Making your home heat pump ready: what you can do now.
Why should I get heat pump ready? Why not? It might save you money immediately, and help avoid some costs later too. Read on to find our more….
What does a “heat pump ready” look like?
It could be an Edwardian terraced house, a 1990’s semi, or even a detached Victorian home. The type of house matters less than what preparation you have done to move towards a net-zero future with economic and efficient renewable heating. So, what do you need to consider?
1. Plan a logical sequence of actions
If your existing heating system is working fine, then you have some time to plan ahead and schedule preparations to align plans for heating electrification with other plans for your home such as; redecoration, refurbishments or internal alterations, extensions, replacement of other heating system components (like hot water cylinder), or addition of solar PV and battery systems. Focus on “no regrets” actions so that you don’t end up with wasted investments (e.g. replacing an old radiator when it may need up-sizing in the future to suit a heat pump operating at lower temperature).
2. Understand, and reduce, your heat losses now
Heat is lost through the building fabric itself (walls, floor, roof, windows and doors), and through excessive ventilation (through gaps and holes). Addressing these opportunities now will reduce heating costs immediately, and also reduce your peak heat demand which might mean that a smaller, cheaper, heat pump can be specified when the time comes to replace your boiler.
Airtightness
High air permeability can account for more than 40% of total heat loss. While a home needs to “breathe” to prevent condensation and mould, and occupants need some fresh air, many homes haemorrhage heat through excessive ventilation.
Airtightness is now a specific item on an Energy Performance Certificate (EPC) with a default, poor, value used in the calculations unless there is actual test data. Having an airtightness test with a decent score can immediately help achieve an improved EPC rating, making it more attractive to future buyers or tenants. A test costs around £200 from an organisation like BSRIA and the process will help identify significant leaks. During the test, the building is usually de-pressurised to a defined level and then the rate of air leakage measured. While the test is underway, you can walk round the building noting where draughts are being sucked into the house and make a plan to tackle these.
Your test findings can also be used to provide a more accurate result in the heat loss calculations which must be undertaken during design for a heat pump installation. Again, a poor default value is required to be used unless actual test results are available, so reducing air leakage will not only save energy but could reduce the size of heat pump and radiators needed and ongoing running costs.
Addressing sources of air leakage can often be a low-cost DIY job – sealing up around pipe and cable entries into the house, caulking gaps (under skirting boards for example), adding a letter box cover or brushes, draught excluder strips around doors, windows and loft hatches, or blocking up unused fireplaces.
Building fabric
Upgrading insulation to reduce heat lost through the building fabric is also important. Quick-wins such as adding loft insulation, or cavity wall insulation where suitable, are relatively low cost, and there is a wealth of advice available from the Energy Saving Trust. Other upgrades, like double glazing have significantly higher cost and longer payback through are often worth doing for other reasons like improved security or reduced maintenance.
3. Plan for lower flow temperature and possible pipework modifications
Heat pumps run most efficiently at lower temperatures than fossil fuel boilers. While they can operate at similar temperatures to a gas boiler (60C or more), this will not reduce running costs, so heat pump systems should be designed to operate at a maximum of 45C, ideally lower. This means that some radiators are likely to need to be increased in size to provide the same output, and pipework may need to be upgraded or modified to ensure adequate heat can be delivered to the radiators.
Where a home has already had major thermal improvements such as upgrading from single to double glazing, addition of loft and cavity wall insulation for example, the existing radiators may already be oversized so often only a few require changing.
If you are planning to install a heat pump, try and map out where your existing pipework is located and if it is under floorboards then you might want to delay laying new floor coverings just in case they need to be lifted again as part of the works. Early discussions with a quality installation partner like Xpert Energy will help you plan for your future heat pump project.
4. Review your electrical infrastructure for capacity and safety
A gas or oil-fired central heating system usually has a small electricity supply to the boiler and controls, and a separate supply to an immersion heater in the hot water cylinder. These are likely to have separate fuses or miniature circuit breakers on your electricity consumer unit. A heat pump will typically need a larger power supply to the outdoor unit, and a power supply to the heat pump controls and immersion. It is likely that you would need to upgrade MCB(s) and/or have a spare “way” on the consumer unit to add a new dedicated circuit. If there is no spare capacity on the consumer unit then the heat pump installer or your electrician can arrange for an additional consumer unit to be installed. If you are planning other future electrical works like adding solar PV, battery system or EV charger, or need to modernise your consumer unit anyway, then it is worth planning allowance for suitable capacity rather than upgrading in a more piecemeal way and ending up with a messy installation.
Many homes now have a 100A incoming power supply which is often adequate, but if yours is only 60 or 80A then additional capacity may be needed especially if you’re planning other electrification projects like installing an EV charger. Xpert Energy liaise with the local electricity distribution companies to check capacity and obtain permission for heat pump connection as part of our installation processes.
5. Floor plans
Having floor plans of your home available will be helpful to a heat pump installer. They will also be needed if you want an airtightness test undertaken. A decent sketch with dimensions is fine, but if your home has had significant extensions, or been sold in the last few years, there may already be floor plans on the local authority Planning Portal, or on Rightmove.