Multizone HVAC: Forced Air Systems

Forced Air HVAC systems are an ideal candidate for a multizone installation or even retrofitting the necessary controls to an existing system. With air-based systems, leaks are easy enough to fix and it’s pretty straight forward to add in dampers, sensors, and the central control hardware without majorly disrupting the system. In contrast, water based heating systems require the lines to be drained, soldering, and a lot of effort to seal leaks in tight spaces.   The Basics Your standard, single zone/whole building forced air system is going to come down to the furnace/air conditioner, a bunch of ducts, some sensors, vents where it feeds into the rooms, and probably a single thermostat. By adding some sensors and controls, this easily turns into a multi-zone system. All we have to do is block the flow of air in strategic locations and have some central hardware manage the strategy for where air should and should not flow. Blocking the air flow is achieved with a damper and an actuator to control it. These come in a variety of shapes and sizes to accommodate near any system. They fit in over other pieces of duct work and get wired into a central control that sets how opened or closed that damper needs to be, to achieve the desired temperature. In principal, these can simply be added as part of a new installation, or put in place of an existing piece of duct […]

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What is a Multi-Zone System?

Most residential and older HVAC Systems have one enormous flaw: They don’t provide a uniform or even well controlled environment. These simpler systems have one point of measuring temperature, and generally have to just hope that the single thermostat is a good representation of the temperature in the house. In practical terms, this means one room can be twenty degrees hotter than the rest of the building or a good draft from a single window can fool the thermostat into roasting everyone. This is the old way of doing things, from before we had cheap electronics and a mature industry to deliver on our comforts day and night. Take for example, my house. It was built probably in the late 1940s or early 1950s with hot water heat, two floors, and a single thermostat in the center of a house. This proves to be a challenge in the winter. The rooms first on the heating loops will become scorching hot. You open a window in those rooms and they become comfortable. The cold draft blows into the other rooms and they’re suddenly not comfortable. We might bake in the kitchen one night, whipping up a lovely ten to fifteen degrees of extra warmth, which happens to heat the thermostat. The kitchen eventually becomes comfortable, but the bed rooms freeze over.   Single Zone Systems This single-thermostat arrangement is called a Single-Zone system. There’s one data sample and one place all […]

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