Posted by Harold Kestenholz - Hydronic Network on July 27, 2000 at 03:16:35:
In Reply to: Residential wood boiler posted by Skip Hayden on July 26, 2000 at 11:43:41:
Some questions are left to answer:
If the wood-fired boiler is a backup to solar because there is no way to have an alternate fuel delivered, how does the occupant cook and make domestic hot water?
If the purpose is to have a utility-independent home, how does one prevent freeze-up in unusual weather conditions if no-one is there? Antifreeze in the boiler circuit helps, but the plumbing requires drain and fill upon entry and leaving for any length of time - unless it is really a temporary occupancy hunting cabin and has no conveniences.
A well-insulated house specification is R-30 ceilings, R13 walls, R-22 floors and tight double-pane windows (or better.) This means that the heat loss per 1000 square feet is 25,000 btuh. If the house is efficient for a family it is no larger than 3000 square feet - that is, has a heat loss less than 80,000 btuh. the cost of fuel oil would be about $800 per year without solar helping. How does one justify the inconvenience and the extra cost of a wood-fuel boiler?