This section is from the book "The Gardener's Monthly And Horticulturist V26", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
Few persons are aware of the capacity of water for heating if properly applied, especially when more or less pressure, as with steam, is applied. On that principle, no boiler is required, plain coils of pipes (I use 1 1/4 inch) is all that is needed, at the rate of one foot of coil to every twenty of piping. I am using now, one inch, inch and half, and two inch pipes, and give the preference to the last size, as offering less friction, better circulation, and containing also a larger body of water. Now the advantage claimed by this method, is economy in the first cost of boiler and piping, as under compression we get as much heat from a two inch pipe as of a four inch one with no pressure, while there is only one quarter of the quantity of water to heat. The circulation is extremely rapid, and once established is maintained with a very small fire; with the same quantity of fuel we will send the heat as far again as steam will. These assertions are actual facts, as our houses were heated by steam originally, which was rejected as not being economical. A double or treble coil (circular) may be used if more power is needed, set in brick work and fed from the top, as any common cylinder stove.
The whole top ought to be made movable so as to enable to clean the coils when needed.
Half a gallon to every 100 feet of pipe is necessary and sufficient for expansion. The rate of pressure is from five to twenty pounds, according to the weather.
We are heating a range of four houses on that principle, each about 100 feet long. We are well satisfied with it, as it does not require any more care than a common furnace, with comparatively little fuel, and do not hesitate to recommend it to any person starting anew. We do not claim any prior right to the principle, but leave every body free to succeed with it as it does here.