Compost piles trap heat generated by the activity of millions of microorganisms. A 3-foot by 3-foot by 3-foot compost pile is considered a minimum size for hot, fast composting. Piles wider or taller than 5 feet don't allow enough air to reach the microorganisms at the center.
Oil-fired boilers should be professionally cleaned and tuned once a year. Gas-fired equipment needs to be checked every other year.