Green square blog featuring current issues and information on renewable energy and its efficiency, reliability and how to make the swap to renewable energy. Information on products biomass boilers, biomass stoves, air source heat pumps, ground source heat pumps, solar PV, solar thermal.

Back up heating for Air Source Heat Pumps - the great misconception

To many, Solar Panels and Heat pumps are akin to black magic - we know they create free energy, but we're not entirely sure how.  Theories and beliefs strengthened by subliminal snapshots of articles and Facebook ads, fuels misunderstandings and misconceptions.

We've already shared one of these misconceptions; the perfect partnership of a domestic Solar PV (Photovoltaic system) installation supporting a heat Pump, to take the home completely 'off-grid'.  

Another regular comment is the need for a back up boiler if using a heat pump.   

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Why would you have a back up boiler?
Do you currently have two boilers?  

Arguably an approved Heat Pump in a well designed system installed correctly will out last a traditional condensing gas boiler.  

The average home needs around 12 kw.  Heat pumps go to 50kw+. To be balanced, often three phase is typically required over 16kw, and the average home only use single phase.  But you can double up units without any costly electrical work and it doesn't double the cost. With the RHI incentive and lower energy bills, the payback point is normally within 5-7 years for a large 30kw system and much sooner for the average home. 

You can integrate a second fossil fuel boiler as back-up, but it comes at a cost.  Firstly, you need a specific approved heat meter, and they aren't cheap!  Furthermore, when you have a heat meter you now have to give meter readings which you are then paid against, in terms of the RHI. Without a back-up boiler no meter is required and you are paid against the deemed figure on a homes EPC. This allows you to budget effectively as you know exactly how much the RHI will be before you start.

So, a back-up boiler if it's desired, but a back-up boiler is not required.