1. Lub hnab nqus plua plav: Cov no siv lub tshuab nqus tsev los rho tawm hauv lub hnab, tswj qhov kub ntawm cov zaub mov thiab dej haus. Lub tshuab nqus tsev insulated hnab feem ntau muab rwb thaiv tsev zoo, tab sis kuj tseem siv kim.
2. Lawv yog qhov tsim nyog rau luv dua-} kev ua kom cua sov yuav tsum muaj kev tiv thaiv kom sov thiab muaj peev xwm pheej yig.
3. Niam -}} -} Cov hnab nqus cov me nyuam: Cov hnab ntim tau tsim nyog rau ob qho kub txuag kev txuag hluav taws xob thiab txuag kom sov. Lawv feem ntau muaj ob txheej: ib txheej sab hauv ntawm insulating cov ntaub ntawv thiab txheej sab nraud ntawm cov khoom tiv thaiv.