3 Furnaces & Air Conditioners You Must Consider.
The year is 2019. We have electric cars and automated single serve coffee makers…why are we still cooling our home like its 1902?
Willis Carrier invented the first electrical air conditioner in 1902. If your home has a single stage heating or cooling system, it's based on this old technology. But fear not, we now have options that are far more efficient and comfortable.
A common question I get asked is: “what’s the difference between single stage, two stage, and variable capacity (also called modulating) HVAC equipment". Most major brands offer these 3 types of technology in furnaces, air conditioners, and heat pumps. It’s important to understand how these different types of technology affect your home comfort.
I’ll start by insisting that whoever installs your new HVAC equipment should be performing a heat load calculation. This involves measuring windows, walls, and insulation to determine precisely how much heat your home gains in the summer and how much heat your home looses in the winter. It’s only after these figures have been calculated that a contractor can know exactly what size of equipment is needed to efficiently heat and cool your home.
Regardless of equipment type, it must have the capacity to maintain comfortable temperatures during the hottest summer days and the coldest winter nights. But what about all the in-between days when temperatures are not at extremes? On these days, your single-stage equipment is actually producing more heating or cooling than your home needs. You may notice the equipment will turn on, blast your home with a large volume of hot or cold air, then shut off. This “short cycle” will repeat all day.
The disadvantage of this is two-fold. First, the blower motor is not running long enough to pull all the old unconditioned air from the furthest parts of your home and replace it with air of the desired temperature. You will notice this in the form of hot and cold spots as you walk from one end of your home to the other. This symptom is exacerbated exponentially if you have a multi-story home where temperatures could fluctuate by as much as 5 degrees.
The second disadvantage comes in the form of large temperature variances between run cycles. Because the volume of conditioned air being produced is too high, the desired thermostat temperature set point is often exceeded. You may notice the thermostat is set to cool the home to 72 degrees, but when the air conditioning actually turns off, the reading could be as low as 70 degrees. These temperature swings waste energy and create discomfort throughout your home.
The first line of defense against these uncomfortable temperature swings is two-stage equipment. Just like the name suggests, this equipment offers two capacities of output. The first typically being 60% and the second being 100%. With this equipment installed, your thermostat can choose 100% capacity to quickly bring your home to a desired temperature. Once this has been achieved, it can operate in the lower 60% capacity to gently maintain your desired set point. All while running the blower at lower speeds for longer durations to provide a better air mixture from end to end of your home.
Variable capacity equipment:
The most precise equipment available is that of variable (or modulating) capacity. This equipment type goes far beyond the principles of two-stage by constantly adjusting its’ output. Variable capacity technology monitors and adjusts on the fly to deliver between 30 and 100 % capacity. This is the most efficient equipment available today. It features longer run cycles while using the least energy in order to achieve efficient temperature control. The precision of this equipment is so exact that many manufactures guarantee no more than a 1 degree variance in temperature from end to end of a single story home.
Just like anything you buy; be it a car or a cell phone, as the list of features grows, so does the price tag. The same is true for HVAC equipment. Variable capacity will always cost more than single stage. But this doesn’t mean you should shy away from choosing the best equipment for your home. After all, most Americans spend 1/3rd of each day inside their home. Shouldn’t your time sleeping and making dinner be spent in comfort?