The principle of a boiler is to use a controlled fire to heat water in a vessel, then pump the heated water to radiators, baseboard radiators, fan coils, and radiant heat, with these devices emitting or radiating the heat into the room or space.


Natural Gas and Propane boilers come in efficiencies ranging from 80% to 96%.
Oil-fired boilers range in efficiency from 80% to 86%.

Boiler Construction

A typical boiler, (standard) is constructed of cast iron and will last 20 to 30 years. Many boiler manufacturers issue limited lifetime warranties on this type of boiler. Economy boilers are constructed of steel and have the advantage of being lighter than cast iron, making their installation a lot easier. But this type of boiler will not last as long, and it carries a limited 10-year warranty. The high efficiency gas and propane models are constructed in stainless steel and carry a limited 15-year warranty.

Ballpark Pricing

Depending on conditions too numerous to list without visiting your home,

Steel boilers range from $3,500 to $6,500 80% efficient
Cast Iron range from $4,500 to 8,500 80% efficient
Stainless Steel from $8,000 to 12,000 95+% efficient

 How Calvert installs a boiler that’s different from our competitors

Air in a hot water circulation system is not good. It creates noise and reduces efficiency. Confucius say, “two objects cannot occupy the same space.” If you want to heat the radiator with water from the boiler, you have remove the air first.

1. Our approach to air removal is replace your antiquated steel expansion tank with a new modern style diaphragm tank. We all know when an object is heated it expands. Same is true of water in a boiler. The expansion tank gives the water some place to expand to. Without an expansion tank, the pressure on the boiler would increase as the water heats up, creating an unsafe and messy situation.

We use a diaphragm expansion tank because steel expansion tanks have air in the tank on purpose. This air can be absorbed into the water and distributed throughout the system, causing a problem where you have to “bleed the system” annually.

2. We also install an “air purger”, a device that is permanently installed in the boiler piping system that is specifically constructed to absorb and expel air from the system.

3. Every boiler manufacturer agrees that the best place to install a circulator is in the supply, after the expansion tank. Problem is, factory ships the circulator installed on the return because it fits, and ships, better on the pallet. It will work this way, but not as good.

Installation of boiler

To clear the factory’s conscience, boilers today are often shipped with the circulator in a box, separate from the boiler. What we see is installing contractors still install it in the return, because that is where the old one was and they don’t fully understand the benefits of pumping in the supply.

Instant Glossary

Supply is the water that exits the boiler.
Return is the water that enters the boiler
Circulator is the system pump
The pressure reducing valves reduces the water pressure from the street down to the pressure of the boiler.

Options Available to You

#1 Outdoor Reset

Boilers are designed to operate by heating the water to a temperature of 180 degrees. then pumping this heated water to the radiators. The boiler and the pump are turned on and off by the thermostat.

This 180 degrees was picked by the factory to provide enough heat for the home on the coldest day of the year. Any other time when it’s warmer, the boiler water temperature could be lower. The warmer it is outside, the less you have to heat your water – and the more energy you could save.

Outdoor Reset is a boiler control that automatically “resets” the boiler water temperature based on the outdoor temperature. On the 10-degree day the temperature will be 180 degrees, but on the 40-degree day the boiler water temperature automatically lowers to just 135 degrees.

Option A – Partial Reset

Unfortunately a standard boiler will be damaged if it is allowed to continuously operate at temperature below 140 degrees, so a standard boiler has a minimum temperature that must be maintained. The Reset control does partial reset that allows the water to fluctuate between 140 and 180 depending on the outdoor temperature.

Option B – Full Reset

Full reset can be accomplished with a piping arrangement called primary/secondary that can either be field-installed or factory-installed. With this arrangement, the water temperature can fluctuate between 70 degrees and 180 with no damage to the boiler.

Indirect Tank or Tankless Coil

# 2 Domestic Hot Water

Domestic hot water is the heater man’s term when the boiler is used to heat the house and the water used for cooking, cleaning and bathing, (potable water). Boiler water is nasty and would make you sick should you accidently drink it, so the potable water and boiler water are kept separate in a manner that’s impossible to cross contaminate.

