The first two case studies show how a poorly rated property can be improved using insulation and new heating systems. From april 2018 any newly rented property rated F or G will have to undertake any fundable improvements (with any subsidies if available) to bring it to at least an E rating. See 'Minimum energy ratings' page for more detail.
Case Study 1 - Braddon
Braddon is a semi-detached cottage, most of the walls are solid although there is a cavity extension on the rear. Heating is from a solid fuel range with radiators and an open fire in the living room. The loft and sloping ceilings have been insulated.
The current rating is 30 (an F), 8 points short of the E rating that will be required for new letting of properties from 2018 (providing improvements can be funded by the green deal).
| - Changing the open fire to a closed stove with no open chimneys adds 4 points making it | 34 | An F still |
| - Replacing the range with an air source heat pump* adds a further 15 points taking it to *(to radiators and doing domestic hot water) | 49 | An E |
| - Or replacing the range with a ground source heat pump* adds 20 points taking it to *(to radiators and doing domestic hot water with additional top up heater) | 54 | Nearly a D |
| - Or a biomass boiler with the wood stove and new hot water tank achieves (As the domestic energy rating is based on cost rather than carbon, biomass boilers have less effect than you might expect) | 39 | An E - just |
| - Alternatively the solid walls could be insulated internally which adds 16 points giving | 46 | An E |
Case Study 2 – Greylees
Greylees is a detached house converted from 2 smaller cottages, with unfilled cavity walls, uninsulated sloping ceilings, partial double glazing, an old LPG boiler and an LPG open fire.
The current rating is 1 (a G), 37 points short of the E rating that will be required for new letting of properties from 2018 (providing improvements can be funded by the green deal).
| - Insulating the cavities and sloping ceilings, removing open chimneys and adding draughtstripping brings the rating to | 16 | Still a G |
| - Adding a wood stove brings the rating to | 24 | An F |
| - Then changing to a biomass boiler brings the rating from 24 up to | 46 | An E |
| - Or fitting an air source heat pump* brings the rating from 24 up to * to radiators and domestic hot water |
54 | Nearly a D |
| - Or fitting a Ground source heat pump* brings the rating from 24 to | 60 | A D |
| - Whereas fitting a condensing LPG boiler only improves the rating from 24 to | 51 | An E |
| - A 3kW peak PV system would give an extra 6 to 10 points for this property depending on which heating option is chosen |
Please note, all properties should be assessed individually, the figures given here are specific to the property shown and can only give an indication of the likely effect on similar properties.
Click on the links to see some notes on when heat pumps are appropriate and advice on insulation.