As far as I know it's the cheapest way to raise a significant figure. You can raise cash at 0% by using credit cards but you have limited pay back terms and amounts.
May not be the best option It depends on how old you are and whether you want to leave the equity in the house to someone after you've gone to that great football stadium in the sky (where Barnsley beat Sheffield Wednesday 10-0 every Saturday afternoon). It may be better to remortgage, even against pension income. Check out http://www.learnmoney.co.uk/equity-release/er-01.html for suggestions. And get some expert financial advice. Perhaps someone on here is, or can recommend, a decent independent financial adviser in the Barnsley area?