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Old 10-30-17, 05:29 AM   #73
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Join Date: Nov 2011
Location: NC
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Originally Posted by ecomodded View Post
Im using the AC in dual hose mode now and its been running with night temps between 3 and 8c regularly. Its been on the kill watt meter for 505 hours , its working out to run 50% of the time 50% off for a average of 500w an hour.

That costs me $35 a month

I want to use $70 to $75 on heat and $25 to $30 on utilities for $100 total electric costs not $100 on heat as I typed earlier.

So I can double the current heat out put Im using now to heat with a average outside temp of 10c the winter lows are usually 0 to -1 or 2c

Be nice if it squeezes heat out of the air still when its below zero

Im hoping it does as that's the time it can reduce electrical consumption the most

It'll pull heat out of the air as long as there is heat in the house. The question is will it cause you to run your furnace more or not. Where that point is, is entirely dependent on how much stack effect driven air leakage your house has.

As long as you are only de-powering the stack effect you shouldn't see an increase in gas usage, even in below freezing temperatures.

Think of it like this, when it is cold outside the stack effect drives a certain amount of ventilation in the home. Heated air inside the home rises creating a higher air pressure at the ceiling than at the floor. This is because we are adding energy to the air. This is also the reverse of natural air pressures. outside the air has a higher pressure at the ground than it does 20' up (generally anyway). This creates some fairly major pressure differentials that drives air flow through the building.

We can use mechanical fans and change how the pressures are inside the house. By negatively pressurizing the house with mechanical ventilation we are in effect doing the same thing the stack effect does, only we are controlling where the air exits from. With your unit as long as the CFM is less than or equal to what the stack effect would be, then it actually acts like a HRV that is probably around 90+% efficient. *that has nothing to do with energy use only the amount of "available" energy the unit is able to harvest from the ventilation air. Of course to do that we need to be cognizant of how we are adding the heat back into the house and where we are pulling air from, it is possible that we could just end up pulling more air through the house and not doing anything about the stack effect.
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