FURNACES

Furnaces (regardless of whether or not they are standard or high efficiency) are available in single stage, two stage, and fully modulating configurations. But what does this actually mean? With a natural gas furnace, this is referring to how the valve that controls the flow of natural gas to the appliance operates, and how it affects the comfort level in your home.

Single Stage Furnaces – These furnaces should be familiar to most people, and are how most furnaces have operated for decades. Single stage just means that your furnace is on or off. The gas valve is either opened or closed, creating heat or not. It’s that simple! Typically, this allows for a degree or so of temperature fluctuation in your home as the thermostat has to drop, call for heat, then the furnace comes on at full fire, brings it up to temperature, and shuts back down.

Two Stage Furnaces –  These models are very similar to a single stage units, but think of them as having a ‘high’ and a ‘low’ fire mode. When the thermostat tells the furnace that your home needs heat, it will kick on in a low fire mode, which uses less gas, and creates less heat. If the system realizes that this is not enough heat it will adjust the timing of when it needs to switch to its high fire, full on mode, and ramp up. The idea here is that unlike the single stage models, this unit will have a smaller temperature swing in your home, increasing comfort levels. Typically, these units do not cost much more than single stage units and the benefits can be noticeable.

Modulating Furnaces – These take the two stage concept up a level. All this means is that instead of a high and low fire mode, the gas valve is fully variable (meaning it has an even greater range of options). This is often marketed as the most comfortable option (referring to temperature fluctuation within the home). This is all well and good, but we really don’t sell these models unless they are specifically requested. The reason for this is simple, the cost vs. benefit does not usually make sense. Modulating furnaces are a huge leap up in price (unlike the gap between single and two stage models) for a much smaller increase in comfort. 

The blower (fan) motor in your furnace is responsible for pushing hot or cold air through your home. It is part of the furnace, but it is used for both heating and air conditioning functions.

ECM and PSC – What’s with all of the acronyms? These are easy ones really, ECM motors are mandatory in all new furnace based on government regulations, and this is good! Old furnaces used incredibly inefficient PSC motors. The new ECM motors are simply more efficient, more effective, and more intelligent. This all leads to a drop in your electricity bills. At the end of the day, you don’t need to worry about picking one or the other, since any new furnace will now have an ECM drive motor.

Multi-Speed Furnace– When referring to blower motors in a furnace this just means there are a number of speeds that a technician can select on your motor. Ideally, this will be based on the pressures and temperatures measured in your home during the installation process, not guess work. Once set, the furnace will always use the speeds that are selected. This is how blower motors have worked for decades, and is no different with the new ECM motors. This is very common, extremely efficient, and very comfortable when properly set up by a qualified installer.

Variable-Speed Furnace – All this means is that the blower motor can adjust the fan / air speed in your home on a variable scale, based on demand for hot or cold air. The idea (just like with stages in the above section) is to create a greater level of comfort. Just like with modulating gas valves, we don’t think the cost vs. the benefit is there with this option. These furnaces typically cost quite a bit more to install, and the benefit isn’t really noticeable. It’s more or less marketing hype, and a way to make more money if you work on commission. A properly adjusted multi-speed furnace will accomplish a phenomenal comfort level with great reliability.

There are a few differences to be aware of when deciding between a high efficiency and standard efficiency furnace, if you have the option of being able to decide. The obvious difference is… their efficiencies!

Furnace Efficiency (AFUE) – Standard models utilize 80% of the natural gas that they consume to actually heat your home, the other 20% is essentially wasted via exhaust. High efficiency furnaces from York utilize 95.5% to 98% depending on the model.

Exhaust Ventilation – For the most part, in the Rochester area, standard efficiency furnaces are vented through your chimney via a metal pipe. High efficiency furnaces are a bit different though. They are vented through PVC (plastic) pipes that will typically exit through the side of your home. Location for this exhaust exit is critical, and unfortunately we see a lot of installers mess this up. Getting this wrong can cause major reliability / no heat issues, and can also violate actual safety regulations.

Water / Condensation – Standard furnaces have no water / drainage to worry about. Any drainage you have in a system like this would strictly be from the air conditioning system. High efficiency furnaces generate condensation in their exhaust, which is actually acidic. This must be drained safely away from the furnace. If a drain is not available, a pump must be installed as well. This isn’t a big deal, but it is just something to know.