The basics of heat pump suitability

The first question often asked is whether heat pumps are any good and if they will work with both old and new houses. The suitability of a heat pump depends on whether your house is ready for this technology. Heat pumps can be highly effective when installed correctly, but they can also fail if not matched appropriately with the property’s requirements. Therefore, the focus should be on preparing your home to be suitable for a heat pump rather than questioning the heat pump’s efficacy.

Insulation and ventilation: The foundation of energy efficiency 

Before considering a heat pump, it’s crucial to reduce your overall energy usage by improving insulation. Better insulation lowers the heat load required, reducing the power needed to heat your property. Key areas to focus on include:

• Roof Insulation: Often the easiest and most effective upgrade. Ensure that the roof is ventilated to prevent condensation.
• Wall Insulation: Especially important for detached properties, as walls cover the largest surface area.
• Floor Insulation: Usually less critical unless you have an older property with a suspended timber floor.
• Doors and Windows: Updating old, draughty windows and doors can significantly improve energy efficiency.

Ventilation is also vital, particularly as homes become more airtight with better insulation. Controlled ventilation, such as trickle vents or mechanical ventilation systems, ensures fresh air circulation, maintaining good indoor air quality and preventing issues like condensation

Assessing heating pptions

Various heating options are available, each with its advantages and considerations:

• Natural gas: Widely available and cost-effective, but high in carbon emissions.
• LPG and Oil: Common in rural areas but subject to market fluctuations and high carbon output.
• Direct Electric: Low capital cost but expensive to run.
• Heat Pumps: Can be more costly to install but are efficient and reduce carbon emissions.

For those serious about reducing their carbon footprint, heat pumps are a compelling option, especially with available grants to offset installation costs.

Preparing for a heat pump

Before installing a heat pump, a thorough survey of your property is necessary. This includes evaluating your home’s thermal performance and identifying areas for improvement. Improving insulation and draught-proofing should precede heat pump installation to ensure the system is appropriately sized and effective. The size of the heat pump must match the heat output required for your property. This involves measuring heat and ventilation losses to determine the correct specifications for the heat pump and radiators.

A common misconception is that heat pumps are unsuitable for old houses. However, with proper insulation and the correct size and installation, heat pumps can work efficiently even in older properties. For example, Rob has successfully used a heat pump in his 200-300 year-old stone cottage in the Cotswolds.

Heat pumps run at lower temperatures than gas boilers, but if your home is well-insulated, your existing radiators may still be suitable. The efficiency of heat pumps is measured by the Seasonal Coefficient of Performance (SCOP), which typically averages around 3, meaning 1 kW of input power generates about 3 kW of heat. This efficiency can increase with systems like underfloor heating.

Ground source heat pumps offer higher efficiency compared to air source heat pumps, with SCOP values around 5. They involve significant groundworks, requiring a large area for installation but are quiet and highly effective.

Action Plan

To summarise, determining heat pump suitability involves:

1. Defining your requirements: Understand your energy needs and future plans for your property.
2. Conducting a comprehensive survey: Evaluate your property’s thermal performance and necessary improvements.
3. Developing a strategy: Plan the insulation and draught-proofing measures needed before installing a heat pump.
4. Engaging qualified contractors: Ensure contractors are MCS accredited to guarantee quality and access to grants.