Oil fired boilers:
Oil fired boilers fall in two catagories. Cold start boilers, and maintain temperture boilers.
Cold start boilers are made of high quality cast iron and are your best option as they only use fuel when you require heat or hot water. They are the more expensive choice initially, but year over year the savings quickly outweigh the initial cost. They also require a seperate tank to provide potable hot water, but as you will soon see this is a very good thing because the old style hot water coil is both extremely in-efficient and also does a poor job of providing constant hot water as you may have noticed if you've ever tried to fill a bathtub with one.
Maintain temperture boilers are steel boilers that maintain a minimum temperture of 140 degrees farienheit all year round, regardless of your energy needs at the time. This is due to the fact that the steel they are constructed from will rapidly corrode if this minimum temperture is not maintained all year round. This technology came out in the 1960's and is an outdated and in-efficient design. You can not shut these boilers off in the summer when you are on vacation. They provide unneccessary heat in your boiler room during the summer months and their life span is around twenty years. These boilers can make potable hot water from a coil, although the amount of hot water is not usually sufficient to fully fill a bathtub. This is definitely the more econonomical choice initially, but will cost you much more to operate year over year.
Cold start boilers:
A genuine triple-pass boiler of cast iron sectional design.
Rated input: 91 to 245 MBH - 27 to 72 kW
Viessman is one of the worlds leading heating companies. They feature a triple pass heat exchanger which allows for maximum heat transfer from your fuel to your home. This provides optimal efficiency and low green house gas emmisions. A very smart choice for anyone looking to minimize their energy costs as well as their enviromental footprint.
The MPO-IQ blends unmatched performance with long lasting durability and exclusive energy saving features. Designed as an optimal replacement boiler for millions of homes with existing chimneys, the MPO-IQ has the highest average efficiency in its class. Its rating as high as 87% AFUE, easily exceeds ENERGY STAR levels for efficiency and may qualify for tax credits and/or utility rebates (check for availability in your area). At the heart of the MPO-IQ is an advanced 3-pass cast iron heat exchanger, combined with a well-insulated powder-coated steel jacket. Even the MPO-IQs Control System is best in class. The IQ Control System allows the MPO-IQ to be easily equipped with an optional Energy Saving control package that can achieve up to a 15-20% reduction in fuel consumption according to most studies. Ask your contractor today for an MPO-IQ oil-fired boiler; an unmatched combination of advanced features and proven durability.
Maintain temperture boilers:
The Comet is one of the better maintain temperture boilers availible. It has a horizontal tube design that helps to extract more heat from your fuel than traditional vertical tube boilers. It is also a wet leg design meaning that water surrounds the combustion chamber on all sides, further adding to the heat transfer abilities of this unit. It can be paired with an indirect water heater to provide potable hot water, or be installed with the optional hot water coil, a cheaper but much less efficient option.
The Saturn would be the most economical choice of boiler. Install costs will be lower than any other option, but operating costs will be the highest. This is your typical hot water boiler and has changed very little since the 1960's. It is a dry leg boiler meaning water does not surround the combustion process, hence your heat transfer will be the least efficient of all the units I mentioned. This is a fine choice to heat your home if you can not afford the higher up front cost of a cold start unit, but expect to use up to 40% more oil year over year with this unit as opposed to a cold start. This unit can also provide potable hot water by hooking it to an indirect water heater or with the optional hot water coil.