I got wind of powerzoning a few months ago while I was searching for ways to heat and cool my old home more efficiently. The issue I and many other owners of older, two-story homes have is heating and cooling both floors of our homes equally. It’s particularly bad during the summer months when the AC never seems to adequately cool the upstairs and everyone is all sweaty and uncomfortable throughout the night.
Here’s a direct excerpt from the powerzoning site explaining how their system works:
“Our temperture balancing solution accelerates the air flow throughout the house and takes advantage of geothermally-controlled air. This is easily achieved by adapting a secondary return air system with absolutely no remodeling involved. We simply modify your existing furnace. Even high-efficiency furnaces! And can you believe it actually helps hvac problems in new construction homes?
We do this by routing additional ductwork to the blower cabinet of your existing furnace. Nearly all furnace manufacturers in this country recommend adding more than one penetration into this blower cabinet to improve air flow, yet more than 95% of homes do not have this done. Accelerated air flow achieve balanced temperatures is not a new concept, except when applied to home cooling and heating. It just hasn’t been done in the past.”
And here’s what my HVAC Engineer neighbor had to say:
“I agree with the principles behind how the system keeps the homes various floors at the same temperature. The system eliminates stratification by using a secondary fan system and ductwork in conjunction with your furnace/AC indoor fan. The powerzone will circulate the cooler basement air up to the upper floors even when the AC unit is off. Great idea if you can install the ducts in your home in an unobtrusive way.
I do take issue with their claim that their system can save you about 30% on you energy bill. Say you have a home that is hot (say 78deg F) upstairs when the thermostat on the first floor is maintaining 70deg F. Then you come along and add the powerzone system in your home. Now your first floor thermostat still reads 70 deg F but your second floor is also a comfortable 70 deg F too. You can’t expect to cool the second floor to the same temperature as the first without paying for the energy to do that cooling. I would actually expect your cooling energy costs to increase NOT decrease.”
There is a series of three videos below that explains the powerzoning process in detail and it’s the process laid out in these videos that seems to have triggered a number of comments on the HVAC-Talk forums where a number of HVAC professionals voiced their skepticism about the powerzoning method. The discussion is a couple years old so it’s possible that the powerzoning method has changed since then but all the negative comments would definitely make me hesitant to purchase this product. Some of the comments from the HVAC forum discussion are below:
“We “the techs” had a long debate over powerzoning and we all concluded that it will not do it’s job but also cause safety problems. Do not trust miracle cures.”
“Conclusion: During the summer you could gain some cooling from a cool soil, largerly varied by the R-Value of your basement walls and floor; however, during the winter, your thermal losses would be much greater, offsetting any savings during the summer.
Other factors – You would distribute moisture from the soil to the living space. During the summer this would be undesired. If you live in a region with high radon concentrations, you would blow radon through the home, increasing your risk in lung cancer, unless your basement was radon proofed.”
“I wonder how many heat exchangers and compressors have been killed by his recommendation to close all the vents in the house, except the ones in the problem areas?”
“If you suck basement air into the return plenum, you can severely depressurize the basement to the point you backdraft water heaters and furnaces or boilers. If you don’t provide warm supply air back into the basement, you severely imbalance the house. The high pressure upstairs may tend to drive moisture into the interstitial wall spaces. Meanwhile, the negative pressure in the basement is bringing foul basment air into the rest of the home.
If you cut a large opening into the return plenum, you risk losing the returns at the far end of the system. Therefore, you get air stagnation in the far corners of the house. Conditioned air is being pumped in with mainly passive returns. Not a good setup. The best systems employ balanced venting–period.”
I think I’ll get some more input from my neighbor. Check out the videos below and judge for yourself. I’d love to hear other’s comments.
I’ve contacted the folks at Powerzoning to get a comment so hopefully they’ll contribute to this discussion. I’d like to hear the other side of this story. I need more input before making a decision on this one. At this point I’ll reserve any opinion I have until I hear from all sides.
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