The RNRB otherwise known as the residential nil rate band comes into effect from the 6th April 2017. It will be relevant to homes with a maximum value of £1 million but not until 2021. It is being phased in relatively equally over the period from 6th April 2017 to 6th April 2021.
It is important to note that this only applies to a residence passed on death to 'direct descendants'.
As with all tax legislation there are other complications, such as where somebody down sizes in a property, but please contact us if you need any further help or more defined information.
It is difficult to provide advice on inheritance tax planning on this particular point as the RNRB is under consultation and potentially and indeed is likely to change somewhat.