1. Part of the BRE Trust BRE: Investigation into Longtown Heating Systems David Butler 9 October 2014

2. Part of the BRE Trust BRE – Building Research Establishment Ltd BRE is an independent research based consultancy, free of commercial and government interests and is owned by the BRE Trust. The BRE Trust is a charity and all of BRE’s profits go back into research and education projects supported by the BRE Trust. BRE’s scope includes buildings, the environmental, fire, security and safety.

3. BRE was commissioned by Riverside to undertake an independent investigation: 1.Are the new heating systems suitable? 2.Were the systems and specifications appropriate? 3.Are the running costs (electricity bills) reasonable or not? 4.Do the solar PV installations affect the heating systems? BRE investigation into Longtown Heating Systems

4. Scope of BRE Work –Two BRE specialists: –Heating expert - David Butler –Solar energy expert - Steve Pester –Visited and inspected 5 representative Longtown properties in May 2014. –Provided a detailed report on findings and recommendations to Riverside

5. Choice of heating system –Riverside has provided modern whole house radiator based heating systems. –Mains gas is the cheapest fuel and the standard choice. –Lack of mains gas in Longtown restricted the options. –BRE confirms that electricity is best fuel for Longtown but is more expensive than gas. –Oil, LPG, propane are alternatives but are expensive, have safety and storage issues and potentially large and unpredictable price fluctuations.

6. Choice of heating boiler - ASHPs –Air source heat pumps (ASHPs) can replace conventional boilers. –ASHPs “pump” heat from outside – they provide 2x to 3x the amount of energy consumed to run the machine. –Running cost of an ASHP is similar to a gas boiler.

7. Choice of heating boiler – electric boilers –Some Longtown properties are not suitable for ASHPs –Flooding risk and strength of house walls. –Electric boilers have been used instead.

8. Cost of running heating systems –Whole house central heating provides high comfort levels and convenience. –But, must be controlled sensibly to avoid high heating bills.

9. Heating bills –Most tenants appeared to be on standard electricity tariff or Economy 7 (E7). –Standard tariff is not usually suitable for electric heating. –E7 is designed for storage heaters. –E10 is designed for electric boilers. –BRE has advised Riverside to help tenants choose most suitable tariff.

10. Electricity tariffs –E10 off-peak rate - 5 hours overnight, 3 hours early afternoon and 2 hours in the evening. –May not suit all tenants. –Heating system programmer times should be set to heat house as much as possible during off-peak times. –Hot water timer should heat hot water only during off- peak hours.

11. Electricity tariffs –E10 is not available from all suppliers. –EDF and SSE offer E10. –Check peak and off-peak prices – there may be a difference between suppliers. –Total savings from switching to E10 may be 15 to 20% a year. –Some tenants will need help in switching to most appropriate supplier and tariff and in setting programmers.

12. Solar PV systems

13. –BRE inspected 5. –All were wired & working as expected. –House electricity meter only registers what electricity is consumed from the grid. –A second electricity meter shows how much energy has been generated by the PV. –BRE confirms no interaction is possible with the heating systems. Incoming from main meter PV generation meter and PV system PV AC isolator

14. Solar PV systems –BRE confirms solar PV systems are working well (4.7 kWh / day in May in one property inspected by BRE). –PV electricity is free to tenant but any surplus power goes to the grid.

15. Making the most of the free PV electricity –Most PV electricity is generated on sunny days when most people use least energy so a lot may be exported to the grid. –A special Power Diverter can be fitted that diverts PV electricity to heat the hot water tank – a form of energy storage. –BRE recommends that Riverside considers installing Power Diverters so that tenants benefit more from the solar PV.

16. Improvements to insulation and windows –The Riverside properties are 60 years old - heating bills can be reduced by improving thermal insulation. –BRE recommends that Riverside continues with investment in improving insulation, e.g. external wall insulation and new windows. –Any defective pipe and loft insulation (BRE and Avoca found some missing or defective insulation) should be rectified.

17. Conclusions –Riverside have provided tenants with a modern whole house central heating system >> higher comfort & convenience. –No mains gas in Longtown means that more expensive electricity has to be used instead of gas. –ASHPs use electricity very efficiency (provide 2x to 3x the energy) but not suitable for all houses. –Electric boilers are usually cheaper to run on E10. –Solar PV provides tenants with some free electricity but the amount may be increased by fitting Power Diverters. –Further investment in insulation and help in setting controls and choosing best tariffs will reduce tenants’ energy costs.