Hi, I would would like input if anyone has experience of this issue. The figure/situation below is simplified but issue the same. Situation: I have 100k at 6% rate on a buy to let property loan. The 6% interest is hurting me. I am buying a new house as a principal private residence for 200k and need no finance to do this. Potential Solution: I was thus thinking of taking out a home mortgage at 4% for 100k at the same time as the house purchase for 200k. The 100k would then be immediately paid of the commercial loan thereby saving me 1% per year for 30 years. The bank is fine with this, but the security and purpose of the loan will state the new house and not specifically the buy to let property i.e. it will be considered by them a home mortgage. Question My question is, can I still use the 4% interest charge as a deductible against the rental income from the original property. I see this as refinancing, but will the tax man? and how do I help him/her see this as refinancing? I have received advise, but there was no clear answer.