Are Air Source Heat Pumps Suitable For Old Houses?

With traditional fossil fuel energy prices increasing and looking to be phased out, air source heat pumps can provide a way to heat a home from a renewable energy source.

However, air source heat pumps work differently to other heating systems and extract and deliver heat more slowly, meaning that the right internal heating equipment must also be used.

Proper insulation of a home is also important to help keep the heat in for long enough for temperatures to rise, and so can an air source heat pump work with older houses?

Air source heat pumps can be suitable for most houses, but further work such as upgrading insultation, pipes and/or ductwork, and other internal heating apparatus, may be required for older properties to make the most out of a heat pump.

We’ve been using our own air source heat pump for over 5 years, but it was installed when the house was built and so all the internal apparatus was designed to work with the heat pump from the start.

Air Source Heat Pump
Our air source heat pump was installed in our newly built house, but they can still work in older houses with the right setup

It can be more difficult and costly to install an air source heat pump (ASHP) in an older home that doesn’t have the required existing heating setup, but it can still be possible and suitable to do so.

In this article we explain why air source heat pumps can be suitable for older houses and how to make them operate more efficiently in the space you have. We’ll also discuss how air source heat pumps can be used with existing radiators and where to place them at your home.

Are Air Source Heat Pumps Suitable For Old Houses?

While it can be more cost-effective to install an air source heat pump in a more modern home with existing heating apparatus that’s suitable for use with a heat pump, it can still be feasible to install one in an older property.

Air source heat pumps work by extracting heat energy stored naturally within the outside air and transfer for use indoors.

ASHP’s can’t provide the same instantaneous heat that other more traditional gas or oil heating and domestic hot water systems can provide. They extract and deliver heat more slowly but can reach the same desired temperatures given enough time.

As a result, air source heat pumps need to be accompanied by a suitable internal heating system that helps this heat to be released more efficiently.

As internal temperatures can also take longer to rise when using an air source heat pump, a building must be sufficiently insulated so that heat doesn’t escape as quickly as it’s released.

While the vast majority of homes, old and new, can be upgraded to work with ASHP’s, more emphasis may need to be put on following when installing in an older home.

  • Insulation levels. Providing greater insulation in a home can help to keep heat in for longer and reduce energy bills.
  • Pipes & ducts. The pipes and/or ducts as part of an internal heating system may need to be upgraded for use with an air source heat pump.
  • Radiators. Larger sized radiators, and increased numbers of radiators, can be required to ensure that the lower temperature heat is released effectively.
  • Underfloor heating. Air source heat pumps work very well with underfloor heating as their large surface area helps to release heat.
  • Space for outdoor unit installation. See our article on air source heat pump installation requirements.

A larger and more powerful air source heat pump unit may be required in an older property to counteract the potentially lower quality heating system and insulation levels.

Air Source Heat Pump
Our ASHP is sized appropriately for our modern detached 5-bed house, but may need to be oversized to work with an older home with poorer insulation and an outdated internal heating system

If you’re looking to restore an old home and completely replace the whole heating system then installing a new air source heat pump system can definitely be worth it.

Benefits of Installing Air Source Heat Pumps in Old Houses

While any heating device can be installed in an old house after making the necessary modifications, air source heat pumps are especially suitable for old homes for the following reasons:

  • Easy to install. They simply need to be secured to a concrete floor and connected to pipework and power cables heading into the house.
Air Source Heat Pump Back
Our ASHP installed outside with two pipes connected into the house behind the unit
  • Can be installed without ductwork. It can expensive and laborious to install ductwork in an old house. Instead, air to air heat pumps are easily installed by drilling a hole in the wall to connect the outdoor and indoor units. See our article on ducted and ductless heat pumps for more information.
  • Take up less space. Roughly the size of an air conditioning unit, an air source heat pump takes up less space than other types of heat pumps. Air source heat pumps don’t take up too much space outside and can be put out of the way down the side of a house.
Air Source Heat Pump
An older home may have more space for installing the outside heat pump unit
  • Can be fitted with other heating devices. Air source heat pumps can be connected with existing heating devices, such as radiators and hot water tanks. This means that if an existing heating system is already sufficient then there can be no need to buy new appliances or undertake renovation work installing new indoor equipment.
  • Dehumidify better than central air conditioners. Many old homes tend to have high humidity levels. High-efficiency air source heat pumps dehumidify more efficiently than conventional central air conditioners. This saves energy and makes summers cool and comfortable.  
  • Work well even in sub-zero temperatures. Modern versions of air source heat pumps can heat an indoor space even in sub-freezing temperatures. These pumps can therefore be suitable for installing in old houses in cold climates.
  • More eco-friendly than oil pumps and boilers. According to the U.S. Department of Energy, air source heat pumps use 50% less electricity than furnaces and baseboard heaters.
  • Don’t require fuel storage space. It’s challenging to carve out space in old houses, which are usually constructed with hefty materials. However, there’s no need to create storage space for fuel if you install an air source heat pump.
  • Modernizes your period property. Installing an air source heat pump modernizes an old house and can increase its resale value.

