11 heat pump myths explored

Heat pumps are an essential part of Scotland's drive to have one million low-carbon homes by 2030.

Scotland’s cool weather means over half the typical Scottish energy bill goes on heating and hot water. Adopting air source and ground source heat pumps will be part of the Scottish Government's drive to a net-zero emission economy by 2045.

However, recent research commissioned by Home Energy Scotland and Energy Saving Trust showed more than half of those asked (51%) hadn’t heard of heat pumps.

Let's explore the misconceptions and common myths around a technology that may revolutionise Scotland's relationship with heating and renewable energy consumption.

A heat pump system can be designed for lots of types of homes, even those without much space. There are three main types of heat pumps, all with slightly different space requirements.

  • An air source heat pump only needs a small amount of outside space, although ideally positioned somewhere where the air is free flowing.
  • A ground source heat pump requires a garden or land accessible to digging machinery to lay underground pipes. Once installed, the trenches are filled, and the garden returned to previous use. People with smaller gardens can bury the pipes into drilled boreholes.
  • Water source heat pumps need access to a water body, and its pipes are submerged underwater.

Indoors, you’ll need space for a hot water cylinder if you don’t already have one. Each heat pump has slightly different indoor space requirements.

The air source monobloc system needs a compressor and controls. The air-to-air system needs an internal air circulation system.

Air source split system, ground source, and water source heat pumps all need room for a compressor and controls. They also require an internal unit that is often smaller than a standard boiler.

Underfloor heating isn't essential, but installing it can help improve the efficiency of your heat pump.

A heat pump operates most efficiently when delivering lower temperature water than a traditional boiler would. A larger radiator can be run at a lower temperature and still provide as much heat into the room as a smaller radiator.

The bigger the radiator's surface area, the lower the water temperature needed to provide the same amount of heat into the room.

If you have underfloor heating - or you can fit it - then the whole floor is emitting heat into the room. You can run the heat pump at an even lower temperature because underfloor heating offers a more extensive surface area than even large radiators.

However, neither underfloor heating nor oversized radiators are essential. A heat pump system can be designed to work with smaller radiators. Speak to your installer about your options if upgrading your radiators isn’t practical.

Your hot water needs will need to be considered when designing the heat pump system.

Many heat pumps can provide hot water over 60°C consistently (the minimum temperature your hot water cylinder will need to reach to kill harmful bacteria). However, it is often more cost-effective to run the heat pump at this temperature periodically, called a sterilisation cycle. An electric immersion heater (or even solar hot water heating) in your hot water cylinder can top up the water temperature when you need it.

Talk with your installer about your hot water needs. High volume hot water users may need a different design to low volume hot water users. The installer can set these controls for you.

Early heat pumps were a little noisy, and the tag has, unjustly, stuck. Heat pump technology advances mean modern, energy-efficient heat pumps are much quieter. 

The noise comes from the heat pump's fan pulling air into the system. While heat pumps operate quietly, you might want to consider locating the unit away from a bedroom window, particularly if you live in a tranquil area.

Heat pumps do work nicely during winter, so you can keep your thermostat up and your home warm during the coldest of snaps.

One of the key benefits of ground and water source heat pumps is the consistency of temperature.  The seasonal performance factors of ground and water heat pumps — an efficiency measurement — is often better than their equivalent air source heat pump. Ground and water heat pumps are good choices for areas that regularly experience very cold air temperatures.

Underground temperatures are constant year-round (typically around 10-13°C). The earth's geothermal warmth provides a ground source heat pump with all the heat it needs to work, no matter how cold the air temperature outside.

Watercourses, such as a river, stream or loch offer similar, stable annual temperatures (7-12°C).

An air source heat pump can still draw heat from the air when temperatures drop as low as -15°C. However, its efficiency will reduce slightly as air temperatures fall.

Remember, the key to living in a cosy home is good insulation and draught proofing – read our insulation guide to find out more.

Heat pumps do have significant upfront costs, but these can be offset by:

  • Financial support: For example, the Home Energy Scotland Loan offers Scottish homeowners support to help with heat pump installation costs.
  • Reduced energy bills: A heat pump uses electricity, so you will continue to receive energy bills. But you may save on the fuel you are replacing, especially if you are replacing an electric heating system.
  • Heat generation payments: The Renewable Heat Incentive (RHI) offers payments for heat generated by an eligible heat pump. 

Depending on your heat demand, a typical air source heat pump costs £9,000-£11,000 and a ground source heat pump around £14,000 to £19,000 to install.

A heat pump doesn’t need to be on all the time, but the best way to heat your home with a heat pump is different from traditional systems.

Most gas or oil heating boilers run at full output when they first come on, producing very hot water to heat the home quickly. With a heat pump, it is better to have the heating coming on earlier and running for longer, heating the house slowly and keeping it comfortable. Using the heat pump at lower temperatures for more extended periods prevents the heat pump from stopping and starting and having to produce really hot water.

If you go out for a few hours, it won’t be worth turning the heating off as this would mean the heat pump has to operate at a high temperature to heat the home when you get back.

The heating can all be automatically controlled by your thermostats or zone controls — you don’t need to worry about changing your heat pump settings.

There are many examples of heat pumps running successfully and cost-effectively in older properties.

An installer will design your system based on your heating needs and property type. There are many heat pump models, so they’ll select one that best matches your needs. A good installer will also discuss options to increase insulation and draught-proofing, as well as potentially upgrading radiators to get the most out of your new system.

Sometimes, it might be challenging to install a heat pump in a property for practical or financial reasons. In that case, installers may suggest a hybrid (also known as bivalent) system, which usually involves installing a fossil fuel boiler along with the heat pump.

Always check with your local planning authority if you require planning permission, especially if you live in a conservation area or listed building.

Heat pumps are energy efficient — they can produce two-and-a-half to four times more heat energy than the electricity needed to run them. 

In 2019, some 90% of Scotland's electricity was supplied by renewable energy sources. Heat pumps offer Scotland the chance to warm its homes powered by renewable energy rather than burning fossil fuels. Heat pumps help reduce your carbon footprint.

Once installed, your heat pump requires very little maintenance. They are safer than gas, oil, or LPG systems because they don't use flammable fuels, and there is no risk of carbon monoxide accumulation.

You should always follow your heat pump installer’s advice and recommendations about system maintenance. An air source heat pump needs an occasional pressure gauge check plus an annual check to ensure the heat pump is debris-free. The recommended practice is to have a heat pump professionally serviced every two to three years.

Ground source heat pumps need a yearly inspection of fixtures and fittings and the electronics board, with a professional service every four to five years.

Many heat pump installations won’t require planning permission. However, always check with your local authority if you need planning permission.

People living in conservation areas, national parks, and listed buildings have more restrictions.

Water and ground-source open loop systems require a water abstraction license, separate from planning permission. In Scotland, abstraction permission comes from the Scottish Environment Protection Agency (SEPA).

Heat pumps: from myth to reality

All the chatter around heat pumps is not just hot air; the next decade will see mass adoption of heat pump technology. Recent Home Energy Scotland and Energy Saving Trust research showed one in five people in Scotland say they are 'likely to install a heat pump within the next five years.'

The Scottish and UK governments are firmly behind the move to low carbon heating:

Now is the time to take advantage of financial support and payment initiatives and start enjoying low-carbon heating in your home.

Take action today

Home Renewables Selector

Check if your home is suitable for a heat pump and find out how much carbon and money you could save.

Green Homes Network

Read stories from those who've installed, or book a visit or chat with a homeowner to find out more.

Funding Finder

Find out what funding and support is available to help you install a heat pump.

Follow us and keep saving