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What is a heat pump?

A heat pump extracts heat energy from the air or ground, even when it is cold outside, and uses it to warm your home.

A well-designed heat pump system transfers around three to four times more energy into a property as heat then it uses to extract it. As a result, heat pumps are incredibly efficient and also have the potential to significantly lower fuel bills, particularly in properties without access to mains gas.

  • Ideal for off-grid properties
  • Provides heating and hot water from the energy stored in the air or ground
  • Generates more energy than it uses
  • Qualifies for Renewable Heat Incentive (RHI) payments to offset the cost of MCS-compliant installation
What is an air source heat pump system?

The benefits of a heat pump

Heat pumps have a wide range of benefits, from reducing your carbon footprint to potentially saving money on your energy bills. Discover how a heat pump could benefit you:

Renewable energy option

As a renewable energy source, they are a great option for households looking to reduce their carbon footprint.
Renewable energy solution

Reduced running costs

Around three times more efficient than a boiler, heat pumps can significantly reduce your energy bills.
Reduced running costs

Eligible for RHI payments

MCS compliant heat pump installations are eligible for the Renewable Heat Incentive.
Enjoy low running costs

Up to 400% efficient

Generating more energy than they use, heat pumps are an extremely efficient heat source.
400% efficient

Types of heat pumps

There are two main types of heat pump: air source heat pumps and ground source heat pumps. Air source heat pumps are the most popular option as they require little space and cost less to install. Because of the land required, ground source heat pumps are generally better suited to larger sites.

Find out more about ground source heat pumps.

Which type of heat pump should I choose?

Air Source Ground Source (ground loops)
Efficiency Much more efficient than boilers, but generally less efficient than a ground source heat pump Generally more efficient than air source heat pumps
Aesthetics Unit located close to the property Ground loops are invisible once fitted
Sound All produce some noise, but some are much quieter than you might expect Very quiet operation
Planning Can fall under permitted development, but also need to meet MCS020 standards Planning permission is generally not required (subject to groundworks & archaeological considerations)
Site Suitable for smaller sites Suitable for larger sites
Property suitability Suitable for most properties – number of required heat pumps is dependent upon property size Generally more suitable for medium to large properties
Example installation cost for a 250m2property £11,500 £15,000 – £20,000
Example RHI tariff payments over 7 years (Ofgem figures, Sept 2018) £8,400 £17,500

In this video you’ll discover

Nu-Heat Account Manager, Rachel, talks you through the key considerations for installing a heat pump at your property in our helpful video.

What is a heat pump system?
Air source (ASHP) or ground source (GSHP)?
Is a heat pump right for your project?
Choosing the right heating system
Other renewable solutions

Everything you need to know about heat pumps


Air source heat pumps

An air source heat pump is a low-carbon, renewable heat source that is suitable for a wide range of homes.

They extract heat energy from the air in order to warm your home and provide hot water. Aside from their eco-credentials, an ASHP system is also very efficient.

For every unit of energy it uses to extract heat from the air, it typically outputs three times more as heat, meaning ASHP efficiency is around 300%!

Air source heat pump benefits include:

  • Low carbon, environmentally-friendly heat source
  • Highly efficient, transferring around three times more energy into a home as heat than it uses to extract it from the air
  • MCS approved for the Renewable Heat Incentive (RHI)
  • Little outdoor space required, meaning an air source heat pump system is suitable for most urban properties
The benefits of air source heat pumps

How does an air source heat pump work?


An air source heat pump collects energy from the air, even at low temperatures.

1. Evaporator

The energy is absorbed from the air to the refrigerant in the evaporator.

This process increases the temperature of the refrigerant, changing it from a liquid to a vapour.

2. Compressor

The vapour is compressed by an electrically driven compressor, increasing its temperature.

3. Condenser

The condenser releases this heat energy into the water used in your heating and hot water system.

4. Expansion Valve

The cooled refrigerant turns back into a liquid and the process starts again.

Is an air source heat pump right for my home?

