Many landlords have long suspected that the DCLG approved national calculation methodologies and software programs were seriously flawed when they produced EPC ratings for buildings following energy assessments.So news that new software is being introduced which is claimed to be more accurate is to be welcomed by the landlord community. It could mean, according to the Residential Landlords' Association (RLA) - which has campaigned for the change '� that up to 80,000 private landlord rentals could be positively re-rated. It could make the difference between spending thousands on improvements to reach MEES standards, and not having to do so.The new rules concerning Minimum Energy Efficiency Standards (MEES) come into force from April 2018. After April any new tenancy (which includes renewal tenancies) will require the property to have a minimum energy performance (EPC) rating of E. The new rules will also apply to all existing tenancies (periodic tenancies) from 1st April 2020.The RLA claims to have been campaigning on the software issue for six years on the basis of empirical evidence from practitioners that the government software used to calculate EPCs was flawed.Following the update the new RdSAP software issued to energy assessors should be more accurate and will in some cases change the EPC rating to a higher value.According to the RLA these are the changes landlords can expect to see:

• '�Non-traditional' solid wall properties are expected to see the biggest improvement. These homes will typically have walls made of 330mm (13'�) thick stone, mixed earth or brick and stone.
• Those with traditional 228mm (9'�) solid brick walls will see a lower but still significant improvement.
• Filled cavity walled premises will see a reduced EPC rating, but it is very unlikely that many could go down into Band F.
• Homes with low rated Band G are unlikely there will be much movement.

Since it is 10 years since EPCs were introduced many properties will be coming up for renewal in any case, so a new assessment will not be an extra cost even if the property does not rate well enough to increase its rating.However, since the whole exercise is to improve energy efficiency and reduce heating costs for tenants, landlords should look carefully at how their properties' energy consumption can be reduced, with minimal improvement costs to them.RLA company secretary, Richard Jones, says:'This change comes after six years of campaigning by the RLA for a proper scientific appraisal of the insulation properties of walls.'This led to the Building Research Establishment undertaking research that demonstrated that solid walls in particular provide better insulation for homes than was shown in the EPC rating.'We are delighted the new software is now in use, however time is getting short and we would advise anyone who wants to get a new EPC carried out to do so as quickly as possible.'It is also worth being mindful of the fact that the minimum requirements may change in the future and to consider including further energy efficiency improvements if you are carrying out renovation works.'