The 42-year-old information and communications technology teacher at Sheffield girls' high, has agreed to be tagged and have the time she spends working at home measured for a research project developed by Nottingham university.
Ms Parnell and her family have been selected from 70 families who applied to live in a concept house in Sheffield for six months.
For two months, each family member will wear an electronic wristwatch tag, monitoring how long they spend in each room in the Project:LIFE home.
Ms Parnell is not concerned the data will reveal any hidden slacking or self-indulgence. "I don't mind, as long as there aren't Big Brother cameras watching us in the shower. The tags only monitor what room you're in, not what you're actually doing in there." For Lucy and Hazel, Ms Parnell's two teenage daughters, this comes as a relief.
"My parents will think I'm doing my homework, because I'm in my room," said 13-year-old Hazel. "But I can be watching TV or on thecomputer."
Each room offers a range of entertainment and labour-saving devices. The aim is to assess what a consumer might want in the house of the future, so it includes a balcony hot tub, plasma-screen TV in the bathroom (complete with floating remote control) and a machine that automatically dries and irons the washing. After the experiment, the home is expected to sell for around Pounds 750,000.
Ms Parnell admits the hot tub may be a distraction from work:
"Teachers don't usually experience this sort of luxury. But Hazel says the house will help her at school.
"It won't matter if I don't do my homework," she said. "I'll just say to the teachers, well, you can come over and use our hot tub instead. It's a good bribe."