An ASHP can be installed in a range of properties, whether small or large, rural or urban.

An air source heat pump is right for you if:

  • You are looking for a low-carbon, eco-friendly and sustainable way to heat your home
  • The property is well insulated – this is important for efficiency and keeping running costs low
  • There is not enough outside space needed for a ground source heat pump – typically three times the total floor area of the property. For an ASHP, all you need is room for the unit to be fitted to an exterior wall, with enough space around it to get a good flow of air
  • You are installing, or already have, an underfloor heating system. Air source heat pumps work particularly well with underfloor heating because they are at their most efficient when producing low water temperatures

Both new and existing properties can benefit from the energy-saving capabilities of a heat pump.

Is an air source heat pump system right for me?

Heat pump costs

In a well-insulated property, every kilowatt hour (kWh) of electricity used to power the heat pump can provide around three to four kWh of ‘free’ thermal energy. This means that a heat pump’s efficiency can reach around 400% – far more than boilers that tend to run at around 92%.

In addition to reduced running costs, the Renewable Heat Incentive (RHI) also offers quarterly tariff payments to help eligible households to offset the cost of their renewable installation.

How much does an air source heat pump cost?

You can expect a high-quality and well-designed air source heat pump system to costfrom £5,000. This includes:

  • A bespoke design, tailored to the property
  • Installation schematics
  • Lifetime technical support
  • MCS support to successfully apply for the RHI
  • The ASHP, domestic hot water cylinder, buffer tank, circulation pumps and all of the connecting brassware for the components

It’s possible to offset the initial cost of installing an air source heating system by applying for government incentives like the Renewable Heat Incentive.

To find out more about ground source heat pump costs, head over to our GSHP information page.

How much does an air source heat pump cost?

What are the running costs of an Air Source Heat Pump?

A correctly designed ASHP system can provide low running costs that are on par with mains gas, so you benefit from a greener way to heat your home that is also cost-effective long term.

Off the gas grid? An ASHP is even more appealing as it’s likely to offer you significant savings on running costs. Take a look at this running cost comparison:

ASHP 15.0p/kWh 300% efficient  5.0p/kWh
Mains Gas 4.3p/kWh 89% efficient  4.8p/kWh
Oil 4.9p/kWh 91.6% efficient  5.3p/kWh
LPG 5.8p/kWh 89% efficient  6.6p/kWh
Electric 15.0p/kWh 100% efficient  15.0p/kWh
Logs 8.3p/kWh 80% efficient  10.4p/kWh
Coal 6.3p/kWh 80% efficient  7.9p/kWh
Wood Pellet 5.5p/kWh 90% efficient  6.1p/kWh

*Please use this table as a guide as energy prices can vary.

How much does it cost to maintain an ASHP?

Like most heat sources, an air source heat pump should be serviced each year by a competent heating engineer.

The service will include mostly visual checks, checking settings haven’t changed and that the heat pump is still working efficiently.

Maintaining your ASHP annually is also a requirement for the RHI tariff payments.

You can expect an annual air source heat pump service to cost around £200.

Heat pump installer

Air source heat pump grants

By choosing to install an air source heat pump, you are helping the Government in their 10 point plan for a green revolution. Part of this plan is to make the move away from fossil fuels to low carbon heating, installing 600,000 heat pumps every year by 2028.

To encourage the uptake of heat pumps and help reduce the costs, the Government offers financial incentives.

The Renewable Heat Incentive

The Government recognises that ASHPs play an important role in reducing carbon emissions from the UK’s homes. This is why air source heat pump grants have been included in the Renewable Heat Incentive (RHI).

To help offset the cost of installation, the RHI air source heat pump grant is set at a tariff rate of 7.3p/kWh. The exact ASHP grant amount over seven years depends on how much energy the household uses.

A typical home using around 20,000kWh per annum of heating requirement could receive around £7000 in payments over a seven-year period – a considerable sum to go alongside the savings on energy bills. Visit Ofgem to find out more about ASHP grants.

