Rowan House
Rowan House has undergone a full structural renovation since it changed hands in 2007. The existing oil boiler had broken down, a new oil tank was needed and the central heating pipe work was leaking. Due to rising oil prices, and the location in a remote village in the Hambleton Hills without a mains gas connection, biomass central heating was considered as a reliable, cost effective alternative to oil.
During the renovations, PureGlo worked with the new owners to design a new biomass heating system with underfloor heating on the ground floor.
Boiler system
Rowan House is home to a young family so a reliable low maintenance system was needed. The model selected was a BioWIN 21 wood pellet boiler from Windhager, the leading Austrian manufacturer specialising in turnkey high quality automated systems. The BioWIN is fully automated with an efficiency of 90% . The automatic pellet feed system takes fuel to the boiler through vacuum suction pipes from the pellet hopper as it is needed. The system is fed with just enough fuel to maintain the required temperature which makes it economical to run.
The ash from the boiler is collected and compressed in an ash box which forms part of the boiler unit. This is emptied just once a month in winter and every two months in the summer.
The ground floor of the property is fitted with under floor heating which is more energy efficient to run and can save up to 30% compared to traditional radiator systems. Biomass boilers lend themselves well to under floor heat distribution systems as the under floor heating requires a lower but more constant temperature. Biomass boilers work most cost efficiently when kept ticking over at a lower temperature rather than a frequent variation in heat requirement.
Fuel storage and handling
A purpose built hopper has been designed within the fabric of the building so that pellets can be blown directly into the hopper from a delivery lorry in a similar way to the way oil tanks are filled by a tanker.
The hopper has a carrying capacity of one tonne, to reduce the number of deliveries to 5 per annum.
Fuel supply
The boiler uses around 5 tonnes of wood pellets per annum, supplied and delivered by PureGlo Ltd.Installation
The system was supplied and installed by PureGlo in May 2008. The installation was completed within 3 days.
The proposed location of the boiler presented both an opportunity and a challenge in terms of design and installation. The building has a one storey extension which was originally built as a swimming pool. When the house changed hands, the concrete lined swimming pool pit had not been filled in, but had been covered over with plasterboard to create additional living space. This presented an opportunity to create a kitchen and utility area on the ground floor and convert the swimming pool into an underground boiler room and fuel storage facility.
The dimensions of the boiler presented a challenge as the top of the boiler rises just above the floor height for the new kitchen area. So in the utility room above, a cupboard has been created with a cut out in the floor to allow space for the top section of the boiler. This has a dual purpose of concealing the boiler safely within the utility while also allowing the internal boiler hopper to be filled manually with pellets if required.
The boiler was lowered into the basement using a JCB and then positioned using steel rollers.
Financial assistance
Rowan House was awarded a £1500 grant towards the biomass installation under the BERR low carbon buildings programme.
For improved energy efficiency, the owners have also fitted Kingspan insulation in the roof and flooring along with cavity wall insulation and new double glazed windows. Insulated plasterboard has also been fitted to the interior walls. The high standard of insulation helped the property to qualify for the BERR funding.
Cost savings
The boiler was a direct replacement to an inefficient oil system. The savings in running costs of burning pellets are 47% in comparison with heating oil at 60p per litre.
Technical summary
| Boiler | BioWIN 21 |
| Power rating | 21 kW |
| Energy efficiency | 90% |
| Fuel type | wood pellets |
| Fuel storage | purpose designed hopper linked to the boiler by a Windhager auto suction pellet feed system |
Summary of benefits
- The fully automated wood pellet system is reliable and efficient, offering the same level of convenience as an oil installation, at a fraction of the running cost.
- The improved energy efficiency measures recommended by PureGlo are also helping to reduce the family fuel bill.
