Martin Usborne, a photographer from London, told the BBC he had experienced problems with his Nest thermostat earlier this month.
"It broke down twice. I got an error message saying it was not connected. The house was very cold and I had to reboot it," he said.
"I have a love/hate relationship with Nest. Since it was installed, the house is warmer but my heating bill has gone up by 60% so it doesn't seem to be doing its job in saving money," he added.
A spokesman for Nest said he could not comment on Mr Usborne's specific case without speaking to him directly.
Ovum analyst Rik Turner said that the issue was likely to be repeated in other smart devices.
"As we increasingly put distance between humans and their devices so we will increasingly become hostages to fortune," he said.
"In the past you might have been able to fix hardware or get a bloke round who could but now it requires a patch from the manufacturer."
The trend to connect more and more devices to the internet of things is gathering pace as the cost of connecting physical things to the network continues to fall.
Analyst firm Gartner predicts that 6.4 billion connected things will be in use in 2016 but it warns that the costs of making sure such systems were secure would also rise.
There have already been cases of hackers remotely taking control of internet-connected cars.