Cost of renewable heating

RHI payments

RHI Payments Air source heat pump
RHI Tariff payment pence / kWh 10.71p
Potential RHI payments over 7 years using an air source heat pump* £7,000

*An average three-bed house using 15,000kWh of heating per year with a SPF of 2.7 for the ASHP. February 2020.

The cost to have an air source heat pump installed varies, but as a rough estimate, it is usually around half of the cost of the unit itself.

Looking for an installer? We can help through Nu-Heat’s Registered Installer Network.

5 must ask questions about heat pumps

Find out how to choose the right heat pump for your home

Download free guide

Nu-Heat download

Our ASHP heat pump range

At Nu-Heat, we only use the highest quality, tried-and-tested components for all our systems. That’s why we design and supply NIBE and Panasonic ASHPs as an efficient, low-carbon, solution for domestic hot water and space heating.

NIBE air source heat pumps

Swedish company, NIBE, has been manufacturing heat pumps globally for 40 years. Their industry-leading ASHPs not only look great, they also offer the highest levels of performance and functionality.

  • Incredibly quiet thanks to Owl Wing fan design, producing maximum sound power levels as low as 50 decibels
  • Intuitive control with smart connectivity
  • Compact units available from 6kW up to 16kW
  • Cascade and hybrid options to suit a wide range of properties
  • MCS approved for Renewable Heat Incentive applications
  • 7-year warranty when commissioned by a Nu-Heat engineer
Why we supply NIBE air source heat pumps
NIBE Model 6kW 8kW 12kW 16kW
CoP at 7/35 °C* 3.5 4.3 4.5 4.53
Operating voltage 230V 50Hz
Weight (kg) 66 90 105 135
Dimensions (height includes stand) H791 x W993 x
D364 mm
H945 x W1035 x
D422 mm
H1045 x W1145 x
D452 mm
H1500 x W1145 x
D452 mm
Max sound power level (dB(A))** 50 54 57 61

Panasonic air source heat pumps

Another highly efficient option is the Panasonic air source heat pump range. Available as single units from just 5kW, they offer a lower initial investment for homeowners looking to make the switch to renewable, low-carbon heating.

  • 5kW – 16kW models available
  • Maximum sound power levels as low as 59 decibels
  • Simple, compact controller
  • Built-in filter and charge pump
  • MCS approved for Renewable Heat Incentive applications
  • 7-year warranty when commissioned by a Nu-Heat engineer
Panasonic air source heat pumps

Why choose an air source heat pump from Nu-Heat?

Because we are experts in designing and integrating heat pumps and underfloor heating – it’s what we do!

As a Microgeneration Certification Scheme (MCS) accredited company, we know what it takes to provide you with an efficient system that effectively heats a home, whilst also keeping running costs low.

We are here to provide the perfect heating package, meticulously tailored to each home. You also benefit from one point of responsibility – we will carefully design everything – for complete peace of mind.

Bespoke heating design

Seamlessly integrating the ASHP and underfloor heating
Bespoke heating design

Long warranty

Our ASHPs are covered by a 7-year warranty when commissioned by Nu-Heat
7 year guarantee

Supporting RHI applications

Access the RHI with our MCS support package which includes on-site commissioning
MCS approved heat pumps

Free lifetime support

We support Nu-Heat systems for life, so you can always call on us for technical support
Lifetime technical support

Award-winning customer service

We’re the only heating company to hold a Distinction from the Institute of Customer Service
Award winning service

Ideal for underfloor heating

The perfect partner for Nu-Heat underfloor heating
Easy to install

Industry-leading technology

Market-leading, energy-efficient range of heat pumps
Low carbon heating

User-friendly guides

Comprehensive, step-by-step installation guides and user manuals
Installation guides and manuals

It’s definitely a far cheaper and greener option than oil – and we will receive around £1,000 back from the RHI each year. Nu-Heat were brilliant from the start; so professional and helpful.

Frieda Garrett – Homeowner

How are air source heat pumps installed?

