MLongford

I've pm'd you the info. Mark

We spent a fair bit of time researching heat pumps for our barn conversion, and know that they work with underfloor, radiators or fan-coil units (which you can have if you want cooling as well).  Air source or geothermal will work with any of these and so long as you get your system designed by someone who knows their stuff then you won't have a problem.  We found a brilliant company who actually manufacture them, and will design the system properly.   Ours works down to minus 20 degrees C and we don't need a back up system.  They can also be installed onto an existing heating system if you want to change an oil boiler or a wood burner.

Annie, from my research it appears that it is possible to change your old oil boiler for an air source heat pump, connected to your existing radiator set up.  The pump does the same thing (heat and hot water) but without the hassle of fuel ordering/storage; which could be handy in your situation.  If you like I can email you details of the crowd that we're using for ours.

No, it won't work.  While it will initially work for a very short period, an air source heat pump gets all its heat from the air surrounding the outdoor unit.  If you put this in your attic space and the same amount of heat isn't coming into the attice space as new heat (equal to the amount of heat your heat pump is taking out of the attic space) your attic temperature will drop and your unit will shut down.  The unit has to be outdoors so that it is surrounded with a constant supply of fresh air which carries new heat.  I have been doing some research along similar lines myself, and have decided to change my heating system to an air source unit with fan coils (they can be plumbed into your radiator pipework and will do heating and cooling).  We have a barn conversion and the attic space gets too hot in summer and the barn is difficult to heat in winter with our current woodburning set up.  I will be able to use my existing pipework if I switch systems.  This could be worth considering.  A geothermal unit with fan coils is another possibility.  I was recommended to a company in the Dordogne, and if you would like their details I can pm you.

I am interested in this thread as I am currently researching the best way to go with my own heating system.  I agree with Cooperlola that life is too short to be stoking a woodstove 24/7.  We have an old stone barn which we've converted, but even though I've insulated it where possible in the renovating process, it's cold in the winter and the upstairs is ridiculously hot in summer. I have a woodburner and rads at the moment, and I want to change the woodstove for an air source heat pump, and the rads for fan coil radiators so that I can have heating in the summer and cooling in the winter.  I can defnitely see the advantages of being able to flick a switch, especially when you come home in the winter and have to start turning round to light the fire and wait for it to get going.   Someone has recommended a company in the Dordogne that I'm going to contact.  It might be worth considering.