Re: "reduction in waste heat"
"Anybody heating their house with electricity who doesn't have a private wind turbine is either unfortunate (renting) or needs a serious rethink (owner), because electricity costs more per Joule than does gas."
Gas isn't available to around one in eight of the UK population because they are off the gas grid, and it isn't available in high rise buildings for safety reasons (noting some use communal gas boilers, some use dry electric heat). The cost balance between electric and gas should also take account of the depreciation of a gas boiler (say £150 a year), interest on the capital tied up (say £100 a year), and an annual safety check and clean (say £100). That's £350 a year of hidden costs before you've done anything. And there's a further couple of grand tied up in a wet heating system (say £250 a year, maybe more if you pay for "heating cover"). Added together the standing costs of a wet, gas fired heating system are around £700-800 a year, which would buy around 5 GWh of heat. And that doesn't include the gas supply standing charge, typically a further £100-150 a year (in terms of figures above, the gas standing charge would pay the depreciation on a dry electric system).
Against that a dry electric system is cheap to install and lasts longer so has lower depreciation, and has virtually no maintenance costs. In a typical draughty, poorly insulated house I'd agree gas is a no brainer where available. But in a very well insulated modern house a dry electric system can start to look a credible option. Economy 7 tariffs and storage heaters (with peak top up) can be as cost effective in the longer term as gas in a typical house, even though you'd have higher electricity bills. If I were doing a self build or a self-specify, I'd be looking for passivhaus levels of insulation, and use underfloor dry electric heating, and do without gas at all (that's a pipe dream, or non-pipe dream, depending on how you look at it).
Industry insider hint for those currently on E7 tariffs: Switch supplier twice a year - outside of the heating season you need the cheapest normal non-E7 tariff, during the heating season the cheapest E7 or E10. When switching in spring you're looking for a supplier who will offer you single rate electricity on a dual rate meter, as not all do. Do the sums, see if it works for you. Also, if you've not got night storage heaters, and you're on E7, chances are that you're paying a lot more than you would on a single rate tariff (to be in the money you need 35-40% of all electricity used across the year to be used in the cheaper off peak period). If either the seasonal strategy or the 35% of all power off peak things are news to you, I may have just saved you £150-200 a year, so in lieu of my beer fund, contributions welcome to the RNLI.