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Electricity Supply and Heat Pumps
Posted on 17 August 2021 in Blog
Everything you need to know about single phase, three phase and district network operators (DNOs).
If you’ve been making enquiries about having a heat pump installed, you may have been asked about your electricity supply and wondered why this matters. The reason is that because heat pumps are operated by electricity, the type of supply you have can affect the heat pump model available to you as not all are manufactured for both single and three phase supply.
What is single phase supply?
Single phase is a two-wire alternating current (ac) power circuit. Often one of these wires is the power wire (the phase wire) and the other is a neutral wire. A current flows between the power and neutral wire. Domestic properties are usually equipped with single-phase power supply as this is sufficient for lighting and heating (it’s for this reason single phase is often referred to as ‘residential voltage’).
What is three phase supply?
Three-phase power provides three alternating currents, making it a constant power source that never drops into zero. Three phase supply is usually found in commercial properties as it’s better for managing higher loads.
How do they differ?
An important difference between single and three phase supply is the consistency of the delivery of power. Three phase is more consistent.
What are the limitations on power supply for heat pumps?
Single phase is capable of serving a MasterTherm heat pump up to 22kW - the AQ45i has an output of 7-22kW and it’s our most-sold heat pump for domestic properties and ideally suited for larger 3-4 bedroom homes. This means that most homes will be able to run a heat pump system without converting to three phase.
What if I need a higher output heat pump?
If you require a higher output you have a couple of options:
- You could opt to put in two or more single phase heat pumps in a cascade system. This means you won’t have to pay to upgrade your power supply, however it does mean you’d have the cost of purchasing additional heat pumps.
- You could upgrade your power supply. The cost of this can vary from £2,500 to £5,500+ (plus VAT) and it can take around 2 weeks to complete. You can see average prices and durations on the UK Power Networks website. The price can differ depending on accessibility. To upgrade your electricity supply the nearest electricity cable is located. It’s usually in the road or pathway so a large hole is dug to expose the cable. A trench then needs to be dug on your land from this hole to where you want your electricity meter.
Other factors may affect your decision on which to opt for, including if you’re also considering installing solar pv, battery storage or EV charging.
How will I know what size heat pump I need?
When we conduct a site visit and carry out head load reports, we’ll be able to advise you of the required heat output for your property. If the required output is over 22kW we’ll discuss your options with you. We’ve had customers who have opted to upgrade to three phase and those who have decided on installing multiple single phase heat pumps, so we have plenty of experience in either option and can help with next steps to move your project forward.
Energy Suppliers and District Network Operators (DNOs)
Your energy supplier is who you pay your electricity or gas bill to such as Octopus, EDF Energy and Ovo Energy. You can change your energy supplier once your contract ends (usually within 12 months or less), shopping around for the best offer to suit your level of usage.
District Network Operators are those who are licensed to distribute electricity, they operate and maintain the energy supply. Companies include Western Power, SSE and SP Energy Networks. If you need to upgrade to three phase, you would normally submit your application to your DNO through a dedicated application form on their website. You can find out who your DNO is by entering your postcode on the Energy Networks website.
