Everything you need to know about heat pump systems
Technical Account Manager, Rachel Roberts, who has over 17 years’ experience with heat pumps and integrated underfloor heating systems, talks through heat pumps and their benefits.
The above video answers the most commonly asked questions we hear, covering:
- What is a heat pump system? (0:12)
- Air source (ASHP) or ground source (GSHP)? (0:48)
- Is a heat pump right for your project? (2:35)
- Choosing the right heating system (3:44)
- Other renewable solutions (4:17)
Read on to find out more about heat pumps, including their pros and cons, how to combine them with underfloor heating, and how much they cost to install and run day-to-day.
How do ground and air source heat pumps work?
Heat pumps use the free supply of natural heat from the air (ASHPs) or ground (GSHPs) to generate domestic heating and hot water.
An efficient heat pump system transfers significantly more energy into a property as heat, compared to what it uses to extract it from the ground or air. This helps to lower the cost of fuel bills and reduce environmental impact. Here’s how heat pumps work:
- A buffer tank holds water heated by the heat pump, which supplies the heating system. Rather than switching on and off, like radiators on a schedule, the buffer tank keeps the water at a constant, pre-set temperature.
- The heat pump only increases the temperature of the water in the buffer tank when additional heat is required, and holds a minimum pre-set temperature when extra heat is not needed.
- Domestic hot water (DHW) is stored in a cylinder in much the same way as with a traditional central heating system. The water in the cylinder is heated by the heat pump and held at a pre-set temperature.
What are the benefits of a heat pump, do they cost less to run?
A heat pump typically transfers three times the amount of energy into a property as heat than it uses to extract it from the air or ground, so has the potential to significantly lower your fuel bills.
If you meet the Government’s Renewable Heat Incentive (RHI) scheme criteria, you can also receive additional payments to offset the initial cost of installation.
|Energy Source||Input Cost||Efficiency||Output Cost|
|Wood Pellet||5.5p/kWh||90% efficient||6.1p/kWh|
|Mains Gas||4.3p/kWh||89% efficient||4.8p/kWh|
*Please use this table as a guide as energy prices can vary.
We love the difference that having underfloor heating, an air source heat pump and solar thermal has made to our comfort and our energy bills. It’s definitely a far cheaper off-grid option than the oil and logs we needed to buy for our old property – and we will receive around £1,000 back from the Government’s RHI scheme each year.
– Graham and Frieda Garrett
Is my property suitable for a heat pump?
A heat pump (whether air source or ground source) is a great eco-solution for any property, but is particularly beneficial to those without access to mains gas. Your home will need to be well-insulated in order for the heat pump to operate efficiently.
If your house meets current building regulations it should be suitable for heat pumps without any alterations. If you’re renovating your home, older properties may require additional insulation – check your Energy Performance Certificate to find out your property’s current insulation levels and any recommendations for their improvement during renovation.
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.
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 much room do I need for a heat pump, do I need lots of land?
The amount of space you will need is different for a ground source or air source heat pump.
- Ground source heat pumps (GSHP) generally require an area of up to three times the total floor area of the property (ground and upper floors) for the installation of ground loops. If you don’t have sufficient land to accommodate ground loops, a bore hole is an effective – but more costly – alternative. The GSHP itself is installed indoors, along with a buffer tank and cylinder. The combination of these provide all of the property’s heating and domestic hot water requirements, without the need for boiler back up.
- Air source heat pumps (ASHP) need to be positioned outside. While less space is required for an ASHP than a GSHP, it’s best practice to consider your neighbours and locate the heat pump at least 1 metre away from your neighbour’s boundary (3 metres if your property is in Wales). Your heat pump will need to work harder if it is situated in a cooler, north-facing, shady position, than if it is located in a southern-facing, sunny spot. The cylinder and buffer tank need to be accommodated within the property. The cylinder is designed to sit on top of the buffer tank for a compact installation, and can often be housed in an area no larger than an oversized airing cupboard.
Will I need planning permission to install a heat pump?
Heat pump installations generally fall under permitted development rights, and planning permission is generally not needed unless the property is listed or located in an Area of Outstanding Natural Beauty.
Due to the additional load on the electricity network, you will need to seek approval from your electricity supplier before your heat pump is installed.
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.
All Nu-Heat heating systems come with a straightforward, comprehensive user guide as standard.
Will my heat pump come with a warranty and how long do they last?
Yes – Nu-Heat offer a choice of warranties to support your requirements. Your heating system will be designed to meet your specific property needs and to maintain your desired internal temperature even when it is -3°C outside.
If you have any queries or concerns, you have access to free, expert advice from our Technical Support team.
My heat pump is weather compensating – what does this mean?
All Nu-Heat supplied air source and ground source heat pumps come with 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.
Will my heat pump system provide enough hot water at peak times?
The most efficient means of providing domestic hot water (DHW) for your home is to allow the DHW cylinder to remain ‘topped up’, with the ground source or air source 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 there is no disruption to the hot water supply at times of high demand.
What is a hygiene purge on a domestic hot water cylinder?
Your Nu-Heat heat pump will automatically run a hygiene purge on any stored DHW once a day. This heats the stored water in the cylinder to a minimum of 60°C to eliminate the risk of harmful bacteria.
If for any reason the system is unable to complete the scheduled hygiene purge, it will attempt to do so every day for another seven days, before displaying an alarm on the control panel. If you choose to upgrade your remote monitoring and control package, you will also receive an email at this point advising you to contact your installer.
What is heat pump remote monitoring and control?
This is an optional data package that allows you to monitor and control the performance of your heat pump remotely, and includes access to the last month of running data as standard.
Additional remote control of your heat pump is available as an optional extra, allowing you to change settings or modes whilst away from home, and also receive email alerts from the heat pump if action is required.
Will I still have heating when my heat pump is being serviced?
Yes! There is a manual override function which maintains the UFH and DHW temperatures whilst the heat pump is being serviced. Electric back up heaters within the cylinder and buffer tank also ensure that heating and hot water can be maintained if the heat pump is in fault or cannot keep up with demand.
Do heat pumps work in cold weather?
Who can forget the images of The Beast from The East? As schools closed and the grit ran out, the nation huddled inside snug with their heating systems. Or did they? This was a testing time for heating systems. So, how do heat pumps perform in freezing temperatures?
Air source vs ground source heat pumps below zero
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.
I’m interested in installing a heat pump! What are the next steps?
- Call our team on 01404 549770 to discuss your project requirements
- Send us a copy of your project plans online, by email or in the post for a free bespoke quote
- Sign up to our mailing list to receive advice for your project, product news and free tickets to meet our underfloor heating and renewables experts at shows in your area