Cooling a bathroom in the summer

[Ricky Smith]

We seem to have a lot of incorrect people here speaking as electrical experts. "Amperage" is not what kills you a 15A circuit is just as deadly as a 1A or 500A. It takes only miliamps to kill.

Technically it's not voltage either, it's the current that does it. However ohms law shows that voltage is in correlation with current. A high voltage has more force to it, thus breaking the resistance of your body.

Your body (dry) has a high resistance. So it takes more voltage at any amperage to cook you faster.

You need the voltage to create the current, the current is the actual flow of electrons which kill you. If you were for example more resistive the higher voltage would be less harmful.

So neither voltage nor amps kill, current (flow of electrons) do.

That's how ground fault interrupters work they check for current over a certain path.

 

[Gregg2]

Did you also install a heat exchanger? Basically there is a 2nd duct that brings fresh air in, and the heat exchanger allows the warm air going out transfer its heat to the cool air coming in. The exchanger itself is just a metal box (no motors or moving parts) though of course it involves the addition of 2nd air duct.

Otherwise, you are pumping your heated air inside the house into the great outdoors. It's the same as leaving a window wide open, and can cost you some serious bucks. The cost of installing the exchanger can be recovered in a very short time if you live in a cold winter climate.

No I didn't. What you refer to is a Heat Recovery Ventilation system. It's the cadillac of air exchange systems. It certainly isn't a bad idea, but costs almost as much to install as a furnace. Including the furnace itself, that's not chump change. But, installing that fan was not cheap either! Nothing is these days.

My house is less than 10 years old, and is pretty "tight". Compared to an older home that leaks air all over, I'm probably losing less air from that fan. Actually, since I don't need it unless it's cold, I turn it off. Now, it probably would exhaust the hot air near the ceiling and make my A/C run more efficiently.... maybe I should turn it back on!

 

[snberk103]

No I didn't. What you refer to is a Heat Recovery Ventilation system. It's the cadillac of air exchange systems. It certainly isn't a bad idea, but costs almost as much to install as a furnace. Including the furnace itself, that's not chump change. But, installing that fan was not cheap either! Nothing is these days.

My house is less than 10 years old, and is pretty "tight". Compared to an older home that leaks air all over, I'm probably losing less air from that fan. Actually, since I don't need it unless it's cold, I turn it off. Now, it probably would exhaust the hot air near the ceiling and make my A/C run more efficiently.... maybe I should turn it back on!

I think we are talking about different systems that do similar things. Our house is less than 3 years old, and the contractor recommended the system. Installed, it would have only been less than $2000. Luckily we live in a place were we can keep our windows cracked most of the winter (West coast BC - similar to the Pacific North West of the US).

I have a different understanding of the importance of a Heat Exchanger (as we call it) and an HRV (as you call it) in a tight house. They are really only necessary in a tight house.... and running a fan without one is the equivalent of opening a window, making the tight house less airtight. During the heating season, running a fan without the HE/HRV means you are pumping all that nice heated air outside ... air that you paid to heat, and you are bring a lot of cold air inside - after spending a lot of money sealing the house to keep the cold air outside. The HE/HVR is designed to take that paid-for heat and transfer it to the cold air before it gets into the house.

If your house is 2000 sq ft, then say you have 16000 cubic ft (hypothetically). A bathroom fan can easily move 80 cubic ft/minute, so in less than 3 hours a typical bathroom fan can move the entire volume of heated air inside a house to the outside. (I know it's a bit more complicated than that since the mass of the house also retains heat, but it's for illustration purposes only.) The HE/HVR at least retains a good portion of heat from the air and keeps it inside the house.

Of course, in the winter, it's the heat you are trying to keep out.

We can get away without an HE/HVR because in our climate the outside temperature is usually within 10º of room temperature. The vast majority of homes don't even bother with AC, and apartment dwellers use their gas fireplaces for heat.