Hi, I am about to undertake a minor extension and rather more major internal reorganisation of my house to enable me to work from home more effectively. The existing kitchen (in an 1990/91 extension and renovation of 1800s granite cottage) has a solid concrete floor which is none too flat or even and I am having this stripped out and converted to my practice room (I am a medical herbalist) and am considering how to heat it. The house is out in the country in Aberdeenshire, quite exposed and all electric as there is no mains gas available. I am with Scottish Hydro electric on their green tarriff "Power2", which I'm fairly stuck with as our heating is storage heaters on their Total Control system - like offpeak/white meter but we get a boost during the afternoon so evenings are not too cold in winter and none of the other green electric companies wanted to know when they heard that!
My first question is whether electric underfloor heating would be more or less efficient than the current storage heater for this room (about 9 sq m floor area). For me UFH would have two main advantages in this room (a) no loss of wall area to storage heater and (b) safety aspect of no very hot surface for patients to burn themselves on.

I also have planning permission for a roof mounted wind turbine (I did make enquiries about a larger free standing device but was told this would be turned down as we are in sight line of Aberdeen airport radar - which made me very cross!) and had been planning to install a Swift system as it seemed much more robust and versatile than the one available through B&Q. The DTi wind stats for here are pretty good and I can vouch for how windy it is as we are on an exposed site with no other buildings nearer than 400m and they are all down hill from us. However since Scottish and Southern energy took over marketing of the Swift system it seems to have stalled and my communications to them result in "holding" replies about doing more testing and monitoring of current installations before rolling out - this has been going on for nearly a year now so my second question is does anyone knew of any other roof mounted systems that might be suitable or any insider knowledge of what is actually happening with the Swift and whether it is likely to become available anytime soon?

Other options would obviously be to move to a different style of heating entirely e.g. multifuel stove and "wet" heating system but with mainly sold concrete floors I cannot face the disruption of this right now, never mind the expense.

My third and last question regards floor coverings - I am planning to use ceramic tiles in the utility room extension and probably in the new practice room too although I have also been considering marmoleum although I am having trouble finding out whether it can be laid direct on concrete or what sort of underlay it requires. The old study/practice room which is becoming my new kitchen/dining room actually has a raised floor - made of some kind of chipboard type stuff and I definitely don't want wool carpet in the kitchen but would like something warmer to the touch than ceramic tiles not sure what the green options are. Floor covering seem to be little covered either in green building forums or in eco decorating forums which seem to concentrate on paint and wall covering.

Review of current roof insulation is underway and we have already switched to low energy light bulbs throughout.

Electric underfloor heating is storage heating - you're just replacing the bricks in the storage heater with the concrete of the floor.

If you're all-electric, you'd be much better off using a heat pump (either ground source or air source) to provide the heat for the underfloor system as you'll get out about 3x as much energy as you put in compared to straight electric heating. Surely that would be much more environmentally friendly. If you go with a wet system like that you also have the flexibility in the future to heat the floor by whatever means you want - could be solar, could be biomass (though this has very dubious green credentials) etc. If you stick with electric heating (i.e. by embedding heating wires in the floor) you have zero flexibility in the future and you'd need a wind turbine with 3x the capacity compared to running a heatpump to heat the floor.

Paul in Montreal

Two main problems with biomass: in an urban setting, pollution (people forget what causes smog). In general, there isn't enough land area to supply biomass and food for the population we have. If everyone used it, there wouldn't be enough land area to grew the fuel, let alone food.

Current land area of Germany could only support 60% of the requirements for heating using biomass - and that's if everyone had houses built to the passivhaus standard - which of course, they don't - so it's even worse.

Same thing can be said for biofuels - they're an environmental disaster and a dead end IMHO.

Paul in Montreal

We are never stuck with the status Que. Probably you have a screed on top of the concrete floor this could be broken off easily and pipes installed and re screeded with suitable additives. Or you can get overlay systems 18mm thick. There is no minimum ceiling height now. Then you could use an air source heat pump if you dont want to do digging. Pay back for this could be just a few years.