Installing an ASHP is simple. There’s no need for extensive groundworks and any plumber or heating engineer can install an ASHP with our support. Nu-Heat can even take on all of the MCS paperwork and commissioning for the system, ensuring the heat pump is installed correctly and meets the criteria required for the Renewable Heat Incentive.

There are 3 key stages to installing an air source heat pump:

Step 1 – Finding the right heat pump supplier and design

Choosing an experienced ASHP supplier is essential when it comes to heat pump system design. You need to be confident that the system will be efficient and work as expected, keeping running costs low. Nu-Heat offers the following as standard:

  • Advice and guidance on the suitability of an ASHP for the project
  • Full heat loss calculations for the property in order to correctly size the ASHP
  • An accurate quotation for the system components in line with MCS and RECC standards
  • Support with MCS compliance, including on-site commissioning
  • Mechanical and electrical drawings specific to the installation as well as clear installation manuals and customer user guides
Nu-Heat underfloor heating design

Step 2 – Installing an air source heat pump

Installing an ASHP is relatively simple for any plumbing and heating engineer. The heat pump controls and pipework layout are very similar to a traditional gas or oil boiler, configured as a Y or S plan industry standard layout.

  • The ASHP is placed on a flat concrete base external to the property with the appropriately sized flow and return heating pipes and electrical power cable running from the unit into the property
  • Electrical work should be carried out by a qualified electrician in the conventional way as you would for a gas or oil boiler
  • To simplify the process, Nu-Heat provides a complete set of ‘as installed’ mechanical and electrical drawings, which will provide a fault-free template of the complete air source heating system layout.
Air source heat pump installation

Step 3 – Getting the heating system up and running

Once the installation of the mechanical and electrical heat pump components is completed, the ASHP unit will be ready for commissioning. As an MCS accredited company, we can help with this final step by providing:

  • The MCS paperwork – Pass over the cumbersome compliance paperwork to Nu-Heat, freeing up time to spend on the ASHP installation. Nu-Heat also completes and provides all of the relevant MCS support documentation for the homeowner’s RHI application, warranties and guarantees.
  • Onsite commissioning – To ensure the system is MCS compliant, Nu-Heat can send out one of our own field service engineers to commission and explain the system set up and functionality of the heat pump controls. We can also support with the handover to the homeowner.
NIBE Air Source Heat Pump with Underfloor Heating

I’m interested in installing an ASHP, what are the next steps?

Should I use underfloor heating or radiators with a heat pump?

Both underfloor heating and radiators can be paired with a heat pump but there are a few important considerations to take into account.

Whichever option you choose, is it important to understand how each system works alongside a heat pump.

Underfloor heating with heat pumps

An air source heat pump is at its most efficient when producing low temperatures which is why underfloor heating is the heat emitter we always recommend.

An underfloor heating system uses water that is around 40-45°C, circulating this across the entire floor area to heat your home. In comparison, a traditional radiator system needs to use water that is far hotter, around 70-80°C, in order to heat the room/s using a much smaller surface area.

Nu-Heat will design and supply a fully integrated heating solution that combines the full range of underfloor heating benefits with your energy-efficient heat pump.

  • Low flow temperature solution
  • Up to 40% more efficient than a boiler and radiators system
  • Reduces energy bills and carbon footprint
  • Qualifies for the RHI
  • Fully designed and integrated heat pump and underfloor heating solution from a single supplier
Does Underfloor Heating Increase Property Value

Radiators with heat pumps

You may choose to use radiators to minimise disruption within your home or to save on costs.

If radiators are the preferred option, it’s worth bearing in mind that they will need to be sized in line with the lower water flow temperatures associated with heat pumps. This means they are generally twice the size of those used with a gas or oil boiler.

Find out more with our blog post on UFH vs Radiators.

Radiator on blue wall

Air Source Heating FAQs

Is my property suitable for an air source heat pump?