The advantage of having a domestic hot water option is that you have a near endless supply of hot water and boilers are typically more efficient than hot water heaters, so you are heating your potable water for less.

Option A Indirect Tank

Indirect Tanks are hot water storage tanks that are insulated so well, the water loses less than 1 degree of heat per hour. The concept is, inside
the storage tank is a coil of copper piping with porcupine needles attached. As the storage tank cools, the boiler is fired up and very hot water flows through the porcupine coil, transferring the heat from the boiler into the potable water storage tank. Partial and Full reset options are available with the indirect hot water tank.

Option B Tankless Coil

If your boiler is oil fired, than you have the option of a tankless coil. This option is less expensive than an indirect, but is also less efficient. It eliminates the possibility of the outdoor reset option because the water in the boiler must always remain 180 degrees. The concept is a coil of copper pipe laid inside the boiler. Cold, “potable” water enters one end of the copper coil at say, 58 degrees. By the time it travels the entire length of pipe the water has been heated to 125 degrees. Its an on-demand option.

Radiant Heat In-Floor Heat

Radiant Flooring

Radiant heat typically refers to in-floor heating. It is very popular up north where you are not likely to need an air conditioning system. If you have an
air conditioning system, you have the duct work necessary to add a heater or heat-pump for relatively little extra cost. Living in Delaware, you
need air conditioning, so adding radiant heat becomes an expensive option.

Radiant heat works best as floor warming of ceramic tiles in kitchens baths and patios. There are applications for hardwood and carpet but
there are also other applications for the use of your money, you should explore them first and radiant second.

Radiant heat can be installed several ways.

1- The best is hydronic pipes laid in 1 1/2 inches of “mud” This mud is a field mixed mortar that your tile contractor prepares and installs over the pipes. His tiles then go on top of the mud. This type of floor is high density radiant and it does a excellent job of warming and transferring its heat.

2- Mud floors are old school and a most modern tile contractors use a thin setting glue between 1/4 an 1/8th inch thick. The hydronic pipes are 1/2 inch thick so the pipes have to routed under and stapled to the bottom of the plywood floor. This method is caused “staple up” and it involves metallic plates that help extract the heat from the piping and transfer it to the plywood floor and then into the tile.

3- The other option is floor warming electric. In this situation, an electric heating wire is stapled to the top side of the plywood. The tile contractor pours a leveling agent over the heating element and then applies the thin set and tile on top of it. This is the least expensive way to install but more expensive to operate. It best applies itself to smaller rooms like bathrooms.

Another thing to consider is radiant heat travels in all directions which means you have to insulate below the pipes so that the heat travels up, through the floor, only.

If you are heating your floor with hot water, you can heat the water with a hot water heater or small boiler. It depends on the size of the floor.

Cast Iron Radiators

Cast Iron Radiator

Cast Iron Radiators are the old school radiators found in older homes and buildings that are heated with either steam or hot water boilers.

Fin Tube Baseboard

Fin Tube BaseboardBaseboard Radiators have a low profile and usually cover the outside perimeter of the building. The product is made from either cast iron or is fin-tube, a copper pipe with aluminum fins attached.

The disadvantages of fin-tube is that through rapid expansion and contraction, the baseboard tubing pings and pangs, snap crackles and pops. The noise can be substantially reduced with outdoor reset because the fin-tube is not subjected to violent changes in operating temperatures

Fan Coils

Fan coils

Fan Coils look and work like a radiator in a car. Hot water circulates inside them and air blows across them, cooling the water and heating the air. You find fan coils in systems that are heated by a boiler, but the heat is distributed to the home through duct work.

Fan coils are found in larger homes where they don’t have access to natural gas and where a heat pump is not acceptable. With fan coils, its easy to have a boiler in the basement and pipe the heat via circulating water, up to the zone (duct system), where it is needed.

Fan coils are sometimes installed because the existing radiators in home, room or zone are no longer appreciated, wanted nor loved.