Condensing Boiler vs Non condensing Boiler

The main theory of what a conventional non condensing boiler does is pretty simple. A boiler works by igniting a combustible fuel source (oil, natural gas, or LP gas) , with an appropriate air mixture. The heat from the flame and hot combustion gases pass through a heat exchanger within the boiler, where water is heated and then circulated through radiators, under floor radiant tubing, and hot water cylinders throughout the house. The flue gases then escape through the chimney or venting system. A decent amount of heat is wasted with this type of boiler, where the heated gases are just directly vented out. These types of boilers have a lower efficiency rating; no higher than 75%. An efficiency rating is basically a gauge of how much energy the boiler transfers from fuel used to how much heat is supplied to the system.

Condensing boilers work a bit differently. They essentially have some of the same components non condensing boilers do, except for a second heat exchanger. One of the gases produced in the combustion of fuel is water vapour .Where the hot flue gases just got vented out in a traditional boiler; condensing boilers condense these vapours around a second heat exchanger before venting. By the time the gases are ready to be vented out they are much cooler, around 60 degrees Celsius. As a result the vent pipe used in installation can be made of PVC.

With these systems some of the internal components have to be made of more durable material, because the condensed water tends to be acidic with a 3-5 pH. This results in the cost of the condensing boiler being higher than average. The secondary heat exchanger is where the system return enters first. So by the time the water enters the primary heat exchanger it is already been preheated, allowing the boiler to work more efficiently. The efficiency rating from condensing boilers range from between 80% to 98%.

Combi boiler / Combination boiler

Combi boiler / Combination boiler is an excellent choice for homes with limited space. Combi boiler / Combination boiler is a domestic water heater and a central heating system combined into one unit. They have a heating coil inside of them, and function like an unlimited on-demand water heater. Combi boilers don’t have cylinders or external holding tanks like traditional systems do, so they can be installed in areas where a typical system would never work.

Condensing Boiler Pros

1 They are fuel economical and have a 15-30% higher efficiency rating than non condensing counterparts

2 Considerable savings on annual energy expenses

3 Most units are very quite ( they make as much noise as a window mounted air conditioner)

4 Many Models could easily fit in a small closet and have combination boiler

5 They are more environmentally friendly with Co2 output

Condensing Boiler Cons

1 Initial cost of the unit is more

2 Units need to have the acidic condensate plumbed outside or to a waste line

3 The dwelling the boiler is installed in needs to be insulated well, otherwise the heat saved through efficiency will be lost through the walls.

4 Most units need an outdoor weather sensor to operate effectively