VAT on ASHP installation (refurbishment of old property)

Hello We have begun a full refurb of our property, we do not qualify from any other VAT relief but asked our contractor about getting zero vat relief on the installation and supply of the two air source heat pumps we are putting in and also the external wall insulation to allow for this. We need new pipework, underfloor heating throughout, 2 heat pumps, hot water cylinder, thermostats etc. We are also using the same contractor to replace the roof, do internal changes to the property and a small rear extension. The contractor has told us they won't do zero vat on the energy efficiency parts of the build - heat pump installation inc UFH, new pipework etc nor the external wall insulation because it's part of a single supply - the full house refurb - but I think there are clearly different elements to the job they are doing and it's mixed. I have looked the HMRC guidance and find it very confusing. It's not clear to me and the contractor/builder says it's not really clear to them so they don't want to take the risk of chargiing zero vat and then getting penalized by HMRC. We are doing this work to increase our energy efficiency primarily and make an old house work much better, cleaner (replacing old boiler) so I don't know why it's so complicated to get zero vat on this when it's clearly done to increase energy efficiency. Any advise please? Thanks Clare

Hi Clare_74 Porter,
It can be sometimes difficult to work out whether a supply of construction work is deemed a single supply or a multiple supply.
The guidance states:
When energy-saving materials are installed at the same time as other goods and services, you must determine whether they constitute a single supply (which is subject to just one VAT rate) or multiple supplies (which may potentially be subject to different rates of VAT).
A single supply is where one element of the supply is the principal element to which all other elements are ancillary.
An ancillary element does not constitute, for the customer, an aim in itself, but is a better means of enjoying the principal supply.
Indicators of a single supply include:
a single price
the supply is advertised as a package
the components are not available separately
the installation of all the components are carried out at the same time, such that, the customer perceives that what they are getting is a single supply
Please see below:
Energy-saving materials and heating equipment (VAT Notice 708/6)
The supplier will need to decide the nature of the supply/supplies by carefully following this guidance to judge whether it is indeed a single supply of construction services or a mutiply supply of construction services and energy saving services.
Thank you.