The drain need only be made of a short length of pipe and should include a vapor trap to prevent exhaust gasses from being expelled into the building. This is accomplished by connecting the system to a drain using inexpensive polymer pipe. A system will lose a certain amount of efficiency when installed in a home for a variety of reasons concerning the home's design features, implementation and other factors as well. Better education for installers and home owners will raise the efficiency of these units by enabling proper application and use. Earlier conventional designs are being replaced by high efficiency boilers in domestic central heating systems throughout the world. A conventional boiler burns fuel to heat water and utilizes the hot gases. This will enable higher efficiencies and lower fuel consumption. Allowing the use of low- temperature PVC gives the additional benefit of easy exhausting. The most modern designs include a drain-free system which eliminates the need for a drain pipe, thus making them even more economical and efficient. How it applies to heating systems is our focus here.A high efficiency boiler has the job of applying heat to water and making steam. The increase in fuel costs has encouraged the retrofit of many existing boiler installations to accommodate new high efficiency boiler systems. The condensed liquid that is produced is acidic with a pH around 3 or 4, but your average hardware store variety PCV will be adequate. In the US, Federal and State tax rebates for the installation of these boilers apply in some cases. The primary function of a boiler system is to extract the latent heat of water and utilize its energy to produce heat for a home or building. The technology for a high efficiency boiler is evolving rapidly, however. The technology originates from ancient times and has seen entire ages evolve since its inception. Manufacturers claim up to 98% thermal efficiency. Today's systems are manufactured to be highly efficient and compact, making them an economical option for meeting residential and commercial heating needs.&amp;nbsp; Some concerns exist among professionals concerning corrosive issues within the heat exchangers in these systems. The use of aluminum materials has gone a long way toward resolving many of these issues in modern designs. Fuel is burned, hot gasses pass through a heat exchanger, and most of the heat is transferred to water.Condensation is produced during normal operation with these systems and must be expelled. It is no longer necessary to use conventional masonry chimneys for venting. The relevant parts of the boiler must be constructed of materials that can withstand this acidity. New designs have created a life expectancy for residential applications of four to six decades. The 1\/2"\u00d71\/2" water supply fittings 90 degree female elbow raised water temperature produces steam and a condensing boiler will condense the steam back into water and extracts the additional heat thus recovering the latent heat from the water and creating efficiency. Aluminum and stainless steel is used extensively as well as modern PCV materials in the design of today's high efficiency boiler. The exhaust's low temperatures require that a fan be included in the system to expel the gases from the unit to outside the structure. Polymer venting allows for the added benefit in the flexibility for retrofitting applications also.