pete_c
Guru
Here questioned last week on methodologies by a neighbor as I used to do this a few years back.
1 - Winter - cover all return vents on second floor or cover all return vents on the first floor
2 - Summer - cover all return vents on first floor or cover all return vents on the second floor.
I read that this was a bad thing to do and quit doing it. Neighbor did it and stated that the heat is getting to the right places now in his two story home.
I do leave my single unit HVAC multispeed fan running 24/7. I also use two sets of filters in the integrated electronic air cleaner which by default I change once a month (one is a charcoal filter).
Some stuff I have read:
Here in the midwest temperatures outside have been around 0°F to 10°F (-18°C to -12°C) outdoors.
Curious if anyone is doing anything proactively to keep the heating temperatures even in their homes.
1 - Winter - cover all return vents on second floor or cover all return vents on the first floor
2 - Summer - cover all return vents on first floor or cover all return vents on the second floor.
I read that this was a bad thing to do and quit doing it. Neighbor did it and stated that the heat is getting to the right places now in his two story home.
I do leave my single unit HVAC multispeed fan running 24/7. I also use two sets of filters in the integrated electronic air cleaner which by default I change once a month (one is a charcoal filter).
Some stuff I have read:
In the case of the ECM (electronically commutated motor), a high pressure will cause the motor will ramp up in an attempt to maintain proper air flow. An ECM is much more efficient than a PSC motor under ideal conditions, but as it ramps up to work against higher pressure, you lose that efficiency. You still get the air flow (maybe), but it costs you more.
The majority of blowers, however, are of the permanent split capacitor (PSC) type, which is not a variable speed motor.
The PSC motor, on the other hand, will keep spinning but at lower speeds as the pressure goes up. Thus, higher pressure means less air flow, and, as we’ll see below, low air flow can cause some serious problems.
The important thing to remember here is that no matter which type of blower motor your HVAC system has, it's not a good thing when it has to push against a higher pressure.
Closed vents increase pressure
In a well-designed system, the blower moves the air against a pressure that's no greater than the maximum specified by the manufacturer (typically 0.5 iwc). The ideal system also has low duct leakage.
The typical system, however, is far from ideal. Although most systems are rated for 0.5 iwc, the National Comfort Institute, which has measured static pressure and air flow in a lot of systems, finds the typical system to be pushing against a static pressure of about 0.8 iwc. Now we're ready to address the question of closing vents.
When you start closing vents in unused rooms, you make the duct system more restrictive. The pressure increases, and that means an ECM blower will ramp up to keep air flow up whereas a PSC blower will move less air. Most homes don't have sealed ducts either, so the higher pressure in the duct system will mean more duct leakage, as shown below.
Here in the midwest temperatures outside have been around 0°F to 10°F (-18°C to -12°C) outdoors.
Curious if anyone is doing anything proactively to keep the heating temperatures even in their homes.