Once you’ve decided what type of heating system you want for your home, there are still several factors in making sure that you pick the right furnace for the job.
You have many choices when it comes to furnace efficiency. Typically, the more efficient the furnace, the more expensive it is to install. However high-efficiency furnaces cost less to operate since they use less fuel in order to create the same amount of heat as a low-efficiency furnace. So the overall cost of a high-efficiency furnace is lower over time.
The best way to ascertain the optimal level of efficiency is to determine the length of your “pay-off period,” the length of time it takes for the monthly savings created by a higher-efficiency furnace to offset the initial increase in cost. You will only see the savings created by a higher-efficiency furnace if you stay in your home longer than the pay-off period. Different furnaces have different lengths of pay-off periods, so always make sure to check with your furnace installer.
The second major consideration in picking a furnace is the size. When you use a furnace that is too large for the space, the furnace will have a higher rate of cycling on and off. Since it is more energy-efficient to run your furnace consistently for long periods of time, the increased on and off cycling of an oversized furnace will increase your heating cost.
In order to determine the correct furnace size for your home, ask your HVAC contractor to do a load calculation. A load calculation factors in the size of the house, amount of insulation in your windows, walls and roof, and other factors. Whether you are buying a furnace for a new house or replacing an existing furnace, it is always wise to do a load calculation to make sure the furnace is the right size.