heating with normal steel radiators, even when outside temperatures are as low as -15°C, WITHOUT electrical support! This is the technical bit ” EVI technology allows a flash tank to recycle gas from the condenser and send it back to the compressor during the heat pump cycle, and thus extract every last ounce of energy. It’s a difficult process and that’s why not most companies can’t do it, but Spanish heat pump leaders, Ecoforest, have managed it. This is a unique feature of Ecoforest heat pumps and is a patented software.

What is HTR technology?

HTR technology is an advanced and unique system which allows production of domestic hot water free of charge, by redirecting heat removed from the housing to the DHW cylinder, instead of wasting it in the air. Domestic hot water temperatures of over 70°C can be achieved through HTR, without any ancillary electrical support. This is possible, through the use of an additional heat exchanger and in conjunction with advanced software developments, pioneered by Spanish heat pump leaders, Ecoforest. This is a patented system and can only be found in Ecoforest heat pumps.

Can I use my existing DHW cylinder?

Yes, in some cases, it may be possible to use your existing DHW cylinder. This will depend on a number of factors such as your cylinder size, type, and number of coils. An existing coil may be used or an externally mounted heat exchanger may be preferable. Importantly, only some heat pumps are suitable for using an existing cylinder as many heat pump manufacturers give you no choice but to use their internal unit which incorporates a DHW cylinder.

Why does a heat pump need to defrost?

A heat pump system incorporates a procedure called a defrost cycle, which removes the frost from the outdoor coil. As the refrigerant within the system runs at much lower temperatures than air, a heat pump unit will defrost regularly in cold weather. A defrost cycle should be long enough to melt the ice, and short enough to be energy-efficient. Some advanced heat pumps offer unique ways of defrosting without using ancillary electrical equipment.

What is a buffer tank?

Also known as an accumulation tank or buffer store, a buffer tank is a ‘back up’ or reserve tank for storing hot water which can be called upon as and when needed. It provides a very efficient way of heating as it allows the heating appliance (whatever it may be) to work at it’s most efficient, when it heats the tank. This hot water is stored in the highly insulated buffer tank until it’s required by the building. A buffer tank also provides a great way to combine heat sources, allowing multiple systems to heat the water at the same time. Most heat pump systems either require or recommend the use of a buffer tank (due to the lower output temperatures) but this is often something that resellers fail to mention. Some higher end heat pump systems don’t require a buffer tank.

Why does underfloor heating work best with a heat pump?

Traditionally, underfloor heating was almost imperative as the heat emitter for a heat pump. This is because a heat pump is using our natural environment as the heat source and has to increase this temperature to make it heat our homes. Therefore, it makes sense that we only raise this temperature as little as possible, to keep the system as efficient as possible. The vast surface area of underfloor heating means that it doesn’t require temperatures to be as high, as say with radiators. Today, higher quality heat pumps can produce much higher emission temperatures, whilst maintaining a very high efficiency so underfloor heating is not strictly necessary with these heat pumps.

Also, as underfloor heating emits radiant heat, most people find they are comfortable at temperature settings several degrees lower than with other conventional heating system, which of course is more efficient and saves money, but this is more an advantage of underfloor heating itself.

What is COP?

The Coefficient of Performance or COP of a heat pump describes the efficiency of the unit and is the ratio of the heating performance provided over the electrical energy consumed. The COP is normally related to a specific operating condition. The main benefit of a COP rating is that we can easily compare the efficiency of different heat pumps (but it’s not the only thing to consider). The COP number refers to the number of units of heat that a heat pump produces in relation to a single electrical unit to power it. For cooling applications, we use the Energy Efficiency Ration (EER).

What is SCOP?

The Seasonal Coefficient of Performance describes the average COP over the duration of a heating season. It’s very similar to the COP but it allows for temperature fluctuations and typical standby periods. For cooling applications, the Seasonal Energy Efficiency Ratio (SEER) is normally used.

What is brine?

Brine is the fluid used within the external pipework of a heat pump. It’s a mixture of water and antifreeze which means it’ll flow freely, even in freezing conditions. This mixture is what absorbs the heat from the collector and transfers it to the heat pump system.

What is a heat exchanger?

A heat exchanger is a device, that transfers heat from one substance, into a different substance but without mixing the substances. Heat exchangers are very common in the heating and cooling industry; one such exchanger is the pipe coil within your DHW cylinder which transfers heat from the hot water in the pipe coil, into the water in the cylinder. There are several other types of heat exchangers, including plate heat exchangers which are commonly used in heat pumps.

What is refrigerant?

This is a substance which readily absorbs heat from the environment and easily changes phase between liquid and gas at low temperatures. The vaporising and condensation of refrigerants effectively moves heat from one heat exchanger to another. Without refrigerant, there would be no air conditioning, refrigeration, freezing or heat pump technologies!

What are the differences between various types of refrigerants?

Refrigerant is a hot topic of contention, especially in relation to air to water heat pumps, where the refrigerant is often contained in the outside unit. Traditionally, refrigerant has been extremely harmful to the environment, in the event of a leakage or during end of life disposal. Older types of refrigerants were very harmful to the environment, causing ozone depletion and global warming. In recent years, different mixtures of refrigerants have been developed which don’t cause ozone depletion, however most still cause global warming. These are commonly used in heat pump technology today. Examples include R410a and R32.

In very recent times, a select few heat pump manufacturers have developed technology which allows them to operate with natural refrigerants such as R290 propane. This does not cause any ozone depletion and the global warming potential is negligible compared to others. R290 refrigerant, with a GWP of 3 and ODP of 0, is 700 times less harmful than the most common refrigerant gases used in current heat pump equipment. However, the issue is that it’s more difficult to work with and only the higher-end manufacturers have perfected the technology to allow them to work with it.

What is GWP?

The global warming potential (GWP) is a value that indicates the contribution to global warming as a comparison to the much more familiar carbon dioxide (CO2). The GWP refers to the value of CO2 (GWP=1) as a benchmark. This means that a refrigerant gas like R32 for example, (which some companies actually boast as being environmentally friendly) with its GWP of 675 contributes 675 times more to global warming than the same amount of CO2. The natural hydrocarbon refrigerant R290 has a GWP of only 3.

What is ODP?

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