3.5% can stay for how long.

https://www.uob.com.sg/homesolution/...bank-loan.html

Today however, the Fed is gradually raising interest rates again (there are four proposed rate hikes in 2018). This is due to America’s economy having, at least in theory, recovered. Meanwhile, the Fed cannot keep interest rates low forever, as this will cause inflation to rise uncontrollably.

It’s quite possible that bank home loans will be at 2.4% per annum (or greater) by the end of 2018. This is much closer to HDB rates, albeit still lower. In the long term however (say 15 or 20 years), it’s possible – although not guaranteed – that bank loan rates will again soar higher than HDB rates.