Can Air Source Heat Pumps Use Existing Radiators?

Air source heat pumps can use existing radiators if a low flow temp is maintained. Occasionally, an existing radiator must be replaced by a larger unit that matches the flow temp of the heat pump. Air source heat pumps work more efficiently with existing radiators if the building is well-insulated.

Air Source Heat Pump Radiator
The upper floor of our house uses large and modern radiators to help make the most out of the air source heat pump

See our article on whether air source heat pumps can be used with radiators for more information.

Where Is the Best Place to Put an Air Source Heat Pump?

The external unit of an air source heat pump is always installed outside. As air source heat pumps can make a certain level of noise, the best place to install the heat pump can be down the side of the property.

Typically, the compressor unit of an air source heat pump is installed outside a building. If you have large grounds available, it’s recommended to place the compressor down the side of a house to keep the humming noise from disturbing you when you are outside.

Our air source heat pump is located on the side of our house adjacent to the internal garage and away from windows.

Air Source Heat Pump
The ideal place for an air source heat pump can be down the side of a house

See our guide on where to install an air source heat pump for more information.

How To Make Air Source Heat Pumps More Efficient

If you decide to install an air source heat pump in your old house, here are some tips on how you can make the unit work more efficiently:

Operate at a Low Temperature

The harder an air source heat pump works, the more energy it consumes.

To keep energy consumption at a minimum, set up the pump to generate heat at a lower temperature for a longer duration. Keep in mind, you may have to resize your existing radiators to heat your home to comfortable levels.

Insulate the House

Insulate your home to prevent cold air from coming in or warm air escaping from the inside of the building. Close all doors and windows when the heating is on.

A well-insulated house lessens the work the pump has to do to keep the house warm during winter and cool during summer.

Maintain Smooth Airflow Around the Vents

To keep air source heat pumps working efficiently, ensure the airflow vents on the compressor installed outside are free of obstructions. Prune any bush or shrub blocking that may be blocking the air vents, and remove any snow or ice in winter as needed.

Air Source Heat Pump Back
Space must be kept around an ASHP for heat to be captured effectively and can be especially important for older homes

Service the Pump Annually

Proper maintenance of your air source heat pump is the best way to keep it working at its best for as long as possible. For instance, periodic servicing ensures the pump is utilizing its full capacity. It also detects and fixes glitches before they become serious issues that can shut down the pump.

See our articles on air source heat pump servicing and air source heat pump maintenance requirements for more information.

Are Air Source Heat Pumps Suitable For Older Homes?

Air source heat pumps can be suitable for older properties as a well as new, but more thought will need to be given to the internal heating system and the insulation levels of the house to ensure that a heat pump installation remains cost-effective, and worth it.

Air source heat pumps are some of the most energy-efficient heating devices currently on the market. They perform multiple tasks, such as heating, cooling, and dehumidifying. Plus, they can be easy to install and maintain.

Overall, air source heat pumps can make living in an older house more comfortable and attractive, and an installer will be able to find the best option for your home.

Further Reading

How Air Source Heat Pumps Work

Can Air Source Heat Pumps Be Installed Indoors?

Air Source Heat Pumps & Underfloor Heating

Air to Air vs Air to Water Heat Pumps Explained

Air Source Heat Pump Electrical Requirements

Can An Air Source Heat Pump Replace An Oil Boiler?