Providing the property is well-insulated, an air source heat pump is likely to be suitable. Insulation is really important because it prevents heat escaping, enabling the heat pump to work efficiently at lower flow temperatures.

The levels of insulation in new build properties, and generally those built in the last 10 years, are likely to be suitable for an air source heat pump. Older properties will require insulation upgrades like loft, cavity wall and glazing improvements.

I don’t have access to mains gas – could a heat pump be a suitable alternative?

A heat pump could be a particularly cost-effective choice if your property doesn’t have access to mains gas. This is because for every unit of electricity the heat pump uses, it typically outputs three times the amount in heat energy. You can expect a heat pump to be more efficient and cheaper to run than an electric-only heating system or an LPG boiler.

Can air source heating be installed in an older building?

Yes, it can, providing that the insulation is being improved – ideally as close to current build regulations as possible. This enables the air source heat pump to work efficiently and keeps running costs low.

Does my property need to be well-insulated to have a heat pump?

Insulation should be up to modern Building Regulation standards to ensure the heat pump both effectively and efficiently heats the property.

How efficient are air source heat pumps?

An air source heat pump is around 300% efficient. This is because for every unit of energy it uses to extract heat from the air, it typically outputs over 3 units of heat energy into the property.

How do I find a heat pump installer?

We can help you to find an installer for your heat pump through our Registered Installer Network.

If you already have an installer in mind, we can support heating engineers to fit heat pumps to Microgeneration Scheme standards, offering a range of commissioning packages.

The installer will need to have the following pre-requisite qualifications:

  • Part L Energy Efficiency
  • G3 Domestic Hot Water Systems
  • Water Regulations 1999

They will also need to hold public liability insurance of over £2million.

What are the incentives of buying an air source heat pump?

An air source heat pump is a low-carbon, efficient renewable technology. A big benefit is that it offers a cleaner and greener way to heat a home – no fossil fuels.

Aside from their eco credentials, an ASHP is also inexpensive to run and cost-effective in most projects, especially when you factor in the potential payback through the Renewable Heat Incentive.

What does MCS stand for?

The Microgeneration Certification Scheme or MCS is often described as the renewables equivalent of Gas Safe. You will need your heat pump system to be MCS compliant if you wish to benefit from RHI payments for your installation.

Do I need planning permission to install an air source heat pump?

In the majority of cases an air source heat pump does not require planning permission, falling under Permitted Development in line with MCS020. Obviously, it is important to check this before getting started!

If the property is listed, in an Area of Outstanding Natural Beauty or Conservation Area, planning permission will be required.

Are heat pumps compatible with underfloor heating?

Yes! Heat pumps are at their most efficient when operating at lower temperatures, making this technology a perfect partner for underfloor heating (UFH), which operates at a much lower flow temperature than radiators.

Heat pumps can still be used in conjunction with radiators, but the radiators would need to be oversized in order to heat the property adequately.

How much space do I need for an air source heat pump?

Not much! The air source heat pump unit is fitted outside of the property. You will need some space inside for the domestic hot water cylinder, buffer tank and the other components.

For heat pumps up to 12kW, you need a footprint around the same size as a standard hot water cylinder – similar to a large airing cupboard.

What floor coverings should I choose with heat pump powered UFH?

Heat pump powered underfloor heating works best with highly conductive floor coverings such as stone or ceramic tiles, vinyl or lino. If the floor covering has good thermal conductivity, the heat pump and UFH can operate at a lower flow temperature for optimum efficiency.

How far away does the heat pump need to be from my neighbour’s house?

The actual distance a heat pump needs to be from a neighbouring property depends on the unit used and any fences, hedges, walls etc. between the heat pump’s location and the assessment position. This is covered by MCS020 – something we take care of for you.

How do I control my heat pump – are they easy to use?

You can easily control your heat pump via a series of icons on the control panel that enable you to set heating and domestic hot water (DHW) schedules, as well as view live operating data and current temperatures. Every on-screen menu has a help button which provides clarification on each of the functions.

Can any plumber install an air source heat pump?

