HEAT DEMAND (Kw/h)
RHI PAYMENT (£)
FUEL SAVINGS (£)
This property is a large domestic dwelling which was only 10 years old so very well insulated. Mr Jobling decided to choose Marshall & McCourt as we have vast experience in the installation of heat pumps combined with underfloor heating systems along with the expertise in gas boiler installation.
The customer required advise on the best way to heat his new extension which was going to be combined with the existing kitchen diner and form a large 100m2 open plan kitchen / living area. He was looking for a long term solution that would save him money on his fuel bills, as well as create a carbon saving.
With this in mind, we suggested an Air Source Heat Pump combined with underfloor heating. The air source heat pump is able to provide a low flow temperature heat, perfect for the requirement of underfloor heating. As the underfloor heating is likely to be constantly on, the heat pump is able to be set in ‘fixed flow mode’ to provide a constant flow temperature and deliver high COPs of up to 4.2 which means the heat pump can perform at an efficiency over 420% based on an outdoor air temperature of 7 degrees. This also meant that the customer was eligible to claim the RHI with this renewable solution which has a lifespan of over 20 years with low maintenance costs.
It was also possible to provide a higher output heat pump and turn the system into a hybrid system where it would run in combination with the new gas boiler installed. This would automatically switch between the heat pump and gas boiler providing the heating and got water requirements depending on what was the most cost effective at the time of demand. The customer decided to have a smaller capacity heat pump to supply the UFH to maximise efficiencies and meet his budget.
The UFH installed was a 15mm system with 150mm pipe centres. This was to ensure the system could run at the lowest flow temperature possible yet still deliver the required heat into the property – the lower the flow temperature, the more efficient the heat pump will operate.
The UFH was a complex system as the existing floor was the original concrete slab and the extension had a new floor with 100mm of insulation. With this in mind, we installed the zones in the extension straight onto the insulation and this was covered by a 75mm screed. The existing floor area was covered by the Speedfit overboard system which is 25mm insulation which was pre grooved, ready to lay the pipe work into to prevent any further gain to the finished floor level. 2″ x 1″ battens were installed in between the overfit boards and then an 18mm floor board covering was applied. This then made the overall floor area the same level. All zones were fed straight back to the manifold and controlled by Internet enabled wireless thermostats.
Along with the ASHP and UFH a new heat only gas boiler was also installed. The customer decided to choose both a Vaillant boiler and heat pump to take advantage of the extended warranties we were able to offer by being a Vaillant partner and approved installer and so there is one point of contact if a fault ever occurred on either appliance.