Good afternoon ricfrench,
Thanks for your interest in the Myson iVector, below I have attached a link for the sales brochure, if you check page 9 you will see the iVector can be typically half the size of a traditional radiator...
I have sent an email to you to say unfortunately we are unable to email you the calculator.
However if you can email me your address I will post a disc out in the post tonight.
If you require the accurate heat calculations, we could provide you with a heatloss calculator or be able to clarify the measurements over the phone in order for you to purchase the correct radiator.
Depending on how old your property actually is would determine whether you need a complete rewire due to the new regulations however a qualified electrician would be able to tell you whether the work is required and also the cost.
Our electric underfloor heating works on 150watts per square...
PeterthePlumber is correct, replacing the valve would solve the problem rather than replacing a good condition radiator. When replacing the valve why not use a myson matchmaster valve that will compensate the myson radiator. The myson matchmaster conforms to BS2767-10. The valve is available...