Yes. Any competent plumber can install an ASHP to MCS standards with our support.

Will my heat pump come with a warranty and how long do they last?

Yes. Our heat pump systems come with a 7-year warranty when commissioned by a Nu-Heat engineer.

How can I ensure it is installed correctly?

Nu-Heat offers a unique air source heat pump MCS support package. This includes an on-site commissioning visit from one of our engineers who will check that the ASHP has been installed correctly.

My heat pump is weather compensating – what does this mean?

Nu-Heat supplies NIBE heat pumps that offer weather compensating technology.

Weather compensation works by adjusting the amount of energy it uses to achieve the desired inside temperature, according to the outside weather conditions. For example, your heating system will not have to work as hard to achieve and maintain a set minimum inside temperature on a warm summer’s day as it would in the depths of winter.

This is a more efficient alternative to a traditional central heating schedule, which will fire up the boiler to deliver heat to your radiators at certain times of the day or night, regardless of the outside temperature, and only regulates the heat output according to the temperature of the water circulating around the system.

How long does it take to install?

Plumbing an air source heat pump takes a similar amount of time to installing a conventional boiler. Electrically, heat pumps are a little more involved, so it may take a couple more hours to wire than a boiler.

Will my heat pump system provide enough hot water at peak times?

Yes. The most efficient way to provide domestic hot water (DHW) for your home is to allow the DHW cylinder to remain ‘topped up’, with the heat pump operating to replace the used hot water.

Most heat pumps can be set to switch on a standby electric immersion heater to ensure that you always have hot water when you need it.

Are air source heat pumps noisy?

No. An air source heat pump makes less noise than the flue of a gas boiler. NIBE ASHPs are the quietest on the market thanks to their Owl Wing Technology.

Do heat pumps work in cold weather?

Yes. Heat pumps work effectively year-round.

The top 15m of the Earth’s surface maintains an average year-round temperature of 12ºC. Ground source heat pumps (GSHPs) use this heat source to supply the energy required to heat domestic water, and a low temperature heating system such as underfloor heating.

Air source heat pumps work in a similar way, except they extract available warmth from passing air rather than from the ground. In theory they should be able to extract useful energy from the outside air down to temperatures as low as -15°C. The storage cylinder provides both domestic hot water and a boost of heating energy in the coldest weather.

What are the maintenance processes and costs?

An air source heat pump should be serviced yearly to maintain the warranty and to ensure the system is working as it should be. Servicing is also a requirement under the Renewable Heat Incentive. It costs around £200-£300 for an annual service.

Can I use my heat pump 24 hours a day?

Yes, absolutely. It’s the most efficient way.

What is the lifespan of an air source heat pump?

NIBE air source heat pumps come with a 7-year warranty when commissioned by a Nu-Heat engineer but you can expect a life expectancy well in excess of 10 years.

Will an air source heat pump work with my existing radiators?

No, we would not recommend it. Air source heat pumps are at their most efficient when producing low flow temperatures. Because of this, they should be paired with low temperature heat emitters, like warm water underfloor heating.

This stops the heat pump from overworking and keeps running costs low. Radiators are still an option but they would need to be oversized to effectively heat the room/s with lower water temperatures.

Can you program an air source hear pump to provide heating at certain times?

Yes, you can, but we would advise against it. This is because an air source heat pump is designed to work as a weather compensation system, running as and when needed to heat the home, rather than at predefined times.

Is an air source heat pump just an off-grid option?

No. Well-insulated properties that have access to mains gas are still suitable for an air source heat pump. Providing it is designed and installed correctly, the running costs will be low – comparable to mains gas – but with the added bonus of lower carbon emissions and quarterly RHI payments.

You will find that air source heat pumps are generally more popular in off-grid areas, and this is because they offer far lower running costs in comparison to oil, LPG or electric-only heating systems.

More information on heat pumps

Want help finding the right renewables solution?

We would love to speak with you to discuss your project. If you have a question about your existing Nu-Heat system, our technical support team are at hand.