Do heat pumps work in old houses?
A source of low carbon heating, heat pumps use natural thermal energy from the ground or air to heat buildings. According to the Government’s Future Home Standard (FHS), from 2025 new homes will need to be built with low carbon heating systems. So, while heat pumps are very common in new homes, what about old houses?
In this guide, we’ll take a look at whether heat pumps work in older homes, discussing potential challenges and the different heating options available.
Can heat pumps be installed in old houses?
Put simply, yes - heat pumps can be installed in older homes. While modern houses are often built with energy efficiency and low-carbon heating in mind, many period properties can still benefit from a heat pump with the right preparation.
Heat pumps are most efficient in well-insulated homes, as they transfer heat rather than generate it. In a poorly insulated property, more heat is lost through walls, windows and roofs, which means the heat pump must work harder to maintain a comfortable temperature - reducing overall efficiency and increasing running costs. Older properties tend to be less well insulated so they may need some upgrades, such as loft insulation or underfloor heating, before installing a heat pump.
What makes older homes tricky for heat pumps?
While it can vary depending on the property, in general older properties have a few common challenges when installing a heat pump:
Insulation
Many period homes have solid walls, single glazing or minimal loft insulation, all of which can make it harder to retain heat. Since heat pumps operate at lower flow temperatures than gas boilers, good insulation is important to help maintain a comfortable indoor temperature.
Radiator size
Traditional radiators were typically sized to work with higher-temperature systems like gas boilers. As heat pumps deliver warmth more gradually older radiators may need to be resized to compensate.
System compatibility
Homes with older pipework, gravity-fed hot water systems or aging controls might require some upgrades to ensure compatibility with modern heat pumps.
Despite these issues, most can be resolved with relatively straightforward improvements - such as topping up loft insulation, upgrading certain radiators, or updating controls - making heat pumps a practical option for many older homes.
Can old radiators be used with a heat pump?
In some cases, yes but it depends on the size and efficiency of your current radiators. Heat pumps work best with large surface-area emitters that can effectively distribute warmth at lower flow temperatures. If your existing radiators are generously sized and your home is reasonably well insulated, they may be sufficient. A qualified installer can assess your current system and advise whether your radiators are compatible or need upgrading to a larger one.
Another good alternative to radiators is underfloor heating which is very efficient with heat pumps. While this may not be feasible for every room, it could be worth considering if you’re planning to upgrade your kitchen or bathroom.
Take a look at a 1930's retrofit
Are heat pumps better than gas boilers for older properties?
Heat pumps offer a number of advantages over gas boilers, even in older homes. While gas boilers heat water to a higher temperature and can be more forgiving in poorly insulated spaces, they rely on fossil fuels and come with higher carbon emissions.
Heat pumps, by contrast, use electricity and extract renewable heat from the air or ground. This makes them much more efficient, especially when paired with good insulation, and significantly lowers a home’s carbon footprint. Over time, they can also reduce your heating bills, particularly as electricity continues to decarbonise and energy prices fluctuate.
For homeowners willing to make modest upgrades to their property, heat pumps are a future-proof and environmentally responsible alternative to traditional gas heating.
What type of heat pump is best for older homes?
The best type of heat pump for an older property depends on your home’s layout, insulation levels and outdoor space. There are two main types to consider:
These absorb heat from the air outside and use it to warm your home. They work efficiently in many older homes, especially if some insulation improvements are made. You will require external space for the outdoor unit and space for a water tank.
These systems draw heat from the ground using buried pipes. They’re incredibly efficient and can be a great long-term investment. However, installation is more costly and you will need land near your home to install the pipework.
Old homes and heat pumps might not seem like the most natural pairing. However, with preparation and necessary upgrades, installing a heat pump in your home can be a worthwhile investment no matter the age of the building. With expert guidance and a variety of heating solutions, Viessmann makes it easy to improve the overall efficiency of your home.
