No fuse, no interference suppression, and the fan motor will get real upset about the waveform and may overheat even without the heater being on:palm:...
Also, £2.24 for the transformer, a couple of quid for the rest, say maybe £7 for the PCA, plus case and such, say £10 BOM, means £25 factory gate absolute minimum, meh, cheaper to use a light dimmer and about as effective, they are made in huge numbers so they get proper economies of scale.
Then we come to getting it CE and such certified so your insurance carrier will play ball, and it will be legal to sell.....
Nope, and you really need to stop playing in the bottomfeeder market there is money to be made down there but it requires massive vertical integration which you do not have.
Regards, Dan.